A feasibility study on the design and walking operation of a biped locomotor via dynamic simulation

NASA Astrophysics Data System (ADS)

Wang, Mingfeng; Ceccarelli, Marco; Carbone, Giuseppe

2016-06-01

A feasibility study on the mechanical design and walking operation of a Cassino biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degrees-of-freedom tripod leg mechanisms with a parallel manipulator architecture. Planning of the biped walking gait is performed by coordinating the motions of the two leg mechanisms and waist. A threedimensional model is elaborated in SolidWorks® environment in order to characterize a feasible mechanical design. Dynamic simulation is carried out in MSC.ADAMS® environment with the aims of characterizing and evaluating the dynamic walking performance of the proposed design. Simulation results show that the proposed biped locomotor with proper input motions of linear actuators performs practical and feasible walking on flat surfaces with limited actuation and reaction forces between its feet and the ground. A preliminary prototype of the biped locomotor is built for the purpose of evaluating the operation performance of the biped walking gait of the proposed locomotor.

Dynamic legged locomotion in robots and animals

NASA Astrophysics Data System (ADS)

Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

1995-01-01

This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

Agile and dexterous robot for inspection and EOD operations

NASA Astrophysics Data System (ADS)

Handelman, David A.; Franken, Gordon H.; Komsuoglu, Haldun

2010-04-01

The All-Terrain Biped (ATB) robot is an unmanned ground vehicle with arms, legs and wheels designed to drive, crawl, walk and manipulate objects for inspection and explosive ordnance disposal tasks. This paper summarizes on-going development of the ATB platform. Control technology for semi-autonomous legged mobility and dual-arm dexterity is described as well as preliminary simulation and hardware test results. Performance goals include driving on flat terrain, crawling on steep terrain, walking on stairs, opening doors and grasping objects. Anticipated benefits of the adaptive mobility and dexterity of the ATB platform include increased robot agility and autonomy for EOD operations, reduced operator workload and reduced operator training and skill requirements.

Stereo vision with distance and gradient recognition

NASA Astrophysics Data System (ADS)

Kim, Soo-Hyun; Kang, Suk-Bum; Yang, Tae-Kyu

2007-12-01

Robot vision technology is needed for the stable walking, object recognition and the movement to the target spot. By some sensors which use infrared rays and ultrasonic, robot can overcome the urgent state or dangerous time. But stereo vision of three dimensional space would make robot have powerful artificial intelligence. In this paper we consider about the stereo vision for stable and correct movement of a biped robot. When a robot confront with an inclination plane or steps, particular algorithms are needed to go on without failure. This study developed the recognition algorithm of distance and gradient of environment by stereo matching process.

Single-step collision-free trajectory planning of biped climbing robots in spatial trusses.

PubMed

Zhu, Haifei; Guan, Yisheng; Chen, Shengjun; Su, Manjia; Zhang, Hong

For a biped climbing robot with dual grippers to climb poles, trusses or trees, feasible collision-free climbing motion is inevitable and essential. In this paper, we utilize the sampling-based algorithm, Bi-RRT, to plan single-step collision-free motion for biped climbing robots in spatial trusses. To deal with the orientation limit of a 5-DoF biped climbing robot, a new state representation along with corresponding operations including sampling, metric calculation and interpolation is presented. A simple but effective model of a biped climbing robot in trusses is proposed, through which the motion planning of one climbing cycle is transformed to that of a manipulator. In addition, the pre- and post-processes are introduced to expedite the convergence of the Bi-RRT algorithm and to ensure the safe motion of the climbing robot near poles as well. The piecewise linear paths are smoothed by utilizing cubic B-spline curve fitting. The effectiveness and efficiency of the presented Bi-RRT algorithm for climbing motion planning are verified by simulations.

Minimal feedback to a rhythm generator improves the robustness to slope variations of a compass biped.

PubMed

Spitz, Jonathan; Evstrachin, Alexandrina; Zacksenhouse, Miriam

2015-08-20

In recent years there has been a growing interest in the field of dynamic walking and bio-inspired robots. However, while walking and running on a flat surface have been studied extensively, walking dynamically over terrains with varying slope remains a challenge. Previously we developed an open loop controller based on a central pattern generator (CPG). The controller applied predefined torque patterns to a compass-gait biped, and achieved stable gaits over a limited range of slopes. In this work, this range is greatly extended by applying a once per cycle feedback to the CPG controller. The terrain's slope is measured and used to modify both the CPG frequency and the torque amplitude once per step. A multi-objective optimization algorithm was used to tune the controller parameters for a simulated CB model. The resulting controller successfully traverses terrains with slopes ranging from +7° to -8°, comparable to most slopes found in human constructed environments. Gait stability was verified by computing the linearized Poincaré Map both numerically and analytically.

Walking on a moving surface: energy-optimal walking motions on a shaky bridge and a shaking treadmill can reduce energy costs below normal.

PubMed

Joshi, Varun; Srinivasan, Manoj

2015-02-08

Understanding how humans walk on a surface that can move might provide insights into, for instance, whether walking humans prioritize energy use or stability. Here, motivated by the famous human-driven oscillations observed in the London Millennium Bridge, we introduce a minimal mathematical model of a biped, walking on a platform (bridge or treadmill) capable of lateral movement. This biped model consists of a point-mass upper body with legs that can exert force and perform mechanical work on the upper body. Using numerical optimization, we obtain energy-optimal walking motions for this biped, deriving the periodic body and platform motions that minimize a simple metabolic energy cost. When the platform has an externally imposed sinusoidal displacement of appropriate frequency and amplitude, we predict that body motion entrained to platform motion consumes less energy than walking on a fixed surface. When the platform has finite inertia, a mass- spring-damper with similar parameters to the Millennium Bridge, we show that the optimal biped walking motion sustains a large lateral platform oscillation when sufficiently many people walk on the bridge. Here, the biped model reduces walking metabolic cost by storing and recovering energy from the platform, demonstrating energy benefits for two features observed for walking on the Millennium Bridge: crowd synchrony and large lateral oscillations.

Walking on a moving surface: energy-optimal walking motions on a shaky bridge and a shaking treadmill can reduce energy costs below normal

PubMed Central

Joshi, Varun; Srinivasan, Manoj

2015-01-01

Understanding how humans walk on a surface that can move might provide insights into, for instance, whether walking humans prioritize energy use or stability. Here, motivated by the famous human-driven oscillations observed in the London Millennium Bridge, we introduce a minimal mathematical model of a biped, walking on a platform (bridge or treadmill) capable of lateral movement. This biped model consists of a point-mass upper body with legs that can exert force and perform mechanical work on the upper body. Using numerical optimization, we obtain energy-optimal walking motions for this biped, deriving the periodic body and platform motions that minimize a simple metabolic energy cost. When the platform has an externally imposed sinusoidal displacement of appropriate frequency and amplitude, we predict that body motion entrained to platform motion consumes less energy than walking on a fixed surface. When the platform has finite inertia, a mass- spring-damper with similar parameters to the Millennium Bridge, we show that the optimal biped walking motion sustains a large lateral platform oscillation when sufficiently many people walk on the bridge. Here, the biped model reduces walking metabolic cost by storing and recovering energy from the platform, demonstrating energy benefits for two features observed for walking on the Millennium Bridge: crowd synchrony and large lateral oscillations. PMID:25663810

SVR versus neural-fuzzy network controllers for the sagittal balance of a biped robot.

PubMed

Ferreira, João P; Crisóstomo, Manuel M; Coimbra, A Paulo

2009-12-01

The real-time balance control of an eight-link biped robot using a zero moment point (ZMP) dynamic model is difficult due to the processing time of the corresponding equations. To overcome this limitation, two alternative intelligent computing control techniques were compared: one based on support vector regression (SVR) and another based on a first-order Takagi-Sugeno-Kang (TSK)-type neural-fuzzy (NF) network. Both methods use the ZMP error and its variation as inputs and the output is the correction of the robot's torso necessary for its sagittal balance. The SVR and the NF were trained based on simulation data and their performance was verified with a real biped robot. Two performance indexes are proposed to evaluate and compare the online performance of the two control methods. The ZMP is calculated by reading four force sensors placed under each robot's foot. The gait implemented in this biped is similar to a human gait that was acquired and adapted to the robot's size. Some experiments are presented and the results show that the implemented gait combined either with the SVR controller or with the TSK NF network controller can be used to control this biped robot. The SVR and the NF controllers exhibit similar stability, but the SVR controller runs about 50 times faster.

Pareto Design of State Feedback Tracking Control of a Biped Robot via Multiobjective PSO in Comparison with Sigma Method and Genetic Algorithms: Modified NSGAII and MATLAB's Toolbox

PubMed Central

Mahmoodabadi, M. J.; Taherkhorsandi, M.; Bagheri, A.

2014-01-01

An optimal robust state feedback tracking controller is introduced to control a biped robot. In the literature, the parameters of the controller are usually determined by a tedious trial and error process. To eliminate this process and design the parameters of the proposed controller, the multiobjective evolutionary algorithms, that is, the proposed method, modified NSGAII, Sigma method, and MATLAB's Toolbox MOGA, are employed in this study. Among the used evolutionary optimization algorithms to design the controller for biped robots, the proposed method operates better in the aspect of designing the controller since it provides ample opportunities for designers to choose the most appropriate point based upon the design criteria. Three points are chosen from the nondominated solutions of the obtained Pareto front based on two conflicting objective functions, that is, the normalized summation of angle errors and normalized summation of control effort. Obtained results elucidate the efficiency of the proposed controller in order to control a biped robot. PMID:24616619

Quantifying dynamic characteristics of human walking for comprehensive gait cycle.

PubMed

Mummolo, Carlotta; Mangialardi, Luigi; Kim, Joo H

2013-09-01

Normal human walking typically consists of phases during which the body is statically unbalanced while maintaining dynamic stability. Quantifying the dynamic characteristics of human walking can provide better understanding of gait principles. We introduce a novel quantitative index, the dynamic gait measure (DGM), for comprehensive gait cycle. The DGM quantifies the effects of inertia and the static balance instability in terms of zero-moment point and ground projection of center of mass and incorporates the time-varying foot support region (FSR) and the threshold between static and dynamic walking. Also, a framework of determining the DGM from experimental data is introduced, in which the gait cycle segmentation is further refined. A multisegmental foot model is integrated into a biped system to reconstruct the walking motion from experiments, which demonstrates the time-varying FSR for different subphases. The proof-of-concept results of the DGM from a gait experiment are demonstrated. The DGM results are analyzed along with other established features and indices of normal human walking. The DGM provides a measure of static balance instability of biped walking during each (sub)phase as well as the entire gait cycle. The DGM of normal human walking has the potential to provide some scientific insights in understanding biped walking principles, which can also be useful for their engineering and clinical applications.

Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking.

PubMed

Hamed, Kaveh Akbari; Gregg, Robert D

2016-07-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg.

Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking*

PubMed Central

Hamed, Kaveh Akbari; Gregg, Robert D.

2016-01-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:27990059

A new biarticular actuator design facilitates control of leg function in BioBiped3.

PubMed

Sharbafi, Maziar Ahmad; Rode, Christian; Kurowski, Stefan; Scholz, Dorian; Möckel, Rico; Radkhah, Katayon; Zhao, Guoping; Rashty, Aida Mohammadinejad; Stryk, Oskar von; Seyfarth, Andre

2016-07-01

Bioinspired legged locomotion comprises different aspects, such as (i) benefiting from reduced complexity control approaches as observed in humans/animals, (ii) combining embodiment with the controllers and (iii) reflecting neural control mechanisms. One of the most important lessons learned from nature is the significant role of compliance in simplifying control, enhancing energy efficiency and robustness against perturbations for legged locomotion. In this research, we investigate how body morphology in combination with actuator design may facilitate motor control of leg function. Inspired by the human leg muscular system, we show that biarticular muscles have a key role in balancing the upper body, joint coordination and swing leg control. Appropriate adjustment of biarticular spring rest length and stiffness can simplify the control and also reduce energy consumption. In order to test these findings, the BioBiped3 robot was developed as a new version of BioBiped series of biologically inspired, compliant musculoskeletal robots. In this robot, three-segmented legs actuated by mono- and biarticular series elastic actuators mimic the nine major human leg muscle groups. With the new biarticular actuators in BioBiped3, novel simplified control concepts for postural balance and for joint coordination in rebounding movements (drop jumps) were demonstrated and approved.

Numerical Estimation of Balanced and Falling States for Constrained Legged Systems

NASA Astrophysics Data System (ADS)

Mummolo, Carlotta; Mangialardi, Luigi; Kim, Joo H.

2017-08-01

Instability and risk of fall during standing and walking are common challenges for biped robots. While existing criteria from state-space dynamical systems approach or ground reference points are useful in some applications, complete system models and constraints have not been taken into account for prediction and indication of fall for general legged robots. In this study, a general numerical framework that estimates the balanced and falling states of legged systems is introduced. The overall approach is based on the integration of joint-space and Cartesian-space dynamics of a legged system model. The full-body constrained joint-space dynamics includes the contact forces and moments term due to current foot (or feet) support and another term due to altered contact configuration. According to the refined notions of balanced, falling, and fallen, the system parameters, physical constraints, and initial/final/boundary conditions for balancing are incorporated into constrained nonlinear optimization problems to solve for the velocity extrema (representing the maximum perturbation allowed to maintain balance without changing contacts) in the Cartesian space at each center-of-mass (COM) position within its workspace. The iterative algorithm constructs the stability boundary as a COM state-space partition between balanced and falling states. Inclusion in the resulting six-dimensional manifold is a necessary condition for a state of the given system to be balanced under the given contact configuration, while exclusion is a sufficient condition for falling. The framework is used to analyze the balance stability of example systems with various degrees of complexities. The manifold for a 1-degree-of-freedom (DOF) legged system is consistent with the experimental and simulation results in the existing studies for specific controller designs. The results for a 2-DOF system demonstrate the dependency of the COM state-space partition upon joint-space configuration (elbow-up vs. elbow-down). For both 1- and 2-DOF systems, the results are validated in simulation environments. Finally, the manifold for a biped walking robot is constructed and illustrated against its single-support walking trajectories. The manifold identified by the proposed framework for any given legged system can be evaluated beforehand as a system property and serves as a map for either a specified state or a specific controller's performance.

Four-Component Catalytic Machinery: Reversible Three-State Control of Organocatalysis by Walking Back and Forth on a Track.

PubMed

Mittal, Nikita; Özer, Merve S; Schmittel, Michael

2018-04-02

A three-component supramolecular walker system is presented where a two-footed ligand (biped) walks back and forth on a tetrahedral 3D track upon the addition and removal of copper(I) ions, respectively. The addition of N-methylpyrrolidine as a catalyst to the walker system generates a four-component catalytic machinery, which acts as a three-state switchable catalytic ensemble in the presence of substrates for a conjugate addition. The copper(I)-ion-initiated walking process of the biped ligand on the track regulates the catalytic activity in three steps: ON versus int ON (intermediate ON) versus OFF. To establish the operation of the four-component catalytic machinery in a mixture of all constituents, forward and backward cycles were performed in situ illustrating that both the walking process and catalytic action are fully reversible and reproducible.

Arbitrary Symmetric Running Gait Generation for an Underactuated Biped Model.

PubMed

Dadashzadeh, Behnam; Esmaeili, Mohammad; Macnab, Chris

2017-01-01

This paper investigates generating symmetric trajectories for an underactuated biped during the stance phase of running. We use a point mass biped (PMB) model for gait analysis that consists of a prismatic force actuator on a massless leg. The significance of this model is its ability to generate more general and versatile running gaits than the spring-loaded inverted pendulum (SLIP) model, making it more suitable as a template for real robots. The algorithm plans the necessary leg actuator force to cause the robot center of mass to undergo arbitrary trajectories in stance with any arbitrary attack angle and velocity angle. The necessary actuator forces follow from the inverse kinematics and dynamics. Then these calculated forces become the control input to the dynamic model. We compare various center-of-mass trajectories, including a circular arc and polynomials of the degrees 2, 4 and 6. The cost of transport and maximum leg force are calculated for various attack angles and velocity angles. The results show that choosing the velocity angle as small as possible is beneficial, but the angle of attack has an optimum value. We also find a new result: there exist biped running gaits with double-hump ground reaction force profiles which result in less maximum leg force than single-hump profiles.

Arbitrary Symmetric Running Gait Generation for an Underactuated Biped Model

PubMed Central

Esmaeili, Mohammad; Macnab, Chris

2017-01-01

This paper investigates generating symmetric trajectories for an underactuated biped during the stance phase of running. We use a point mass biped (PMB) model for gait analysis that consists of a prismatic force actuator on a massless leg. The significance of this model is its ability to generate more general and versatile running gaits than the spring-loaded inverted pendulum (SLIP) model, making it more suitable as a template for real robots. The algorithm plans the necessary leg actuator force to cause the robot center of mass to undergo arbitrary trajectories in stance with any arbitrary attack angle and velocity angle. The necessary actuator forces follow from the inverse kinematics and dynamics. Then these calculated forces become the control input to the dynamic model. We compare various center-of-mass trajectories, including a circular arc and polynomials of the degrees 2, 4 and 6. The cost of transport and maximum leg force are calculated for various attack angles and velocity angles. The results show that choosing the velocity angle as small as possible is beneficial, but the angle of attack has an optimum value. We also find a new result: there exist biped running gaits with double-hump ground reaction force profiles which result in less maximum leg force than single-hump profiles. PMID:28118401

Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

NASA Astrophysics Data System (ADS)

Khusainov, R.; Klimchik, A.; Magid, E.

2017-01-01

The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

An asymptotic solution to a passive biped walker model

NASA Astrophysics Data System (ADS)

Yudaev, Sergey A.; Rachinskii, Dmitrii; Sobolev, Vladimir A.

2017-02-01

We consider a simple model of a passive dynamic biped robot walker with point feet and legs without knee. The model is a switched system, which includes an inverted double pendulum. Robot’s gait and its stability depend on parameters such as the slope of the ramp, the length of robot’s legs, and the mass distribution along the legs. We present an asymptotic solution of the model. The first correction to the zero order approximation is shown to agree with the numerical solution for a limited parameter range.

A study of the passive gait of a compass-like biped robot: Symmetry and chaos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goswami, A.; Espiau, B.; Thuilot, B.

1998-12-01

The focus of this work is a systematic study of the passive gait of a compass-like planar, biped robot on inclined slopes. The robot is kinematically equivalent to a double pendulum, possessing two kneeless legs with point masses and a third point mass at the hip joint. Three parameters, namely, the ground-slope angle and the normalized mass and length of the robot describe its gait. The authors show that in response to a continuous change in any one of its parameters, the symmetric and steady stable gait of the unpowered robot gradually evolves through a regime of bifurcations characterized bymore » progressively complicated asymmetric gaits, eventually arriving at an apparently chaotic gait where not two steps are identical. The robot can maintain this gait indefinitely. A necessary (but not sufficient) condition for the stability of such gaits is the contraction of the phase-fluid volume. For this frictionless robot, the volume contraction, which the authors compute, is caused by the dissipative effects of the ground-impact model. In the chaotic regime, the fractal dimension of the robot`s strange attractor (2.07) compared to its state-space dimension (4) also reveals strong contraction. The authors present a novel graphical technique based on the first return map that compactly captures the entire evolution of the gait, from symmetry to chaos. Additional passive dissipative elements in the robot joint results in a significant improvement in the stability and the versatility of the gait, and provide a rich repertoire for simple controls laws.« less

Stride lengths, speed and energy costs in walking of Australopithecus afarensis: using evolutionary robotics to predict locomotion of early human ancestors

PubMed Central

Sellers, William I; Cain, Gemma M; Wang, Weijie; Crompton, Robin H

2005-01-01

This paper uses techniques from evolutionary robotics to predict the most energy-efficient upright walking gait for the early human relative Australopithecus afarensis, based on the proportions of the 3.2 million year old AL 288-1 ‘Lucy’ skeleton, and matches predictions against the nearly contemporaneous (3.5–3.6 million year old) Laetoli fossil footprint trails. The technique creates gaits de novo and uses genetic algorithm optimization to search for the most efficient patterns of simulated muscular contraction at a variety of speeds. The model was first verified by predicting gaits for living human subjects, and comparing costs, stride lengths and speeds to experimentally determined values for the same subjects. Subsequent simulations for A. afarensis yield estimates of the range of walking speeds from 0.6 to 1.3 m s−1 at a cost of 7.0 J kg−1 m−1 for the lowest speeds, falling to 5.8 J kg−1 m−1 at 1.0 m s−1, and rising to 6.2 J kg−1 m−1 at the maximum speed achieved. Speeds previously estimated for the makers of the Laetoli footprint trails (0.56 or 0.64 m s−1 for Trail 1, 0.72 or 0.75 m s−1 for Trail 2/3) may have been underestimated, substantially so for Trail 2/3, with true values in excess of 0.7 and 1.0 m s−1, respectively. The predictions conflict with suggestions that A. afarensis used a ‘shuffling’ gait, indicating rather that the species was a fully competent biped. PMID:16849203

Spatio-temporal features for tracking and quadruped/biped discrimination

NASA Astrophysics Data System (ADS)

Rickman, Rick; Copsey, Keith; Bamber, David C.; Page, Scott F.

2012-05-01

Techniques such as SIFT and SURF facilitate efficient and robust image processing operations through the use of sparse and compact spatial feature descriptors and show much potential for defence and security applications. This paper considers the extension of such techniques to include information from the temporal domain, to improve utility in applications involving moving imagery within video data. In particular, the paper demonstrates how spatio-temporal descriptors can be used very effectively as the basis of a target tracking system and as target discriminators which can distinguish between bipeds and quadrupeds. Results using sequences of video imagery of walking humans and dogs are presented, and the relative merits of the approach are discussed.

Modeling, Control and Simulation of Three-Dimensional Robotic Systems with Applications to Biped Locomotion.

NASA Astrophysics Data System (ADS)

Zheng, Yuan-Fang

A three-dimensional, five link biped system is established. Newton-Euler state space formulation is employed to derive the equations of the system. The constraint forces involved in the equations can be eliminated by projection onto a smaller state space system for deriving advanced control laws. A model-referenced adaptive control scheme is developed to control the system. Digital computer simulations of point to point movement are carried out to show that the model-referenced adaptive control increases the dynamic range and speeds up the response of the system in comparison with linear and nonlinear feedback control. Further, the implementation of the controller is simpler. Impact effects of biped contact with the environment are modeled and studied. The instant velocity change at the moment of impact is derived as a function of the biped state and contact speed. The effects of impact on the state, as well as constraints are studied in biped landing on heels and toes simultaneously or on toes first. Rate and nonlinear position feedback are employed for stability of the biped after the impact. The complex structure of the foot is properly modeled. A spring and dashpot pair is suggested to represent the action of plantar fascia during the impact. This action prevents the arch of the foot from collapsing. A mathematical model of the skeletal muscle is discussed. A direct relationship between the stimulus rate and the active state is established. A piecewise linear relation between the length of the contractile element and the isometric force is considered. Hill's characteristic equation is maintained for determining the actual output force during different shortening velocities. A physical threshold model is proposed for recruitment which encompasses the size principle, its manifestations and exceptions to the size principle. Finally the role of spindle feedback in stability of the model is demonstrated by study of a pair of muscles.

Generation of the Human Biped Stance by a Neural Controller Able to Compensate Neurological Time Delay

PubMed Central

Jiang, Ping; Chiba, Ryosuke; Takakusaki, Kaoru; Ota, Jun

2016-01-01

The development of a physiologically plausible computational model of a neural controller that can realize a human-like biped stance is important for a large number of potential applications, such as assisting device development and designing robotic control systems. In this paper, we develop a computational model of a neural controller that can maintain a musculoskeletal model in a standing position, while incorporating a 120-ms neurological time delay. Unlike previous studies that have used an inverted pendulum model, a musculoskeletal model with seven joints and 70 muscular-tendon actuators is adopted to represent the human anatomy. Our proposed neural controller is composed of both feed-forward and feedback controls. The feed-forward control corresponds to the constant activation input necessary for the musculoskeletal model to maintain a standing posture. This compensates for gravity and regulates stiffness. The developed neural controller model can replicate two salient features of the human biped stance: (1) physiologically plausible muscle activations for quiet standing; and (2) selection of a low active stiffness for low energy consumption. PMID:27655271

Children and adults minimise activated muscle volume by selecting gait parameters that balance gross mechanical power and work demands.

PubMed

Hubel, Tatjana Y; Usherwood, James R

2015-09-01

Terrestrial locomotion on legs is energetically expensive. Compared with cycling, or with locomotion in swimming or flying animals, walking and running are highly uneconomical. Legged gaits that minimise mechanical work have previously been identified and broadly match walking and running at appropriate speeds. Furthermore, the 'cost of muscle force' approaches are effective in relating locomotion kinetics to metabolic cost. However, few accounts have been made for why animals deviate from either work-minimising or muscle-force-minimising strategies. Also, there is no current mechanistic account for the scaling of locomotion kinetics with animal size and speed. Here, we report measurements of ground reaction forces in walking children and adult humans, and their stance durations during running. We find that many aspects of gait kinetics and kinematics scale with speed and size in a manner that is consistent with minimising muscle activation required for the more demanding between mechanical work and power: spreading the duration of muscle action reduces activation requirements for power, at the cost of greater work demands. Mechanical work is relatively more demanding for larger bipeds--adult humans--accounting for their symmetrical M-shaped vertical force traces in walking, and relatively brief stance durations in running compared with smaller bipeds--children. The gaits of small children, and the greater deviation of their mechanics from work-minimising strategies, may be understood as appropriate for their scale, not merely as immature, incompletely developed and energetically sub-optimal versions of adult gaits. © 2015. Published by The Company of Biologists Ltd.

The basic mechanics of bipedal walking lead to asymmetric behavior.

PubMed

Gregg, Robert D; Degani, Amir; Dhaher, Yasin; Lynch, Kevin M

2011-01-01

This paper computationally investigates whether gait asymmetries can be attributed in part to basic bipedal mechanics independent of motor control. Using a symmetrical rigid-body model known as the compass-gait biped, we show that changes in environmental or physiological parameters can facilitate asymmetry in gait kinetics at fast walking speeds. In the environmental case, the asymmetric family of high-speed gaits is in fact more stable than the symmetric family of low-speed gaits. These simulations suggest that lower extremity mechanics might play a direct role in functional and pathological asymmetries reported in human walking, where velocity may be a common variable in the emergence and growth of asymmetry. © 2011 IEEE

Kinematically stable bipedal locomotion using ionic polymer-metal composite actuators

NASA Astrophysics Data System (ADS)

Hosseinipour, Milad; Elahinia, Mohammad

2013-08-01

Ionic conducting polymer-metal composites (abbreviated as IPMCs) are interesting actuators that can act as artificial muscles in robotic and microelectromechanical systems. Various black or gray box models have modeled the electrochemical-mechanical behavior of these materials. In this study, the governing partial differential equation of the behavior of IPMCs is solved using finite element methods to find the critical actuation parameters, such as strain distribution, maximum strain, and response time. One-dimensional results of the FEM solution are then extended to 2D to find the tip displacement of a flap actuator and experimentally verified. A model of a seven-degree-of-freedom biped robot, actuated by IPMC flaps, is then introduced. The possibility of fast and stable bipedal locomotion using IPMC artificial muscles is the main motivation of this study. Considering the actuator limits, joint path trajectories are generated to achieve a fast and smooth motion. The stability of the proposed gait is then evaluated using the ZMP criterion and motion simulation. The fabrication parameters of each actuator, such as length, platinum plating thickness and installation angle, are then determined using the generated trajectories. A discussion on future studies on force-torque generation of IPMCs for biped locomotion concludes this paper.

Optimal bipedal interactions with dynamic terrain: synthesis and analysis via nonlinear programming

NASA Astrophysics Data System (ADS)

Hubicki, Christian; Goldman, Daniel; Ames, Aaron

In terrestrial locomotion, gait dynamics and motor control behaviors are tuned to interact efficiently and stably with the dynamics of the terrain (i.e. terradynamics). This controlled interaction must be particularly thoughtful in bipeds, as their reduced contact points render them highly susceptible to falls. While bipedalism under rigid terrain assumptions is well-studied, insights for two-legged locomotion on soft terrain, such as sand and dirt, are comparatively sparse. We seek an understanding of how biological bipeds stably and economically negotiate granular media, with an eye toward imbuing those abilities in bipedal robots. We present a trajectory optimization method for controlled systems subject to granular intrusion. By formulating a large-scale nonlinear program (NLP) with reduced-order resistive force theory (RFT) models and jamming cone dynamics, the optimized motions are informed and shaped by the dynamics of the terrain. Using a variant of direct collocation methods, we can express all optimization objectives and constraints in closed-form, resulting in rapid solving by standard NLP solvers, such as IPOPT. We employ this tool to analyze emergent features of bipedal locomotion in granular media, with an eye toward robotic implementation.

Learning gait of quadruped robot without prior knowledge of the environment

NASA Astrophysics Data System (ADS)

Xu, Tao; Chen, Qijun

2012-09-01

Walking is the basic skill of a legged robot, and one of the promising ways to improve the walking performance and its adaptation to environment changes is to let the robot learn its walking by itself. Currently, most of the walking learning methods are based on robot vision system or some external sensing equipment to estimate the walking performance of certain walking parameters, and therefore are usually only applicable under laboratory condition, where environment can be pre-defined. Inspired by the rhythmic swing movement during walking of legged animals and the behavior of their adjusting their walking gait on different walking surfaces, a concept of walking rhythmic pattern(WRP) is proposed to evaluate the walking specialty of legged robot, which is just based on the walking dynamics of the robot. Based on the onboard acceleration sensor data, a method to calculate WRP using power spectrum in frequency domain and diverse smooth filters is also presented. Since the evaluation of WRP is only based on the walking dynamics data of the robot's body, the proposed method doesn't require prior knowledge of environment and thus can be applied in unknown environment. A gait learning approach of legged robots based on WRP and evolution algorithm(EA) is introduced. By using the proposed approach, a quadruped robot can learn its locomotion by its onboard sensing in an unknown environment, where the robot has no prior knowledge about this place. The experimental result proves proportional relationship exits between WRP match score and walking performance of legged robot, which can be used to evaluate the walking performance in walking optimization under unknown environment.

Human-Robot Interaction: Does Robotic Guidance Force Affect Gait-Related Brain Dynamics during Robot-Assisted Treadmill Walking?

PubMed

Knaepen, Kristel; Mierau, Andreas; Swinnen, Eva; Fernandez Tellez, Helio; Michielsen, Marc; Kerckhofs, Eric; Lefeber, Dirk; Meeusen, Romain

2015-01-01

In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support). Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force) and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning.

Modelling gait transition in two-legged animals

NASA Astrophysics Data System (ADS)

Pinto, Carla M. A.; Santos, Alexandra P.

2011-12-01

The study of locomotor patterns has been a major research goal in the last decades. Understanding how intralimb and interlimb coordination works out so well in animals' locomotion is a hard and challenging task. Many models have been proposed to model animal's rhythms. These models have also been applied to the control of rhythmic movements of adaptive legged robots, namely biped, quadruped and other designs. In this paper we study gait transition in a central pattern generator (CPG) model for bipeds, the 4-cells model. This model is proposed by Golubitsky, Stewart, Buono and Collins and is studied further by Pinto and Golubitsky. We briefly resume the work done by Pinto and Golubitsky. We compute numerically gait transition in the 4-cells CPG model for bipeds. We use Morris-Lecar equations and Wilson-Cowan equations as the internal dynamics for each cell. We also consider two types of coupling between the cells: diffusive and synaptic. We obtain secondary gaits by bifurcation of primary gaits, by varying the coupling strengths. Nevertheless, some bifurcating branches could not be obtained, emphasizing the fact that despite analytically those bifurcations exist, finding them is a hard task and requires variation of other parameters of the equations. We note that the type of coupling did not influence the results.

Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds.

PubMed

Bishop, P J; Clemente, C J; Weems, R E; Graham, D F; Lamas, L P; Hutchinson, J R; Rubenson, J; Wilson, R S; Hocknull, S A; Barrett, R S; Lloyd, D G

2017-07-01

How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width-the mediolateral (transverse) distance between successive footfalls-was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods ( p < 0.001), as well as the five tallest bird species studied ( p < 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk-run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history. © 2017 The Author(s).

Human-Robot Interaction: Does Robotic Guidance Force Affect Gait-Related Brain Dynamics during Robot-Assisted Treadmill Walking?

PubMed Central

Knaepen, Kristel; Mierau, Andreas; Swinnen, Eva; Fernandez Tellez, Helio; Michielsen, Marc; Kerckhofs, Eric; Lefeber, Dirk; Meeusen, Romain

2015-01-01

In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support). Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force) and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning. PMID:26485148

Optimal foot shape for a passive dynamic biped.

PubMed

Kwan, Maxine; Hubbard, Mont

2007-09-21

Passive walking dynamics describe the motion of a biped that is able to "walk" down a shallow slope without any actuation or control. Instead, the walker relies on gravitational and inertial effects to propel itself forward, exhibiting a gait quite similar to that of humans. These purely passive models depend on potential energy to overcome the energy lost when the foot impacts the ground. Previous research has demonstrated that energy loss at heel-strike can vary widely for a given speed, depending on the nature of the collision. The point of foot contact with the ground (relative to the hip) can have a significant effect: semi-circular (round) feet soften the impact, resulting in much smaller losses than point-foot walkers. Collisional losses are also lower if a single impulse is broken up into a series of smaller impulses that gradually redirect the velocity of the center of mass rather than a single abrupt impulse. Using this principle, a model was created where foot-strike occurs over two impulses, "heel-strike" and "toe-strike," representative of the initial impact of the heel and the following impact as the ball of the foot strikes the ground. Having two collisions with the flat-foot model did improve efficiency over the point-foot model. Representation of the flat-foot walker as a rimless wheel helped to explain the optimal flat-foot shape, driven by symmetry of the virtual spoke angles. The optimal long period foot shape of the simple passive walking model was not very representative of the human foot shape, although a reasonably anthropometric foot shape was predicted by the short period solution.

Robot-assisted walking with the Lokomat: the influence of different levels of guidance force on thorax and pelvis kinematics.

PubMed

Swinnen, Eva; Baeyens, Jean-Pierre; Knaepen, Kristel; Michielsen, Marc; Clijsen, Ron; Beckwée, David; Kerckhofs, Eric

2015-03-01

Little attention has been devoted to the thorax and pelvis movements during gait. The aim of this study is to compare differences in the thorax and pelvis kinematics during unassisted walking on a treadmill and during walking with robot assistance (Lokomat-system (Hocoma, Volketswil, Switzerland)). 18 healthy persons walked on a treadmill with and without the Lokomat system at 2kmph. Three different conditions of guidance force (30%, 60% and 100%) were used during robot-assisted treadmill walking (30% body weight support). The maximal movement amplitudes of the thorax and pelvis were measured (Polhemus Liberty™ (Polhemus, Colchester, Vermont, USA) (240/16)). A repeated measurement ANOVA was conducted. Robot-assisted treadmill walking with different levels of guidance force showed significantly smaller maximal movement amplitudes for thorax and pelvis, compared to treadmill walking. Only the antero-posterior tilting of the pelvis was significantly increased during robot-assisted treadmill walking compared to treadmill walking. No significant changes of kinematic parameters were found between the different levels of guidance force. With regard to the thorax and pelvis movements, robot-assisted treadmill walking is significantly different compared to treadmill walking. It can be concluded that when using robot assistance, the thorax is stimulated in a different way than during walking without robot assistance, influencing the balance training during gait. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of reduced gravity on the preferred walk-run transition speed

NASA Technical Reports Server (NTRS)

Kram, R.; Domingo, A.; Ferris, D. P.

1997-01-01

We investigated the effect of reduced gravity on the human walk-run gait transition speed and interpreted the results using an inverted-pendulum mechanical model. We simulated reduced gravity using an apparatus that applied a nearly constant upward force at the center of mass, and the subjects walked and ran on a motorized treadmill. In the inverted pendulum model for walking, gravity provides the centripetal force needed to keep the pendulum in contact with the ground. The ratio of the centripetal and gravitational forces (mv2/L)/(mg) reduces to the dimensionless Froude number (v2/gL). Applying this model to a walking human, m is body mass, v is forward velocity, L is leg length and g is gravity. In normal gravity, humans and other bipeds with different leg lengths all choose to switch from a walk to a run at different absolute speeds but at approximately the same Froude number (0.5). We found that, at lower levels of gravity, the walk-run transition occurred at progressively slower absolute speeds but at approximately the same Froude number. This supports the hypothesis that the walk-run transition is triggered by the dynamics of an inverted-pendulum system.

Development of a neuromorphic control system for a lightweight humanoid robot

NASA Astrophysics Data System (ADS)

Folgheraiter, Michele; Keldibek, Amina; Aubakir, Bauyrzhan; Salakchinov, Shyngys; Gini, Giuseppina; Mauro Franchi, Alessio; Bana, Matteo

2017-03-01

A neuromorphic control system for a lightweight middle size humanoid biped robot built using 3D printing techniques is proposed. The control architecture consists of different modules capable to learn and autonomously reproduce complex periodic trajectories. Each module is represented by a chaotic Recurrent Neural Network (RNN) with a core of dynamic neurons randomly and sparsely connected with fixed synapses. A set of read-out units with adaptable synapses realize a linear combination of the neurons output in order to reproduce the target signals. Different experiments were conducted to find out the optimal initialization for the RNN’s parameters. From simulation results, using normalized signals obtained from the robot model, it was proven that all the instances of the control module can learn and reproduce the target trajectories with an average RMS error of 1.63 and variance 0.74.

Walking Robot Locomotion System Conception

NASA Astrophysics Data System (ADS)

Ignatova, D.; Abadjieva, E.; Abadjiev, V.; Vatzkitchev, Al.

2014-09-01

This work is a brief analysis on the application and perspective of using the walking robots in different areas in practice. The most common characteristics of walking four legs robots are presented here. The specific features of the applied actuators in walking mechanisms are also shown in the article. The experience of Institute of Mechanics - BAS is illustrated in creation of Spiroid and Helicon1 gears and their assembly in actuation of studied robots. Loading on joints reductors of robot legs is modelled, when the geometrical and the walking parameters of the studied robot are preliminary defined. The obtained results are purposed for designing the control of the loading of reductor type Helicon in the legs of the robot, when it is experimentally tested.

[Walking assist robot and its clinical application].

PubMed

Kakou, Hiroaki; Shitama, Hideo; Kimura, Yoshiko; Nakamoto, Yoko; Furuta, Nami; Honda, Kanae; Wada, Futoshi; Hachisuka, Kenji

2009-06-01

The walking assist robot was developed to improve gait disturbance in patients with severe disabilities. The robot had a trunk supporter, power generator and operating arms which held patient's lower extremities and simulated walking, a control unit, biofeedback system, and a treadmill. We applied the robot-aided gait training to three patients with severe gait disturbance induced by stroke, axonal Guillan-Barré syndrome or spinal cord injury, and the walking assist robot turned out to be effective in improving the gait disturbance.

Bipedal animals, and their differences from humans.

PubMed

Alexander, R McN

2004-05-01

Humans, birds and (occasionally) apes walk bipedally. Humans, birds, many lizards and (at their highest speeds) cockroaches run bipedally. Kangaroos, some rodents and many birds hop bipedally, and jerboas and crows use a skipping gait. This paper deals only with walking and running bipeds. Chimpanzees walk with their knees bent and their backs sloping forward. Most birds walk and run with their backs and femurs sloping at small angles to the horizontal, and with their knees bent. These differences from humans make meaningful comparisons of stride length, duty factor, etc., difficult, even with the aid of dimensionless parameters that would take account of size differences, if dynamic similarity were preserved. Lizards and cockroaches use wide trackways. Humans exert a two-peaked pattern of force on the ground when walking, and an essentially single-peaked pattern when running. The patterns of force exerted by apes and birds are never as markedly two-peaked as in fast human walking. Comparisons with quadrupedal mammals of the same body mass show that human walking is relatively economical of metabolic energy, and human running is expensive. Bipedal locomotion is remarkably economical for wading birds, and expensive for geese and penguins.

Bipedal animals, and their differences from humans

PubMed Central

Alexander, R McN

2004-01-01

Humans, birds and (occasionally) apes walk bipedally. Humans, birds, many lizards and (at their highest speeds) cockroaches run bipedally. Kangaroos, some rodents and many birds hop bipedally, and jerboas and crows use a skipping gait. This paper deals only with walking and running bipeds. Chimpanzees walk with their knees bent and their backs sloping forward. Most birds walk and run with their backs and femurs sloping at small angles to the horizontal, and with their knees bent. These differences from humans make meaningful comparisons of stride length, duty factor, etc., difficult, even with the aid of dimensionless parameters that would take account of size differences, if dynamic similarity were preserved. Lizards and cockroaches use wide trackways. Humans exert a two-peaked pattern of force on the ground when walking, and an essentially single-peaked pattern when running. The patterns of force exerted by apes and birds are never as markedly two-peaked as in fast human walking. Comparisons with quadrupedal mammals of the same body mass show that human walking is relatively economical of metabolic energy, and human running is expensive. Bipedal locomotion is remarkably economical for wading birds, and expensive for geese and penguins. PMID:15198697

A bipedal DNA Brownian motor with coordinated legs.

PubMed

Omabegho, Tosan; Sha, Ruojie; Seeman, Nadrian C

2009-04-03

A substantial challenge in engineering molecular motors is designing mechanisms to coordinate the motion between multiple domains of the motor so as to bias random thermal motion. For bipedal motors, this challenge takes the form of coordinating the movement of the biped's legs so that they can move in a synchronized fashion. To address this problem, we have constructed an autonomous DNA bipedal walker that coordinates the action of its two legs by cyclically catalyzing the hybridization of metastable DNA fuel strands. This process leads to a chemically ratcheted walk along a directionally polar DNA track. By covalently cross-linking aliquots of the walker to its track in successive walking states, we demonstrate that this Brownian motor can complete a full walking cycle on a track whose length could be extended for longer walks. We believe that this study helps to uncover principles behind the design of unidirectional devices that can function without intervention. This device should be able to fulfill roles that entail the performance of useful mechanical work on the nanometer scale.

Walking dynamics of the passive compass-gait model under OGY-based control: Emergence of bifurcations and chaos

NASA Astrophysics Data System (ADS)

Gritli, Hassène; Belghith, Safya

2017-06-01

An analysis of the passive dynamic walking of a compass-gait biped model under the OGY-based control approach using the impulsive hybrid nonlinear dynamics is presented in this paper. We describe our strategy for the development of a simplified analytical expression of a controlled hybrid Poincaré map and then for the design of a state-feedback control. Our control methodology is based mainly on the linearization of the impulsive hybrid nonlinear dynamics around a desired nominal one-periodic hybrid limit cycle. Our analysis of the controlled walking dynamics is achieved by means of bifurcation diagrams. Some interesting nonlinear phenomena are displayed, such as the period-doubling bifurcation, the cyclic-fold bifurcation, the period remerging, the period bubbling and chaos. A comparison between the raised phenomena in the impulsive hybrid nonlinear dynamics and the hybrid Poincaré map under control was also presented.

Trotting, pacing and bounding by a quadruped robot.

PubMed

Raibert, M H

1990-01-01

This paper explores the quadruped running gaits that use the legs in pairs: the trot (diagonal pairs), the pace (lateral pairs), and the bound (front and rear pairs). Rather than study these gaits in quadruped animals, we studied them in a quadruped robot. We found that each of the gaits that use the legs in pairs can be transformed into a common underlying gait, a virtual biped gait. Once transformed, a single set of control algorithms produce all three gaits, with modest parameter variations between them. The control algorithms manipulated rebound height, running speed, and body attitude, while a low-level mechanism coordinated the behavior of the legs in each pair. The approach was tested with laboratory experiments on a four-legged robot. Data are presented that show the details of the running motion for the three gaits and for transitions from one gait to another.

Energy-Saving Control of a Novel Hydraulic Drive System for Field Walking Robot

NASA Astrophysics Data System (ADS)

Fang, Delei; Shang, Jianzhong; Xue, Yong; Yang, Junhong; Wang, Zhuo

2018-01-01

To improve the efficiency of the hydraulic drive system in field walking robot, this paper proposed a novel hydraulic system based on two-stage pressure source. Based on the analysis of low efficiency of robot single-stage hydraulic system, the paper firstly introduces the concept and design of two-stage pressure source drive system. Then, the new hydraulic system energy-saving control is planned according to the characteristics of walking robot. The feasibility of the new hydraulic system is proved by the simulation of the walking robot squatting. Finally, the efficiencies of two types hydraulic system are calculated, indicating that the novel hydraulic system can increase the efficiency by 41.5%, which can contribute to enhance knowledge about hydraulic drive system for field walking robot.

The immediate effects of robot-assistance on energy consumption and cardiorespiratory load during walking compared to walking without robot-assistance: a systematic review.

PubMed

Lefeber, Nina; Swinnen, Eva; Kerckhofs, Eric

2017-10-01

The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted. Effect sizes were calculated. Fourteen studies were included, concerning 155 participants (85 healthy subjects, 39 stroke and 31 spinal cord injury patients), 9 robots (2 end-effectors, 1 treadmill-based and 6 wearable exoskeletons), and 7 outcome parameters (mostly oxygen consumption and heart rate). Overall, metabolic and cardiorespiratory parameters were lower during RAG compared to walking without robot-assistance (moderate to large effect sizes). In healthy subjects, when no body-weight support (BWS) was provided, RAG with an end-effector device was more energy demanding than walking overground (p > .05, large effect sizes). Generally, results suggest that RAG is less energy-consuming and cardiorespiratory stressful than walking without robot-assistance, but results depend on factors such as robot type, walking speed, BWS and effort. Additional research is needed to draw firm conclusions. Implications for Rehabilitation Awareness of the energy consumption and cardiorespiratory load of robot-assisted gait (RAG) training is important in the rehabilitation of (neurological) patients with impaired cardiorespiratory fitness and patients who are at risk of cardiovascular diseases. On the other hand, the integration of sufficient cardiometabolic stress in RAG training could combine the effects of both RAG and aerobic training. Energy consumption and cardiorespiratory load during walking with robot-assistance seems to depend on factors such as robot type, walking speed, body-weight support or amount of effort. These parameters could be adjusted in RAG rehabilitation to make RAG more or less energy-consuming and cardiorespiratory stressful. Overall, short duration exoskeleton walking seems less energy-consuming and cardiorespiratory stressful than walking without robot-assistance. This might implicate that the exercise intensity is safe for (neurological) patients at risk of cardiovascular diseases. How this changes in extended walking time is unclear.

Mechanism And Control Of The Quadruped Walking Robot

NASA Astrophysics Data System (ADS)

Adachi, Hironori; Nakano, Eiji; Koyachi, Noriho

1987-10-01

This paper provides a description of the quadruped walking robot "TURTLE-1". A new link mechanism named ASTBALLEM is used for the legs of this robot. With this mechanism highly rigid and easily controllable legs are constructed. Each leg has two degrees of freedom and is driven by two DC servo motors. The motion of the legs is controlled by a micro computer and various gaits are generated. Static stability is maintained as the robot walks. Moreover, its walk is quasi-dynamic; that is, it has a manner of walking that has a two legged supporting period.

Research on Walking Wheel Slippage Control of Live Inspection Robot

NASA Astrophysics Data System (ADS)

Yan, Yu; Liu, Xiaqing; Guo, Hao; Li, Jinliang; Liu, Lanlan

2017-07-01

To solve the problem of walking wheel slippage of a live inspection robot during walking or climbing, this paper analyzes the climbing capacity of the robot with a statics method, designs a pressing wheel mechanism, and presents a method of indirectly identifying walking wheel slippage by reading speed of the pressing wheel due to the fact that the linear speed of the pressing wheel and the walking wheel at the contract point is the same; and finds that the slippage state can not be controlled through accurate mathematical models after identifying the slippage state, whereas slippage can be controlled with fuzzy control. The experiment results indicate that due to design of the pressing wheel mechanism, friction force of the walking wheel is increased, and the climbing capability of the robot is improved. Within the range of climbing capability of the robot, gradient is the key factor that has influence on slippage of robot, and slippage can be effectively eliminated through the fuzzy control method proposed in this paper.

An Algorithm for Pedestrian Detection in Multispectral Image Sequences

NASA Astrophysics Data System (ADS)

Kniaz, V. V.; Fedorenko, V. V.

2017-05-01

The growing interest for self-driving cars provides a demand for scene understanding and obstacle detection algorithms. One of the most challenging problems in this field is the problem of pedestrian detection. Main difficulties arise from a diverse appearances of pedestrians. Poor visibility conditions such as fog and low light conditions also significantly decrease the quality of pedestrian detection. This paper presents a new optical flow based algorithm BipedDetet that provides robust pedestrian detection on a single-borad computer. The algorithm is based on the idea of simplified Kalman filtering suitable for realization on modern single-board computers. To detect a pedestrian a synthetic optical flow of the scene without pedestrians is generated using slanted-plane model. The estimate of a real optical flow is generated using a multispectral image sequence. The difference of the synthetic optical flow and the real optical flow provides the optical flow induced by pedestrians. The final detection of pedestrians is done by the segmentation of the difference of optical flows. To evaluate the BipedDetect algorithm a multispectral dataset was collected using a mobile robot.

Motor modules in robot-aided walking

PubMed Central

2012-01-01

Background It is hypothesized that locomotion is achieved by means of rhythm generating networks (central pattern generators) and muscle activation generating networks. This modular organization can be partly identified from the analysis of the muscular activity by means of factorization algorithms. The activity of rhythm generating networks is described by activation signals whilst the muscle intervention generating network is represented by motor modules (muscle synergies). In this study, we extend the analysis of modular organization of walking to the case of robot-aided locomotion, at varying speed and body weight support level. Methods Non Negative Matrix Factorization was applied on surface electromyographic signals of 8 lower limb muscles of healthy subjects walking in gait robotic trainer at different walking velocities (1 to 3km/h) and levels of body weight support (0 to 30%). Results The muscular activity of volunteers could be described by low dimensionality (4 modules), as for overground walking. Moreover, the activation signals during robot-aided walking were bursts of activation timed at specific phases of the gait cycle, underlying an impulsive controller, as also observed in overground walking. This modular organization was consistent across the investigated speeds, body weight support level, and subjects. Conclusions These results indicate that walking in a Lokomat robotic trainer is achieved by similar motor modules and activation signals as overground walking and thus supports the use of robotic training for re-establishing natural walking patterns. PMID:23043818

Cardiorespiratory demand and rate of perceived exertion during overground walking with a robotic exoskeleton in long-term manual wheelchair users with chronic spinal cord injury: A cross-sectional study.

PubMed

Escalona, Manuel J; Brosseau, Rachel; Vermette, Martin; Comtois, Alain Steve; Duclos, Cyril; Aubertin-Leheudre, Mylène; Gagnon, Dany H

2018-07-01

Many wheelchair users adopt a sedentary lifestyle, which results in progressive physical deconditioning with increased risk of musculoskeletal, cardiovascular and endocrine/metabolic morbidity and mortality. Engaging in a walking program with an overground robotic exoskeleton may be an effective strategy for mitigating these potential negative health consequences and optimizing fitness in this population. However, additional research is warranted to inform the development of adapted physical activity programs incorporating this technology. To determine cardiorespiratory demands during sitting, standing and overground walking with a robotic exoskeleton and to verify whether such overground walking results in at least moderate-intensity physical exercise. We enrolled 13 long-term wheelchair users with complete motor spinal cord injury in a walking program with an overground robotic exoskeleton. Cardiorespiratory measures and rate of perceived exertion (RPE) were recorded by using a portable gas analyzer system during sitting, standing and four 10m walking tasks with the robotic exoskeleton. Each participant also performed an arm crank ergometer test to determine maximal cardiorespiratory ability (i.e., peak heart rate and O 2 uptake [HR peak , VO 2peak ]). Cardiorespiratory measures increased by a range of 9%-35% from sitting to standing and further increased by 22%-52% from standing to walking with the robotic exoskeleton. During walking, median oxygen cost (O 2Walking ), relative HR (%HR peak ), relative O 2 consumption (%VO 2peak ) and respiratory exchange ratio (RER) reached 0.29mL/kg/m, 82.9%, 41.8% and 0.9, respectively, whereas median RPE reached 3.2/10. O 2Walking was moderately influenced by total number of sessions and steps taken with the robotic exoskeleton since the start of the walking program. Overground walking with the robotic exoskeleton over a short distance allowed wheelchair users to achieve a moderate-intensity level of exercise. Hence, an overground locomotor training program with a robotic exoskeleton may have cardiorespiratory health benefits in the population studied. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Brief biomechanical analysis on the walking of spinal cord injury patients with a lower limb exoskeleton robot.

PubMed

Jung, Jun-Young; Park, Hyunsub; Yang, Hyun-Dae; Chae, Mingi

2013-06-01

This paper presents a brief biomechanical analysis on the walking behavior of spinal cord injury (SCI) patients. It is known that SCI patients who have serious injuries to their spines cannot walk, and hence, several walking assistance lower limb exoskeleton robots have been proposed whose assistance abilities are shown to be well customized. However, these robots are not yet fully helpful to all SCI patients for several reasons. To overcome these problems, an exact analysis and evaluation of the restored walking function while the exoskeleton is worn is important. In this work, walking behavior of SCI patients wearing the rehabilitation of brain injuries (ROBIN) lower-limb walking assistant exoskeleton was analyzed in comparison to that of normal unassisted walking. The analysis method and results presented herein can be used by other researchers to improve their robots.

Honda humanoid robots development.

PubMed

Hirose, Masato; Ogawa, Kenichi

2007-01-15

Honda has been doing research on robotics since 1986 with a focus upon bipedal walking technology. The research started with straight and static walking of the first prototype two-legged robot. Now, the continuous transition from walking in a straight line to making a turn has been achieved with the latest humanoid robot ASIMO. ASIMO is the most advanced robot of Honda so far in the mechanism and the control system. ASIMO's configuration allows it to operate freely in the human living space. It could be of practical help to humans with its ability of five-finger arms as well as its walking function. The target of further development of ASIMO is to develop a robot to improve life in human society. Much development work will be continued both mechanically and electronically, staying true to Honda's 'challenging spirit'.

Stability analysis via the concept of Lyapunov exponents: a case study in optimal controlled biped standing

NASA Astrophysics Data System (ADS)

Sun, Yuming; Wu, Christine Qiong

2012-12-01

Balancing control is important for biped standing. In spite of large efforts, it is very difficult to design balancing control strategies satisfying three requirements simultaneously: maintaining postural stability, improving energy efficiency and satisfying the constraints between the biped feet and the ground. In this article, a proportional-derivative (PD) controller is proposed for a standing biped, which is simplified as a two-link inverted pendulum with one additional rigid foot-link. The genetic algorithm (GA) is used to search for the control gain meeting all three requirements. The stability analysis of such a deterministic biped control system is carried out using the concept of Lyapunov exponents (LEs), based on which, the system stability, where the disturbance comes from the initial states, and the structural stability, where the disturbance comes from the PD gains, are examined quantitively in terms of stability region. This article contributes to the biped balancing control, more significantly, the method shown in the studied case of biped provides a general framework of systematic stability analysis for certain deterministic nonlinear dynamical systems.

Horse-like walking, trotting, and galloping derived from kinematic Motion Primitives (kMPs) and their application to walk/trot transitions in a compliant quadruped robot.

PubMed

Moro, Federico L; Spröwitz, Alexander; Tuleu, Alexandre; Vespignani, Massimo; Tsagarakis, Nikos G; Ijspeert, Auke J; Caldwell, Darwin G

2013-06-01

This manuscript proposes a method to directly transfer the features of horse walking, trotting, and galloping to a quadruped robot, with the aim of creating a much more natural (horse-like) locomotion profile. A principal component analysis on horse joint trajectories shows that walk, trot, and gallop can be described by a set of four kinematic Motion Primitives (kMPs). These kMPs are used to generate valid, stable gaits that are tested on a compliant quadruped robot. Tests on the effects of gait frequency scaling as follows: results indicate a speed optimal walking frequency around 3.4 Hz, and an optimal trotting frequency around 4 Hz. Following, a criterion to synthesize gait transitions is proposed, and the walk/trot transitions are successfully tested on the robot. The performance of the robot when the transitions are scaled in frequency is evaluated by means of roll and pitch angle phase plots.

Development of biomimetic quadruped walking robot with 2-DOF waist joint

NASA Astrophysics Data System (ADS)

Kim, Kyoung-Ho; Park, Se-Hoon; Lee, Yun-Jung

2005-12-01

This paper presented a novel bio-mimetic quadruped walking robot with 2-DOF (Degree Of Freedom) waist joint, which connects the front and the rear parts of the body. The waist-jointed walking robot can guarantee more stable and more animal-like gait than that of a conventional single-rigid-body walking robot. The developed robot, called ELIRO-II (Eating LIzard RObot version 2), can bend its body from side to side by using 1-DOF passive waist joint while the legs is transferred, thereby increasing the stride and speed of the robot. In addition, ELIRO-II has one more active DOF to bend its body up and down, which increases the mobility in irregular terrain such as slope and stairs. We design the mechanical structure of the robot, which is small and light to have high mobility. This research described characteristics of the 2-DOF waists joint and leg mechanism as well as a hardware and software of the controller of ELIRO-II.

Novel Door-opening Method for Six-legged Robots Based on Only Force Sensing

NASA Astrophysics Data System (ADS)

Chen, Zhi-Jun; Gao, Feng; Pan, Yang

2017-09-01

Current door-opening methods are mainly developed on tracked, wheeled and biped robots by applying multi-DOF manipulators and vision systems. However, door-opening methods for six-legged robots are seldom studied, especially using 0-DOF tools to operate and only force sensing to detect. A novel door-opening method for six-legged robots is developed and implemented to the six-parallel-legged robot. The kinematic model of the six-parallel-legged robot is established and the model of measuring the positional relationship between the robot and the door is proposed. The measurement model is completely based on only force sensing. The real-time trajectory planning method and the control strategy are designed. The trajectory planning method allows the maximum angle between the sagittal axis of the robot body and the normal line of the door plane to be 45º. A 0-DOF tool mounted to the robot body is applied to operate. By integrating with the body, the tool has 6 DOFs and enough workspace to operate. The loose grasp achieved by the tool helps release the inner force in the tool. Experiments are carried out to validate the method. The results show that the method is effective and robust in opening doors wider than 1 m. This paper proposes a novel door-opening method for six-legged robots, which notably uses a 0-DOF tool and only force sensing to detect and open the door.

Modeling of R/C Servo Motor and Application to Underactuated Mechanical Systems

NASA Astrophysics Data System (ADS)

Ishikawa, Masato; Kitayoshi, Ryohei; Wada, Takashi; Maruta, Ichiro; Sugie, Toshiharu

An R/C servo motor is a compact package of a DC geard-motor associated with a position servo controller. They are widely used in small-sized robotics and mechatronics by virtue of their compactness, easiness-to-use and high/weight ratio. However, it is crucial to clarify their internal model (including the embedded position servo) in order to improve control performance of mechatronic systems using R/C servo motors, such as biped robots or underactuted sysyems. In this paper, we propose a simple and realistic internal model of the R/C servo motors including the embedded servo controller, and estimate their physical parameters using continuous-time system identification method. We also provide a model of reference-to-torque transfer function so that we can estimate the internal torque acting on the load.

Advanced robot locomotion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry

This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics naturalmore » human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.« less

Parallel elastic elements improve energy efficiency on the STEPPR bipedal walking robot

DOE PAGES

Mazumdar, Anirban; Spencer, Steven J.; Hobart, Clinton; ...

2016-11-23

This study describes how parallel elastic elements can be used to reduce energy consumption in the electric motor driven, fully-actuated, STEPPR bipedal walking robot without compromising or significantly limiting locomotive behaviors. A physically motivated approach is used to illustrate how selectively-engaging springs for hip adduction and ankle flexion predict benefits for three different flat ground walking gaits: human walking, human-like robot walking and crouched robot walking. Based on locomotion data, springs are designed and substantial reductions in power consumption are demonstrated using a bench dynamometer. These lessons are then applied to STEPPR (Sandia Transmission-Efficient Prototype Promoting Research), a fully actuatedmore » bipedal robot designed to explore the impact of tailored joint mechanisms on walking efficiency. Featuring high-torque brushless DC motors, efficient low-ratio transmissions, and high fidelity torque control, STEPPR provides the ability to incorporate novel joint-level mechanisms without dramatically altering high level control. Unique parallel elastic designs are incorporated into STEPPR, and walking data shows that hip adduction and ankle flexion springs significantly reduce the required actuator energy at those joints for several gaits. These results suggest that parallel joint springs offer a promising means of supporting quasi-static joint torques due to body mass during walking, relieving motors of the need to support these torques and substantially improving locomotive energy efficiency.« less

Parallel elastic elements improve energy efficiency on the STEPPR bipedal walking robot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazumdar, Anirban; Spencer, Steven J.; Hobart, Clinton

This study describes how parallel elastic elements can be used to reduce energy consumption in the electric motor driven, fully-actuated, STEPPR bipedal walking robot without compromising or significantly limiting locomotive behaviors. A physically motivated approach is used to illustrate how selectively-engaging springs for hip adduction and ankle flexion predict benefits for three different flat ground walking gaits: human walking, human-like robot walking and crouched robot walking. Based on locomotion data, springs are designed and substantial reductions in power consumption are demonstrated using a bench dynamometer. These lessons are then applied to STEPPR (Sandia Transmission-Efficient Prototype Promoting Research), a fully actuatedmore » bipedal robot designed to explore the impact of tailored joint mechanisms on walking efficiency. Featuring high-torque brushless DC motors, efficient low-ratio transmissions, and high fidelity torque control, STEPPR provides the ability to incorporate novel joint-level mechanisms without dramatically altering high level control. Unique parallel elastic designs are incorporated into STEPPR, and walking data shows that hip adduction and ankle flexion springs significantly reduce the required actuator energy at those joints for several gaits. These results suggest that parallel joint springs offer a promising means of supporting quasi-static joint torques due to body mass during walking, relieving motors of the need to support these torques and substantially improving locomotive energy efficiency.« less

Robot-supported assessment of balance in standing and walking.

PubMed

Shirota, Camila; van Asseldonk, Edwin; Matjačić, Zlatko; Vallery, Heike; Barralon, Pierre; Maggioni, Serena; Buurke, Jaap H; Veneman, Jan F

2017-08-14

Clinically useful and efficient assessment of balance during standing and walking is especially challenging in patients with neurological disorders. However, rehabilitation robots could facilitate assessment procedures and improve their clinical value. We present a short overview of balance assessment in clinical practice and in posturography. Based on this overview, we evaluate the potential use of robotic tools for such assessment. The novelty and assumed main benefits of using robots for assessment are their ability to assess 'severely affected' patients by providing assistance-as-needed, as well as to provide consistent perturbations during standing and walking while measuring the patient's reactions. We provide a classification of robotic devices on three aspects relevant to their potential application for balance assessment: 1) how the device interacts with the body, 2) in what sense the device is mobile, and 3) on what surface the person stands or walks when using the device. As examples, nine types of robotic devices are described, classified and evaluated for their suitability for balance assessment. Two example cases of robotic assessments based on perturbations during walking are presented. We conclude that robotic devices are promising and can become useful and relevant tools for assessment of balance in patients with neurological disorders, both in research and in clinical use. Robotic assessment holds the promise to provide increasingly detailed assessment that allows to individually tailor rehabilitation training, which may eventually improve training effectiveness.

Reinforcement learning: Solving two case studies

NASA Astrophysics Data System (ADS)

Duarte, Ana Filipa; Silva, Pedro; dos Santos, Cristina Peixoto

2012-09-01

Reinforcement Learning algorithms offer interesting features for the control of autonomous systems, such as the ability to learn from direct interaction with the environment, and the use of a simple reward signalas opposed to the input-outputs pairsused in classic supervised learning. The reward signal indicates the success of failure of the actions executed by the agent in the environment. In this work, are described RL algorithmsapplied to two case studies: the Crawler robot and the widely known inverted pendulum. We explore RL capabilities to autonomously learn a basic locomotion pattern in the Crawler, andapproach the balancing problem of biped locomotion using the inverted pendulum.

Variety Wins: Soccer-Playing Robots and Infant Walking.

PubMed

Ossmy, Ori; Hoch, Justine E; MacAlpine, Patrick; Hasan, Shohan; Stone, Peter; Adolph, Karen E

2018-01-01

Although both infancy and artificial intelligence (AI) researchers are interested in developing systems that produce adaptive, functional behavior, the two disciplines rarely capitalize on their complementary expertise. Here, we used soccer-playing robots to test a central question about the development of infant walking. During natural activity, infants' locomotor paths are immensely varied. They walk along curved, multi-directional paths with frequent starts and stops. Is the variability observed in spontaneous infant walking a "feature" or a "bug?" In other words, is variability beneficial for functional walking performance? To address this question, we trained soccer-playing robots on walking paths generated by infants during free play and tested them in simulated games of "RoboCup." In Tournament 1, we compared the functional performance of a simulated robot soccer team trained on infants' natural paths with teams trained on less varied, geometric paths-straight lines, circles, and squares. Across 1,000 head-to-head simulated soccer matches, the infant-trained team consistently beat all teams trained with less varied walking paths. In Tournament 2, we compared teams trained on different clusters of infant walking paths. The team trained with the most varied combination of path shape, step direction, number of steps, and number of starts and stops outperformed teams trained with less varied paths. This evidence indicates that variety is a crucial feature supporting functional walking performance. More generally, we propose that robotics provides a fruitful avenue for testing hypotheses about infant development; reciprocally, observations of infant behavior may inform research on artificial intelligence.

Development of quadruped walking locomotion gait generator using a hybrid method

NASA Astrophysics Data System (ADS)

Jasni, F.; Shafie, A. A.

2013-12-01

The earth, in many areas is hardly reachable by the wheeled or tracked locomotion system. Thus, walking locomotion system is becoming a favourite option for mobile robot these days. This is because of the ability of walking locomotion to move on the rugged and unlevel terrains. However, to develop a walking locomotion gait for a robot is not a simple task. Central Pattern Generator (CPGs) method is a biological inspired method that is introduced as a method to develop the gait for the walking robot recently to tackle the issue faced by the conventional method of pre-designed trajectory based method. However, research shows that even the CPG method do have some limitations. Thus, in this paper, a hybrid method that combines CPG and the pre-designed trajectory based method is introduced to develop a walking gait for quadruped walking robot. The 3-D foot trajectories and the joint angle trajectories developed using the proposed method are compared with the data obtained via the conventional method of pre-designed trajectory to confirm the performance.

Evolving a Behavioral Repertoire for a Walking Robot.

PubMed

Cully, A; Mouret, J-B

2016-01-01

Numerous algorithms have been proposed to allow legged robots to learn to walk. However, most of these algorithms are devised to learn walking in a straight line, which is not sufficient to accomplish any real-world mission. Here we introduce the Transferability-based Behavioral Repertoire Evolution algorithm (TBR-Evolution), a novel evolutionary algorithm that simultaneously discovers several hundreds of simple walking controllers, one for each possible direction. By taking advantage of solutions that are usually discarded by evolutionary processes, TBR-Evolution is substantially faster than independently evolving each controller. Our technique relies on two methods: (1) novelty search with local competition, which searches for both high-performing and diverse solutions, and (2) the transferability approach, which combines simulations and real tests to evolve controllers for a physical robot. We evaluate this new technique on a hexapod robot. Results show that with only a few dozen short experiments performed on the robot, the algorithm learns a repertoire of controllers that allows the robot to reach every point in its reachable space. Overall, TBR-Evolution introduced a new kind of learning algorithm that simultaneously optimizes all the achievable behaviors of a robot.

Feasibility of Synergy-Based Exoskeleton Robot Control in Hemiplegia.

PubMed

Hassan, Modar; Kadone, Hideki; Ueno, Tomoyuki; Hada, Yasushi; Sankai, Yoshiyuki; Suzuki, Kenji

2018-06-01

Here, we present a study on exoskeleton robot control based on inter-limb locomotor synergies using a robot control method developed to target hemiparesis. The robot control is based on inter-limb locomotor synergies and kinesiological information from the non-paretic leg and a walking aid cane to generate motion patterns for the assisted leg. The developed synergy-based system was tested against an autonomous robot control system in five patients with hemiparesis and varying locomotor abilities. Three of the participants were able to walk using the robot. Results from these participants showed an improved spatial symmetry ratio and more consistent step length with the synergy-based method compared with that for the autonomous method, while the increase in the range of motion for the assisted joints was larger with the autonomous system. The kinematic synergy distribution of the participants walking without the robot suggests a relationship between each participant's synergy distribution and his/her ability to control the robot: participants with two independent synergies accounting for approximately 80% of the data variability were able to walk with the robot. This observation was not consistently apparent with conventional clinical measures such as the Brunnstrom stages. This paper contributes to the field of robot-assisted locomotion therapy by introducing the concept of inter-limb synergies, demonstrating performance differences between synergy-based and autonomous robot control, and investigating the range of disability in which the system is usable.

"You gotta try it all": Parents' Experiences with Robotic Gait Training for their Children with Cerebral Palsy.

PubMed

Beveridge, Briony; Feltracco, Deanna; Struyf, Jillian; Strauss, Emily; Dang, Saniya; Phelan, Shanon; Wright, F Virginia; Gibson, Barbara E

2015-01-01

Innovative robotic technologies hold strong promise for improving walking abilities of children with cerebral palsy (CP), but may create expectations for parents pursuing the "newest thing" in treatment. The aim of this qualitative study was to explore parents' values about walking in relation to their experiences with robotic gait training for their children. Semi-structured interviews were conducted with parents of five ambulatory children with CP participating in a randomized trial investigating robotic gait training effectiveness. Parents valued walking, especially "correct" walking, as a key component of their children's present and future well-being. They continually sought the "next best thing" in therapy and viewed the robotic gait trainer as a potentially revolutionary technology despite mixed experiences. The results can help inform rehabilitation therapists' knowledge of parents' values and perspectives, and guide effective collaborations toward meeting the therapeutic needs of children with CP.

Design, implementation and stabilization of a Bipedal robot

NASA Astrophysics Data System (ADS)

Nath, Alok; Das, Goutam; Mallick, Anik; Chowdhury, Shovan

2017-12-01

In this paper, we have presented the mechanical design and fabrication of a Bipedal walking robot as well as control strategies to be implemented for walking and balance recovery. For this robot, we considered Six Degree of Freedom (D.O.P) in the lower body one at each hip, one at each knee and one at each ankle. Each degree of freedom is powered by a RC servo motor and this robot is controlled by Arduino Mega 2560 micro controller. By balancing center of mass (C.O.M) it walks in rhythmic way as like as human one.

The effect of impedance-controlled robotic gait training on walking ability and quality in individuals with chronic incomplete spinal cord injury: an explorative study.

PubMed

Fleerkotte, Bertine M; Koopman, Bram; Buurke, Jaap H; van Asseldonk, Edwin H F; van der Kooij, Herman; Rietman, Johan S

2014-03-04

There is increasing interest in the use of robotic gait-training devices in walking rehabilitation of incomplete spinal cord injured (iSCI) individuals. These devices provide promising opportunities to increase the intensity of training and reduce physical demands on therapists. Despite these potential benefits, robotic gait-training devices have not yet demonstrated clear advantages over conventional gait-training approaches, in terms of functional outcomes. This might be due to the reduced active participation and step-to-step variability in most robotic gait-training strategies, when compared to manually assisted therapy. Impedance-controlled devices can increase active participation and step-to-step variability. The aim of this study was to assess the effect of impedance-controlled robotic gait training on walking ability and quality in chronic iSCI individuals. A group of 10 individuals with chronic iSCI participated in an explorative clinical trial. Participants trained three times a week for eight weeks using an impedance-controlled robotic gait trainer (LOPES: LOwer extremity Powered ExoSkeleton). Primary outcomes were the 10-meter walking test (10 MWT), the Walking Index for Spinal Cord Injury (WISCI II), the six-meter walking test (6 MWT), the Timed Up and Go test (TUG) and the Lower Extremity Motor Scores (LEMS). Secondary outcomes were spatiotemporal and kinematics measures. All participants were tested before, during, and after training and at 8 weeks follow-up. Participants experienced significant improvements in walking speed (0.06 m/s, p = 0.008), distance (29 m, p = 0.005), TUG (3.4 s, p = 0.012), LEMS (3.4, p = 0.017) and WISCI after eight weeks of training with LOPES. At the eight-week follow-up, participants retained the improvements measured at the end of the training period. Significant improvements were also found in spatiotemporal measures and hip range of motion. Robotic gait training using an impedance-controlled robot is feasible in gait rehabilitation of chronic iSCI individuals. It leads to improvements in walking ability, muscle strength, and quality of walking. Improvements observed at the end of the training period persisted at the eight-week follow-up. Slower walkers benefit the most from the training protocol and achieve the greatest relative improvement in speed and walking distance.

The effect of impedance-controlled robotic gait training on walking ability and quality in individuals with chronic incomplete spinal cord injury: an explorative study

PubMed Central

2014-01-01

Background There is increasing interest in the use of robotic gait-training devices in walking rehabilitation of incomplete spinal cord injured (iSCI) individuals. These devices provide promising opportunities to increase the intensity of training and reduce physical demands on therapists. Despite these potential benefits, robotic gait-training devices have not yet demonstrated clear advantages over conventional gait-training approaches, in terms of functional outcomes. This might be due to the reduced active participation and step-to-step variability in most robotic gait-training strategies, when compared to manually assisted therapy. Impedance-controlled devices can increase active participation and step-to-step variability. The aim of this study was to assess the effect of impedance-controlled robotic gait training on walking ability and quality in chronic iSCI individuals. Methods A group of 10 individuals with chronic iSCI participated in an explorative clinical trial. Participants trained three times a week for eight weeks using an impedance-controlled robotic gait trainer (LOPES: LOwer extremity Powered ExoSkeleton). Primary outcomes were the 10-meter walking test (10MWT), the Walking Index for Spinal Cord Injury (WISCI II), the six-meter walking test (6MWT), the Timed Up and Go test (TUG) and the Lower Extremity Motor Scores (LEMS). Secondary outcomes were spatiotemporal and kinematics measures. All participants were tested before, during, and after training and at 8 weeks follow-up. Results Participants experienced significant improvements in walking speed (0.06 m/s, p = 0.008), distance (29 m, p = 0.005), TUG (3.4 s, p = 0.012), LEMS (3.4, p = 0.017) and WISCI after eight weeks of training with LOPES. At the eight-week follow-up, participants retained the improvements measured at the end of the training period. Significant improvements were also found in spatiotemporal measures and hip range of motion. Conclusion Robotic gait training using an impedance-controlled robot is feasible in gait rehabilitation of chronic iSCI individuals. It leads to improvements in walking ability, muscle strength, and quality of walking. Improvements observed at the end of the training period persisted at the eight-week follow-up. Slower walkers benefit the most from the training protocol and achieve the greatest relative improvement in speed and walking distance. PMID:24594284

Walking robot: A design project for undergraduate students

NASA Technical Reports Server (NTRS)

1991-01-01

The objective of the University of Maryland walking robot project was to design, analyze, assemble, and test an intelligent, mobile, and terrain-adaptive system. The robot incorporates existing technologies in novel ways. The legs emulate the walking path of a human by an innovative modification of a crank-and-rocker mechanism. The body consists of two tripod frames connected by a turning mechanism. The two sets of three legs are mounted so as to allow the robot to walk with stability in its own footsteps. The computer uses a modular hardware design and distributed processing. Dual-port RAM is used to allow communication between a supervisory personal computer and seven microcontrollers. The microcontrollers provide low-level control for the motors and relieve the processing burden on the PC.

Passive dynamics is a good basis for robot design and control, not!

NASA Astrophysics Data System (ADS)

Ruina, Andy

Many airplanes can, or nearly can, glide stably without control. So, it seems natural that the first successful powered flight followed from mastery of gliding. Many bicycles can, or nearly can, balance themselves when in motion. Bicycle design seems to have evolved to gain this feature. Also, we can make toys and 'robots' that, like a stable glider or coasting bicycle, stably walk without motors or control in a remarkably human-like way. Again, it seems to make sense to use `passive-dynamics' as a core for developing the control of walking robots and to gain understanding of the control of walking people. That's what I used to think. But, so far, this has not led to robust walking robots. What about human evolution? We didn't evolve dynamic bodies and then learn to control them. Rather, people had elaborate control systems way back when we were fish and even worms. However: if control is paramount, why is it that uncontrolled passive-dynamic walkers walk so much like humans? It seems that energy optimal, yet robust, control, perhaps a proxy for evolutionary development, arrives at solutions that have some features in common with passive-dynamics. Rather than thinking of good powered walking as passive walking with a small amount of control added, I now think of good powered walking, human or robotic, as highly controlled, while optimized for, in part, minimal actuator use. Thus, much of the motor effort, always at the ready, is usually titrated out.

Variety Wins: Soccer-Playing Robots and Infant Walking

PubMed Central

Ossmy, Ori; Hoch, Justine E.; MacAlpine, Patrick; Hasan, Shohan; Stone, Peter; Adolph, Karen E.

2018-01-01

Although both infancy and artificial intelligence (AI) researchers are interested in developing systems that produce adaptive, functional behavior, the two disciplines rarely capitalize on their complementary expertise. Here, we used soccer-playing robots to test a central question about the development of infant walking. During natural activity, infants' locomotor paths are immensely varied. They walk along curved, multi-directional paths with frequent starts and stops. Is the variability observed in spontaneous infant walking a “feature” or a “bug?” In other words, is variability beneficial for functional walking performance? To address this question, we trained soccer-playing robots on walking paths generated by infants during free play and tested them in simulated games of “RoboCup.” In Tournament 1, we compared the functional performance of a simulated robot soccer team trained on infants' natural paths with teams trained on less varied, geometric paths—straight lines, circles, and squares. Across 1,000 head-to-head simulated soccer matches, the infant-trained team consistently beat all teams trained with less varied walking paths. In Tournament 2, we compared teams trained on different clusters of infant walking paths. The team trained with the most varied combination of path shape, step direction, number of steps, and number of starts and stops outperformed teams trained with less varied paths. This evidence indicates that variety is a crucial feature supporting functional walking performance. More generally, we propose that robotics provides a fruitful avenue for testing hypotheses about infant development; reciprocally, observations of infant behavior may inform research on artificial intelligence. PMID:29867427

A model of cerebrocerebello-spinomuscular interaction in the sagittal control of human walking.

PubMed

Jo, Sungho; Massaquoi, Steve G

2007-03-01

A computationally developed model of human upright balance control (Jo and Massaquoi on Biol cybern 91:188-202, 2004) has been enhanced to describe biped walking in the sagittal plane. The model incorporates (a) non-linear muscle mechanics having activation level -dependent impedance, (b) scheduled cerebrocerebellar interaction for control of center of mass position and trunk pitch angle, (c) rectangular pulse-like feedforward commands from a brainstem/ spinal pattern generator, and (d) segmental reflex modulation of muscular synergies to refine inter-joint coordination. The model can stand when muscles around the ankle are coactivated. When trigger signals activate, the model transitions from standing still to walking at 1.5 m/s. Simulated natural walking displays none of seven pathological gait features. The model can simulate different walking speeds by tuning the amplitude and frequency in spinal pattern generator. The walking is stable against forward and backward pushes of up to 70 and 75 N, respectively, and with sudden changes in trunk mass of up to 18%. The sensitivity of the model to changes in neural parameters and the predicted behavioral results of simulated neural system lesions are examined. The deficit gait simulations may be useful to support the functional and anatomical correspondences of the model. The model demonstrates that basic human-like walking can be achieved by a hierarchical structure of stabilized-long loop feedback and synergy-mediated feedforward controls. In particular, internal models of body dynamics are not required.

Three-dimensional kinematics of the pelvis and hind limbs in chimpanzee (Pan troglodytes) and human bipedal walking.

PubMed

O'Neill, Matthew C; Lee, Leng-Feng; Demes, Brigitte; Thompson, Nathan E; Larson, Susan G; Stern, Jack T; Umberger, Brian R

2015-09-01

The common chimpanzee (Pan troglodytes) is a facultative biped and our closest living relative. As such, the musculoskeletal anatomies of their pelvis and hind limbs have long provided a comparative context for studies of human and fossil hominin locomotion. Yet, how the chimpanzee pelvis and hind limb actually move during bipedal walking is still not well defined. Here, we describe the three-dimensional (3-D) kinematics of the pelvis, hip, knee and ankle during bipedal walking and compare those values to humans walking at the same dimensionless and dimensional velocities. The stride-to-stride and intraspecific variations in 3-D kinematics were calculated using the adjusted coefficient of multiple correlation. Our results indicate that humans walk with a more stable pelvis than chimpanzees, especially in tilt and rotation. Both species exhibit similar magnitudes of pelvis list, but with segment motion that is opposite in phasing. In the hind limb, chimpanzees walk with a more flexed and abducted limb posture, and substantially exceed humans in the magnitude of hip rotation during a stride. The average stride-to-stride variation in joint and segment motion was greater in chimpanzees than humans, while the intraspecific variation was similar on average. These results demonstrate substantial differences between human and chimpanzee bipedal walking, in both the sagittal and non-sagittal planes. These new 3-D kinematic data are fundamental to a comprehensive understanding of the mechanics, energetics and control of chimpanzee bipedalism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Locomotion training of legged robots using hybrid machine learning techniques

NASA Technical Reports Server (NTRS)

Simon, William E.; Doerschuk, Peggy I.; Zhang, Wen-Ran; Li, Andrew L.

1995-01-01

In this study artificial neural networks and fuzzy logic are used to control the jumping behavior of a three-link uniped robot. The biped locomotion control problem is an increment of the uniped locomotion control. Study of legged locomotion dynamics indicates that a hierarchical controller is required to control the behavior of a legged robot. A structured control strategy is suggested which includes navigator, motion planner, biped coordinator and uniped controllers. A three-link uniped robot simulation is developed to be used as the plant. Neurocontrollers were trained both online and offline. In the case of on-line training, a reinforcement learning technique was used to train the neurocontroller to make the robot jump to a specified height. After several hundred iterations of training, the plant output achieved an accuracy of 7.4%. However, when jump distance and body angular momentum were also included in the control objectives, training time became impractically long. In the case of off-line training, a three-layered backpropagation (BP) network was first used with three inputs, three outputs and 15 to 40 hidden nodes. Pre-generated data were presented to the network with a learning rate as low as 0.003 in order to reach convergence. The low learning rate required for convergence resulted in a very slow training process which took weeks to learn 460 examples. After training, performance of the neurocontroller was rather poor. Consequently, the BP network was replaced by a Cerebeller Model Articulation Controller (CMAC) network. Subsequent experiments described in this document show that the CMAC network is more suitable to the solution of uniped locomotion control problems in terms of both learning efficiency and performance. A new approach is introduced in this report, viz., a self-organizing multiagent cerebeller model for fuzzy-neural control of uniped locomotion is suggested to improve training efficiency. This is currently being evaluated for a possible patent by NASA, Johnson Space Center. An alternative modular approach is also developed which uses separate controllers for each stage of the running stride. A self-organizing fuzzy-neural controller controls the height, distance and angular momentum of the stride. A CMAC-based controller controls the movement of the leg from the time the foot leaves the ground to the time of landing. Because the leg joints are controlled at each time step during flight, movement is smooth and obstacles can be avoided. Initial results indicate that this approach can yield fast, accurate results.

The contact condition influence on stability and energy efficiency of quadruped robot

NASA Astrophysics Data System (ADS)

Lei, Jingtao; Wang, Tianmiao; Gao, Feng

2008-10-01

Quadruped robot has attribute of serial and parallel manipulator with multi-loop mechanism, with more DOF of each leg and intermittent contact with ground during walking, the trot gait of quadruped robot belongs to dynamic waking, compared to the crawl gait, the walking speed is higher, but the robot becomes unstable, it is difficult to keep dynamically stable walking. In this paper, we mainly analyze the condition for the quadruped robot to realize dynamically stable walking, establish centroid orbit equation based on ZMP (Zero Moment Point) stability theory, on the other hand , we study contact impact and friction influence on stability and energy efficiency. Because of the periodic contact between foots and ground, the contact impact and friction are considered to establish spring-damp nonlinear dynamics model. Robot need to be controlled to meet ZMP stability condition and contact constraint condition. Based on the virtual prototyping model, we study control algorithm considering contact condition, the contact compensator and friction compensator are adopted. The contact force and the influence of different contact conditions on the energy efficiency during whole gait cycle are obtained.

Invariant hip moment pattern while walking with a robotic hip exoskeleton

PubMed Central

Lewis, Cara L.; Ferris, Daniel P.

2011-01-01

Robotic lower limb exoskeletons hold significant potential for gait assistance and rehabilitation; however, we have a limited understanding of how people adapt to walking with robotic devices. The purpose of this study was to test the hypothesis that people reduce net muscle moments about their joints when robotic assistance is provided. This reduction in muscle moment results in a total joint moment (muscle plus exoskeleton) that is the same as the moment without the robotic assistance despite potential differences in joint angles. To test this hypothesis, eight healthy subjects trained with the robotic hip exoskeleton while walking on a force-measuring treadmill. The exoskeleton provided hip flexion assistance from approximately 33% to 53% of the gait cycle. We calculated the root mean squared difference (RMSD) between the average of data from the last 15 minutes of the powered condition and the unpowered condition. After completing three 30-minute training sessions, the hip exoskeleton provided 27% of the total peak hip flexion moment during gait. Despite this substantial contribution from the exoskeleton, subjects walked with a total hip moment pattern (muscle plus exoskeleton) that was almost identical and more similar to the unpowered condition than the hip angle pattern (hip moment RMSD 0.027, angle RMSD 0.134, p<0.001). The angle and moment RMSD were not different for the knee and ankle joints. These findings support the concept that people adopt walking patterns with similar joint moment patterns despite differences in hip joint angles for a given walking speed. PMID:21333995

An Ultralightweight and Living Legged Robot.

PubMed

Vo Doan, Tat Thang; Tan, Melvin Y W; Bui, Xuan Hien; Sato, Hirotaka

2018-02-01

In this study, we describe the most ultralightweight living legged robot to date that makes it a strong candidate for a search and rescue mission. The robot is a living beetle with a wireless electronic backpack stimulator mounted on its thorax. Inheriting from the living insect, the robot employs a compliant body made of soft actuators, rigid exoskeletons, and flexure hinges. Such structure would allow the robot to easily adapt to any complex terrain due to the benefit of soft interface, self-balance, and self-adaptation of the insect without any complex controller. The antenna stimulation enables the robot to perform not only left/right turning but also backward walking and even cessation of walking. We were also able to grade the turning and backward walking speeds by changing the stimulation frequency. The power required to drive the robot is low as the power consumption of the antenna stimulation is in the order of hundreds of microwatts. In contrast to the traditional legged robots, this robot is of low cost, easy to construct, simple to control, and has ultralow power consumption.

Influence of the amount of body weight support on lower limb joints' kinematics during treadmill walking at different gait speeds: Reference data on healthy adults to define trajectories for robot assistance.

PubMed

Ferrarin, Maurizio; Rabuffetti, Marco; Geda, Elisabetta; Sirolli, Silvia; Marzegan, Alberto; Bruno, Valentina; Sacco, Katiuscia

2018-06-01

Several robotic devices have been developed for the rehabilitation of treadmill walking in patients with movement disorders due to injuries or diseases of the central nervous system. These robots induce coordinated multi-joint movements aimed at reproducing the physiological walking or stepping patterns. Control strategies developed for robotic locomotor training need a set of predefined lower limb joint angular trajectories as reference input for the control algorithm. Such trajectories are typically taken from normative database of overground unassisted walking. However, it has been demonstrated that gait speed and the amount of body weight support significantly influence joint trajectories during walking. Moreover, both the speed and the level of body weight support must be individually adjusted according to the rehabilitation phase and the residual locomotor abilities of the patient. In this work, 10 healthy participants (age range: 23-48 years) were asked to walk in movement analysis laboratory on a treadmill at five different speeds and four different levels of body weight support; besides, a trial with full body weight support, that is, with the subject suspended on air, was performed at two different cadences. The results confirm that lower limb kinematics during walking is affected by gait speed and by the amount of body weight support, and that on-air stepping is radically different from treadmill walking. Importantly, the results provide normative data in a numerical form to be used as reference trajectories for controlling robot-assisted body weight support walking training. An electronic addendum is provided to easily access to such reference data for different combinations of gait speeds and body weight support levels.

Neuromorphic walking gait control.

PubMed

Still, Susanne; Hepp, Klaus; Douglas, Rodney J

2006-03-01

We present a neuromorphic pattern generator for controlling the walking gaits of four-legged robots which is inspired by central pattern generators found in the nervous system and which is implemented as a very large scale integrated (VLSI) chip. The chip contains oscillator circuits that mimic the output of motor neurons in a strongly simplified way. We show that four coupled oscillators can produce rhythmic patterns with phase relationships that are appropriate to generate all four-legged animal walking gaits. These phase relationships together with frequency and duty cycle of the oscillators determine the walking behavior of a robot driven by the chip, and they depend on a small set of stationary bias voltages. We give analytic expressions for these dependencies. This chip reduces the complex, dynamic inter-leg control problem associated with walking gait generation to the problem of setting a few stationary parameters. It provides a compact and low power solution for walking gait control in robots.

Walking with robot assistance: the influence of body weight support on the trunk and pelvis kinematics.

PubMed

Swinnen, Eva; Baeyens, Jean-Pierre; Knaepen, Kristel; Michielsen, Marc; Hens, Gerrit; Clijsen, Ron; Goossens, Maggie; Buyl, Ronald; Meeusen, Romain; Kerckhofs, Eric

2015-05-01

The goal was to assess in healthy participants the three-dimensional kinematics of the pelvis and the trunk during robot-assisted treadmill walking (RATW) at 0%, 30% and 50% body weight support (BWS), compared with treadmill walking (TW). 18 healthy participants walked (2 kmph) on a treadmill with and without robot assistance (Lokomat; 60% guidance force; 0%, 30% and 50% BWS). After an acclimatisation period (four minutes), trunk and pelvis kinematics were registered in each condition (Polhemus Liberty [240 Hz]). The results were analysed using a repeated measures analysis of variance with Bonferroni correction, with the level of suspension as within-subject factor. During RATW with BWS, there were significantly (1) smaller antero-posterior and lateral translations of the trunk and the pelvis; (2) smaller antero-posterior flexion and axial rotation of the trunk; (3) larger lateral flexion of the trunk; and (4) larger antero-posterior tilting of the pelvis compared with TW. There are significant differences in trunk and pelvis kinematics in healthy persons during TW with and without robot assistance. These data are relevant in gait rehabilitation, relating to normal balance regulation. Additional research is recommended to further assess the influence of robot assistance on human gait. The trunk and pelvis moves in a different way during walking with robot assistance. The data suggest that the change in movement is due to the robot device and the harness of the suspension system more than due to the level of suspension itself.

Long-term dynamics of freshwater red tide in shallow lake in central Japan.

PubMed

Hirabayashi, Kimio; Yoshizawa, Kazuya; Yoshida, Norihiko; Ariizumi, Kazunori; Kazama, Futaba

2007-01-01

The aim of this study is to clarify the long-term dynamics of the red tide occurring in Lake Kawaguchi. The measurement of environmental factors and water sampling were carried out monthly at a fixed station in Lake Kawaguchi's center basin from April 1993 to March 2004. On June 26, 1995, the horizontal distribution ofPeridinium bipes was investigated using a plastic pipe, obtaining 0∼1-m layers of water column samples at 68 locations across the entire lake. P. bipes showed an explosive growth and formed a freshwater red tide in the early summer of 1995, when the nutrient level was higher than those in the other years, particularly the phosphate concentration in the surface layer. The dissolved total phosphorus (DTP) concentration was sufficient forP. bipes growth in that year. In the study of its horizontal distribution,P. bipes was found at all the locations. The numbers of cells per milliliter ranged from 67 to 5360, averaging 1094±987 cells/ml, with particularly high densities along the northern shore. Since then,P. bipes has annually averaged about 25 cells/ml in Lake Kawaguchi. We observed that the red tide caused byP. bipes correlates with a high DTP concentration in Lake Kawaguchi.

Adaptive walking of a quadrupedal robot based on layered biological reflexes

NASA Astrophysics Data System (ADS)

Zhang, Xiuli; Mingcheng, E.; Zeng, Xiangyu; Zheng, Haojun

2012-07-01

A multiple-legged robot is traditionally controlled by using its dynamic model. But the dynamic-model-based approach fails to acquire satisfactory performances when the robot faces rough terrains and unknown environments. Referring animals' neural control mechanisms, a control model is built for a quadruped robot walking adaptively. The basic rhythmic motion of the robot is controlled by a well-designed rhythmic motion controller(RMC) comprising a central pattern generator(CPG) for hip joints and a rhythmic coupler (RC) for knee joints. CPG and RC have relationships of motion-mapping and rhythmic couple. Multiple sensory-motor models, abstracted from the neural reflexes of a cat, are employed. These reflex models are organized and thus interact with the CPG in three layers, to meet different requirements of complexity and response time to the tasks. On the basis of the RMC and layered biological reflexes, a quadruped robot is constructed, which can clear obstacles and walk uphill and downhill autonomously, and make a turn voluntarily in uncertain environments, interacting with the environment in a way similar to that of an animal. The paper provides a biologically inspired architecture, with which a robot can walk adaptively in uncertain environments in a simple and effective way, and achieve better performances.

Is body-weight-supported treadmill training or robotic-assisted gait training superior to overground gait training and other forms of physiotherapy in people with spinal cord injury? A systematic review.

PubMed

Mehrholz, J; Harvey, L A; Thomas, S; Elsner, B

2017-08-01

Systematic review about randomised trials comparing different training strategies to improve gait in people with spinal cord injuries (SCI). The aim of this systematic review was to compare the effectiveness of body-weight-supported treadmill training (BWSTT) and robotic-assisted gait training with overground gait training and other forms of physiotherapy in people with traumatic SCI. Systematic review conducted by researchers from Germany and Australia. An extensive search was conducted for randomised controlled trials involving people with traumatic SCI that compared either BWSTT or robotic-assisted gait training with overground gait training and other forms of physiotherapy. The two outcomes of interest were walking speed (m s -1 ) and walking distance (m). BWSTT and robotic-assisted gait training were analysed separately, and data were pooled across trials to derive mean between-group differences using a random-effects model. Thirteen randomised controlled trials involving 586 people were identified. Ten trials involving 462 participants compared BWSTT to overground gait training and other forms of physiotherapy, but only nine trials provided useable data. The pooled mean (95% confidence interval (CI)) between-group differences for walking speed and walking distance were -0.03 m s -1 (-0.10 to 0.04) and -7 m (-45 to 31), respectively, favouring overground gait training. Five trials involving 344 participants compared robotic-assisted gait training to overground gait training and other forms of physiotherapy but only three provided useable data. The pooled mean (95% CI) between-group differences for walking speed and walking distance were -0.04 m s -1 (95% CI -0.21 to 0.13) and -6 m (95% CI -86 to 74), respectively, favouring overground gait training. BWSTT and robotic-assisted gait training do not increase walking speed more than overground gait training and other forms of physiotherapy do, but their effects on walking distance are not clear.

Invariant hip moment pattern while walking with a robotic hip exoskeleton.

PubMed

Lewis, Cara L; Ferris, Daniel P

2011-03-15

Robotic lower limb exoskeletons hold significant potential for gait assistance and rehabilitation; however, we have a limited understanding of how people adapt to walking with robotic devices. The purpose of this study was to test the hypothesis that people reduce net muscle moments about their joints when robotic assistance is provided. This reduction in muscle moment results in a total joint moment (muscle plus exoskeleton) that is the same as the moment without the robotic assistance despite potential differences in joint angles. To test this hypothesis, eight healthy subjects trained with the robotic hip exoskeleton while walking on a force-measuring treadmill. The exoskeleton provided hip flexion assistance from approximately 33% to 53% of the gait cycle. We calculated the root mean squared difference (RMSD) between the average of data from the last 15 min of the powered condition and the unpowered condition. After completing three 30-min training sessions, the hip exoskeleton provided 27% of the total peak hip flexion moment during gait. Despite this substantial contribution from the exoskeleton, subjects walked with a total hip moment pattern (muscle plus exoskeleton) that was almost identical and more similar to the unpowered condition than the hip angle pattern (hip moment RMSD 0.027, angle RMSD 0.134, p<0.001). The angle and moment RMSD were not different for the knee and ankle joints. These findings support the concept that people adopt walking patterns with similar joint moment patterns despite differences in hip joint angles for a given walking speed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Research the Gait Characteristics of Human Walking Based on a Robot Model and Experiment

NASA Astrophysics Data System (ADS)

He, H. J.; Zhang, D. N.; Yin, Z. W.; Shi, J. H.

2017-02-01

In order to research the gait characteristics of human walking in different walking ways, a robot model with a single degree of freedom is put up in this paper. The system control models of the robot are established through Matlab/Simulink toolbox. The gait characteristics of straight, uphill, turning, up the stairs, down the stairs up and down areanalyzed by the system control models. To verify the correctness of the theoretical analysis, an experiment was carried out. The comparison between theoretical results and experimental results shows that theoretical results are better agreement with the experimental ones. Analyze the reasons leading to amplitude error and phase error and give the improved methods. The robot model and experimental ways can provide foundation to further research the various gait characteristics of the exoskeleton robot.

Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude.

PubMed

Kao, Pei-Chun; Lewis, Cara L; Ferris, Daniel P

2010-07-26

To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by approximately 35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H-) reflex responses during powered versus unpowered walking. We tested soleus H-reflex responses in neurologically intact subjects (n=8) that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered), then with power (powered), and finally without power again (second unpowered). We also collected joint kinematics and electromyography. When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG) activation (27-48%) and had concomitant reductions in H-reflex amplitude (12-24%) compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance. Future studies should determine if the findings also apply to long-term adaption to the exoskeleton.

Reference trajectory generation for rehabilitation robots: complementary limb motion estimation.

PubMed

Vallery, Heike; van Asseldonk, Edwin H F; Buss, Martin; van der Kooij, Herman

2009-02-01

For gait rehabilitation robots, an important question is how to ensure stable gait, while avoiding any interaction forces between robot and human in case the patient walks correctly. To achieve this, the definition of "correct" gait needs to adapted both to the individual patient and to the situation. Recently, we proposed a method for online trajectory generation that can be applied for hemiparetic subjects. Desired states for one (disabled) leg are generated online based on the movements of the other (sound) leg. An instantaneous mapping between legs is performed by exploiting physiological interjoint couplings. This way, the patient generates the reference motion for the affected leg autonomously. The approach, called Complementary Limb Motion Estimation (CLME), is implemented on the LOPES gait rehabilitation robot and evaluated with healthy subjects in two different experiments. In a previously described study, subjects walk only with one leg, while the robot's other leg acts as a fake prosthesis, to simulate complete loss of function in one leg. This study showed that CLME ensures stable gait. In a second study, to be presented in this paper, healthy subjects walk with both their own legs to assess the interference with self-determined walking. Evaluation criteria are: Power delivered to the joints by the robot, electromyography (EMG) distortions, and kinematic distortions, all compared to zero torque control, which is the baseline of minimum achievable interference. Results indicate that interference of the robot is lower with CLME than with a fixed reference trajectory, mainly in terms of lowered exchanged power and less alteration of EMG. This implies that subjects can walk more naturally with CLME, and they are assisted less by the robot when it is not needed. Future studies with patients are yet to show whether these properties of CLME transfer to the clinical domain.

Biologically-inspired hexapod robot design and simulation

NASA Technical Reports Server (NTRS)

Espenschied, Kenneth S.; Quinn, Roger D.

1994-01-01

The design and construction of a biologically-inspired hexapod robot is presented. A previously developed simulation is modified to include models of the DC drive motors, the motor driver circuits and their transmissions. The application of this simulation to the design and development of the robot is discussed. The mechanisms thought to be responsible for the leg coordination of the walking stick insect were previously applied to control the straight-line locomotion of a robot. We generalized these rules for a robot walking on a plane. This biologically-inspired control strategy is used to control the robot in simulation. Numerical results show that the general body motion and performance of the simulated robot is similar to that of the robot based on our preliminary experimental results.

INS/EKF-based stride length, height and direction intent detection for walking assistance robots.

PubMed

Brescianini, Dario; Jung, Jun-Young; Jang, In-Hun; Park, Hyun Sub; Riener, Robert

2011-01-01

We propose an algorithm used to obtain the information on stride length, height difference, and direction based on user's intent during walking. For exoskeleton robots used to assist paraplegic patients' walking, this information is used to generate gait patterns by themselves in on-line. To obtain this information, we attach an inertial measurement unit(IMU) on crutches and apply an extended kalman filter-based error correction method to reduce the phenomena of drift due to bias of the IMU. The proposed method is verifed in real walking scenarios including walking, climbing up-stairs, and changing direction of walking with normal. © 2011 IEEE

Two-legged walking robot prescribed motion on a rough cylinder

NASA Astrophysics Data System (ADS)

Golubev, Yury; Melkumova, Elena

2018-05-01

The motion of a walking robot with n legs, that ensure the desired motion of the robot body, is described using general dynamics theoretical framework. When each of the robot legs contacts the surface in a single foothold, the momentum and angular momentum theorems yield a system of six differential equations that form a complete description of the robot motion. In the case of two-leg robot (n = 2) the problem of the existence of the solution can be reduced to a system of algebraic inequalities. Using numerical analysis, the classification of footholds positions for different values of the friction coefficient is obtained.

The walking robot project

NASA Technical Reports Server (NTRS)

Williams, P.; Sagraniching, E.; Bennett, M.; Singh, R.

1991-01-01

A walking robot was designed, analyzed, and tested as an intelligent, mobile, and a terrain adaptive system. The robot's design was an application of existing technologies. The design of the six legs modified and combines well understood mechanisms and was optimized for performance, flexibility, and simplicity. The body design incorporated two tripods for walking stability and ease of turning. The electrical hardware design used modularity and distributed processing to drive the motors. The software design used feedback to coordinate the system and simple keystrokes to give commands. The walking machine can be easily adapted to hostile environments such as high radiation zones and alien terrain. The primary goal of the leg design was to create a leg capable of supporting a robot's body and electrical hardware while walking or performing desired tasks, namely those required for planetary exploration. The leg designers intent was to study the maximum amount of flexibility and maneuverability achievable by the simplest and lightest leg design. The main constraints for the leg design were leg kinematics, ease of assembly, degrees of freedom, number of motors, overall size, and weight.

Walking with springs

NASA Astrophysics Data System (ADS)

Sugar, Thomas G.; Hollander, Kevin W.; Hitt, Joseph K.

2011-04-01

Developing bionic ankles poses great challenges due to the large moment, power, and energy that are required at the ankle. Researchers have added springs in series with a motor to reduce the peak power and energy requirements of a robotic ankle. We developed a "robotic tendon" that reduces the peak power by altering the required motor speed. By changing the required speed, the spring acts as a "load variable transmission." If a simple motor/gearbox solution is used, one walking step would require 38.8J and a peak motor power of 257 W. Using an optimized robotic tendon, the energy required is 21.2 J and the peak motor power is reduced to 96.6 W. We show that adding a passive spring in parallel with the robotic tendon reduces peak loads but the power and energy increase. Adding a passive spring in series with the robotic tendon reduces the energy requirements. We have built a prosthetic ankle SPARKy, Spring Ankle with Regenerative Kinetics, that allows a user to walk forwards, backwards, ascend and descend stairs, walk up and down slopes as well as jog.

Agile Walking Robot

NASA Technical Reports Server (NTRS)

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.

1990-01-01

Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.

Biologically inspired adaptive walking of a quadruped robot.

PubMed

Kimura, Hiroshi; Fukuoka, Yasuhiro; Cohen, Avis H

2007-01-15

We describe here the efforts to induce a quadruped robot to walk with medium-walking speed on irregular terrain based on biological concepts. We propose the necessary conditions for stable dynamic walking on irregular terrain in general, and we design the mechanical and the neural systems by comparing biological concepts with those necessary conditions described in physical terms. PD-controller at joints constructs the virtual spring-damper system as the viscoelasticity model of a muscle. The neural system model consists of a central pattern generator (CPG), reflexes and responses. We validate the effectiveness of the proposed neural system model control using the quadruped robots called 'Tekken1&2'. MPEG footage of experiments can be seen at http://www.kimura.is.uec.ac.jp.

[Exoskeleton robot system based on real-time gait analysis for walking assist].

PubMed

Xie, Zheng; Wang, Mingjiang; Huang, Wulong; Yong, Shanshan; Wang, Xin'an

2017-04-01

This paper presents a wearable exoskeleton robot system to realize walking assist function, which oriented toward the patients or the elderly with the mild impairment of leg movement function, due to illness or natural aging. It reduces the loads of hip, knee, ankle and leg muscles during walking by way of weight support. In consideration of the characteristics of the psychological demands and the disease, unlike the weight loss system in the fixed or followed rehabilitation robot, the structure of the proposed exoskeleton robot is artistic, lightweight and portable. The exoskeleton system analyzes the user's gait real-timely by the plantar pressure sensors to divide gait phases, and present different control strategies for each gait phase. The pressure sensors in the seat of the exoskeleton system provide real-time monitoring of the support efforts. And the drive control uses proportion-integral-derivative (PID) control technology for torque control. The total weight of the robot system is about 12.5 kg. The average of the auxiliary support is about 10 kg during standing, and it is about 3 kg during walking. The system showed, in the experiments, a certain effect of weight support, and reduction of the pressure on the lower limbs to walk and stand.

Hybrid FES-robot cooperative control of ambulatory gait rehabilitation exoskeleton.

PubMed

del-Ama, Antonio J; Gil-Agudo, Angel; Pons, José L; Moreno, Juan C

2014-03-04

Robotic and functional electrical stimulation (FES) approaches are used for rehabilitation of walking impairment of spinal cord injured individuals. Although devices are commercially available, there are still issues that remain to be solved. Control of hybrid exoskeletons aims at blending robotic exoskeletons and electrical stimulation to overcome the drawbacks of each approach while preserving their advantages. Hybrid actuation and control have a considerable potential for walking rehabilitation but there is a need of novel control strategies of hybrid systems that adequately manage the balance between FES and robotic controllers. Combination of FES and robotic control is a challenging issue, due to the non-linear behavior of muscle under stimulation and the lack of developments in the field of hybrid control. In this article, a cooperative control strategy of a hybrid exoskeleton is presented. This strategy is designed to overcome the main disadvantages of muscular stimulation: electromechanical delay and change in muscle performance over time, and to balance muscular and robotic actuation during walking.Experimental results in healthy subjects show the ability of the hybrid FES-robot cooperative control to balance power contribution between exoskeleton and muscle stimulation. The robotic exoskeleton decreases assistance while adequate knee kinematics are guaranteed. A new technique to monitor muscle performance is employed, which allows to estimate muscle fatigue and implement muscle fatigue management strategies. Kinesis is therefore the first ambulatory hybrid exoskeleton that can effectively balance robotic and FES actuation during walking. This represents a new opportunity to implement new rehabilitation interventions to induce locomotor activity in patients with paraplegia.Acronym list: 10 mWT: ten meters walking test; 6 MWT: six minutes walking test; FSM: finite-state machine; t-FSM: time-domain FSM; c-FSM: cycle-domain FSM; FES: functional electrical stimulation; HKAFO: hip-knee-ankle-foot orthosis; ILC: iterative error-based learning control; MFE: muscle fatigue estimator; NILC: Normalized stimulation output from ILC controller; PID: Proportional-Integral-derivative Control; PW: Stimulation pulse width; QUEST: Quebec User Evaluation of Satisfaction with assistive Technology; SCI: Spinal cord injury; TTI: torque-time integral; VAS: Visual Analog Scale.

Hybrid FES-robot cooperative control of ambulatory gait rehabilitation exoskeleton

PubMed Central

2014-01-01

Robotic and functional electrical stimulation (FES) approaches are used for rehabilitation of walking impairment of spinal cord injured individuals. Although devices are commercially available, there are still issues that remain to be solved. Control of hybrid exoskeletons aims at blending robotic exoskeletons and electrical stimulation to overcome the drawbacks of each approach while preserving their advantages. Hybrid actuation and control have a considerable potential for walking rehabilitation but there is a need of novel control strategies of hybrid systems that adequately manage the balance between FES and robotic controllers. Combination of FES and robotic control is a challenging issue, due to the non-linear behavior of muscle under stimulation and the lack of developments in the field of hybrid control. In this article, a cooperative control strategy of a hybrid exoskeleton is presented. This strategy is designed to overcome the main disadvantages of muscular stimulation: electromechanical delay and change in muscle performance over time, and to balance muscular and robotic actuation during walking. Experimental results in healthy subjects show the ability of the hybrid FES-robot cooperative control to balance power contribution between exoskeleton and muscle stimulation. The robotic exoskeleton decreases assistance while adequate knee kinematics are guaranteed. A new technique to monitor muscle performance is employed, which allows to estimate muscle fatigue and implement muscle fatigue management strategies. Kinesis is therefore the first ambulatory hybrid exoskeleton that can effectively balance robotic and FES actuation during walking. This represents a new opportunity to implement new rehabilitation interventions to induce locomotor activity in patients with paraplegia. Acronym list: 10mWT: ten meters walking test; 6MWT: six minutes walking test; FSM: finite-state machine; t-FSM: time-domain FSM; c-FSM: cycle-domain FSM; FES: functional electrical stimulation; HKAFO: hip-knee-ankle-foot orthosis; ILC: iterative error-based learning control; MFE: muscle fatigue estimator; NILC: Normalized stimulation output from ILC controller; PID: Proportional-Integral-derivative Control; PW: Stimulation pulse width; QUEST: Quebec User Evaluation of Satisfaction with assistive Technology; SCI: Spinal cord injury; TTI: torque-time integral; VAS: Visual Analog Scale. PMID:24594302

Reducing robotic guidance during robot-assisted gait training improves gait function: a case report on a stroke survivor.

PubMed

Krishnan, Chandramouli; Kotsapouikis, Despina; Dhaher, Yasin Y; Rymer, William Z

2013-06-01

To test the feasibility of patient-cooperative robotic gait training for improving locomotor function of a chronic stroke survivor with severe lower-extremity motor impairments. Single-subject crossover design. Performed in a controlled laboratory setting. A 62-year-old man with right temporal lobe ischemic stroke was recruited for this study. The baseline lower-extremity Fugl-Meyer score of the subject was 10 on a scale of 34, which represented severe impairment in the paretic leg. However, the subject had a good ambulation level (community walker with the aid of a stick cane and ankle-foot orthosis) and showed no signs of sensory or cognitive impairments. The subject underwent 12 sessions (3 times per week for 4wk) of conventional robotic training with the Lokomat, where the robot provided full assistance to leg movements while walking, followed by 12 sessions (3 times per week for 4wk) of patient-cooperative robotic control training, where the robot provided minimal guidance to leg movements during walking. Clinical outcomes were evaluated before the start of the intervention, immediately after 4 weeks of conventional robotic training, and immediately after 4 weeks of cooperative control robotic training. These included: (1) self-selected and fast walking speed, (2) 6-minute walk test, (3) Timed Up & Go test, and (4) lower-extremity Fugl-Meyer score. Results showed that clinical outcomes changed minimally after full guidance robotic training, but improved considerably after 4 weeks of reduced guidance robotic training. The findings from this case study suggest that cooperative control robotic training is superior to conventional robotic training and is a feasible option to restoring locomotor function in ambulatory stroke survivors with severe motor impairments. A larger trial is needed to verify the efficacy of this advanced robotic control strategy in facilitating gait recovery after stroke. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Orthotic Body-Weight Support Through Underactuated Potential Energy Shaping with Contact Constraints

PubMed Central

Lv, Ge; Gregg, Robert D.

2015-01-01

Body-weight support is an effective clinical tool for gait rehabilitation after neurological impairment. Body-weight supported training systems have been developed to help patients regain mobility and confidence during walking, but conventional systems constrain the patient's treatment in clinical environments. We propose that this challenge could be addressed by virtually providing patients with body-weight support through the actuators of a powered orthosis (or exoskeleton) utilizing potential energy shaping control. However, the changing contact conditions and degrees of underactuation encountered during human walking present significant challenges to consistently matching a desired potential energy for the human in closed loop. We therefore introduce a generalized matching condition for shaping Lagrangian systems with holonomic contact constraints. By satisfying this matching condition for four phases of gait, we derive control laws to achieve virtual body-weight support through a powered knee-ankle orthosis. We demonstrate beneficial effects of virtual body-weight support in simulations of a human-like biped model, indicating the potential clinical value of this proposed control approach. PMID:26900254

Kinematic effects of inertia and friction added by a robotic knee exoskeleton after prolonged walking.

PubMed

Shirota, C; Tucker, M R; Lambercy, O; Gassert, R

2017-07-01

The capabilities of robotic gait assistive devices are ever increasing; however, their adoption outside of the lab is still limited. A critical barrier for the functionality of these devices are the still unknown mechanical properties of the human leg during dynamic conditions such as walking. We built a robotic knee exoskeleton to address this problem. Here, we present the effects of our device on the walking pattern of four subjects. We assessed the effects after a short period of acclimation as well as after a 1.5h walking protocol. We found that the knee exoskeleton decreased (towards extension) the peak hip extension and peak knee flexion of the leg with the exoskeleton, while minimally affecting the non-exoskeleton leg. Comparatively smaller changes occurred after prolonged walking. These results suggest that walking patterns attained after a few minutes of acclimation with a knee exoskeleton are stable for at least a couple of hours.

Simulated Lidar Images of Human Pose using a 3DS Max Virtual Laboratory

DTIC Science & Technology

2015-12-01

developed in Autodesk 3DS Max, with an animated, biofidelic 3D human mesh biped character ( avatar ) as the subject. The biped animation modifies the digital...character ( avatar ) as the subject. The biped animation modifies the digital human model through a time sequence of motion capture data representing an...AFB. Mr. Isiah Davenport from Infoscitex Corp developed the method for creating the biofidelic avatars from laboratory data and 3DS Max code for

Invariant ankle moment patterns when walking with and without a robotic ankle exoskeleton.

PubMed

Kao, Pei-Chun; Lewis, Cara L; Ferris, Daniel P

2010-01-19

To guide development of robotic lower limb exoskeletons, it is necessary to understand how humans adapt to powered assistance. The purposes of this study were to quantify joint moments while healthy subjects adapted to a robotic ankle exoskeleton and to determine if the period of motor adaptation is dependent on the magnitude of robotic assistance. The pneumatically powered ankle exoskeleton provided plantar flexor torque controlled by the wearer's soleus electromyography (EMG). Eleven naïve individuals completed two 30-min sessions walking on a split-belt instrumented treadmill at 1.25m/s while wearing the ankle exoskeleton. After two sessions of practice, subjects reduced their soleus EMG activation by approximately 36% and walked with total ankle moment patterns similar to their unassisted gait (r(2)=0.98+/-0.02, THSD, p>0.05). They had substantially different ankle kinematic patterns compared to their unassisted gait (r(2)=0.79+/-0.12, THSD, p<0.05). Not all of the subjects reached a steady-state gait pattern within the two sessions, in contrast to a previous study using a weaker robotic ankle exoskeleton (Gordon and Ferris, 2007). Our results strongly suggest that humans aim for similar joint moment patterns when walking with robotic assistance rather than similar kinematic patterns. In addition, greater robotic assistance provided during initial use results in a longer adaptation process than lesser robotic assistance. Copyright 2009 Elsevier Ltd. All rights reserved.

An integrated gait rehabilitation training based on Functional Electrical Stimulation cycling and overground robotic exoskeleton in complete spinal cord injury patients: Preliminary results.

PubMed

Mazzoleni, S; Battini, E; Rustici, A; Stampacchia, G

2017-07-01

The aim of this study is to investigate the effects of an integrated gait rehabilitation training based on Functional Electrical Stimulation (FES)-cycling and overground robotic exoskeleton in a group of seven complete spinal cord injury patients on spasticity and patient-robot interaction. They underwent a robot-assisted rehabilitation training based on two phases: n=20 sessions of FES-cycling followed by n= 20 sessions of robot-assisted gait training based on an overground robotic exoskeleton. The following clinical outcome measures were used: Modified Ashworth Scale (MAS), Numerical Rating Scale (NRS) on spasticity, Penn Spasm Frequency Scale (PSFS), Spinal Cord Independence Measure Scale (SCIM), NRS on pain and International Spinal Cord Injury Pain Data Set (ISCI). Clinical outcome measures were assessed before (T0) after (T1) the FES-cycling training and after (T2) the powered overground gait training. The ability to walk when using exoskeleton was assessed by means of 10 Meter Walk Test (10MWT), 6 Minute Walk Test (6MWT), Timed Up and Go test (TUG), standing time, walking time and number of steps. Statistically significant changes were found on the MAS score, NRS-spasticity, 6MWT, TUG, standing time and number of steps. The preliminary results of this study show that an integrated gait rehabilitation training based on FES-cycling and overground robotic exoskeleton in complete SCI patients can provide a significant reduction of spasticity and improvements in terms of patient-robot interaction.

Best facilitated cortical activation during different stepping, treadmill, and robot-assisted walking training paradigms and speeds: A functional near-infrared spectroscopy neuroimaging study.

PubMed

Kim, Ha Yeon; Yang, Sung Phil; Park, Gyu Lee; Kim, Eun Joo; You, Joshua Sung Hyun

2016-01-01

Robot-assisted and treadmill-gait training are promising neurorehabilitation techniques, with advantages over conventional gait training, but the neural substrates underpinning locomotor control remain unknown particularly during different gait training modes and speeds. The present optical imaging study compared cortical activities during conventional stepping walking (SW), treadmill walking (TW), and robot-assisted walking (RW) at different speeds. Fourteen healthy subjects (6 women, mean age 30.06, years ± 4.53) completed three walking training modes (SW, TW, and RW) at various speeds (self-selected, 1.5, 2.0, 2.5, and 3.0  km/h). A functional near-infrared spectroscopy (fNIRS) system determined cerebral hemodynamic changes associated with cortical locomotor network areas in the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), prefrontal cortex (PFC), and sensory association cortex (SAC). There was increased cortical activation in the SMC, PMC, and SMA during different walking training modes. More global locomotor network activation was observed during RW than TW or SW. As walking speed increased, multiple locomotor network activations were observed, and increased activation power spectrum. This is the first empirical evidence highlighting the neural substrates mediating dynamic locomotion for different gait training modes and speeds. Fast, robot-assisted gait training best facilitated cortical activation associated with locomotor control.

Feasibility and effects of patient-cooperative robot-aided gait training applied in a 4-week pilot trial

PubMed Central

2012-01-01

Background Functional training is becoming the state-of-the-art therapy approach for rehabilitation of individuals after stroke and spinal cord injury. Robot-aided treadmill training reduces personnel effort, especially when treating severely affected patients. Improving rehabilitation robots towards more patient-cooperative behavior may further increase the effects of robot-aided training. This pilot study aims at investigating the feasibility of applying patient-cooperative robot-aided gait rehabilitation to stroke and incomplete spinal cord injury during a therapy period of four weeks. Short-term effects within one training session as well as the effects of the training on walking function are evaluated. Methods Two individuals with chronic incomplete spinal cord injury and two with chronic stroke trained with the Lokomat gait rehabilitation robot which was operated in a new, patient-cooperative mode for a period of four weeks with four training sessions of 45 min per week. At baseline, after two and after four weeks, walking function was assessed with the ten meter walking test. Additionally, muscle activity of the major leg muscles, heart rate and the Borg scale were measured under different walking conditions including a non-cooperative position control mode to investigate the short-term effects of patient-cooperative versus non-cooperative robot-aided gait training. Results Patient-cooperative robot-aided gait training was tolerated well by all subjects and performed without difficulties. The subjects trained more actively and with more physiological muscle activity than in a non-cooperative position-control mode. One subject showed a significant and relevant increase of gait speed after the therapy, the three remaining subjects did not show significant changes. Conclusions Patient-cooperative robot-aided gait training is feasible in clinical practice and overcomes the main points of criticism against robot-aided gait training: It enables patients to train in an active, variable and more natural way. The limited number of subjects in this pilot trial does not permit valid conclusions on the effect of patient-cooperative robot-aided gait training on walking function. A large, possibly multi-center randomized controlled clinical trial is required to shed more light on this question. PMID:22650320

A stability-based mechanism for hysteresis in the walk-trot transition in quadruped locomotion.

PubMed

Aoi, Shinya; Katayama, Daiki; Fujiki, Soichiro; Tomita, Nozomi; Funato, Tetsuro; Yamashita, Tsuyoshi; Senda, Kei; Tsuchiya, Kazuo

2013-04-06

Quadrupeds vary their gaits in accordance with their locomotion speed. Such gait transitions exhibit hysteresis. However, the underlying mechanism for this hysteresis remains largely unclear. It has been suggested that gaits correspond to attractors in their dynamics and that gait transitions are non-equilibrium phase transitions that are accompanied by a loss in stability. In the present study, we used a robotic platform to investigate the dynamic stability of gaits and to clarify the hysteresis mechanism in the walk-trot transition of quadrupeds. Specifically, we used a quadruped robot as the body mechanical model and an oscillator network for the nervous system model to emulate dynamic locomotion of a quadruped. Experiments using this robot revealed that dynamic interactions among the robot mechanical system, the oscillator network, and the environment generate walk and trot gaits depending on the locomotion speed. In addition, a walk-trot transition that exhibited hysteresis was observed when the locomotion speed was changed. We evaluated the gait changes of the robot by measuring the locomotion of dogs. Furthermore, we investigated the stability structure during the gait transition of the robot by constructing a potential function from the return map of the relative phase of the legs and clarified the physical characteristics inherent to the gait transition in terms of the dynamics.

Effects of robotic treadmill training on functional mobility, walking capacity, motor symptoms and quality of life in ambulatory patients with Parkinson's disease: a preliminary prospective longitudinal study.

PubMed

Paker, Nurdan; Bugdayci, Derya; Goksenoglu, Goksen; Sen, Aysu; Kesiktas, Nur

2013-01-01

Decreased mobility and walking capacity occur frequently in Parkinson's disease (PD). Robotic treadmill training is a novel method to improve the walking capacity in rehabilitation. The primary aim of this study was to investigate the effects of robotic treadmill training on functional mobility and walking capacity in PD. Secondly, we aimed to assess the effects of the robotic treadmill training the motor symptoms and quality of life in patients with PD. Seventy patients with idiopathic Parkinson's disease who admitted to the outpatient clinic of the rehabilitation hospital were screened and 12 ambulatory volenteers who met the study criteria were included in this study. Patients were evaluated by Hoehn Yahr (HY) scale clinically. Two sessions robotic treadmill training per week during 5 weeks was planned for every patient. Patients were evaluated by the Timed Up and Go (TUG) test, 10 meter walking test (10 MWT), Unified Parkinson's Disease Rating Scale (UPDRS) motor section and Parkinson's Disease Questionnaire-39 (PDQ-39) at the baseline, at the 5 and 12 weeks. Cognitive and emotional states of the patients were assessed by Mini Mental State Examination (MMSE) test and Hospital Anxiety and Depression Scale (HADS) at the baseline. All patients were under medical treatment for the PD in this study and drug treatment was not changed during the study. Ten patients completed the study. The mean age was 65.6 ± 6.6 years. Five patients (50%) were women. Disease severity was between the HY stage 1-3. Two patients did not continue the robotic treadmill training after 7 sessions. They also did not want to come for control visits. TUG test, 10 MWT and UPDRS motor subscale scores showed statistically significant improvement after robotic treadmill training (p = 0.02, p = 0.001, p = 0.016). PDQ-39 scores improved significantly after robotic treadmill training (p = 0.03), however, the scores turned back to the baseline level at the 12. week control. As a result of this preliminary study, robotic treadmill training was useful to improve the functional mobility, walking capacity and motor symptoms in mild to moderate PD. Robotic treadmill training provided a transient improvement in the quality of life during the treatment.

Long-term interventions effects of robotic training on patients after anterior cruciate ligament reconstruction.

PubMed

Hu, Chunying; Huang, Qiuchen; Yu, Lili; Zhou, Yue; Gu, Rui; Ye, Miao; Ge, Meng; Xu, Yanfeng; Liu, Jianfeng

2016-08-01

[Purpose] The aim of this study was to examine the long-term interventions effects of robot-assisted therapy rehabilitation on functional activity levels after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 8 patients (6 males and 2 females) who received anterior cruciate ligament reconstruction. The subjects participated in robot-assisted therapy lasting for one month. The Timed Up-and-Go test, 10-Meter Walk test, Functional Reach Test, surface electromyography of the vastus lateralis and vastus medialis, and extensor strength of isokinetic movement of the knee joint were evaluated before and after the intervention. [Results] The average value of the of vastus medialis EMG, Functional Reach Test, and the maximum and average extensor strength of the knee joint isokinetic movement increased significantly, and the time of the 10-Meter Walk test decreased significantly. [Conclusion] These results suggest that walking ability and muscle strength can be improved by robotic walking training as a long-term intervention.

Long-term interventions effects of robotic training on patients after anterior cruciate ligament reconstruction

PubMed Central

Hu, Chunying; Huang, Qiuchen; Yu, Lili; Zhou, Yue; Gu, Rui; Ye, Miao; Ge, Meng; Xu, Yanfeng; Liu, Jianfeng

2016-01-01

[Purpose] The aim of this study was to examine the long-term interventions effects of robot-assisted therapy rehabilitation on functional activity levels after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 8 patients (6 males and 2 females) who received anterior cruciate ligament reconstruction. The subjects participated in robot-assisted therapy lasting for one month. The Timed Up-and-Go test, 10-Meter Walk test, Functional Reach Test, surface electromyography of the vastus lateralis and vastus medialis, and extensor strength of isokinetic movement of the knee joint were evaluated before and after the intervention. [Results] The average value of the of vastus medialis EMG, Functional Reach Test, and the maximum and average extensor strength of the knee joint isokinetic movement increased significantly, and the time of the 10-Meter Walk test decreased significantly. [Conclusion] These results suggest that walking ability and muscle strength can be improved by robotic walking training as a long-term intervention. PMID:27630396

Development of a Wearable Assist Robot for Walk Rehabilitation After Knee Arthroplasty Surgery

NASA Astrophysics Data System (ADS)

Terada, H.; Zhu, Y.; Horiguchi, K.; Nakamura, M.; Takahashi, R.

In Japan, it is popular that the disease knee joints will be replaced to artificial joints by surgery. And we have to assist so many patients for walk rehabilitation. So, the wearable assist robot has been developed. This robot includes the knee motion assist mechanism and the hip joint support mechanism. Especially, the knee motion assist mechanism consists of a non-circular gear and grooved cams. This mechanism rotates and slides simultaneously, which has two degree-of-freedom. Also, the hip joint support mechanism consists of a hip brace and a ball-joint. This mechanism can avoid motion constraints which are the internal or external rotation and the adduction or abduction. Then, the control algorithm, which considers an assisting timing for the walk rehabilitation, has been proposed. A sensing system of a walk state for this control system uses a heel contacts sensor and knee and hip joint rotation angle sensors. Also, the prototype robot has been tested. And it is confirmed that the assisting system is useful.

Leg surface electromyography patterns in children with neuro-orthopedic disorders walking on a treadmill unassisted and assisted by a robot with and without encouragement

PubMed Central

2013-01-01

Background Robot-assisted gait training and treadmill training can complement conventional physical therapy in children with neuro-orthopedic movement disorders. The aim of this study was to investigate surface electromyography (sEMG) activity patterns during robot-assisted gait training (with and without motivating instructions from a therapist) and unassisted treadmill walking and to compare these with physiological sEMG patterns. Methods Nine children with motor impairments and eight healthy children walked in various conditions: (a) on a treadmill in the driven gait orthosis Lokomat®, (b) same condition, with additional motivational instructions from a therapist, and (c) on the treadmill without assistance. sEMG recordings were made of the tibialis anterior, gastrocnemius lateralis, vastus medialis, and biceps femoris muscles. Differences in sEMG amplitudes between the three conditions were analyzed for the duration of stance and swing phase (for each group and muscle separately) using non-parametric tests. Spearman’s correlation coefficients illustrated similarity of muscle activation patterns between conditions, between groups, and with published reference trajectories. Results The relative duration of stance and swing phase differed between patients and controls, and between driven gait orthosis conditions and treadmill walking. While sEMG amplitudes were higher when being encouraged by a therapist compared to robot-assisted gait training without instructions (0.008 ≤ p-value ≤ 0.015), muscle activation patterns were highly comparable (0.648 ≤ Spearman correlation coefficients ≤ 0.969). In general, comparisons of the sEMG patterns with published reference data of over-ground walking revealed that walking in the driven gait orthosis could induce more physiological muscle activation patterns compared to unsupported treadmill walking. Conclusions Our results suggest that robotic-assisted gait training with therapeutic encouragement could appropriately increase muscle activity. Robotic-assisted gait training in general could induce physiological muscle activation patterns, which might indicate that this training exploits restorative rather than compensatory mechanisms. PMID:23867005

Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot.

PubMed

Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin; Manoonpong, Poramate

2015-01-01

Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles. Consequently, it can successfully explore and navigate in complex environments. We firstly tested our approach on a physical simulation environment and then applied it to our real biomechanical walking robot AMOSII with 19 DOFs to adaptively avoid obstacles and navigate in the real world.

Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot

PubMed Central

Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin; Manoonpong, Poramate

2015-01-01

Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles. Consequently, it can successfully explore and navigate in complex environments. We firstly tested our approach on a physical simulation environment and then applied it to our real biomechanical walking robot AMOSII with 19 DOFs to adaptively avoid obstacles and navigate in the real world. PMID:26528176

The quadruped robot adaptive control in trotting gait walking on slopes

NASA Astrophysics Data System (ADS)

Zhang, Shulong; Ma, Hongxu; Yang, Yu; Wang, Jian

2017-10-01

The quadruped robot can be decomposed into a planar seven-link closed kinematic chain in the direction of supporting line and a linear inverted pendulum in normal direction of supporting line. The ground slope can be estimated by using the body attitude information and supporting legs length. The slope degree is used in feedback, to achieve the point of quadruped robot adaptive control walking on slopes. The simulation results verify that the quadruped robot can achieves steady locomotion on the slope with the control strategy proposed in this passage.

Robot Would Climb Steep Terrain

NASA Technical Reports Server (NTRS)

Kennedy, Brett; Ganino, Anthony; Aghazarian, Hrand; Hogg, Robert; McHerny, Michael; Garrett, Michael

2007-01-01

This brief describes the steep terrain access robot (STAR) -- a walking robot that has been proposed for exploring steep terrain on remote planets. The STAR would be able to climb up or down on slopes as steep as vertical, and even beyond vertical to overhangs. Its system of walking mechanisms and controls would be to react forces and maintain stability. To enable the STAR to anchor itself in the terrain on steep slopes to maintain stability and react forces, it would be necessary to equip the tips of the walking legs with new ultrasonic/ sonic drill corers (USDCs) and to develop sensors and control algorithms to enable robust utilization of the USDCs.

Robot Would Reconfigure Modular Equipment

NASA Technical Reports Server (NTRS)

Purves, Lloyd R.

1993-01-01

Special-purpose sets of equipment, packaged in identical modules with identical interconnecting mechanisms, attached to or detached from each other by specially designed robot, according to proposal. Two-arm walking robot connects and disconnects modules, operating either autonomously or under remote supervision. Robot walks along row of connected modules by grasping successive attachment subassemblies in hand-over-hand motion. Intended application for facility or station in outer space; robot reconfiguration scheme makes it unnecessary for astronauts to venture outside spacecraft or space station. Concept proves useful on Earth in assembly, disassembly, or reconfiguration of equipment in such hostile environments as underwater, near active volcanoes, or in industrial process streams.

Adaptive locomotor training on an end-effector gait robot: evaluation of the ground reaction forces in different training conditions.

PubMed

Tomelleri, Christopher; Waldner, Andreas; Werner, Cordula; Hesse, Stefan

2011-01-01

The main goal of robotic gait rehabilitation is the restoration of independent gait. To achieve this goal different and specific patterns have to be practiced intensively in order to stimulate the learning process of the central nervous system. The gait robot G-EO Systems was designed to allow the repetitive practice of floor walking, stair climbing and stair descending. A novel control strategy allows training in adaptive mode. The force interactions between the foot and the ground were analyzed on 8 healthy volunteers in three different conditions: real floor walking on a treadmill, floor walking on the gait robot in passive mode, floor walking on the gait robot in adaptive mode. The ground reaction forces were measured by a Computer Dyno Graphy (CDG) analysis system. The results show different intensities of the ground reaction force across all of the three conditions. The intensities of force interactions during the adaptive training mode are comparable to the real walking on the treadmill. Slight deviations still occur in regard to the timing pattern of the forces. The adaptive control strategy comes closer to the physiological swing phase than the passive mode and seems to be a promising option for the treatment of gait disorders. Clinical trials will validate the efficacy of this new option in locomotor therapy on the patients. © 2011 IEEE

Bipedal locomotion in granular media

NASA Astrophysics Data System (ADS)

Kingsbury, Mark; Zhang, Tingnan; Goldman, Daniel

Bipedal walking, locomotion characterized by alternating swing and double support phase, is well studied on ground where feet do not penetrate the substrate. On granular media like sand however, intrusion and extrusion phases also occur. In these phases, relative motion of the two feet requires that one or both feet slip through the material, degrading performance. To study walking in these phases, we designed and studied a planarized bipedal robot (1.6 kg, 42 cm) that walked in a fluidized bed of poppy seeds. We also simulated the robot in a multibody software environment (Chrono) using granular resistive force theory (RFT) to calculate foot forces. In experiment and simulation, the robot experienced slip during the intrusion phase, with the experiment presenting additional slip due to motor control error during the double support phase. This exaggerated slip gave insight (through analysis of ground reaction forces in simulation) into how slip occurs when relative motion exists between the two feet in the granular media, where the foot with higher relative drag forces (from its instantaneous orientation, rotation, relative direction of motion, and depth) remains stationary. With this relationship, we generated walking gaits for the robot to walk with minimal slip.

Does robot-assisted gait training ameliorate gait abnormalities in multiple sclerosis? A pilot randomized-control trial.

PubMed

Straudi, S; Benedetti, M G; Venturini, E; Manca, M; Foti, C; Basaglia, N

2013-01-01

Gait disorders are common in multiple sclerosis (MS) and lead to a progressive reduction of function and quality of life. Test the effects of robot-assisted gait rehabilitation in MS subjects through a pilot randomized-controlled study. We enrolled MS subjects with Expanded Disability Status Scale scores within 4.5-6.5. The experimental group received 12 robot-assisted gait training sessions over 6 weeks. The control group received the same amount of conventional physiotherapy. Outcomes measures were both biomechanical assessment of gait, including kinematics and spatio-temporal parameters, and clinical test of walking endurance (six-minute walk test) and mobility (Up and Go Test). 16 subjects (n = 8 experimental group, n = 8 control group) were included in the final analysis. At baseline the two groups were similar in all variables, except for step length. Data showed walking endurance, as well as spatio-temporal gait parameters improvements after robot-assisted gait training. Pelvic antiversion and reduced hip extension during terminal stance ameliorated after aforementioned intervention. Robot-assisted gait training seems to be effective in increasing walking competency in MS subjects. Moreover, it could be helpful in restoring the kinematic of the hip and pelvis.

Biomechanical effects of robot assisted walking on knee joint kinematics and muscle activation pattern.

PubMed

Thangavel, Pavithra; Vidhya, S; Li, Junhua; Chew, Effie; Bezerianos, Anastasios; Yu, Haoyong

2017-07-01

Since manual rehabilitation therapy can be taxing for both the patient and the physiotherapist, a gait rehabilitation robot has been built to reduce the physical strain and increase the efficacy of the rehabilitation therapy. The prototype of the gait rehabilitation robot is designed to provide assistance while walking for patients with abnormal gait pattern and it can also be used for rehabilitation therapy to restore an individual's normal gait pattern by aiding motor recovery. The Gait Rehabilitation Robot uses gait event based synchronization, which enables the exoskeleton to provide synchronous assistance during walking that aims to reduce the lower-limb muscle activation. This study emphasizes on the biomechanical effects of assisted walking on the lower limb by analyzing the EMG signal, knee joint kinematics data that was collected from the right leg during the various experimental conditions. The analysis of the measured data shows an improved knee joint trajectory and reduction in muscle activity with assistance. The result of this study does not only assess the functionality of the exoskeleton but also provides a profound understanding of the human-robot interaction by studying the effects of assistance on the lower limb.

Applicability of a new robotic walking aid in a patient with cerebral palsy. Case report.

PubMed

Smania, N; Gandolfi, M; Marconi, V; Calanca, A; Geroin, C; Piazza, S; Bonetti, P; Fiorini, P; Cosentino, A; Capelli, C; Conte, D; Bendinelli, M; Munari, D; Ianes, P; Fiaschi, A; Picelli, A

2012-03-01

Gait training with the help of assistive technological devices is an innovative field of research in neurological rehabilitation. Most of the available gait training devices do not allow free movement in the environment, which would be the most suitable natural and motivating condition for training children with neurological gait impairment. To evaluate the potential applicability of a new robotic walking aid as a tool for gait training in non-ambulatory children with Cerebral Palsy. Single case study Outpatient regimen A 11-years-old child unable to stand and walk independently as a result of spastic tetraplegic cerebral palsy (CP). The experimental device was a newly actuated version of a dynamic combined walking and standing aid (NF-Walker®) available in the market which was modified by means of two pneumatic artificial muscles driven by a foot-switch inserted in the shoes. The child was tested at baseline (while maintaining the standing position aided by the non-actuated NF-Walker®) and in the experimental condition (while using the actuated robotic aid). The outcome measures were: 2-minute walking test, 10-metre walking test, respiratory and heart parameters, energy cost of locomotion. At baseline, the child was unable to perform any autonomous form of locomotion. When assisted by the actuated aid (i.e. during the experimental condition), the child was successful in moving around in his environment. His performance was 19.63 m in the 2-minute walking test and 64 s in the 10-metre walking test. Respiratory and heart parameters were higher than healthy age-matched children both at baseline and in the experimental condition. The energy cost of gait, which was not valuable in the baseline condition, was significantly higher than normality during the experimental condition. The new robotic walking aid may help children suffering from CP with severe impairment of gait to move around in their environment. This new robotic walking device may have a potential impact in stimulating the development and in training of gait in children with neurological gait impairment. Future studies are warranted in order to test this hypothesis.

Conflicting results of robot-assisted versus usual gait training during postacute rehabilitation of stroke patients: a randomized clinical trial

PubMed Central

Taveggia, Giovanni; Borboni, Alberto; Mulé, Chiara; Negrini, Stefano

2016-01-01

Robot gait training has the potential to increase the effectiveness of walking therapy. Clinical outcomes after robotic training are often not superior to conventional therapy. We evaluated the effectiveness of a robot training compared with a usual gait training physiotherapy during a standardized rehabilitation protocol in inpatient participants with poststroke hemiparesis. This was a randomized double-blind clinical trial in a postacute physical and rehabilitation medicine hospital. Twenty-eight patients, 39.3% women (72±6 years), with hemiparesis (<6 months after stroke) receiving a conventional treatment according to the Bobath approach were assigned randomly to an experimental or a control intervention of robot gait training to improve walking (five sessions a week for 5 weeks). Outcome measures included the 6-min walk test, the 10 m walk test, Functional Independence Measure, SF-36 physical functioning and the Tinetti scale. Outcomes were collected at baseline, immediately following the intervention period and 3 months following the end of the intervention. The experimental group showed a significant increase in functional independence and gait speed (10 m walk test) at the end of the treatment and follow-up, higher than the minimal detectable change. The control group showed a significant increase in the gait endurance (6-min walk test) at the follow-up, higher than the minimal detectable change. Both treatments were effective in the improvement of gait performances, although the statistical analysis of functional independence showed a significant improvement in the experimental group, indicating possible advantages during generic activities of daily living compared with overground treatment. PMID:26512928

Robot-assisted gait training in patients with Parkinson disease: a randomized controlled trial.

PubMed

Picelli, Alessandro; Melotti, Camilla; Origano, Francesca; Waldner, Andreas; Fiaschi, Antonio; Santilli, Valter; Smania, Nicola

2012-05-01

. Gait impairment is a common cause of disability in Parkinson disease (PD). Electromechanical devices to assist stepping have been suggested as a potential intervention. . To evaluate whether a rehabilitation program of robot-assisted gait training (RAGT) is more effective than conventional physiotherapy to improve walking. . A total of 41 patients with PD were randomly assigned to 45-minute treatment sessions (12 in all), 3 days a week, for 4 consecutive weeks of either robotic stepper training (RST; n = 21) using the Gait Trainer or physiotherapy (PT; n = 20) with active joint mobilization and a modest amount of conventional gait training. Participants were evaluated before, immediately after, and 1 month after treatment. Primary outcomes were 10-m walking speed and distance walked in 6 minutes. . Baseline measures revealed no statistical differences between groups, but the PT group walked 0.12 m/s slower; 5 patients withdrew. A statistically significant improvement was found in favor of the RST group (walking speed 1.22 ± 0.19 m/s [P = .035]; distance 366.06 ± 78.54 m [P < .001]) compared with the PT group (0.98 ± 0.32 m/s; 280.11 ± 106.61 m). The RAGT mean speed increased by 0.13 m/s, which is probably not clinically important. Improvements were maintained 1 month later. . RAGT may improve aspects of walking ability in patients with PD. Future trials should compare robotic assistive training with treadmill or equal amounts of overground walking practice.

Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude

PubMed Central

2010-01-01

Background To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by ~35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H-) reflex responses during powered versus unpowered walking. Methods We tested soleus H-reflex responses in neurologically intact subjects (n=8) that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered), then with power (powered), and finally without power again (second unpowered). We also collected joint kinematics and electromyography. Results When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG) activation (27-48%) and had concomitant reductions in H-reflex amplitude (12-24%) compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. Conclusion These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance. Future studies should determine if the findings also apply to long-term adaption to the exoskeleton. PMID:20659331

Online Phase Detection Using Wearable Sensors for Walking with a Robotic Prosthesis

PubMed Central

Goršič, Maja; Kamnik, Roman; Ambrožič, Luka; Vitiello, Nicola; Lefeber, Dirk; Pasquini, Guido; Munih, Marko

2014-01-01

This paper presents a gait phase detection algorithm for providing feedback in walking with a robotic prosthesis. The algorithm utilizes the output signals of a wearable wireless sensory system incorporating sensorized shoe insoles and inertial measurement units attached to body segments. The principle of detecting transitions between gait phases is based on heuristic threshold rules, dividing a steady-state walking stride into four phases. For the evaluation of the algorithm, experiments with three amputees, walking with the robotic prosthesis and wearable sensors, were performed. Results show a high rate of successful detection for all four phases (the average success rate across all subjects >90%). A comparison of the proposed method to an off-line trained algorithm using hidden Markov models reveals a similar performance achieved without the need for learning dataset acquisition and previous model training. PMID:24521944

The 1991-1992 walking robot design

NASA Technical Reports Server (NTRS)

Azarm, Shapour; Dayawansa, Wijesurija; Tsai, Lung-Wen; Peritt, Jon

1992-01-01

The University of Maryland Walking Machine team designed and constructed a robot. This robot was completed in two phases with supervision and suggestions from three professors and one graduate teaching assistant. Bob was designed during the Fall Semester 1991, then machined, assembled, and debugged in the Spring Semester 1992. The project required a total of 4,300 student hours and cost under $8,000. Mechanically, Bob was an exercise in optimization. The robot was designed to test several diverse aspects of robotic potential, including speed, agility, and stability, with simplicity and reliability holding equal importance. For speed and smooth walking motion, the footpath contained a long horizontal component; a vertical aspect was included to allow clearance of obstacles. These challenges were met with a leg design that utilized a unique multi-link mechanism which traveled a modified tear-drop footpath. The electrical requirements included motor, encoder, and voice control circuitry selection, manual controller manufacture, and creation of sensors for guidance. Further, there was also a need for selection of the computer, completion of a preliminary program, and testing of the robot.

Concurrent planning and execution for a walking robot

NASA Astrophysics Data System (ADS)

Simmons, Reid

1990-07-01

The Planetary Rover project is developing the Ambler, a novel legged robot, and an autonomous software system for walking the Ambler over rough terrain. As part of the project, we have developed a system that integrates perception, planning, and real-time control to navigate a single leg of the robot through complex obstacle courses. The system is integrated using the Task Control Architecture (TCA), a general-purpose set of utilities for building and controlling distributed mobile robot systems. The walking system, as originally implemented, utilized a sequential sense-plan-act control cycle. This report describes efforts to improve the performance of the system by concurrently planning and executing steps. Concurrency was achieved by modifying the existing sequential system to utilize TCA features such as resource management, monitors, temporal constraints, and hierarchical task trees. Performance was increased in excess of 30 percent with only a relatively modest effort to convert and test the system. The results lend support to the utility of using TCA to develop complex mobile robot systems.

Comparison of Human and Humanoid Robot Control of Upright Stance

PubMed Central

Peterka, Robert J.

2009-01-01

There is considerable recent interest in developing humanoid robots. An important substrate for many motor actions in both humans and biped robots is the ability to maintain a statically or dynamically stable posture. Given the success of the human design, one would expect there are lessons to be learned in formulating a postural control mechanism for robots. In this study we limit ourselves to considering the problem of maintaining upright stance. Human stance control is compared to a suggested method for robot stance control called zero moment point (ZMP) compensation. Results from experimental and modeling studies suggest there are two important subsystems that account for the low- and mid-frequency (DC to ~1 Hz) dynamic characteristics of human stance control. These subsystems are 1) a “sensory integration” mechanism whereby orientation information from multiple sensory systems encoding body kinematics (i.e. position, velocity) is flexibly combined to provide an overall estimate of body orientation while allowing adjustments (sensory re-weighting) that compensate for changing environmental conditions, and 2) an “effort control” mechanism that uses kinetic-related (i.e., force-related) sensory information to reduce the mean deviation of body orientation from upright. Functionally, ZMP compensation is directly analogous to how humans appear to use kinetic feedback to modify the main sensory integration feedback loop controlling body orientation. However, a flexible sensory integration mechanism is missing from robot control leaving the robot vulnerable to instability in conditions were humans are able to maintain stance. We suggest the addition of a simple form of sensory integration to improve robot stance control. We also investigate how the biological constraint of feedback time delay influences the human stance control design. The human system may serve as a guide for improved robot control, but should not be directly copied because the constraints on robot and human control are different. PMID:19665564

Comparison of human and humanoid robot control of upright stance.

PubMed

Peterka, Robert J

2009-01-01

There is considerable recent interest in developing humanoid robots. An important substrate for many motor actions in both humans and biped robots is the ability to maintain a statically or dynamically stable posture. Given the success of the human design, one would expect there are lessons to be learned in formulating a postural control mechanism for robots. In this study we limit ourselves to considering the problem of maintaining upright stance. Human stance control is compared to a suggested method for robot stance control called zero moment point (ZMP) compensation. Results from experimental and modeling studies suggest there are two important subsystems that account for the low- and mid-frequency (DC to approximately 1Hz) dynamic characteristics of human stance control. These subsystems are (1) a "sensory integration" mechanism whereby orientation information from multiple sensory systems encoding body kinematics (i.e. position, velocity) is flexibly combined to provide an overall estimate of body orientation while allowing adjustments (sensory re-weighting) that compensate for changing environmental conditions and (2) an "effort control" mechanism that uses kinetic-related (i.e., force-related) sensory information to reduce the mean deviation of body orientation from upright. Functionally, ZMP compensation is directly analogous to how humans appear to use kinetic feedback to modify the main sensory integration feedback loop controlling body orientation. However, a flexible sensory integration mechanism is missing from robot control leaving the robot vulnerable to instability in conditions where humans are able to maintain stance. We suggest the addition of a simple form of sensory integration to improve robot stance control. We also investigate how the biological constraint of feedback time delay influences the human stance control design. The human system may serve as a guide for improved robot control, but should not be directly copied because the constraints on robot and human control are different.

Slow walking model for children with multiple disabilities via an application of humanoid robot

NASA Astrophysics Data System (ADS)

Wang, ZeFeng; Peyrodie, Laurent; Cao, Hua; Agnani, Olivier; Watelain, Eric; Wang, HaoPing

2016-02-01

Walk training research with children having multiple disabilities is presented. Orthosis aid in walking for children with multiple disabilities such as Cerebral Palsy continues to be a clinical and technological challenge. In order to reduce pain and improve treatment strategies, an intermediate structure - humanoid robot NAO - is proposed as an assay platform to study walking training models, to be transferred to future special exoskeletons for children. A suitable and stable walking model is proposed for walk training. It would be simulated and tested on NAO. This comparative study of zero moment point (ZMP) supports polygons and energy consumption validates the model as more stable than the conventional NAO. Accordingly direction variation of the center of mass and the slopes of linear regression knee/ankle angles, the Slow Walk model faithfully emulates the gait pattern of children.

Soft Robots: Manipulation, Mobility, and Fast Actuation

NASA Astrophysics Data System (ADS)

Shepherd, Robert; Ilievski, Filip; Choi, Wonjae; Stokes, Adam; Morin, Stephen; Mazzeo, Aaron; Kramer, Rebecca; Majidi, Carmel; Wood, Rob; Whitesides, George

2012-02-01

Material innovation will be a key feature in the next generation of robots. A simple, pneumatically powered actuator composed of only soft-elastomers can perform the function of a complex arrangement of mechanical components and electric motors. This talk will focus on soft-lithography as a simple method to fabricate robots--composed of exclusively soft materials (elastomeric polymers). These robots have sophisticated capabilities: a gripper (with no electrical sensors) can manipulate delicate and irregularly shaped objects and a quadrupedal robot can walk to an obstacle (a gap smaller than its walking height) then shrink its body and squeeze through the gap using an undulatory gait. This talk will also introduce a new method of rapidly actuating soft robots. Using this new method, a robot can be caused to jump more than 30 times its height in under 200 milliseconds.

Photonics walking up a human hair

NASA Astrophysics Data System (ADS)

Zeng, Hao; Parmeggiani, Camilla; Martella, Daniele; Wasylczyk, Piotr; Burresi, Matteo; Wiersma, Diederik S.

2016-03-01

While animals have access to sugars as energy source, this option is generally not available to artificial machines and robots. Energy delivery is thus the bottleneck for creating independent robots and machines, especially on micro- and nano- meter length scales. We have found a way to produce polymeric nano-structures with local control over the molecular alignment, which allowed us to solve the above issue. By using a combination of polymers, of which part is optically sensitive, we can create complex functional structures with nanometer accuracy, responsive to light. In particular, this allowed us to realize a structure that can move autonomously over surfaces (it can "walk") using the environmental light as its energy source. The robot is only 60 μm in total length, thereby smaller than any known terrestrial walking species, and it is capable of random, directional walking and rotating on different dry surfaces.

Simple robot suggests physical interlimb communication is essential for quadruped walking

PubMed Central

Owaki, Dai; Kano, Takeshi; Nagasawa, Ko; Tero, Atsushi; Ishiguro, Akio

2013-01-01

Quadrupeds have versatile gait patterns, depending on the locomotion speed, environmental conditions and animal species. These locomotor patterns are generated via the coordination between limbs and are partly controlled by an intraspinal neural network called the central pattern generator (CPG). Although this forms the basis for current control paradigms of interlimb coordination, the mechanism responsible for interlimb coordination remains elusive. By using a minimalistic approach, we have developed a simple-structured quadruped robot, with the help of which we propose an unconventional CPG model that consists of four decoupled oscillators with only local force feedback in each leg. Our robot exhibits good adaptability to changes in weight distribution and walking speed simply by responding to local feedback, and it can mimic the walking patterns of actual quadrupeds. Our proposed CPG-based control method suggests that physical interaction between legs during movements is essential for interlimb coordination in quadruped walking. PMID:23097501

Simple robot suggests physical interlimb communication is essential for quadruped walking.

PubMed

Owaki, Dai; Kano, Takeshi; Nagasawa, Ko; Tero, Atsushi; Ishiguro, Akio

2013-01-06

Quadrupeds have versatile gait patterns, depending on the locomotion speed, environmental conditions and animal species. These locomotor patterns are generated via the coordination between limbs and are partly controlled by an intraspinal neural network called the central pattern generator (CPG). Although this forms the basis for current control paradigms of interlimb coordination, the mechanism responsible for interlimb coordination remains elusive. By using a minimalistic approach, we have developed a simple-structured quadruped robot, with the help of which we propose an unconventional CPG model that consists of four decoupled oscillators with only local force feedback in each leg. Our robot exhibits good adaptability to changes in weight distribution and walking speed simply by responding to local feedback, and it can mimic the walking patterns of actual quadrupeds. Our proposed CPG-based control method suggests that physical interaction between legs during movements is essential for interlimb coordination in quadruped walking.

Robots in human biomechanics--a study on ankle push-off in walking.

PubMed

Renjewski, Daniel; Seyfarth, André

2012-09-01

In biomechanics, explanatory template models are used to identify the basic mechanisms of human locomotion. However, model predictions often lack verification in a realistic environment. We present a method that uses template model mechanics as a blueprint for a bipedal robot and a corresponding computer simulation. The hypotheses derived from template model studies concerning the function of heel-off in walking are analysed and discrepancies between the template model and its real-world anchor are pointed out. Neither extending the ground clearance of the swinging leg nor an impact reduction at touch-down as an effect of heel lifting was supported by the experiments. To confirm the relevance of the experimental findings, a comparison of robot data to human walking data is discussed and we speculate on an alternative explanation of heel-off in human walking, i.e. that the push-off powers the following leg swing.

Trajectory Correction and Locomotion Analysis of a Hexapod Walking Robot with Semi-Round Rigid Feet

PubMed Central

Zhu, Yaguang; Jin, Bo; Wu, Yongsheng; Guo, Tong; Zhao, Xiangmo

2016-01-01

Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM) is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM. Compared with the previous approximation method, this correction methodology has better accuracy and faster calculation speed with regards to inverse kinematics solutions. Experiments on a leg platform and a hexapod walking robot are conducted with multi-sensors for the analysis of foot tip trajectory, base joint vibration, contact force impact, direction deviation, and power consumption, respectively. The comparative analysis shows that the trajectory correction methodology can effectively correct the joint trajectory, thus eliminating the contact force influence of semi-round rigid feet, significantly improving the locomotion of the walking robot and reducing the total power consumption of the system. PMID:27589766

A study on a robot chasing a human using Kinect while identifying walking parameters using the back view

NASA Astrophysics Data System (ADS)

Konno, S.; Mita, A.

2014-03-01

Recently, the demand of the building spaces to respond to increase of single aged households and the diversification of life style is increasing. Smart house is one of them, but it is difficult for them to be changed and renovated. Therefore, we suggest Biofied builing. In biofied building, we use a mobile robot to get concious and unconcious information about residents and try to make it more secure and comfort builing spaces by realizing the intraction between residents and builing spaces. Walking parameters are one of the most important unconscious information about residents. They are an indicator of autonomy of elderly, and changes of stride length and walking speed may be pridictive of a future fall and a cognitive impairment. By observing their walking and informing residents their walking state, they can forestall such dangers and it helps them to live more securely and autonomously. Many methods to estimate walking parameters have been studied. The famous ones are to use accelerometers and a motion capture camera. Walking parameters estimated by them are high precise but the sensors are attached to a human body in these method and it can make human's walk different from the original walk. Furthermore, some elderly feel it to invade them. In this work, Kinect which can get information about human untouchably was used on the mobile robot. A stride time, stride length, and walking speed were estimated from the back view of human by following him or her. Evaluation was done for 10m, 5m, 4m, and 3m in whole walking. As a result, the proposal system can estimate walking parameters of the walk more than 3m.

Randomized controlled trial of robot-assisted gait training with dorsiflexion assistance on chronic stroke patients wearing ankle-foot-orthosis.

PubMed

Yeung, Ling-Fung; Ockenfeld, Corinna; Pang, Man-Kit; Wai, Hon-Wah; Soo, Oi-Yan; Li, Sheung-Wai; Tong, Kai-Yu

2018-06-19

Robot-assisted ankle-foot-orthosis (AFO) can provide immediate powered ankle assistance in post-stroke gait training. Our research team has developed a novel lightweight portable robot-assisted AFO which is capable of detecting walking intentions using sensor feedback of wearer's gait pattern. This study aims to investigate the therapeutic effects of robot-assisted gait training with ankle dorsiflexion assistance. This was a double-blinded randomized controlled trial. Nineteen chronic stroke patients with motor impairment at ankle participated in 20-session robot-assisted gait training for about five weeks, with 30-min over-ground walking and stair ambulation practices. Robot-assisted AFO either provided active powered ankle assistance during swing phase in Robotic Group (n = 9), or torque impedance at ankle joint as passive AFO in Sham Group (n = 10). Functional assessments were performed before and after the 20-session gait training with 3-month Follow-up. Primary outcome measure was gait independency assessed by Functional Ambulatory Category (FAC). Secondary outcome measures were clinical scores including Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS), Berg Balance Scale (BBS), Timed 10-Meter Walk Test (10MWT), Six-minute Walk Test (SMWT), supplemented by gait analysis. All outcome measures were performed in unassisted gait after patients had taken off the robot-assisted AFO. Repeated-measures analysis of covariance was conducted to test the group differences referenced to clinical scores before training. After 20-session robot-assisted gait training with ankle dorsiflexion assistance, the active ankle assistance in Robotic Group induced changes in gait pattern with improved gait independency (all patients FAC ≥ 5 post-training and 3-month follow-up), motor recovery, walking speed, and greater confidence in affected side loading response (vertical ground reaction force + 1.49 N/kg, peak braking force + 0.24 N/kg) with heel strike instead of flat foot touch-down at initial contact (foot tilting + 1.91°). Sham Group reported reduction in affected leg range of motion (ankle dorsiflexion - 2.36° and knee flexion - 8.48°) during swing. Robot-assisted gait training with ankle dorsiflexion assistance could improve gait independency and help stroke patients developing confidence in weight acceptance, but future development of robot-assisted AFO should consider more lightweight and custom-fit design. ClinicalTrials.gov NCT02471248 . Registered 15 June 2015 retrospectively registered.

Bioinspired locomotion and grasping in water: the soft eight-arm OCTOPUS robot.

PubMed

Cianchetti, M; Calisti, M; Margheri, L; Kuba, M; Laschi, C

2015-05-13

The octopus is an interesting model for the development of soft robotics, due to its high deformability, dexterity and rich behavioural repertoire. To investigate the principles of octopus dexterity, we designed an eight-arm soft robot and evaluated its performance with focused experiments. The OCTOPUS robot presented here is a completely soft robot, which integrates eight arms extending in radial direction and a central body which contains the main processing units. The front arms are mainly used for elongation and grasping, while the others are mainly used for locomotion. The robotic octopus works in water and its buoyancy is close to neutral. The experimental results show that the octopus-inspired robot can walk in water using the same strategy as the animal model, with good performance over different surfaces, including walking through physical constraints. It can grasp objects of different sizes and shapes, thanks to its soft arm materials and conical shape.

Adaptive Gait Control for a Quadruped Robot on 3D Path Planning

NASA Astrophysics Data System (ADS)

Igarashi, Hiroshi; Kakikura, Masayoshi

A legged walking robot is able to not only move on irregular terrain but also change its posture. For example, the robot can pass under overhead obstacles by crouching. The purpose of our research is to realize efficient path planning with a quadruped robot. Therefore, the path planning is expected to extended in three dimensions because of the mobility. However, some issues of the quadruped robot, which are instability, workspace limitation, deadlock and slippage, complicate realizing such application. In order to improve these issues and reinforce the mobility, a new static gait pattern for a quadruped robot, called TFG: Trajectory Following Gait, is proposed. The TFG intends to obtain high controllability like a wheel robot. Additionally, the TFG allows to change it posture during the walk. In this paper, some experimental results show that the TFG improves the issues and it is available for efficient locomotion in three dimensional environment.

Symmetry in locomotor central pattern generators and animal gaits

NASA Astrophysics Data System (ADS)

Golubitsky, Martin; Stewart, Ian; Buono, Pietro-Luciano; Collins, J. J.

1999-10-01

Animal locomotion is controlled, in part, by a central pattern generator (CPG), which is an intraspinal network of neurons capable of generating a rhythmic output. The spatio-temporal symmetries of the quadrupedal gaits walk, trot and pace lead to plausible assumptions about the symmetries of locomotor CPGs. These assumptions imply that the CPG of a quadruped should consist of eight nominally identical subcircuits, arranged in an essentially unique matter. Here we apply analogous arguments to myriapod CPGs. Analyses based on symmetry applied to these networks lead to testable predictions, including a distinction between primary and secondary gaits, the existence of a new primary gait called `jump', and the occurrence of half-integer wave numbers in myriapod gaits. For bipeds, our analysis also predicts two gaits with the out-of-phase symmetry of the walk and two gaits with the in-phase symmetry of the hop. We present data that support each of these predictions. This work suggests that symmetry can be used to infer a plausible class of CPG network architectures from observed patterns of animal gaits.

Insect-computer hybrid legged robot with user-adjustable speed, step length and walking gait.

PubMed

Cao, Feng; Zhang, Chao; Choo, Hao Yu; Sato, Hirotaka

2016-03-01

We have constructed an insect-computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g., gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e., applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. © 2016 The Author(s).

Insect–computer hybrid legged robot with user-adjustable speed, step length and walking gait

PubMed Central

Cao, Feng; Zhang, Chao; Choo, Hao Yu

2016-01-01

We have constructed an insect–computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g. gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e. applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. PMID:27030043

A functional electrical stimulation system for human walking inspired by reflexive control principles.

PubMed

Meng, Lin; Porr, Bernd; Macleod, Catherine A; Gollee, Henrik

2017-04-01

This study presents an innovative multichannel functional electrical stimulation gait-assist system which employs a well-established purely reflexive control algorithm, previously tested in a series of bipedal walking robots. In these robots, ground contact information was used to activate motors in the legs, generating a gait cycle similar to that of humans. Rather than developing a sophisticated closed-loop functional electrical stimulation control strategy for stepping, we have instead utilised our simple reflexive model where muscle activation is induced through transfer functions which translate sensory signals, predominantly ground contact information, into motor actions. The functionality of the functional electrical stimulation system was tested by analysis of the gait function of seven healthy volunteers during functional electrical stimulation-assisted treadmill walking compared to unassisted walking. The results demonstrated that the system was successful in synchronising muscle activation throughout the gait cycle and was able to promote functional hip and ankle movements. Overall, the study demonstrates the potential of human-inspired robotic systems in the design of assistive devices for bipedal walking.

Computer coordination of limb motion for a three-legged walking robot

NASA Technical Reports Server (NTRS)

Klein, C. A.; Patterson, M. R.

1980-01-01

Coordination of the limb motion of a vehicle which could perform assembly and maintenance operations on large structures in space is described. Manipulator kinematics and walking robots are described. The basic control scheme of the robot is described. The control of the individual arms are described. Arm velocities are generally described in Cartesian coordinates. Cartesian velocities are converted to joint velocities using the Jacobian matrix. The calculation of a trajectory for an arm given a sequence of points through which it is to pass is described. The free gait algorithm which controls the lifting and placing of legs for the robot is described. The generation of commanded velocities for the robot, and the implementation of those velocities by the algorithm are discussed. Suggestions for further work in the area of robot legged locomotion are presented.

Maneuvers during legged locomotion

NASA Astrophysics Data System (ADS)

Jindrich, Devin L.; Qiao, Mu

2009-06-01

Maneuverability is essential for locomotion. For animals in the environment, maneuverability is directly related to survival. For humans, maneuvers such as turning are associated with increased risk for injury, either directly through tissue loading or indirectly through destabilization. Consequently, understanding the mechanics and motor control of maneuverability is a critical part of locomotion research. We briefly review the literature on maneuvering during locomotion with a focus on turning in bipeds. Walking turns can use one of several different strategies. Anticipation can be important to adjust kinematics and dynamics for smooth and stable maneuvers. During running, turns may be substantially constrained by the requirement for body orientation to match movement direction at the end of a turn. A simple mathematical model based on the requirement for rotation to match direction can describe leg forces used by bipeds (humans and ostriches). During running turns, both humans and ostriches control body rotation by generating fore-aft forces. However, whereas humans must generate large braking forces to prevent body over-rotation, ostriches do not. For ostriches, generating the lateral forces necessary to change movement direction results in appropriate body rotation. Although ostriches required smaller braking forces due in part to increased rotational inertia relative to body mass, other movement parameters also played a role. Turning performance resulted from the coordinated behavior of an integrated biomechanical system. Results from preliminary experiments on horizontal-plane stabilization support the hypothesis that controlling body rotation is an important aspect of stable maneuvers. In humans, body orientation relative to movement direction is rapidly stabilized during running turns within the minimum of two steps theoretically required to complete analogous maneuvers. During straight running and cutting turns, humans exhibit spring-mass behavior in the horizontal plane. Changes in the horizontal projection of leg length were linearly related to changes in horizontal-plane leg forces. Consequently, the passive dynamic stabilization associated with spring-mass behavior may contribute to stability during maneuvers in bipeds. Understanding the mechanics of maneuverability will be important for understanding the motor control of maneuvers and also potentially be useful for understanding stability.

Task-specific ankle robotics gait training after stroke: a randomized pilot study.

PubMed

Forrester, Larry W; Roy, Anindo; Hafer-Macko, Charlene; Krebs, Hermano I; Macko, Richard F

2016-06-02

An unsettled question in the use of robotics for post-stroke gait rehabilitation is whether task-specific locomotor training is more effective than targeting individual joint impairments to improve walking function. The paretic ankle is implicated in gait instability and fall risk, but is difficult to therapeutically isolate and refractory to recovery. We hypothesize that in chronic stroke, treadmill-integrated ankle robotics training is more effective to improve gait function than robotics focused on paretic ankle impairments. Participants with chronic hemiparetic gait were randomized to either six weeks of treadmill-integrated ankle robotics (n = 14) or dose-matched seated ankle robotics (n = 12) videogame training. Selected gait measures were collected at baseline, post-training, and six-week retention. Friedman, and Wilcoxon Sign Rank and Fisher's exact tests evaluated within and between group differences across time, respectively. Six weeks post-training, treadmill robotics proved more effective than seated robotics to increase walking velocity, paretic single support, paretic push-off impulse, and active dorsiflexion range of motion. Treadmill robotics durably improved gait dorsiflexion swing angle leading 6/7 initially requiring ankle braces to self-discarded them, while their unassisted paretic heel-first contacts increased from 44 % to 99.6 %, versus no change in assistive device usage (0/9) following seated robotics. Treadmill-integrated, but not seated ankle robotics training, durably improves gait biomechanics, reversing foot drop, restoring walking propulsion, and establishing safer foot landing in chronic stroke that may reduce reliance on assistive devices. These findings support a task-specific approach integrating adaptive ankle robotics with locomotor training to optimize mobility recovery. NCT01337960. https://clinicaltrials.gov/ct2/show/NCT01337960?term=NCT01337960&rank=1.

Toward humanoid robots for operations in complex urban environments

NASA Astrophysics Data System (ADS)

Pratt, Jerry E.; Neuhaus, Peter; Johnson, Matthew; Carff, John; Krupp, Ben

2010-04-01

Many infantry operations in urban environments, such as building clearing, are extremely dangerous and difficult and often result in high casualty rates. Despite the fast pace of technological progress in many other areas, the tactics and technology deployed for many of these dangerous urban operation have not changed much in the last 50 years. While robots have been extremely useful for improvised explosive device (IED) detonation, under-vehicle inspection, surveillance, and cave exploration, there is still no fieldable robot that can operate effectively in cluttered streets and inside buildings. Developing a fieldable robot that can maneuver in complex urban environments is challenging due to narrow corridors, stairs, rubble, doors and cluttered doorways, and other obstacles. Typical wheeled and tracked robots have trouble getting through most of these obstacles. A bipedal humanoid is ideally shaped for many of these obstacles because its legs are long and skinny. Therefore it has the potential to step over large barriers, gaps, rocks, and steps, yet squeeze through narrow passageways, and through narrow doorways. By being able to walk with one foot directly in front of the other, humanoids also have the potential to walk over narrow "balance beam" style objects and can cross a narrow row of stepping stones. We describe some recent advances in humanoid robots, particularly recovery from disturbances, such as pushes and walking over rough terrain. Our disturbance recovery algorithms are based on the concept of Capture Points. An N-Step Capture Point is a point on the ground in which a legged robot can step to in order to stop in N steps. The N-Step Capture Region is the set of all N-Step Capture Points. In order to walk without falling, a legged robot must step somewhere in the intersection between an N-Step Capture Region and the available footholds on the ground. We present results of push recovery using Capture Points on our humanoid robot M2V2.

Human-robot cooperative movement training: learning a novel sensory motor transformation during walking with robotic assistance-as-needed.

PubMed

Emken, Jeremy L; Benitez, Raul; Reinkensmeyer, David J

2007-03-28

A prevailing paradigm of physical rehabilitation following neurologic injury is to "assist-as-needed" in completing desired movements. Several research groups are attempting to automate this principle with robotic movement training devices and patient cooperative algorithms that encourage voluntary participation. These attempts are currently not based on computational models of motor learning. Here we assume that motor recovery from a neurologic injury can be modelled as a process of learning a novel sensory motor transformation, which allows us to study a simplified experimental protocol amenable to mathematical description. Specifically, we use a robotic force field paradigm to impose a virtual impairment on the left leg of unimpaired subjects walking on a treadmill. We then derive an "assist-as-needed" robotic training algorithm to help subjects overcome the virtual impairment and walk normally. The problem is posed as an optimization of performance error and robotic assistance. The optimal robotic movement trainer becomes an error-based controller with a forgetting factor that bounds kinematic errors while systematically reducing its assistance when those errors are small. As humans have a natural range of movement variability, we introduce an error weighting function that causes the robotic trainer to disregard this variability. We experimentally validated the controller with ten unimpaired subjects by demonstrating how it helped the subjects learn the novel sensory motor transformation necessary to counteract the virtual impairment, while also preventing them from experiencing large kinematic errors. The addition of the error weighting function allowed the robot assistance to fade to zero even though the subjects' movements were variable. We also show that in order to assist-as-needed, the robot must relax its assistance at a rate faster than that of the learning human. The assist-as-needed algorithm proposed here can limit error during the learning of a dynamic motor task. The algorithm encourages learning by decreasing its assistance as a function of the ongoing progression of movement error. This type of algorithm is well suited for helping people learn dynamic tasks for which large kinematic errors are dangerous or discouraging, and thus may prove useful for robot-assisted movement training of walking or reaching following neurologic injury.

Development of a Guide-Dog Robot: Leading and Recognizing a Visually-Handicapped Person using a LRF

NASA Astrophysics Data System (ADS)

Saegusa, Shozo; Yasuda, Yuya; Uratani, Yoshitaka; Tanaka, Eiichirou; Makino, Toshiaki; Chang, Jen-Yuan (James

A conceptual Guide-Dog Robot prototype to lead and to recognize a visually-handicapped person is developed and discussed in this paper. Key design features of the robot include a movable platform, human-machine interface, and capability of avoiding obstacles. A novel algorithm enabling the robot to recognize its follower's locomotion as well to detect the center of corridor is proposed and implemented in the robot's human-machine interface. It is demonstrated that using the proposed novel leading and detecting algorithm along with a rapid scanning laser range finder (LRF) sensor, the robot is able to successfully and effectively lead a human walking in corridor without running into obstacles such as trash boxes or adjacent walking persons. Position and trajectory of the robot leading a human maneuvering in common corridor environment are measured by an independent LRF observer. The measured data suggest that the proposed algorithms are effective to enable the robot to detect center of the corridor and position of its follower correctly.

Body weight support during robot-assisted walking: influence on the trunk and pelvis kinematics.

PubMed

Swinnen, Eva; Baeyens, Jean-Pierre; Hens, Gerrit; Knaepen, Kristel; Beckwée, David; Michielsen, Marc; Clijsen, Ron; Kerckhofs, Eric

2015-01-01

Efficacy studies concerning robot assisted gait rehabilitation showed limited clinical benefits. A changed kinematic pattern might be responsible for this. Little is known about the kinematics of the trunk and pelvis during robot assisted treadmill walking (RATW). The aim of this study was to assess the trunk and pelvis kinematics of healthy subjects during RATW, with different amounts of body weight support (BWS) compared to regular treadmill walking (TW). Eighteen healthy participants walked on a treadmill, while kinematics were registered by an electromagnetic tracking device. Hereafter, the kinematics of pelvis and trunk were registered during RATW (guidance force 30%) with 0%, 30% and 50% BWS. Compared to TW, RATW showed a decrease in the following trunk movements: axial rotation, anteroposterior flexion, lateral and anteroposterior translation. Besides, a decrease in lateral tilting and all translation of the pelvis was found when comparing RATW with TW. Furthermore, the anteroposterior tilting of the pelvis increased during RATW. In general, there was a decrease in trunk and pelvis movement amplitude during RATW compared with regular TW. Though, it is not known if these changes are responsible for the limited efficacy of robot assisted gait rehabilitation. Further research is indicated.

Regularity in an environment produces an internal torque pattern for biped balance control.

PubMed

Ito, Satoshi; Kawasaki, Haruhisa

2005-04-01

In this paper, we present a control method for achieving biped static balance under unknown periodic external forces whose periods are only known. In order to maintain static balance adaptively in an uncertain environment, it is essential to have information on the ground reaction forces. However, when the biped is exposed to a steady environment that provides an external force periodically, uncertain factors on the regularity with respect to a steady environment are gradually clarified using learning process, and finally a torque pattern for balancing motion is acquired. Consequently, static balance is maintained without feedback from ground reaction forces and achieved in a feedforward manner.

The Ear and Hearing in Bipes biporus

PubMed Central

Wever, Ernest Glen; Gans, Carl

1972-01-01

The sound conduction system of Bipes biporus is unusual among amphisbaenians, in that the columella does not have a catilaginous or bony extra-columella passing laterally to the labial skin. Instead, the terminal disk of the columella ends in fibrous tissue beneath a deep fold of skin forming the nuchal constriction. The occurrence of an epihyal supports earlier suggestions that the amphisbaenian extracolumella may be homologous to the epihyal. Measurements of cochlear potentials, made by direction of the sound stimuli to the region of the head posteroventral to the quadrate bone, show that Bipes biporus ranks high among amphisbaenians in auditory sensitivity. Images PMID:4506791

Robot Rocket Rally

NASA Image and Video Library

2014-03-14

CAPE CANAVERAL, Fla. – A child gets an up-close look at Charli, an autonomous walking robot developed by Virginia Tech Robotics, during the Robot Rocket Rally. The three-day event at Florida's Kennedy Space Center Visitor Complex is highlighted by exhibits, games and demonstrations of a variety of robots, with exhibitors ranging from school robotics clubs to veteran NASA scientists and engineers. Photo credit: NASA/Kim Shiflett

Maximum walking speeds obtained using treadmill and overground robot system in persons with post-stroke hemiplegia

PubMed Central

2012-01-01

Background Previous studies demonstrated that stroke survivors have a limited capacity to increase their walking speeds beyond their self-selected maximum walking speed (SMWS). The purpose of this study was to determine the capacity of stroke survivors to reach faster speeds than their SMWS while walking on a treadmill belt or while being pushed by a robotic system (i.e. “push mode”). Methods Eighteen chronic stroke survivors with hemiplegia were involved in the study. We calculated their self-selected comfortable walking speed (SCWS) and SMWS overground using a 5-meter walk test (5-MWT). Then, they were exposed to walking at increased speeds, on a treadmill and while in “push mode” in an overground robotic device, the KineAssist, until they were tested at a speed that they could not sustain without losing balance. We recorded the time and number of steps during each trial and calculated gait speed, average cadence and average step length. Results Maximum walking speed in the “push mode” was 13% higher than the maximum walking speed on the treadmill and both were higher (“push mode”: 61%; treadmill: 40%) than the maximum walking speed overground. Subjects achieved these faster speeds by initially increasing both step length and cadence and, once individuals stopped increasing their step length, by only increasing cadence. Conclusions With post-stroke hemiplegia, individuals are able to walk at faster speeds than their SMWS overground, when provided with a safe environment that provides external forces that requires them to attempt dynamic stability maintenance at higher gait speeds. Therefore, this study suggests the possibility that, given the appropriate conditions, people post-stroke can be trained at higher speeds than previously attempted. PMID:23057500

Metabolic cost of level-ground walking with a robotic transtibial prosthesis combining push-off power and nonlinear damping behaviors: preliminary results.

PubMed

Yanggang Feng; Jinying Zhu; Qining Wang

2016-08-01

Recent advances in robotic technology are facilitating the development of robotic prostheses. Our previous studies proposed a lightweight robotic transtibial prosthesis with a damping control strategy. To improve the performance of power assistance, in this paper, we redesign the prosthesis and improve the control strategy by supplying extra push-off power. A male transtibial amputee subject volunteered to participate in the study. Preliminary experimental results show that the proposed prosthesis with push-off control improves energy expenditure by a percentage ranged from 9.72 % to 14.99 % for level-ground walking compared with the one using non-push-off control.

A physical model of sensorimotor interactions during locomotion

NASA Astrophysics Data System (ADS)

Klein, Theresa J.; Lewis, M. Anthony

2012-08-01

In this paper, we describe the development of a bipedal robot that models the neuromuscular architecture of human walking. The body is based on principles derived from human muscular architecture, using muscles on straps to mimic agonist/antagonist muscle action as well as bifunctional muscles. Load sensors in the straps model Golgi tendon organs. The neural architecture is a central pattern generator (CPG) composed of a half-center oscillator combined with phase-modulated reflexes that is simulated using a spiking neural network. We show that the interaction between the reflex system, body dynamics and CPG results in a walking cycle that is entrained to the dynamics of the system. We also show that the CPG helped stabilize the gait against perturbations relative to a purely reflexive system, and compared the joint trajectories to human walking data. This robot represents a complete physical, or ‘neurorobotic’, model of the system, demonstrating the usefulness of this type of robotics research for investigating the neurophysiological processes underlying walking in humans and animals.

A wearable robotic orthosis with a spring-assist actuator.

PubMed

Seungmin Jung; Chankyu Kim; Jisu Park; Dongyoub Yu; Jaehwan Park; Junho Choi

2016-08-01

This paper introduces a wearable robotic orthosis with spring-assist actuators, which is designed to assist people who have difficulty in walking. The spring-assist actuator consists of an electrical motor and a spring, which are attached to a rotational axis in parallel to each other. The spring-assist actuator is developed based on the analysis on the stiffness of the knee and hip joints during walking. "COWALK-Mobile," which is a wearable robotic orthosis, is developed using the spring-assist actuators to reduce the required motor torque during walking. The COWALK-Mobile has active hip and knee joints and passive ankle joints to provide assistive torque to the wearer. The required joint torque is generated by the spring as well as the electrical motor, which results in a decrease of maximum required torque for the motor. In order to evaluate the performance of the spring-assist actuator, experiments are carried out. The experiments show that the spring-assist actuators reduced the required motor torque during walking.

The comparison of stepping responses following perturbations applied to pelvis during overground and treadmill walking.

PubMed

Zadravec, Matjaž; Olenšek, Andrej; Matjačić, Zlatko

2017-08-09

Treadmills are used frequently in rehabilitation enabling neurologically impaired subjects to train walking while being assisted by therapists. Numerous studies compared walking on treadmill and overground for unperturbed but not also perturbed conditions. The objective of this study was to compare stepping responses (step length, step width and step time) during overground and treadmill walking in a group of healthy subjects where balance assessment robots applied perturbing pushes to the subject's pelvis in sagittal and frontal planes. During walking in both balance assessment robots (overground and treadmill-based) with applied perturbations the stepping responses of a group of seven healthy subjects were assessed with a motion tracking camera. The results show high degree of similarity of stepping responses between overground and treadmill walking for all perturbation directions. Both devices reproduced similar experimental conditions with relatively small standard deviations in the unperturbed walking as well as in perturbed walking. Based on these results we may conclude that stepping responses following perturbations can be studied on an instrumented treadmill where ground reaction forces can be readily assessed which is not the case during perturbed overground walking.

Use of the robot assisted gait therapy in rehabilitation of patients with stroke and spinal cord injury.

PubMed

Sale, P; Franceschini, M; Waldner, A; Hesse, S

2012-03-01

Difficulty in walking is a major feature of neurological disease, and loss of mobility is the activity of daily living on which patients place the greatest value. The impact on patients is enormous, with negative ramifications on their participation in social, vocational, and recreational activities. In current clinical practice the gait restoration with robotic device is an integral part of rehabilitation program. Robot therapy involves the use of a robot exoskeleton device or end-effector device to help the patient retrain motor coordination by performing well-focused and carefully directed repetitive practice. The exoskeleton, as an assistive device, is also an external structural mechanism with joints and links corresponding to those of the human body. These robots use joint trajectories of the entire gait cycle and offer a uniform (more or less) stiff control along this trajectory. In this field the new powered exoskeleton ReWalk (Argo Medical Technologies Ltd) was developed to have an alternative mobility solution to the wheelchair and rehabilitation treatment for individuals with severe walking impairments, enabling them to stand, walk, ascend/descent stairs and more. The end-effector-based robot is a device with footplates placed on a double crank and rocker gear system. Alternatives to powered exoskeletons are devices that use movable footplates to which the patient's feet are attached. All devices include some form of body weight support. Prominent goals in the field include: developing implementable technologies that can be easily used by patients, therapists, and clinicians; enhancing the efficacy of clinician's therapies and increasing the ease of activities in the daily lives of patients.

Influence of psychologic features on rehabilitation outcomes in patients with subacute stroke trained with robotic-aided walking therapy.

PubMed

Bragoni, Maura; Broccoli, Marco; Iosa, Marco; Morone, Giovanni; De Angelis, Domenico; Venturiero, Vincenzo; Coiro, Paola; Pratesi, Luca; Mezzetti, Giulia; Fusco, Augusto; Paolucci, Stefano

2013-10-01

The aim of this study was to investigate whether the rehabilitation outcomes with robotic-aided gait therapy may be affected by patients' and caregivers' psychologic features after subacute stroke. This is a controlled, longitudinal, observational pilot study conducted on 42 patients divided in robotic-assisted gait training plus conventional physical therapy group, robotic-assisted gait training dropout group, and conventional physical therapy group. The outcome measures were walking ability (Functional Ambulation Category) and independency in activities of daily living (Barthel Index) measured before and after intervention. Psychologic features were measured before intervention using the Hospital Anxiety and Depression Scale, the Eysenck Personality Questionnaire, and recovery locus of control in the patients and the State-Trait Anxiety Inventory and the Beck Depression Inventory in the caregivers. Patient anxiety was significantly higher in those who refused/abandoned robotic therapy (P = 0.002). In the subjects allocated to the robotic group, the recovery of walking ability was significantly affected by the perceived recovery locus of control (P = 0.039, odds ratio = 14); and the recovery of independency in activities of daily living, by anxiety (P = 0.018, odds ratio = 0.042). Conversely, psychologic factors did not significantly affect the outcomes of conventional rehabilitation. Psychologic features, particularly recovery locus of control and anxiety, affected the rehabilitative outcomes of the patients involved in robotic treatment more than those in conventional rehabilitation.

EMG patterns during assisted walking in the exoskeleton

PubMed Central

Sylos-Labini, Francesca; La Scaleia, Valentina; d'Avella, Andrea; Pisotta, Iolanda; Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco; Wang, Shiqian; Wang, Letian; van Asseldonk, Edwin; van der Kooij, Herman; Hoellinger, Thomas; Cheron, Guy; Thorsteinsson, Freygardur; Ilzkovitz, Michel; Gancet, Jeremi; Hauffe, Ralf; Zanov, Frank; Lacquaniti, Francesco; Ivanenko, Yuri P.

2014-01-01

Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts, and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns. PMID:24982628

EMG patterns during assisted walking in the exoskeleton.

PubMed

Sylos-Labini, Francesca; La Scaleia, Valentina; d'Avella, Andrea; Pisotta, Iolanda; Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco; Wang, Shiqian; Wang, Letian; van Asseldonk, Edwin; van der Kooij, Herman; Hoellinger, Thomas; Cheron, Guy; Thorsteinsson, Freygardur; Ilzkovitz, Michel; Gancet, Jeremi; Hauffe, Ralf; Zanov, Frank; Lacquaniti, Francesco; Ivanenko, Yuri P

2014-01-01

Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts, and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns.

Overground walking training with the i-Walker, a robotic servo-assistive device, enhances balance in patients with subacute stroke: a randomized controlled trial.

PubMed

Morone, Giovanni; Annicchiarico, Roberta; Iosa, Marco; Federici, Alessia; Paolucci, Stefano; Cortés, Ulises; Caltagirone, Carlo

2016-05-26

Patients affected by mild stroke benefit more from physiological overground walking training than walking-like training performed in place using specific devices. The aim of the study was to evaluate the effects of overground robotic walking training performed with the servo-assistive robotic rollator (i-Walker) on walking, balance, gait stability and falls in a community setting in patients with mild subacute stroke. Forty-four patients were randomly assigned to two different groups that received the same therapy in two daily 40-min sessions 5 days a week for 4 weeks. Twenty sessions of standard therapy were performed by both groups. In the other 20 sessions the subjects enrolled in the i-Walker-Group (iWG) performed with the i-Walker and the Control-Group patients (CG) performed the same amount of conventional walking oriented therapy. Clinical and instrumented gait assessments were made pre- and post-treatment. The follow-up observation consisted of recording the number of fallers in the community setting after 6 months. Treatment effectiveness was higher in the iWG group in terms of balance improvement (Tinetti: 68.4 ± 27.6 % vs. 48.1 ± 33.9 %, p = 0.033) and 10-m and 6-min timed walking tests (significant interaction between group and time: F(1,40) = 14.252, p = 0.001; and F(1,40) = 7.883, p = 0.008, respectively). When measured, latero-lateral upper body accelerations were reduced in iWG (F = 4.727, p = 0.036), suggesting increased gait stability, which was supported by a reduced number of falls at home. A robotic servo-assisted i-Walker improved walking performance and balance in patients affected by mild/moderate stroke, leading to increased gait stability and reduced falls in the community. This study was registered on anzctr.org.au (July 1, 2015; ACTRN12615000681550 ).

Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy

NASA Astrophysics Data System (ADS)

Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander; Wörgötter, Florentin; Gorb, Stanislav N.; Spinner, Marlene; Heepe, Lars

2016-12-01

Based on the principles of morphological computation, we propose a novel approach that exploits the interaction between a passive anisotropic scale-like material (e.g., shark skin) and a non-smooth substrate to enhance locomotion efficiency of a robot walking on inclines. Real robot experiments show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical stability. It shows high frictional anisotropy due to an array of sloped denticles. The orientation of the denticles to the underlying collagenous material also strongly influences their mechanical interlocking with the substrate. This study not only opens up a new way of achieving energy-efficient legged robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other real-world applications.

Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy

PubMed Central

Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander; Wörgötter, Florentin; Gorb, Stanislav N.; Spinner, Marlene; Heepe, Lars

2016-01-01

Based on the principles of morphological computation, we propose a novel approach that exploits the interaction between a passive anisotropic scale-like material (e.g., shark skin) and a non-smooth substrate to enhance locomotion efficiency of a robot walking on inclines. Real robot experiments show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical stability. It shows high frictional anisotropy due to an array of sloped denticles. The orientation of the denticles to the underlying collagenous material also strongly influences their mechanical interlocking with the substrate. This study not only opens up a new way of achieving energy-efficient legged robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other real-world applications. PMID:28008936

Autonomous planetary rover at Carnegie Mellon

NASA Technical Reports Server (NTRS)

Whittaker, William; Kanade, Takeo; Mitchell, Tom

1990-01-01

This report describes progress in research on an autonomous robot for planetary exploration. In 1989, the year covered by this report, a six-legged walking robot, the Ambler, was configured, designed, and constructed. This configuration was used to overcome shortcomings exhibited by existing wheeled and walking robot mechanisms. The fundamental advantage of the Ambler is that the actuators for body support are independent of those for propulsion; a subset of the planar joints propel the body, and the vertical actuators support and level the body over terrain. Models of the Ambler's dynamics were developed and the leveling control was studied. An integrated system capable of walking with a single leg over rugged terrain was implemented and tested. A prototype of an Ambler leg is suspended below a carriage that slides along rails. To walk, the system uses a laser scanner to find a clear, flat foothold, positions the leg above the foothold, contacts the terrain with the foot, and applies force enough to advance the carriage along the rails. Walking both forward and backward, the system has traversed hundreds of meters of rugged terrain including obstacles too tall to step over, trenches too deep to step in, closely spaced rocks, and sand hills. In addition, preliminary experiments were conducted with concurrent planning and execution, and a leg recovery planner that generates time and power efficient 3D trajectories using 2D search was developed. A Hero robot was used to demonstrate mobile manipulation. Indoor tasks include collecting cups from the lab floor, retrieving printer output, and recharging when its battery gets low. The robot monitors its environment, and handles exceptional conditions in a robust fashion, using vision to track the appearance and disappearance of cups, onboard sonars to detect imminent collisions, and monitors to detect the battery level.

Advantage of straight walk instability in turning maneuver of multilegged locomotion: a robotics approach

PubMed Central

Aoi, Shinya; Tanaka, Takahiro; Fujiki, Soichiro; Funato, Tetsuro; Senda, Kei; Tsuchiya, Kazuo

2016-01-01

Multilegged locomotion improves the mobility of terrestrial animals and artifacts. Using many legs has advantages, such as the ability to avoid falling and to tolerate leg malfunction. However, many intrinsic degrees of freedom make the motion planning and control difficult, and many contact legs can impede the maneuverability during locomotion. The underlying mechanism for generating agile locomotion using many legs remains unclear from biological and engineering viewpoints. The present study used a centipede-like multilegged robot composed of six body segments and twelve legs. The body segments are passively connected through yaw joints with torsional springs. The dynamic stability of the robot walking in a straight line changes through a supercritical Hopf bifurcation due to the body axis flexibility. We focused on a quick turning task of the robot and quantitatively investigated the relationship between stability and maneuverability in multilegged locomotion by using a simple control strategy. Our experimental results show that the straight walk instability does help the turning maneuver. We discuss the importance and relevance of our findings for biological systems and propose a design principle for a simple control scheme to create maneuverable locomotion of multilegged robots. PMID:27444746

Scaling Robotic Displays: Displays and Techniques for Dismounted Movement with Robots

DTIC Science & Technology

2010-04-01

include the following: • Competition for the attention of the wearer/attentional tunneling • Interference with night vision devices • Occlusion...mainstays of society. It is difficult to walk down the street without seeing someone peering at their PDA or BlackBerry * as they are walking. However... BlackBerry is a registered trademark of Research in Motion Limited. 5 A major focus of the Air

Ankle Training With a Robotic Device Improves Hemiparetic Gait After a Stroke

PubMed Central

Forrester, Larry W.; Roy, Anindo; Krebs, Hermano Igo; Macko, Richard F.

2013-01-01

Background Task-oriented therapies such as treadmill exercise can improve gait velocity after stroke, but slow velocities and abnormal gait patterns often persist, suggesting a need for additional strategies to improve walking. Objectives To determine the effects of a 6-week visually guided, impedance controlled, ankle robotics intervention on paretic ankle motor control and gait function in chronic stroke. Methods This was a single-arm pilot study with a convenience sample of 8 stroke survivors with chronic hemiparetic gait, trained and tested in a laboratory. Subjects trained in dorsiflexion–plantarflexion by playing video games with the robot during three 1-hour training sessions weekly, totaling 560 repetitions per session. Assessments included paretic ankle ranges of motion, strength, motor control, and overground gait function. Results Improved paretic ankle motor control was seen as increased target success, along with faster and smoother movements. Walking velocity also increased significantly, whereas durations of paretic single support increased and double support decreased. Conclusions Robotic feedback training improved paretic ankle motor control with improvements in floor walking. Increased walking speeds were comparable with reports from other task-oriented, locomotor training approaches used in stroke, suggesting that a focus on ankle motor control may provide a valuable adjunct to locomotor therapies. PMID:21115945

Computerized visual feedback: an adjunct to robotic-assisted gait training.

PubMed

Banz, Raphael; Bolliger, Marc; Colombo, Gery; Dietz, Volker; Lünenburger, Lars

2008-10-01

Robotic devices for walking rehabilitation allow new possibilities for providing performance-related information to patients during gait training. Based on motor learning principles, augmented feedback during robotic-assisted gait training might improve the rehabilitation process used to regain walking function. This report presents a method to provide visual feedback implemented in a driven gait orthosis (DGO). The purpose of the study was to compare the immediate effect on motor output in subjects during robotic-assisted gait training when they used computerized visual feedback and when they followed verbal instructions of a physical therapist. Twelve people with neurological gait disorders due to incomplete spinal cord injury participated. Subjects were instructed to walk within the DGO in 2 different conditions. They were asked to increase their motor output by following the instructions of a therapist and by observing visual feedback. In addition, the subjects' opinions about using visual feedback were investigated by a questionnaire. Computerized visual feedback and verbal instructions by the therapist were observed to result in a similar change in motor output in subjects when walking within the DGO. Subjects reported that they were more motivated and concentrated on their movements when using computerized visual feedback compared with when no form of feedback was provided. Computerized visual feedback is a valuable adjunct to robotic-assisted gait training. It represents a relevant tool to increase patients' motor output, involvement, and motivation during gait training, similar to verbal instructions by a therapist.

A cargo-sorting DNA robot.

PubMed

Thubagere, Anupama J; Li, Wei; Johnson, Robert F; Chen, Zibo; Doroudi, Shayan; Lee, Yae Lim; Izatt, Gregory; Wittman, Sarah; Srinivas, Niranjan; Woods, Damien; Winfree, Erik; Qian, Lulu

2017-09-15

Two critical challenges in the design and synthesis of molecular robots are modularity and algorithm simplicity. We demonstrate three modular building blocks for a DNA robot that performs cargo sorting at the molecular level. A simple algorithm encoding recognition between cargos and their destinations allows for a simple robot design: a single-stranded DNA with one leg and two foot domains for walking, and one arm and one hand domain for picking up and dropping off cargos. The robot explores a two-dimensional testing ground on the surface of DNA origami, picks up multiple cargos of two types that are initially at unordered locations, and delivers them to specified destinations until all molecules are sorted into two distinct piles. The robot is designed to perform a random walk without any energy supply. Exploiting this feature, a single robot can repeatedly sort multiple cargos. Localization on DNA origami allows for distinct cargo-sorting tasks to take place simultaneously in one test tube or for multiple robots to collectively perform the same task. Copyright © 2017, American Association for the Advancement of Science.

Effects of the Integration of Dynamic Weight Shifting Training Into Treadmill Training on Walking Function of Children with Cerebral Palsy: A Randomized Controlled Study.

PubMed

Wu, Ming; Kim, Janis; Arora, Pooja; Gaebler-Spira, Deborah J; Zhang, Yunhui

2017-11-01

The aim of the study was to determine whether applying an assistance force to the pelvis and legs during treadmill training can improve walking function in children with cerebral palsy. Twenty-three children with cerebral palsy were randomly assigned to the robotic or treadmill only group. For participants who were assigned to the robotic group, a controlled force was applied to the pelvis and legs during treadmill walking. For participants who were assigned to the treadmill only group, manual assistance was provided as needed. Each participant trained 3 times/wk for 6 wks. Outcome measures included walking speed, 6-min walking distance, and clinical assessment of motor function, which were evaluated before, after training, and 8 wks after the end of training, and were compared between two groups. Significant increases in walking speed and 6-min walking distance were observed after robotic training (P = 0.03), but no significant change was observed after treadmill training only. A greater increase in 6-min walking distance was observed after robotic training than that after treadmill only training (P = 0.01). Applying a controlled force to the pelvis and legs, for facilitating weight-shift and leg swing, respectively, during treadmill training may improve walking speed and endurance in children with cerebral palsy. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) discuss the importance of physical activity at the participation level (sports programs) for children with cerebral palsy; (2) contrast the changes in walking ability and endurance for children in GMFCS level I, II and III following sports programs; and (3) identify the impact of higher frequency of sports program attendance over time on walking ability. Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Human-robot cooperative movement training: Learning a novel sensory motor transformation during walking with robotic assistance-as-needed

PubMed Central

Emken, Jeremy L; Benitez, Raul; Reinkensmeyer, David J

2007-01-01

Background A prevailing paradigm of physical rehabilitation following neurologic injury is to "assist-as-needed" in completing desired movements. Several research groups are attempting to automate this principle with robotic movement training devices and patient cooperative algorithms that encourage voluntary participation. These attempts are currently not based on computational models of motor learning. Methods Here we assume that motor recovery from a neurologic injury can be modelled as a process of learning a novel sensory motor transformation, which allows us to study a simplified experimental protocol amenable to mathematical description. Specifically, we use a robotic force field paradigm to impose a virtual impairment on the left leg of unimpaired subjects walking on a treadmill. We then derive an "assist-as-needed" robotic training algorithm to help subjects overcome the virtual impairment and walk normally. The problem is posed as an optimization of performance error and robotic assistance. The optimal robotic movement trainer becomes an error-based controller with a forgetting factor that bounds kinematic errors while systematically reducing its assistance when those errors are small. As humans have a natural range of movement variability, we introduce an error weighting function that causes the robotic trainer to disregard this variability. Results We experimentally validated the controller with ten unimpaired subjects by demonstrating how it helped the subjects learn the novel sensory motor transformation necessary to counteract the virtual impairment, while also preventing them from experiencing large kinematic errors. The addition of the error weighting function allowed the robot assistance to fade to zero even though the subjects' movements were variable. We also show that in order to assist-as-needed, the robot must relax its assistance at a rate faster than that of the learning human. Conclusion The assist-as-needed algorithm proposed here can limit error during the learning of a dynamic motor task. The algorithm encourages learning by decreasing its assistance as a function of the ongoing progression of movement error. This type of algorithm is well suited for helping people learn dynamic tasks for which large kinematic errors are dangerous or discouraging, and thus may prove useful for robot-assisted movement training of walking or reaching following neurologic injury. PMID:17391527

Robotic Resistance Treadmill Training Improves Locomotor Function in Children With Cerebral Palsy: A Randomized Controlled Pilot Study.

PubMed

Wu, Ming; Kim, Janis; Gaebler-Spira, Deborah J; Schmit, Brian D; Arora, Pooja

2017-11-01

To determine whether applying controlled resistance forces to the legs during the swing phase of gait may improve the efficacy of treadmill training as compared with applying controlled assistance forces in children with cerebral palsy (CP). Randomized controlled study. Research unit of a rehabilitation hospital. Children with spastic CP (N=23; mean age, 10.6y; range, 6-14y; Gross Motor Function Classification System levels, I-IV). Participants were randomly assigned to receive controlled assistance (n=11) or resistance (n=12) loads applied to the legs at the ankle. Participants underwent robotic treadmill training 3 times a week for 6 weeks (18 sessions). A controlled swing assistance/resistance load was applied to both legs starting from the toe-off to mid-swing phase of gait during training. Outcome measures consisted of overground walking speed, 6-minute walk distance, and Gross Motor Function Measure scores and were assessed pre and post 6 weeks of training and 8 weeks after the end of training. After 6 weeks of treadmill training in participants from the resistance training group, fast walking speed and 6-minute walk distance significantly improved (18% and 30% increases, respectively), and 6-minute walk distance was still significantly greater than that at baseline (35% increase) 8 weeks after the end of training. In contrast, overground gait speed and 6-minute walk distance had no significant changes after robotic assistance training. The results of the present study indicated that robotic resistance treadmill training is more effective than assistance training in improving locomotor function in children with CP. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Robotically assisted treadmill exercise training for improving peak fitness in chronic motor incomplete spinal cord injury: A randomized controlled trial

PubMed Central

Scott, William; York, Henry; Theyagaraj, Melita; Price-Miller, Naomi; McQuaid, Jean; Eyvazzadeh, Megan; Ivey, Frederick M.; Macko, Richard F.

2016-01-01

Objective To assess the effectiveness of robotically assisted body weight supported treadmill training (RABWSTT) for improving cardiovascular fitness in chronic motor incomplete spinal cord injury (CMISCI). Design Pilot prospective randomized, controlled clinical trial. Setting Outpatient rehabilitation specialty hospital. Participants Eighteen individuals with CMISCI with American Spinal Injury Association (ASIA) level between C4 and L2 and at least one-year post injury. Interventions CMISCI participants were randomized to RABWSTT or a home stretching program (HSP) three times per week for three months. Those in the home stretching group were crossed over to three months of RABWSTT following completion of the initial three month phase. Outcome measures Peak oxygen consumption (peak VO2) was measured during both robotic treadmill walking and arm cycle ergometry: twice at baseline, once at six weeks (mid-training) and twice at three months (post-training). Peak VO2 values were normalized for body mass. Results The RABWSTT group improved peak VO2 by 12.3% during robotic treadmill walking (20.2 ± 7.4 to 22.7 ± 7.5 ml/kg/min, P = 0.018), compared to a non-significant 3.9% within group change observed in HSP controls (P = 0.37). Neither group displayed a significant change in peak VO2 during arm cycle ergometry (RABWSTT, 8.5% (P = 0.25); HSP, 1.76% (P = 0.72)). A repeated measures analysis showed statistically significant differences between treatments for peak VO2 during both robotic treadmill walking (P = 0.002) and arm cycle ergometry (P = 0.001). Conclusion RABWSTT is an effective intervention model for improving peak fitness levels assessed during robotic treadmill walking in persons with CMISCI. PMID:25520035

Gait planning for a quadruped robot with one faulty actuator

NASA Astrophysics Data System (ADS)

Chen, Xianbao; Gao, Feng; Qi, Chenkun; Tian, Xinghua

2015-01-01

Fault tolerance is essential for quadruped robots when they work in remote areas or hazardous environments. Many fault-tolerant gaits planning method proposed in the past decade constrained more degrees of freedom(DOFs) of a robot than necessary. Thus a novel method to realize the fault-tolerant walking is proposed. The mobility of the robot is analyzed first by using the screw theory. The result shows that the translation of the center of body(CoB) can be kept with one faulty actuator if the rotations of the body are controlled. Thus the DOFs of the robot body are divided into two parts: the translation of the CoB and the rotation of the body. The kinematic model of the whole robot is built, the algorithm is developed to actively control the body orientations at the velocity level so that the planned CoB trajectory can be realized in spite of the constraint of the faulty actuator. This gait has a similar generation sequence with the normal gait and can be applied to the robot at any position. Simulations and experiments of the fault-tolerant gait with one faulty actuator are carried out. The CoB errors and the body rotation angles are measured. Comparing to the traditional fault-tolerant gait they can be reduced by at least 50%. A fault-tolerant gait planning algorithm is presented, which not only realizes the walking of a quadruped robot with a faulty actuator, but also efficiently improves the walking performances by taking full advantage of the remaining operational actuators according to the results of the simulations and experiments.

Improving the transparency of a rehabilitation robot by exploiting the cyclic behaviour of walking.

PubMed

van Dijk, W; van der Kooij, H; Koopman, B; van Asseldonk, E H F; van der Kooij, H

2013-06-01

To promote active participation of neurological patients during robotic gait training, controllers, such as "assist as needed" or "cooperative control", are suggested. Apart from providing support, these controllers also require that the robot should be capable of resembling natural, unsupported, walking. This means that they should have a transparent mode, where the interaction forces between the human and the robot are minimal. Traditional feedback-control algorithms do not exploit the cyclic nature of walking to improve the transparency of the robot. The purpose of this study was to improve the transparent mode of robotic devices, by developing two controllers that use the rhythmic behavior of gait. Both controllers use adaptive frequency oscillators and kernel-based non-linear filters. Kernelbased non-linear filters can be used to estimate signals and their time derivatives, as a function of the gait phase. The first controller learns the motor angle, associated with a certain joint angle pattern, and acts as a feed-forward controller to improve the torque tracking (including the zero-torque mode). The second controller learns the state of the mechanical system and compensates for the dynamical effects (e.g. the acceleration of robot masses). Both controllers have been tested separately and in combination on a small subject population. Using the feedforward controller resulted in an improved torque tracking of at least 52 percent at the hip joint, and 61 percent at the knee joint. When both controllers were active simultaneously, the interaction power between the robot and the human leg was reduced by at least 40 percent at the thigh, and 43 percent at the shank. These results indicate that: if a robotic task is cyclic, the torque tracking and transparency can be improved by exploiting the predictions of adaptive frequency oscillator and kernel-based nonlinear filters.

A Hexapod Robot to Demonstrate Mesh Walking in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Foor, David C.

2005-01-01

The JPL Micro-Robot Explorer (MRE) Spiderbot is a robot that takes advantage of its small size to perform precision tasks suitable for space applications. The Spiderbot is a legged robot that can traverse harsh terrain otherwise inaccessible to wheeled robots. A team of Spiderbots can network and can exhibit collaborative efforts to SUCCeSSfUlly complete a set of tasks. The Spiderbot is designed and developed to demonstrate hexapods that can walk on flat surfaces, crawl on meshes, and assemble simple structures. The robot has six legs consisting of two spring-compliant joints and a gripping actuator. A hard-coded set of gaits allows the robot to move smoothly in a zero-gravity environment along the mesh. The primary objective of this project is to create a Spiderbot that traverses a flexible, deployable mesh, for use in space repair. Verification of this task will take place aboard a zero-gravity test flight. The secondary objective of this project is to adapt feedback from the joints to allow the robot to test each arm for a successful grip of the mesh. The end result of this research lends itself to a fault-tolerant robot suitable for a wide variety of space applications.

Statistical Modeling of Robotic Random Walks on Different Terrain

NASA Astrophysics Data System (ADS)

Naylor, Austin; Kinnaman, Laura

Issues of public safety, especially with crowd dynamics and pedestrian movement, have been modeled by physicists using methods from statistical mechanics over the last few years. Complex decision making of humans moving on different terrains can be modeled using random walks (RW) and correlated random walks (CRW). The effect of different terrains, such as a constant increasing slope, on RW and CRW was explored. LEGO robots were programmed to make RW and CRW with uniform step sizes. Level ground tests demonstrated that the robots had the expected step size distribution and correlation angles (for CRW). The mean square displacement was calculated for each RW and CRW on different terrains and matched expected trends. The step size distribution was determined to change based on the terrain; theoretical predictions for the step size distribution were made for various simple terrains. It's Dr. Laura Kinnaman, not sure where to put the Prefix.

The immediate intervention effects of robotic training in patients after anterior cruciate ligament reconstruction.

PubMed

Hu, Chunying; Huang, Qiuchen; Yu, Lili; Ye, Miao

2016-07-01

[Purpose] The purpose of this study was to examine the immediate effects of robot-assisted therapy on functional activity level after anterior cruciate ligament reconstruction. [Subjects and Methods] Participants included 10 patients (8 males and 2 females) following anterior cruciate ligament reconstruction. The subjects participated in robot-assisted therapy and treadmill exercise on different days. The Timed Up-and-Go test, Functional Reach Test, surface electromyography of the vastus lateralis and vastus medialis, and maximal extensor strength of isokinetic movement of the knee joint were evaluated in both groups before and after the experiment. [Results] The results for the Timed Up-and-Go Test and the 10-Meter Walk Test improved in the robot-assisted rehabilitation group. Surface electromyography of the vastus medialis muscle showed significant increases in maximum and average discharge after the intervention. [Conclusion] The results suggest that walking ability and muscle strength can be improved by robotic training.

Generate an Optimum Lightweight Legs Structure Design Based on Critical Posture in A-FLoW Humanoid Robot

NASA Astrophysics Data System (ADS)

Luthfi, A.; Subhan, K. A.; Eko H, B.; Sanggar, D. R.; Pramadihanto, D.

2018-04-01

Lightweight construction and energy efficiency play an important role in humanoid robot development. The application of computer-aided engineering (CAE) in the development process is one of the possibilities to achieve the appropriate reduction of the weight. This paper describes a method to generate an optimum lightweight legs structure design based on critical posture during walking locomotion in A-FLoW Humanoid robot.The criticalposture can be obtained from the highest forces and moments in each joint of the robot body during walking locomotion. From the finite element analysis (FEA) result can be realized leg structure design of A-FLoW humanoid robot with a maximum displacement value of 0.05 mmand weight reduction about 0.598 Kg from the thigh structure and a maximum displacement value of 0,13 mmand weight reduction about 0.57 kg from the shin structure.

Versatile robotic interface to evaluate, enable and train locomotion and balance after neuromotor disorders.

PubMed

Dominici, Nadia; Keller, Urs; Vallery, Heike; Friedli, Lucia; van den Brand, Rubia; Starkey, Michelle L; Musienko, Pavel; Riener, Robert; Courtine, Grégoire

2012-07-01

Central nervous system (CNS) disorders distinctly impair locomotor pattern generation and balance, but technical limitations prevent independent assessment and rehabilitation of these subfunctions. Here we introduce a versatile robotic interface to evaluate, enable and train pattern generation and balance independently during natural walking behaviors in rats. In evaluation mode, the robotic interface affords detailed assessments of pattern generation and dynamic equilibrium after spinal cord injury (SCI) and stroke. In enabling mode,the robot acts as a propulsive or postural neuroprosthesis that instantly promotes unexpected locomotor capacities including overground walking after complete SCI, stair climbing following partial SCI and precise paw placement shortly after stroke. In training mode, robot-enabled rehabilitation, epidural electrical stimulation and monoamine agonists reestablish weight-supported locomotion, coordinated steering and balance in rats with a paralyzing SCI. This new robotic technology and associated concepts have broad implications for both assessing and restoring motor functions after CNS disorders, both in animals and in humans.

Treadmill vs. overground walking: different response to physical interaction.

PubMed

Ochoa, Julieth; Sternad, Dagmar; Hogan, Neville

2017-10-01

Rehabilitation of human motor function is an issue of growing significance, and human-interactive robots offer promising potential to meet the need. For the lower extremity, however, robot-aided therapy has proven challenging. To inform effective approaches to robotic gait therapy, it is important to better understand unimpaired locomotor control: its sensitivity to different mechanical contexts and its response to perturbations. The present study evaluated the behavior of 14 healthy subjects who walked on a motorized treadmill and overground while wearing an exoskeletal ankle robot. Their response to a periodic series of ankle plantar flexion torque pulses, delivered at periods different from, but sufficiently close to, their preferred stride cadence, was assessed to determine whether gait entrainment occurred, how it differed across conditions, and if the adapted motor behavior persisted after perturbation. Certain aspects of locomotor control were exquisitely sensitive to walking context, while others were not. Gaits entrained more often and more rapidly during overground walking, yet, in all cases, entrained gaits synchronized the torque pulses with ankle push-off, where they provided assistance with propulsion. Furthermore, subjects entrained to perturbation periods that required an adaption toward slower cadence, even though the pulses acted to accelerate gait, indicating a neural adaptation of locomotor control. Lastly, during 15 post-perturbation strides, the entrained gait period was observed to persist more frequently during overground walking. This persistence was correlated with the number of strides walked at the entrained gait period (i.e., longer exposure), which also indicated a neural adaptation. NEW & NOTEWORTHY We show that the response of human locomotion to physical interaction differs between treadmill and overground walking. Subjects entrained to a periodic series of ankle plantar flexion torque pulses that shifted their gait cadence, synchronizing ankle push-off with the pulses (so that they assisted propulsion) even when gait cadence slowed. Entrainment was faster overground and, on removal of torque pulses, the entrained gait period persisted more prominently overground, indicating a neural adaptation of locomotor control. Copyright © 2017 the American Physiological Society.

Development of Multi-Legged Walking Robot Using Reconfigurable Modular Design and Biomimetic Control Architecture

NASA Astrophysics Data System (ADS)

Chen, Xuedong; Sun, Yi; Huang, Qingjiu; Jia, Wenchuan; Pu, Huayan

This paper focuses on the design of a modular multi-legged walking robot MiniQuad-I, which can be reconfigured into variety configurations, including quadruped and hexapod configurations for different tasks by changing the layout of modules. Critical design considerations when taking the adaptability, maintainability and extensibility in count simultaneously are discussed and then detailed designs of each module are presented. The biomimetic control architecture of MiniQuad-I is proposed, which can improve the capability of agility and independence of the robot. Simulations and experiments on crawling, object picking and obstacle avoiding are performed to verify functions of the MiniQuad-I.

Design and experiment of a small-scale walking robot employing stick-slip motion principle.

PubMed

Wang, Gangqiang; Li, Chaodong; Yuan, Tao

2017-11-01

We describe the design and control of a four legged walking robot, 45 g in weight and 130 mm × 105 mm × 25 mm in size. Each leg consists of two piezoelectric bimorph actuators that are bonded at the free end by a flexure and an end-effector. The robot generates stick-slip locomotion when applying sawtooth shaped voltage signals. Friction between legs and a contact surface is analyzed by using the Coulomb friction model. Locomotion characteristics are measured in several experiments. The robot was driven with frequencies up to 75 Hz, and a maximum velocity of 65 mm/s was obtained at two frequencies: 45 Hz with 190 Vpp driving voltage and 60 Hz with 170 Vpp driving voltage, respectively.

Design and experiment of a small-scale walking robot employing stick-slip motion principle

NASA Astrophysics Data System (ADS)

Wang, Gangqiang; Li, Chaodong; Yuan, Tao

2017-11-01

We describe the design and control of a four legged walking robot, 45 g in weight and 130 mm × 105 mm × 25 mm in size. Each leg consists of two piezoelectric bimorph actuators that are bonded at the free end by a flexure and an end-effector. The robot generates stick-slip locomotion when applying sawtooth shaped voltage signals. Friction between legs and a contact surface is analyzed by using the Coulomb friction model. Locomotion characteristics are measured in several experiments. The robot was driven with frequencies up to 75 Hz, and a maximum velocity of 65 mm/s was obtained at two frequencies: 45 Hz with 190 Vpp driving voltage and 60 Hz with 170 Vpp driving voltage, respectively.

On the stiffness analysis of a cable driven leg exoskeleton.

PubMed

Sanjeevi, N S S; Vashista, Vineet

2017-07-01

Robotic systems are being used for gait rehabilitation of patients with neurological disorder. These devices are externally powered to apply external forces on human limbs to assist the leg motion. Patients while walking with these devices adapt their walking pattern in response to the applied forces. The efficacy of a rehabilitation paradigm thus depends on the human-robot interaction. A cable driven leg exoskeleton (CDLE) use actuated cables to apply external joint torques on human leg. Cables are lightweight and flexible but can only be pulled, thus a CDLE requires redundant cables. Redundancy in CDLE can be utilized to appropriately tune a robot's performance. In this work, we present the stiffness analysis of CDLE. Different stiffness performance indices are established to study the role of system parameters in improving the human-robot interaction.

Posture Control-Human-Inspired Approaches for Humanoid Robot Benchmarking: Conceptualizing Tests, Protocols and Analyses.

PubMed

Mergner, Thomas; Lippi, Vittorio

2018-01-01

Posture control is indispensable for both humans and humanoid robots, which becomes especially evident when performing sensorimotor tasks such as moving on compliant terrain or interacting with the environment. Posture control is therefore targeted in recent proposals of robot benchmarking in order to advance their development. This Methods article suggests corresponding robot tests of standing balance, drawing inspirations from the human sensorimotor system and presenting examples from robot experiments. To account for a considerable technical and algorithmic diversity among robots, we focus in our tests on basic posture control mechanisms, which provide humans with an impressive postural versatility and robustness. Specifically, we focus on the mechanically challenging balancing of the whole body above the feet in the sagittal plane around the ankle joints in concert with the upper body balancing around the hip joints. The suggested tests target three key issues of human balancing, which appear equally relevant for humanoid bipeds: (1) four basic physical disturbances (support surface (SS) tilt and translation, field and contact forces) may affect the balancing in any given degree of freedom (DoF). Targeting these disturbances allows us to abstract from the manifold of possible behavioral tasks. (2) Posture control interacts in a conflict-free way with the control of voluntary movements for undisturbed movement execution, both with "reactive" balancing of external disturbances and "proactive" balancing of self-produced disturbances from the voluntary movements. Our proposals therefore target both types of disturbances and their superposition. (3) Relevant for both versatility and robustness of the control, linkages between the posture control mechanisms across DoFs provide their functional cooperation and coordination at will and on functional demands. The suggested tests therefore include ankle-hip coordination. Suggested benchmarking criteria build on the evoked sway magnitude, normalized to robot weight and Center of mass (COM) height, in relation to reference ranges that remain to be established. The references may include human likeness features. The proposed benchmarking concept may in principle also be applied to wearable robots, where a human user may command movements, but may not be aware of the additionally required postural control, which then needs to be implemented into the robot.

Posture Control—Human-Inspired Approaches for Humanoid Robot Benchmarking: Conceptualizing Tests, Protocols and Analyses

PubMed Central

Mergner, Thomas; Lippi, Vittorio

2018-01-01

Posture control is indispensable for both humans and humanoid robots, which becomes especially evident when performing sensorimotor tasks such as moving on compliant terrain or interacting with the environment. Posture control is therefore targeted in recent proposals of robot benchmarking in order to advance their development. This Methods article suggests corresponding robot tests of standing balance, drawing inspirations from the human sensorimotor system and presenting examples from robot experiments. To account for a considerable technical and algorithmic diversity among robots, we focus in our tests on basic posture control mechanisms, which provide humans with an impressive postural versatility and robustness. Specifically, we focus on the mechanically challenging balancing of the whole body above the feet in the sagittal plane around the ankle joints in concert with the upper body balancing around the hip joints. The suggested tests target three key issues of human balancing, which appear equally relevant for humanoid bipeds: (1) four basic physical disturbances (support surface (SS) tilt and translation, field and contact forces) may affect the balancing in any given degree of freedom (DoF). Targeting these disturbances allows us to abstract from the manifold of possible behavioral tasks. (2) Posture control interacts in a conflict-free way with the control of voluntary movements for undisturbed movement execution, both with “reactive” balancing of external disturbances and “proactive” balancing of self-produced disturbances from the voluntary movements. Our proposals therefore target both types of disturbances and their superposition. (3) Relevant for both versatility and robustness of the control, linkages between the posture control mechanisms across DoFs provide their functional cooperation and coordination at will and on functional demands. The suggested tests therefore include ankle-hip coordination. Suggested benchmarking criteria build on the evoked sway magnitude, normalized to robot weight and Center of mass (COM) height, in relation to reference ranges that remain to be established. The references may include human likeness features. The proposed benchmarking concept may in principle also be applied to wearable robots, where a human user may command movements, but may not be aware of the additionally required postural control, which then needs to be implemented into the robot. PMID:29867428

Sensor Data Fusion for Body State Estimation in a Bipedal Robot and Its Feedback Control Application for Stable Walking

PubMed Central

Chen, Ching-Pei; Chen, Jing-Yi; Huang, Chun-Kai; Lu, Jau-Ching; Lin, Pei-Chun

2015-01-01

We report on a sensor data fusion algorithm via an extended Kalman filter for estimating the spatial motion of a bipedal robot. Through fusing the sensory information from joint encoders, a 6-axis inertial measurement unit and a 2-axis inclinometer, the robot’s body state at a specific fixed position can be yielded. This position is also equal to the CoM when the robot is in the standing posture suggested by the detailed CAD model of the robot. In addition, this body state is further utilized to provide sensory information for feedback control on a bipedal robot with walking gait. The overall control strategy includes the proposed body state estimator as well as the damping controller, which regulates the body position state of the robot in real-time based on instant and historical position tracking errors. Moreover, a posture corrector for reducing unwanted torque during motion is addressed. The body state estimator and the feedback control structure are implemented in a child-size bipedal robot and the performance is experimentally evaluated. PMID:25734644

Space Robotics: AWIMR an Overview

NASA Technical Reports Server (NTRS)

Wagner, Rick

2006-01-01

This viewgraph presentation reviews the usages of Autonomous Walking Inspection and Maintenance Robots (AWIMR) in space. Some of the uses that these robots in support of space exploration can have are: inspection of a space craft, cleaning, astronaut assistance, assembly of a structure, repair of structures, and replenishment of supplies.

Foot trajectory approximation using the pendulum model of walking.

PubMed

Fang, Juan; Vuckovic, Aleksandra; Galen, Sujay; Conway, Bernard A; Hunt, Kenneth J

2014-01-01

Generating a natural foot trajectory is an important objective in robotic systems for rehabilitation of walking. Human walking has pendular properties, so the pendulum model of walking has been used in bipedal robots which produce rhythmic gait patterns. Whether natural foot trajectories can be produced by the pendulum model needs to be addressed as a first step towards applying the pendulum concept in gait orthosis design. This study investigated circle approximation of the foot trajectories, with focus on the geometry of the pendulum model of walking. Three able-bodied subjects walked overground at various speeds, and foot trajectories relative to the hip were analysed. Four circle approximation approaches were developed, and best-fit circle algorithms were derived to fit the trajectories of the ankle, heel and toe. The study confirmed that the ankle and heel trajectories during stance and the toe trajectory in both the stance and the swing phases during walking at various speeds could be well modelled by a rigid pendulum. All the pendulum models were centred around the hip with pendular lengths approximately equal to the segment distances from the hip. This observation provides a new approach for using the pendulum model of walking in gait orthosis design.

Learning to walk with an adaptive gain proportional myoelectric controller for a robotic ankle exoskeleton.

PubMed

Koller, Jeffrey R; Jacobs, Daniel A; Ferris, Daniel P; Remy, C David

2015-11-04

Robotic ankle exoskeletons can provide assistance to users and reduce metabolic power during walking. Our research group has investigated the use of proportional myoelectric control for controlling robotic ankle exoskeletons. Previously, these controllers have relied on a constant gain to map user's muscle activity to actuation control signals. A constant gain may act as a constraint on the user, so we designed a controller that dynamically adapts the gain to the user's myoelectric amplitude. We hypothesized that an adaptive gain proportional myoelectric controller would reduce metabolic energy expenditure compared to walking with the ankle exoskeleton unpowered because users could choose their preferred control gain. We tested eight healthy subjects walking with the adaptive gain proportional myoelectric controller with bilateral ankle exoskeletons. The adaptive gain was updated each stride such that on average the user's peak muscle activity was mapped to maximal power output of the exoskeleton. All subjects participated in three identical training sessions where they walked on a treadmill for 50 minutes (30 minutes of which the exoskeleton was powered) at 1.2 ms(-1). We calculated and analyzed metabolic energy consumption, muscle recruitment, inverse kinematics, inverse dynamics, and exoskeleton mechanics. Using our controller, subjects achieved a metabolic reduction similar to that seen in previous work in about a third of the training time. The resulting controller gain was lower than that seen in previous work (β=1.50±0.14 versus a constant β=2). The adapted gain allowed users more total ankle joint power than that of unassisted walking, increasing ankle power in exchange for a decrease in hip power. Our findings indicate that humans prefer to walk with greater ankle mechanical power output than their unassisted gait when provided with an ankle exoskeleton using an adaptive controller. This suggests that robotic assistance from an exoskeleton can allow humans to adopt gait patterns different from their normal choices for locomotion. In our specific experiment, subjects increased ankle power and decreased hip power to walk with a reduction in metabolic cost. Future exoskeleton devices that rely on proportional myolectric control are likely to demonstrate improved performance by including an adaptive gain.

Acquiring neural signals for developing a perception and cognition model

NASA Astrophysics Data System (ADS)

Li, Wei; Li, Yunyi; Chen, Genshe; Shen, Dan; Blasch, Erik; Pham, Khanh; Lynch, Robert

2012-06-01

The understanding of how humans process information, determine salience, and combine seemingly unrelated information is essential to automated processing of large amounts of information that is partially relevant, or of unknown relevance. Recent neurological science research in human perception, and in information science regarding contextbased modeling, provides us with a theoretical basis for using a bottom-up approach for automating the management of large amounts of information in ways directly useful for human operators. However, integration of human intelligence into a game theoretic framework for dynamic and adaptive decision support needs a perception and cognition model. For the purpose of cognitive modeling, we present a brain-computer-interface (BCI) based humanoid robot system to acquire brainwaves during human mental activities of imagining a humanoid robot-walking behavior. We use the neural signals to investigate relationships between complex humanoid robot behaviors and human mental activities for developing the perception and cognition model. The BCI system consists of a data acquisition unit with an electroencephalograph (EEG), a humanoid robot, and a charge couple CCD camera. An EEG electrode cup acquires brainwaves from the skin surface on scalp. The humanoid robot has 20 degrees of freedom (DOFs); 12 DOFs located on hips, knees, and ankles for humanoid robot walking, 6 DOFs on shoulders and arms for arms motion, and 2 DOFs for head yaw and pitch motion. The CCD camera takes video clips of the human subject's hand postures to identify mental activities that are correlated to the robot-walking behaviors. We use the neural signals to investigate relationships between complex humanoid robot behaviors and human mental activities for developing the perception and cognition model.

Powered robotic exoskeletons in post-stroke rehabilitation of gait: a scoping review.

PubMed

Louie, Dennis R; Eng, Janice J

2016-06-08

Powered robotic exoskeletons are a potential intervention for gait rehabilitation in stroke to enable repetitive walking practice to maximize neural recovery. As this is a relatively new technology for stroke, a scoping review can help guide current research and propose recommendations for advancing the research development. The aim of this scoping review was to map the current literature surrounding the use of robotic exoskeletons for gait rehabilitation in adults post-stroke. Five databases (Pubmed, OVID MEDLINE, CINAHL, Embase, Cochrane Central Register of Clinical Trials) were searched for articles from inception to October 2015. Reference lists of included articles were reviewed to identify additional studies. Articles were included if they utilized a robotic exoskeleton as a gait training intervention for adult stroke survivors and reported walking outcome measures. Of 441 records identified, 11 studies, all published within the last five years, involving 216 participants met the inclusion criteria. The study designs ranged from pre-post clinical studies (n = 7) to controlled trials (n = 4); five of the studies utilized a robotic exoskeleton device unilaterally, while six used a bilateral design. Participants ranged from sub-acute (<7 weeks) to chronic (>6 months) stroke. Training periods ranged from single-session to 8-week interventions. Main walking outcome measures were gait speed, Timed Up and Go, 6-min Walk Test, and the Functional Ambulation Category. Meaningful improvement with exoskeleton-based gait training was more apparent in sub-acute stroke compared to chronic stroke. Two of the four controlled trials showed no greater improvement in any walking outcomes compared to a control group in chronic stroke. In conclusion, clinical trials demonstrate that powered robotic exoskeletons can be used safely as a gait training intervention for stroke. Preliminary findings suggest that exoskeletal gait training is equivalent to traditional therapy for chronic stroke patients, while sub-acute patients may experience added benefit from exoskeletal gait training. Efforts should be invested in designing rigorous, appropriately powered controlled trials before powered exoskeletons can be translated into a clinical tool for gait rehabilitation post-stroke.

The Effects on Kinematics and Muscle Activity of Walking in a Robotic Gait Trainer During Zero-Force Control.

PubMed

van Asseldonk, Edwin H F; Veneman, Jan F; Ekkelenkamp, Ralf; Buurke, Jaap H; van der Helm, Frans C T; van der Kooij, Herman

2008-08-01

"Assist as needed" control algorithms promote activity of patients during robotic gait training. Implementing these requires a free walking mode of a device, as unassisted motions should not be hindered. The goal of this study was to assess the normality of walking in the free walking mode of the LOPES gait trainer, an 8 degrees-of-freedom lightweight impedance controlled exoskeleton. Kinematics, gait parameters and muscle activity of walking in a free walking mode in the device were compared with those of walking freely on a treadmill. Average values and variability of the spatio-temporal gait variables showed no or small (relative to cycle-to-cycle variability) changes and the kinematics showed a significant and relevant decrease in knee angle range only. Muscles involved in push off showed a small decrease, whereas muscles involved in acceleration and deceleration of the swing leg showed an increase of their activity. Timing of the activity was mainly unaffected. Most of the observed differences could be ascribed to the inertia of the exoskeleton. Overall, walking with the LOPES resembled free walking, although this required several adaptations in muscle activity. These adaptations are such that we expect that Assist as Needed training can be implemented in LOPES.

Humanoid robot Lola: design and walking control.

PubMed

Buschmann, Thomas; Lohmeier, Sebastian; Ulbrich, Heinz

2009-01-01

In this paper we present the humanoid robot LOLA, its mechatronic hardware design, simulation and real-time walking control. The goal of the LOLA-project is to build a machine capable of stable, autonomous, fast and human-like walking. LOLA is characterized by a redundant kinematic configuration with 7-DoF legs, an extremely lightweight design, joint actuators with brushless motors and an electronics architecture using decentralized joint control. Special emphasis was put on an improved mass distribution of the legs to achieve good dynamic performance. Trajectory generation and control aim at faster, more flexible and robust walking. Center of mass trajectories are calculated in real-time from footstep locations using quadratic programming and spline collocation methods. Stabilizing control uses hybrid position/force control in task space with an inner joint position control loop. Inertial stabilization is achieved by modifying the contact force trajectories.

Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots

PubMed Central

Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

2014-01-01

Neurobiological studies have shown that insects are able to adapt leg movements and posture for obstacle negotiation in changing environments. Moreover, the distance to an obstacle where an insect begins to climb is found to be a major parameter for successful obstacle negotiation. Inspired by these findings, we present an adaptive neural control mechanism for obstacle negotiation behavior in hexapod robots. It combines locomotion control, backbone joint control, local leg reflexes, and neural learning. While the first three components generate locomotion including walking and climbing, the neural learning mechanism allows the robot to adapt its behavior for obstacle negotiation with respect to changing conditions, e.g., variable obstacle heights and different walking gaits. By successfully learning the association of an early, predictive signal (conditioned stimulus, CS) and a late, reflex signal (unconditioned stimulus, UCS), both provided by ultrasonic sensors at the front of the robot, the robot can autonomously find an appropriate distance from an obstacle to initiate climbing. The adaptive neural control was developed and tested first on a physical robot simulation, and was then successfully transferred to a real hexapod robot, called AMOS II. The results show that the robot can efficiently negotiate obstacles with a height up to 85% of the robot's leg length in simulation and 75% in a real environment. PMID:24523694

Sensitivity analysis of multi-objective optimization of CPG parameters for quadruped robot locomotion

NASA Astrophysics Data System (ADS)

Oliveira, Miguel; Santos, Cristina P.; Costa, Lino

2012-09-01

In this paper, a study based on sensitivity analysis is performed for a gait multi-objective optimization system that combines bio-inspired Central Patterns Generators (CPGs) and a multi-objective evolutionary algorithm based on NSGA-II. In this system, CPGs are modeled as autonomous differential equations, that generate the necessary limb movement to perform the required walking gait. In order to optimize the walking gait, a multi-objective problem with three conflicting objectives is formulated: maximization of the velocity, the wide stability margin and the behavioral diversity. The experimental results highlight the effectiveness of this multi-objective approach and the importance of the objectives to find different walking gait solutions for the quadruped robot.

The effect of waist twisting on walking speed of an amphibious salamander like robot

NASA Astrophysics Data System (ADS)

Yin, Xin-Yan; Jia, Li-Chao; Wang, Chen; Xie, Guang-Ming

2016-06-01

Amphibious salamanders often swing their waist to coordinate quadruped walking in order to improve their crawling speed. A robot with a swing waist joint, like an amphibious salamander, is used to mimic this locomotion. A control method is designed to allow the robot to maintain the rotational speed of its legs continuous and avoid impact between its legs and the ground. An analytical expression is established between the amplitude of the waist joint and the step length. Further, an optimization amplitude is obtained corresponding to the maximum stride. The simulation results based on automatic dynamic analysis of mechanical systems (ADAMS) and physical experiments verify the rationality and validity of this expression.

Computer coordination of limb motion for locomotion of a multiple-armed robot for space assembly

NASA Technical Reports Server (NTRS)

Klein, C. A.; Patterson, M. R.

1982-01-01

Consideration is given to a possible robotic system for the construction of large space structures, which may be described as a multiple general purpose arm manipulator vehicle that can walk over the structure under construction to a given site for further work. A description is presented of the locomotion of such a vehicle, modeling its arms in terms of a currently available industrial manipulator. It is noted that for whatever maximum speed of operation is chosen, rapid changes in robot velocity create situations in which already-selected handholds are no longer practical. A step is added to the 'free gait' walking algorithm in order to solve this problem.

Rugged Walking Robot

NASA Technical Reports Server (NTRS)

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1990-01-01

Proposed walking-beam robot simpler and more rugged than articulated-leg walkers. Requires less data processing, and uses power more efficiently. Includes pair of tripods, one nested in other. Inner tripod holds power supplies, communication equipment, computers, instrumentation, sampling arms, and articulated sensor turrets. Outer tripod holds mast on which antennas for communication with remote control site and video cameras for viewing local and distant terrain mounted. Propels itself by raising, translating, and lowering tripods in alternation. Steers itself by rotating raised tripod on turntable.

University of Maryland walking robot: A design project for undergraduate students

NASA Technical Reports Server (NTRS)

Olsen, Bob; Bielec, Jim; Hartsig, Dave; Oliva, Mani; Grotheer, Phil; Hekmat, Morad; Russell, David; Tavakoli, Hossein; Young, Gary; Nave, Tom

1990-01-01

The design and construction required that the walking robot machine be capable of completing a number of tasks including walking in a straight line, turning to change direction, and maneuvering over an obstable such as a set of stairs. The machine consists of two sets of four telescoping legs that alternately support the entire structure. A gear-box and crank-arm assembly is connected to the leg sets to provide the power required for the translational motion of the machine. By retracting all eight legs, the robot comes to rest on a central Bigfoot support. Turning is accomplished by rotating the machine about this support. The machine can be controlled by using either a user operated remote tether or the on-board computer for the execution of control commands. Absolute encoders are attached to all motors (leg, main drive, and Bigfoot) to provide the control computer with information regarding the status of the motors (up-down motion, forward or reverse rotation). Long and short range infrared sensors provide the computer with feedback information regarding the machine's relative position to a series of stripes and reflectors. These infrared sensors simulate how the robot might sense and gain information about the environment of Mars.

Terrain interaction with the quarter scale beam walker

NASA Technical Reports Server (NTRS)

Chun, Wendell H.; Price, S.; Spiessbach, A.

1990-01-01

Frame walkers are a class of mobile robots that are robust and capable mobility platforms. Variations of the frame walker robot are in commercial use today. Komatsu Ltd. of Japan developed the Remotely Controlled Underwater Surveyor (ReCUS) and Normed Shipyards of France developed the Marine Robot (RM3). Both applications of the frame walker concept satisfied robotic mobility requirements that could not be met by a wheeled or tracked design. One vehicle design concept that falls within this class of mobile robots is the walking beam. A one-quarter scale prototype of the walking beam was built by Martin Marietta to evaluate the potential merits of utilizing the vehicle as a planetary rover. The initial phase of prototype rover testing was structured to evaluate the mobility performance aspects of the vehicle. Performance parameters such as vehicle power, speed, and attitude control were evaluated as a function of the environment in which the prototype vehicle was tested. Subsequent testing phases will address the integrated performance of the vehicle and a local navigation system.

Terrain Interaction With The Quarter Scale Beam Walker

NASA Astrophysics Data System (ADS)

Chun, Wendell H.; Price, R. S.; Spiessbach, Andrew J.

1990-03-01

Frame walkers are a class of mobile robots that are robust and capable mobility platforms. Variations of the frame walker robot are in commercial use today. Komatsu Ltd. of Japan developed the Remotely Controlled Underwater Surveyor (ReCUS) and Normed Shipyards of France developed the Marine Robot (RM3). Both applications of the frame walker concept satisfied robotic mobility requirements that could not be met by a wheeled or tracked design. One vehicle design concept that falls within this class of mobile robots is the walking beam. A one-quarter scale prototype of the walking beam was built by Martin Marietta to evaluate the potential merits of utilizing the vehicle as a planetary rover. The initial phase of prototype rover testing was structured to evaluate the mobility performance aspects of the vehicle. Performance parameters such as vehicle power, speed, and attitude control were evaluated as a function of the environment in which the prototype vehicle was tested. Subsequent testing phases will address the integrated performance of the vehicle and a local navigation system.

Synthetic Fiber Capstan Drives for Highly Efficient, Torque Controlled, Robotic Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazumdar, Anirban; Spencer, Steven James; Hobart, Clinton

Here this paper describes the design and performance of a synthetic rope on sheave drive system. This system uses synthetic ropes instead of steel cables to achieve low weight and a compact form factor. We demonstrate how this system is capable of 28-Hz torque control bandwidth, 95% efficiency, and quiet operation, making it ideal for use on legged robots and other dynamic physically interactive systems. Component geometry and tailored maintenance procedures are used to achieve high endurance. Endurance tests based on walking data predict that the ropes will survive roughly 247,000 cycles when used on large (90 kg), fully actuatedmore » bipedal robot systems. The drive systems have been incorporated into two novel bipedal robots capable of three-dimensional unsupported walking. Robot data illustrate effective torque tracking and nearly silent operation. Finally, comparisons with alternative transmission designs illustrate the size, weight, and endurance advantages of using this type of synthetic rope drive system.« less

Synthetic Fiber Capstan Drives for Highly Efficient, Torque Controlled, Robotic Applications

DOE PAGES

Mazumdar, Anirban; Spencer, Steven James; Hobart, Clinton; ...

2017-01-05

Here this paper describes the design and performance of a synthetic rope on sheave drive system. This system uses synthetic ropes instead of steel cables to achieve low weight and a compact form factor. We demonstrate how this system is capable of 28-Hz torque control bandwidth, 95% efficiency, and quiet operation, making it ideal for use on legged robots and other dynamic physically interactive systems. Component geometry and tailored maintenance procedures are used to achieve high endurance. Endurance tests based on walking data predict that the ropes will survive roughly 247,000 cycles when used on large (90 kg), fully actuatedmore » bipedal robot systems. The drive systems have been incorporated into two novel bipedal robots capable of three-dimensional unsupported walking. Robot data illustrate effective torque tracking and nearly silent operation. Finally, comparisons with alternative transmission designs illustrate the size, weight, and endurance advantages of using this type of synthetic rope drive system.« less

Hierarchical Shared Control of Cane-Type Walking-Aid Robot

PubMed Central

Tao, Chunjing

2017-01-01

A hierarchical shared-control method of the walking-aid robot for both human motion intention recognition and the obstacle emergency-avoidance method based on artificial potential field (APF) is proposed in this paper. The human motion intention is obtained from the interaction force measurements of the sensory system composed of 4 force-sensing registers (FSR) and a torque sensor. Meanwhile, a laser-range finder (LRF) forward is applied to detect the obstacles and try to guide the operator based on the repulsion force calculated by artificial potential field. An obstacle emergency-avoidance method which comprises different control strategies is also assumed according to the different states of obstacles or emergency cases. To ensure the user's safety, the hierarchical shared-control method combines the intention recognition method with the obstacle emergency-avoidance method based on the distance between the walking-aid robot and the obstacles. At last, experiments validate the effectiveness of the proposed hierarchical shared-control method. PMID:29093805

A simple 5-DOF walking robot for space station application

NASA Technical Reports Server (NTRS)

Brown, H. Benjamin, Jr.; Friedman, Mark B.; Kanade, Takeo

1991-01-01

Robots on the NASA space station have a potential range of applications from assisting astronauts during EVA (extravehicular activity), to replacing astronauts in the performance of simple, dangerous, and tedious tasks; and to performing routine tasks such as inspections of structures and utilities. To provide a vehicle for demonstrating the pertinent technologies, a simple robot is being developed for locomotion and basic manipulation on the proposed space station. In addition to the robot, an experimental testbed was developed, including a 1/3 scale (1.67 meter modules) truss and a gravity compensation system to simulate a zero-gravity environment. The robot comprises two flexible links connected by a rotary joint, with a 2 degree of freedom wrist joints and grippers at each end. The grippers screw into threaded holes in the nodes of the space station truss, and enable it to walk by alternately shifting the base of support from one foot (gripper) to the other. Present efforts are focused on mechanical design, application of sensors, and development of control algorithms for lightweight, flexible structures. Long-range research will emphasize development of human interfaces to permit a range of control modes from teleoperated to semiautonomous, and coordination of robot/astronaut and multiple-robot teams.

Robot-Assisted Training Early After Cardiac Surgery.

PubMed

Schoenrath, Felix; Markendorf, Susanne; Brauchlin, Andreas E; Seifert, Burkhardt; Wilhelm, Markus J; Czerny, Martin; Riener, Robert; Falk, Volkmar; Schmied, Christian M

2015-07-01

To assess feasibility and safety of a robot-assisted gait therapy with the Lokomat® system in patients early after open heart surgery. Within days after open heart surgery 10 patients were subjected to postoperative Lokomat® training (Intervention group, IG) whereas 20 patients served as controls undergoing standard postoperative physiotherapy (Control group, CG). All patients underwent six-minute walk test and evaluation of the muscular strength of the lower limbs by measuring quadriceps peak force. The primary safety end-point was freedom from any device-related wound healing disturbance. Patients underwent clinical follow-up after one month. Both training methods resulted in an improvement of walking distance (IG [median, interquartile range, p-value]: +119 m, 70-201 m, p = 0.005; CG: 105 m, 57-152.5m, p < 0.001) and quadriceps peak force (IG left: +5 N, 3.8 7 N, p = 0.005; IG right: +3.5 N, 1.5-8.8 N, p = 0.011; CG left: +5.5 N, 4-9 N, p < 0.001; CG right: +6 N, 4.3-9.8 N, p < 0.001) in all participants. Results with robot-assisted training were comparable to early postoperative standard in hospital training (median changes in walking distance in percent, p = 0.81; median changes in quadriceps peak force in percent, left: p = 0.97, right p = 0.61). No deep sternal wound infection or any adverse event occurred in the robot-assisted training group. Robot-assisted gait therapy with the Lokomat® system is feasible and safe in patients early after median sternotomy. Results with robot-assisted training were comparable to standard in hospital training. An adapted and combined aerobic and resistance training intervention with augmented feedback may result in benefits in walking distance and lower limb muscle strength (ClinicalTrials.gov number, NCT 02146196). © 2015 Wiley Periodicals, Inc.

Locomotor training using an overground robotic exoskeleton in long-term manual wheelchair users with a chronic spinal cord injury living in the community: Lessons learned from a feasibility study in terms of recruitment, attendance, learnability, performance and safety.

PubMed

Gagnon, Dany H; Escalona, Manuel J; Vermette, Martin; Carvalho, Lívia P; Karelis, Antony D; Duclos, Cyril; Aubertin-Leheudre, Mylène

2018-03-01

For individuals who sustain a complete motor spinal cord injury (SCI) and rely on a wheelchair as their primary mode of locomotion, overground robotic exoskeletons represent a promising solution to stand and walk again. Although overground robotic exoskeletons have gained tremendous attention over the past decade and are now being transferred from laboratories to clinical settings, their effects remain unclear given the paucity of scientific evidence and the absence of large-scale clinical trials. This study aims to examine the feasibility of a locomotor training program with an overground robotic exoskeleton in terms of recruitment, attendance, and drop-out rates as well as walking performance, learnability, and safety. Individuals with a SCI were invited to participate in a 6 to 8-week locomotor training program with a robotic exoskeleton encompassing 18 sessions. Selected participants underwent a comprehensive screening process and completed two familiarization sessions with the robotic exoskeleton. The outcome measures were the rate of recruitment of potential participants, the rate of attendance at training sessions, the rate of drop-outs, the ability to walk with the exoskeleton, and its progression over the program as well as the adverse events. Out of 49 individuals who expressed their interest in participating in the study, only 14 initiated the program (recruitment rate = 28.6%). Of these, 13 individuals completed the program (drop-out rate = 7.1%) and attended 17.6 ± 1.1 sessions (attendance rate = 97.9%). Their greatest standing time, walking time, and number of steps taken during a session were 64.5 ± 10.2 min, 47.2 ± 11.3 min, and 1843 ± 577 steps, respectively. During the training program, these last three parameters increased by 45.3%, 102.1%, and 248.7%, respectively. At the end of the program, when walking with the exoskeleton, most participants required one therapist (85.7%), needed stand-by or contact-guard assistance (57.1%), used forearm crutches (71.4%), and reached a walking speed of 0.25 ± 0.05 m/s. Five participants reported training-related pain or stiffness in the upper extremities during the program. One participant sustained bilateral calcaneal fractures and stopped the program. This study confirms that larger clinical trials investigating the effects of a locomotor training program with an overground robotic exoskeleton are feasible and relatively safe in individuals with complete motor SCI. Moreover, to optimize the recruitment rate and safety in future trials, this study now highlights the need of developing pre-training rehabilitation programs to increase passive lower extremity range of motion and standing tolerance. This study also calls for the development of clinical practice guidelines targeting fragility fracture risk assessment linked to the use of overground robotic exoskeletons.

Turning and Radius Deviation Correction for a Hexapod Walking Robot Based on an Ant-Inspired Sensory Strategy

PubMed Central

Guo, Tong; Liu, Qiong; Zhu, Qianwei; Zhao, Xiangmo; Jin, Bo

2017-01-01

In order to find a common approach to plan the turning of a bio-inspired hexapod robot, a locomotion strategy for turning and deviation correction of a hexapod walking robot based on the biological behavior and sensory strategy of ants. A series of experiments using ants were carried out where the gait and the movement form of ants was studied. Taking the results of the ant experiments as inspiration by imitating the behavior of ants during turning, an extended turning algorithm based on arbitrary gait was proposed. Furthermore, after the observation of the radius adjustment of ants during turning, a radius correction algorithm based on the arbitrary gait of the hexapod robot was raised. The radius correction surface function was generated by fitting the correction data, which made it possible for the robot to move in an outdoor environment without the positioning system and environment model. The proposed algorithm was verified on the hexapod robot experimental platform. The turning and radius correction experiment of the robot with several gaits were carried out. The results indicated that the robot could follow the ideal radius and maintain stability, and the proposed ant-inspired turning strategy could easily make free turns with an arbitrary gait. PMID:29168742

Turning and Radius Deviation Correction for a Hexapod Walking Robot Based on an Ant-Inspired Sensory Strategy.

PubMed

Zhu, Yaguang; Guo, Tong; Liu, Qiong; Zhu, Qianwei; Zhao, Xiangmo; Jin, Bo

2017-11-23

Abstract : In order to find a common approach to plan the turning of a bio-inspired hexapod robot, a locomotion strategy for turning and deviation correction of a hexapod walking robot based on the biological behavior and sensory strategy of ants. A series of experiments using ants were carried out where the gait and the movement form of ants was studied. Taking the results of the ant experiments as inspiration by imitating the behavior of ants during turning, an extended turning algorithm based on arbitrary gait was proposed. Furthermore, after the observation of the radius adjustment of ants during turning, a radius correction algorithm based on the arbitrary gait of the hexapod robot was raised. The radius correction surface function was generated by fitting the correction data, which made it possible for the robot to move in an outdoor environment without the positioning system and environment model. The proposed algorithm was verified on the hexapod robot experimental platform. The turning and radius correction experiment of the robot with several gaits were carried out. The results indicated that the robot could follow the ideal radius and maintain stability, and the proposed ant-inspired turning strategy could easily make free turns with an arbitrary gait.

Task Adaptive Walking Robots for Mars Surface Exploration

NASA Technical Reports Server (NTRS)

Huntsberger, Terry; Hickey, Gregory; Kennedy, Brett; Aghazarian, Hrand

2000-01-01

There are exciting opportunities for robot science that lie beyond the reach of current manipulators, rovers, balloons, penetrators, etc. Examples include mobile explorations of the densely cratered Mars highlands, of asteroids, and of moons. These sites are believed to be rich in geologic history and mineralogical detail, but are difficult to robotically access and sample. The surface terrains are rough and changeable, with variable porosity and dust layering; and the small bodies present further challenges of low-temperature, micro-gravity environments. Even the more benign areas of Mars are highly variegated in character (>VL2 rock densities), presenting significant risk to conventional rovers. The development of compact walking robots would have applications to the current mission set for Mars surface exploration, as well as enabling future Mars Outpost missions, asteroid rendezvous missions for the Solar System Exploration Program (SSE) and the mechanical assembly/inspection of large space platforms for the Human Exploration and Development of Spaces (HEDS).

Robotic Lower Limb Exoskeletons Using Proportional Myoelectric Control

PubMed Central

Ferris, Daniel P.; Lewis, Cara L.

2010-01-01

Robotic lower limb exoskeletons have been built for augmenting human performance, assisting with disabilities, studying human physiology, and re-training motor deficiencies. At the University of Michigan Human Neuromechanics Laboratory, we have built pneumatically-powered lower limb exoskeletons for the last two purposes. Most of our prior research has focused on ankle joint exoskeletons because of the large contribution from plantar flexors to the mechanical work performed during gait. One way we control the exoskeletons is with proportional myoelectric control, effectively increasing the strength of the wearer with a physiological mode of control. Healthy human subjects quickly adapt to walking with the robotic ankle exoskeletons, reducing their overall energy expenditure. Individuals with incomplete spinal cord injury have demonstrated rapid modification of muscle recruitment patterns with practice walking with the ankle exoskeletons. Evidence suggests that proportional myoelectric control may have distinct advantages over other types of control for robotic exoskeletons in basic science and rehabilitation. PMID:19964579

The newly expanded KSC Visitors Complex features a new ticket plaza, information center, exhibits an

NASA Technical Reports Server (NTRS)

1999-01-01

A host robot, Starquester 2000, helps describe for visitors the accomplishments of unsung space heroes - space probes - and their role in space exploration. The walk-through Robot Scouts exhibit is part of the $13 million expansion to KSC's Visitor Complex. Other additions include a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. Inaugurated three decades ago, the Visitor Complex is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge.

KSC-99pp0400

NASA Image and Video Library

1999-04-08

KENNEDY SPACE CENTER, FLA. -- A host robot, Starquester 2000, helps describe for visitors the accomplishments of unsung space heroes space probes and their role in space exploration. The walk-through Robot Scouts exhibit is part of the $13 million expansion to KSC's Visitor Complex. Other additions include a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. Inaugurated three decades ago, the Visitor Complex is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge

Combining gait optimization with passive system to increase the energy efficiency of a humanoid robot walking movement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pereira, Ana I.; ALGORITMI,University of Minho; Lima, José

There are several approaches to create the Humanoid robot gait planning. This problem presents a large number of unknown parameters that should be found to make the humanoid robot to walk. Optimization in simulation models can be used to find the gait based on several criteria such as energy minimization, acceleration, step length among the others. The energy consumption can also be reduced with elastic elements coupled to each joint. The presented paper addresses an optimization method, the Stretched Simulated Annealing, that runs in an accurate and stable simulation model to find the optimal gait combined with elastic elements. Finalmore » results demonstrate that optimization is a valid gait planning technique.« less

Reducing Circumduction and Hip Hiking During Hemiparetic Walking Through Targeted Assistance of the Paretic Limb Using a Soft Robotic Exosuit.

PubMed

Awad, Louis N; Bae, Jaehyun; Kudzia, Pawel; Long, Andrew; Hendron, Kathryn; Holt, Kenneth G; OʼDonnell, Kathleen; Ellis, Terry D; Walsh, Conor J

2017-10-01

The aim of the study was to evaluate the effects on common poststroke gait compensations of a soft wearable robot (exosuit) designed to assist the paretic limb during hemiparetic walking. A single-session study of eight individuals in the chronic phase of stroke recovery was conducted. Two testing conditions were compared: walking with the exosuit powered versus walking with the exosuit unpowered. Each condition was 8 minutes in duration. Compared with walking with the exosuit unpowered, walking with the exosuit powered resulted in reductions in hip hiking (27 [6%], P = 0.004) and circumduction (20 [5%], P = 0.004). A relationship between changes in knee flexion and changes in hip hiking was observed (Pearson r = -0.913, P < 0.001). Similarly, multivariate regression revealed that changes in knee flexion (β = -0.912, P = 0.007), but not ankle dorsiflexion (β = -0.194, P = 0.341), independently predicted changes in hip hiking (R = 0.87, F(2, 4) = 13.48, P = 0.017). Exosuit assistance of the paretic limb during walking produces immediate changes in the kinematic strategy used to advance the paretic limb. Future work is necessary to determine how exosuit-induced reductions in paretic hip hiking and circumduction during gait training could be leveraged to facilitate more normal walking behavior during unassisted walking.

Clinical Characteristics of Proper Robot-Assisted Gait Training Group in Non-ambulatory Subacute Stroke Patients

PubMed Central

Kim, Soo Jeong; Lee, Hye Jin; Hwang, Seung Won; Pyo, Hannah; Yang, Sung Phil; Lim, Mun-Hee; Park, Gyu Lee

2016-01-01

Objective To identify the clinical characteristics of proper robot-assisted gait training group using exoskeletal locomotor devices in non-ambulatory subacute stroke patients. Methods A total of 38 stroke patients were enrolled in a 4-week robotic training protocol (2 sessions/day, 5 times/week). All subjects were evaluated for their general characteristics, Functional Ambulatory Classification (FAC), Fugl-Meyer Scale (FMS), Berg Balance Scale (BBS), Modified Rankin Scale (MRS), Modified Barthel Index (MBI), and Mini-Mental Status Examination (MMSE) at 0, 2, and 4 weeks. Statistical analysis were performed to determine significant clinical characteristics for improvement of gait function after robot-assisted gait training. Results Paired t-test showed that all functional parameters except MMSE were improved significantly (p<0.05). The duration of disease and baseline BBS score were significantly (p<0.05) correlated with FAC score in multiple regression models. Receiver operating characteristic (ROC) curve showed that a baseline BBS score of '9' was a cutoff value (AUC, 0.966; sensitivity, 91%–100%; specificity, 85%). By repeated-measures ANOVA, the differences in improved walking ability according to time were significant between group of patients who had baseline BBS score of '9' and those who did not have baseline BBS score of '9' Conclusion Our results showed that a baseline BBS score above '9' and a short duration of disease were highly correlated with improved walking ability after robot-assisted gait training. Therefore, baseline BBS and duration of disease should be considered clinically for gaining walking ability in robot-assisted training group. PMID:27152266

Design of biped hip simulator using SolidWorks

NASA Astrophysics Data System (ADS)

Zainudin, M. R.; Yahya, A.; Fazli, M. I. M.; Syahrom, A.; Harun, F. K. C.; Nazarudin, M. S.

2017-10-01

The increasing number of people who underwent both hip implant surgery based on World Health Organization (WHO) has received massive attention from researchers lately to develop various types of hip simulators in order to test the hip implant. Various number of hip simulator have been developed with different functions and capabilities. This paper presents the design development of biped hip simulator using SolidWorks software by taking into consideration some improvement and modifications. The finite element method is used to test the design whether it is safe to be used or not. The biped hip simulator has been successfully designed and ready to be fabricated as the endurance testing shown a positive results. The von Mises stress induced in the material is an alloy steel which is 2,975,862.3 N/m2 lower than the yield strength. Thus, the design is safe to be used as it obey the safety criterion.

FootSpring: A Compliance Model for the ATHLETE Family of Robots

NASA Technical Reports Server (NTRS)

Wheeler, Dawn Deborah; Chavez-Clemente, Daniel; Sunspiral, Vytas K.

2010-01-01

This paper describes and evaluates one method of modeling compliance in a wheel-on-leg walking robot. This method assumes that all of the robot s compliance takes place at the ground contact points, specifically the tires and legs, and that the rest of the robot is rigid. Optimization is used to solve for the displacement of the feet and of the center of gravity. This method was tested on both robots of the ATHLETE family, which have different compliance. For both robots, the model predicts the sag of points on the robot chassis with an average error of about one percent of the height of the robot.

Distributed recurrent neural forward models with synaptic adaptation and CPG-based control for complex behaviors of walking robots

PubMed Central

Dasgupta, Sakyasingha; Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

2015-01-01

Walking animals, like stick insects, cockroaches or ants, demonstrate a fascinating range of locomotive abilities and complex behaviors. The locomotive behaviors can consist of a variety of walking patterns along with adaptation that allow the animals to deal with changes in environmental conditions, like uneven terrains, gaps, obstacles etc. Biological study has revealed that such complex behaviors are a result of a combination of biomechanics and neural mechanism thus representing the true nature of embodied interactions. While the biomechanics helps maintain flexibility and sustain a variety of movements, the neural mechanisms generate movements while making appropriate predictions crucial for achieving adaptation. Such predictions or planning ahead can be achieved by way of internal models that are grounded in the overall behavior of the animal. Inspired by these findings, we present here, an artificial bio-inspired walking system which effectively combines biomechanics (in terms of the body and leg structures) with the underlying neural mechanisms. The neural mechanisms consist of (1) central pattern generator based control for generating basic rhythmic patterns and coordinated movements, (2) distributed (at each leg) recurrent neural network based adaptive forward models with efference copies as internal models for sensory predictions and instantaneous state estimations, and (3) searching and elevation control for adapting the movement of an individual leg to deal with different environmental conditions. Using simulations we show that this bio-inspired approach with adaptive internal models allows the walking robot to perform complex locomotive behaviors as observed in insects, including walking on undulated terrains, crossing large gaps, leg damage adaptations, as well as climbing over high obstacles. Furthermore, we demonstrate that the newly developed recurrent network based approach to online forward models outperforms the adaptive neuron forward models, which have hitherto been the state of the art, to model a subset of similar walking behaviors in walking robots. PMID:26441629

A robot and control algorithm that can synchronously assist in naturalistic motion during body-weight-supported gait training following neurologic injury.

PubMed

Aoyagi, Daisuke; Ichinose, Wade E; Harkema, Susan J; Reinkensmeyer, David J; Bobrow, James E

2007-09-01

Locomotor training using body weight support on a treadmill and manual assistance is a promising rehabilitation technique following neurological injuries, such as spinal cord injury (SCI) and stroke. Previous robots that automate this technique impose constraints on naturalistic walking due to their kinematic structure, and are typically operated in a stiff mode, limiting the ability of the patient or human trainer to influence the stepping pattern. We developed a pneumatic gait training robot that allows for a full range of natural motion of the legs and pelvis during treadmill walking, and provides compliant assistance. However, we observed an unexpected consequence of the device's compliance: unimpaired and SCI individuals invariably began walking out-of-phase with the device. Thus, the robot perturbed rather than assisted stepping. To address this problem, we developed a novel algorithm that synchronizes the device in real-time to the actual motion of the individual by sensing the state error and adjusting the replay timing to reduce this error. This paper describes data from experiments with individuals with SCI that demonstrate the effectiveness of the synchronization algorithm, and the potential of the device for relieving the trainers of strenuous work while maintaining naturalistic stepping.

Robot-Assisted Body-Weight-Supported Treadmill Training in Gait Impairment in Multiple Sclerosis Patients: A Pilot Study.

PubMed

Łyp, Marek; Stanisławska, Iwona; Witek, Bożena; Olszewska-Żaczek, Ewelina; Czarny-Działak, Małgorzata; Kaczor, Ryszard

2018-02-13

This study deals with the use of a robot-assisted body-weight-supported treadmill training in multiple sclerosis (MS) patients with gait dysfunction. Twenty MS patients (10 men and 10 women) of the mean of 46.3 ± 8.5 years were assigned to a six-week-long training period with the use of robot-assisted treadmill training of increasing intensity of the Lokomat type. The outcome measure consisted of the difference in motion-dependent torque of lower extremity joint muscles after training compared with baseline before training. We found that the training uniformly and significantly augmented the torque of both extensors and flexors of the hip and knee joints. The muscle power in the lower limbs of SM patients was improved, leading to corrective changes of disordered walking movements, which enabled the patients to walk with less effort and less assistance of care givers. The torque augmentation could have its role in affecting the function of the lower extremity muscle groups during walking. The results of this pilot study suggest that the robot-assisted body-weight-supported treadmill training may be a potential adjunct measure in the rehabilitation paradigm of 'gait reeducation' in peripheral neuropathies.

Movement augmentation to evaluate human control of locomotor stability.

PubMed

Brown, Geoffrey; Wu, Mengnan Mary; Huang, Felix C; Gordon, Keith E

2017-07-01

Controlling center of mass (COM) position and velocity within a dynamic base of support is essential for gait stability. This skill is often compromised following neurologic injury, creating a need to develop effective interventions to enhance gait stability. A movement augmentation paradigm applied to walking could potentially be used to improve control of COM dynamics. We have developed a cable robot system, the Agility Trainer, to apply continuous frontal-plane forces to the pelvis during treadmill walking. This cable robot system uses a set of series elastic actuators powered by linear motors to create bilateral forces. Here we use the Agility Trainer to create a negative viscosity force field proportional to the subject's lateral velocity. Two healthy young subjects performed two 10-minute walking trials, Baseline and Negative Viscosity. During the first minute of walking in the Negative Viscosity field, participants' lateral COM motion became less controlled when compared to the rhythmic sinusoidal motion observed during Baseline walking. By the 10th minute of walking in the Negative Viscosity field the participants had adapted their gait patterns, decreasing their variation in peak lateral COM speed each stride. These results demonstrate that it is feasible to use the Agility Trainer to apply a movement augmentation paradigm to human walking.

The features of Gait Exercise Assist Robot: Precise assist control and enriched feedback.

PubMed

Hirano, Satoshi; Saitoh, Eiichi; Tanabe, Shigeo; Tanikawa, Hiroki; Sasaki, Shinya; Kato, Daisuke; Kagaya, Hitoshi; Itoh, Norihide; Konosu, Hitoshi

2017-01-01

In a patient with severe hemiplegia, the risk of the knee giving way is high during the early stage of gait exercise with an ankle-foot orthosis. However, use of a knee-ankle-foot orthosis has many problems such as large amount of assistance and compensatory motions. To resolve these problems, we have engaged in the development of the Gait Exercise Assist Robot (GEAR). To evaluate the improvement efficiency of walk with GEAR in a stroke patient. The subject was a 70-year-old man presented with left thalamus hemorrhage and right hemiplegia. The patient underwent exercise with the GEAR 5 days a week, for 40 minutes per day. We evaluated the Functional Independence Measure score for walk (FIM-walk score) every week. The control group consisted of 15 patients aged 20-75 years with hemiplegia after primary stroke, who had equivalent walking ability with the subject at start. As the primary outcome, we defined improvement efficiency of FIM-walk, which was gain of FIM-walk divided the number of required weeks. Improvement efficiency of FIM-walk of the subject was 1.5, while that of control group was 0.48±3.2 (mean±SD). GEAR is potentially useful for gait exercise in hemiplegic patients.

Model-based safety analysis of human-robot interactions: the MIRAS walking assistance robot.

PubMed

Guiochet, Jérémie; Hoang, Quynh Anh Do; Kaaniche, Mohamed; Powell, David

2013-06-01

Robotic systems have to cope with various execution environments while guaranteeing safety, and in particular when they interact with humans during rehabilitation tasks. These systems are often critical since their failure can lead to human injury or even death. However, such systems are difficult to validate due to their high complexity and the fact that they operate within complex, variable and uncertain environments (including users), in which it is difficult to foresee all possible system behaviors. Because of the complexity of human-robot interactions, rigorous and systematic approaches are needed to assist the developers in the identification of significant threats and the implementation of efficient protection mechanisms, and in the elaboration of a sound argumentation to justify the level of safety that can be achieved by the system. For threat identification, we propose a method called HAZOP-UML based on a risk analysis technique adapted to system description models, focusing on human-robot interaction models. The output of this step is then injected in a structured safety argumentation using the GSN graphical notation. Those approaches have been successfully applied to the development of a walking assistant robot which is now in clinical validation.

Hardware Development and Locomotion Control Strategy for an Over-Ground Gait Trainer: NaTUre-Gaits.

PubMed

Luu, Trieu Phat; Low, Kin Huat; Qu, Xingda; Lim, Hup Boon; Hoon, Kay Hiang

2014-01-01

Therapist-assisted body weight supported (TABWS) gait rehabilitation was introduced two decades ago. The benefit of TABWS in functional recovery of walking in spinal cord injury and stroke patients has been demonstrated and reported. However, shortage of therapists, labor-intensiveness, and short duration of training are some limitations of this approach. To overcome these deficiencies, robotic-assisted gait rehabilitation systems have been suggested. These systems have gained attentions from researchers and clinical practitioner in recent years. To achieve the same objective, an over-ground gait rehabilitation system, NaTUre-gaits, was developed at the Nanyang Technological University. The design was based on a clinical approach to provide four main features, which are pelvic motion, body weight support, over-ground walking experience, and lower limb assistance. These features can be achieved by three main modules of NaTUre-gaits: 1) pelvic assistance mechanism, mobile platform, and robotic orthosis. Predefined gait patterns are required for a robotic assisted system to follow. In this paper, the gait pattern planning for NaTUre-gaits was accomplished by an individual-specific gait pattern prediction model. The model generates gait patterns that resemble natural gait patterns of the targeted subjects. The features of NaTUre-gaits have been demonstrated by walking trials with several subjects. The trials have been evaluated by therapists and doctors. The results show that 10-m walking trial with a reduction in manpower. The task-specific repetitive training approach and natural walking gait patterns were also successfully achieved.

Hardware Development and Locomotion Control Strategy for an Over-Ground Gait Trainer: NaTUre-Gaits

PubMed Central

Low, Kin Huat; Qu, Xingda; Lim, Hup Boon; Hoon, Kay Hiang

2014-01-01

Therapist-assisted body weight supported (TABWS) gait rehabilitation was introduced two decades ago. The benefit of TABWS in functional recovery of walking in spinal cord injury and stroke patients has been demonstrated and reported. However, shortage of therapists, labor-intensiveness, and short duration of training are some limitations of this approach. To overcome these deficiencies, robotic-assisted gait rehabilitation systems have been suggested. These systems have gained attentions from researchers and clinical practitioner in recent years. To achieve the same objective, an over-ground gait rehabilitation system, NaTUre-gaits, was developed at the Nanyang Technological University. The design was based on a clinical approach to provide four main features, which are pelvic motion, body weight support, over-ground walking experience, and lower limb assistance. These features can be achieved by three main modules of NaTUre-gaits: 1) pelvic assistance mechanism, mobile platform, and robotic orthosis. Predefined gait patterns are required for a robotic assisted system to follow. In this paper, the gait pattern planning for NaTUre-gaits was accomplished by an individual-specific gait pattern prediction model. The model generates gait patterns that resemble natural gait patterns of the targeted subjects. The features of NaTUre-gaits have been demonstrated by walking trials with several subjects. The trials have been evaluated by therapists and doctors. The results show that 10-m walking trial with a reduction in manpower. The task-specific repetitive training approach and natural walking gait patterns were also successfully achieved. PMID:27170876

0g Climbing - The Challenge of Walking in Space

NASA Technical Reports Server (NTRS)

Ambrose, Robert O.; Rehnmark, Frederik; Goza, Michael

2003-01-01

Space walking is poorly named, as it has little in common with how animals walk on Earth. Space walking is more akin to mountain climbing in scuba gear, while parachuting in a freefall -- an odd combination of effects and equipment to help people do a demanding job. Robots are now being studied for service in this same domain, working on large scale space structures like the Space Station, servicing science or military platforms in high orbit, or riding on the outside of a space craft in transit to Mars, the Moon or other destinations. What have we learned about climbing in 0g? How should machines be controlled for serving in this role? What can they do to overcome the problems that humans have faced? In order to move about in this environment, a robot must be able to climb autonomously, using gaits that smoothly manage its momentum and that minimize contact forces (walking lightly) while providing for safety in the event of an emergency requiring the system to stop. All three of these objectives are now being explored at NASA's Johnson Space Center, using the Robonaut system and a set of mockups that emulate the 0g condition. NASA's goal for Robonaut is to develop the control technology that will allow it to climb on the outside of the Space Shuttle, the Space Station, and satellite mockups at JSC, enabling the robot to perform EVA task setups or serve as an Astronaut's assistant.

0g Climbing - The Challenge of Walking in Space

NASA Technical Reports Server (NTRS)

Ambrose, Robert O.; Rehnmark, Frederik; Goza, Michael

2004-01-01

Space walking is poorly named, as it has little in common with how animals walk on Earth. Space walking is more akin to mountain climbing in scuba gear, while parachuting in a freefall-an odd combination of effects and equipment to help people do a demanding job. Robots are now being studied for service in this same domain, working on large scale space structures like the Space Station, servicing science or military platforms in high orbit, or riding on the outside of a space craft in transit to Mars, the Moon or other destinations. What have we learned about climbing in 0g? How should machines be controlled for serving in this role? What can they do to overcome the problems that humans have faced? In order to move about in this environment, a robot must be able to climb autonomously, using gaits that smoothly manage its momentum and that minimize contact forces (walking lightly) while providing for safety in the event of an emergency requiring the system to stop. All three of these objectives are now being explored at NASA's Johnson Space Center, using the Robonaut system and a set of mockups that emulate the 0g condition. NASA's goal for Robonaut is to develop the control technology that will allow it to climb on the outside of the Space Shuttle, the Space Station, and satellite mockups at JSC, enabling the robot to perform EVA task setups or serve as an Astronaut's assistant.

Hairless mutation: a driving force of humanization from a human–ape common ancestor by enforcing upright walking while holding a baby with both hands

PubMed Central

Sutou, Shizuyo

2012-01-01

Three major characteristics distinguish humans from other primates: bipedality, practical nakedness, and the family as a social unit. A hairless mutation introduced into the chimpanzee/human last common ancestor (CLCA) 6 million years ago (Mya) diverged hairless human and hairy chimpanzee lineages. All primates except humans can carry their babies without using their hands. A hairless mother would be forced to stand and walk upright. Her activities would be markedly limited. The male partner would have to collect food and carry it to her by hand to keep her and their baby from starving; irresponsible and selfish males could not have left their offspring. The mother would have sexually accepted her partner at any time as a reward for food. Sexual relations irrespective of estrus cycles might have strengthened the pair bond. Molecular and paleontological dating indicates that CLCA existed 6 Mya, and early hominin fossils show that they were bipeds, indicating that humanization from CLCA occurred rapidly. A single mutation in animals with scalp hair is known to induce hairless phenotype (ectodermal dysplasia). Bipedalism and hairlessness are disadvantageous traits; only those who could survive trials and tribulations in cooperation with family members must have been able to evolve as humans. PMID:22404045

What does best evidence tell us about robotic gait rehabilitation in stroke patients: A systematic review and meta-analysis.

PubMed

Bruni, Maria Federica; Melegari, Corrado; De Cola, Maria Cristina; Bramanti, Alessia; Bramanti, Placido; Calabrò, Rocco Salvatore

2018-02-01

Studies about electromechanical-assisted devices proved the validity and effectiveness of these tools in gait rehabilitation, especially if used in association with conventional physiotherapy in stroke patients. The aim of this study was to compare the effects of different robotic devices in improving post-stroke gait abnormalities. A computerized literature research of articles was conducted in the databases MEDLINE, PEDro, COCHRANE, besides a search for the same items in the Library System of the University of Parma (Italy). We selected 13 randomized controlled trials, and the results were divided into sub-acute stroke patients and chronic stroke patients. We selected studies including at least one of the following test: 10-Meter Walking Test, 6-Minute Walk Test, Timed-Up-and-Go, 5-Meter Walk Test, and Functional Ambulation Categories. Stroke patients who received physiotherapy treatment in combination with robotic devices, such as Lokomat or Gait Trainer, were more likely to reach better results, compared to patients who receive conventional gait training alone. Moreover, electromechanical-assisted gait training in association with Functional Electrical Stimulations produced more benefits than the only robotic treatment (-0.80 [-1.14; -0.46], p > .05). The evaluation of the results confirm that the use of robotics can positively affect the outcome of a gait rehabilitation in patients with stroke. The effects of different devices seems to be similar on the most commonly outcome evaluated by this review. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of a six-legged planetary rover - Power, positioning, and autonomous walking

NASA Technical Reports Server (NTRS)

Krotkov, Eric; Simmons, Reid

1992-01-01

The authors quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. They present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. They document the accuracy of a novel dead reckoning approach, and analyze the accuracy. They describe the results of autonomous walking experiments in terms of terrain traversed, walking speed, number of instructions executed and endurance.

Performance of a six-legged planetary rover - Power, positioning, and autonomous walking

NASA Astrophysics Data System (ADS)

Krotkov, Eric; Simmons, Reid

The authors quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. They present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. They document the accuracy of a novel dead reckoning approach, and analyze the accuracy. They describe the results of autonomous walking experiments in terms of terrain traversed, walking speed, number of instructions executed and endurance.

A Quadruped Robot Exhibiting Spontaneous Gait Transitions from Walking to Trotting to Galloping.

PubMed

Owaki, Dai; Ishiguro, Akio

2017-03-21

The manner in which quadrupeds change their locomotive patterns-walking, trotting, and galloping-with changing speed is poorly understood. In this paper, we provide evidence for interlimb coordination during gait transitions using a quadruped robot for which coordination between the legs can be self-organized through a simple "central pattern generator" (CPG) model. We demonstrate spontaneous gait transitions between energy-efficient patterns by changing only the parameter related to speed. Interlimb coordination was achieved with the use of local load sensing only without any preprogrammed patterns. Our model exploits physical communication through the body, suggesting that knowledge of physical communication is required to understand the leg coordination mechanism in legged animals and to establish design principles for legged robots that can reproduce flexible and efficient locomotion.

NeuroRex: A Clinical Neural Interface Roadmap for EEG-based Brain Machine Interfaces to a Lower Body Robotic Exoskeleton*

PubMed Central

Contreras-Vidal, Jose L.; Grossman, Robert G.

2013-01-01

In this communication, a translational clinical brain-machine interface (BMI) roadmap for an EEG-based BMI to a robotic exoskeleton (NeuroRex) is presented. This multi-faceted project addresses important engineering and clinical challenges: It addresses the validation of an intelligent, self-balancing, robotic lower-body and trunk exoskeleton (Rex) augmented with EEG-based BMI capabilities to interpret user intent to assist a mobility-impaired person to walk independently. The goal is to improve the quality of life and health status of wheelchair-bounded persons by enabling standing and sitting, walking and backing, turning, ascending and descending stairs/curbs, and navigating sloping surfaces in a variety of conditions without the need for additional support or crutches. PMID:24110003

LARM PKM solutions for torso design in humanoid robots

NASA Astrophysics Data System (ADS)

Ceccarelli, Marco

2014-12-01

Human-like torso features are essential in humanoid robots. In this paper problems for design and operation of solutions for a robotic torso are discussed by referring to experiences and designs that have been developed at Laboratory of Robotics and Mechatronics (LARM) in Cassino, Italy. A new solution is presented with conceptual views as waist-trunk structure that makes a proper partition of the performance for walking and arm operations as sustained by a torso.

Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs

NASA Astrophysics Data System (ADS)

Handford, Matthew L.; Srinivasan, Manoj

2016-02-01

Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user’s walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost - even lower than assuming that the non-amputee’s ankle torques are cost-free.

[A robotic system for gait re-education in patients with an incomplete spinal cord injury].

PubMed

Esclarín-De Ruz, A; Alcobendas-Maestro, M; Casado-López, R; Muñoz-Gonzalez, A; Florido-Sánchez, M A; González-Valdizán, E

A spinal cord injury involves the loss or alteration of motor patterns in walking, the recovery of which depends partly on the rearrangement of the preserved neural circuits. AIM. To evaluate the changes that take place in the gait of patients with incomplete spinal cord injuries who were treated with a robotic walking system in association with conventional therapy. The study conducted was an open-label, prospective, descriptive trial with statistical inference in patients with C2-L3 spinal cord injuries that were classified as degrees C and D according to the American Spinal Injury Association (ASIA) scale. The variables that were analysed on the first and the last day of the study were: number of walkers, 10-m gait test, the Walking Index for Spinal Cord Injury scale revision, technical aids, muscle balance in the lower limbs, locomotor subscale of the measure of functional independence, modified Ashworth scale for spasticity and the visual analogue scale for pain. At the end, data were recorded from the impression of change scale. The analysis was conducted by means of Student's t, chi squared and Pearson's correlation; p < or = 0.05. Forty-five patients, with a mean age of 44 +/- 14.3 years, finished the study; 76% were males, injury was caused by trauma in 58% of cases, and the time of progression was 139 +/- 70 days. Statistically significant increases were observed in the number of subjects capable of walking, walking speed, less need for technical aids, strength in the lower limbs and independence in activities of daily living. Treatment using the robotic system in association with conventional therapy improves walking capacity in patients with incomplete spinal cord injuries.

Using robot-applied resistance to augment body-weight-supported treadmill training in an individual with incomplete spinal cord injury.

PubMed

Lam, Tania; Pauhl, Katherine; Krassioukov, Andrei; Eng, Janice J

2011-01-01

The efficacy of task-specific gait training for people with spinal cord injury (SCI) is premised on evidence that the provision of gait-related afferent feedback is key for the recovery of stepping movements. Recent findings have shown that sensory feedback from flexor muscle afferents can facilitate flexor muscle activity during the swing phase of walking. This case report was undertaken to determine the feasibility of using robot-applied forces to resist leg movements during body-weight-supported treadmill training (BWSTT) and to measure its effect on gait and other health-related outcomes. The patient described in this case report was a 43-year-old man with a T11 incomplete chronic SCI. He underwent 36 sessions of BWSTT using a robotic gait orthosis to provide forces that resist hip and knee flexion. Tolerance to the training program was monitored using the Borg CR10 scale and heart rate and blood pressure changes during each training session. Outcome measures (ie, 10-Meter Walk Test, Six-Minute Walk Test, modified Emory Functional Ambulation Profile [mEFAP], Activities-specific Balance Confidence Scale, and Canadian Occupational Performance Measure) were completed and kinematic parameters of gait, lower-extremity muscle strength (force-generating capacity), lower-limb girth, and tolerance to orthostatic stress were measured before and after the training program. The patient could tolerate the training. Overground walking speed, endurance, and performance on all subtasks of the mEFAP improved and were accompanied by increased lower-limb joint flexion and toe clearance during gait. The patient's ambulatory self-confidence and self-perceived performance in walking also improved. These findings suggest that this new approach to BWSTT is a feasible and potentially effective therapy for improving skilled overground walking performance.

Human-like robots for space and hazardous environments

NASA Technical Reports Server (NTRS)

1994-01-01

The three year goal for the Kansas State USRA/NASA Senior Design team is to design and build a walking autonomous robotic rover. The rover should be capable of crossing rough terrain, traversing human made obstacles (such as stairs and doors), and moving through human and robot occupied spaces without collision. The rover is also to evidence considerable decision making ability, navigation, and path planning skills.

Human-like robots for space and hazardous environments

NASA Astrophysics Data System (ADS)

The three year goal for the Kansas State USRA/NASA Senior Design team is to design and build a walking autonomous robotic rover. The rover should be capable of crossing rough terrain, traversing human made obstacles (such as stairs and doors), and moving through human and robot occupied spaces without collision. The rover is also to evidence considerable decision making ability, navigation, and path planning skills.

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study

PubMed Central

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-01-01

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the interlimb coordination appeared in a manner that was similar to the late-type adaptations and after-effects observed in humans. The adaptation results of the robot were then evaluated in comparison with human split-belt treadmill walking, and the adaptation mechanism was clarified from a dynamic viewpoint. PMID:26289658

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study.

PubMed

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-09-06

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the interlimb coordination appeared in a manner that was similar to the late-type adaptations and after-effects observed in humans. The adaptation results of the robot were then evaluated in comparison with human split-belt treadmill walking, and the adaptation mechanism was clarified from a dynamic viewpoint. © 2015 The Authors.

Combined effects of cerebellar transcranial direct current stimulation and transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke: A pilot, single blind, randomized controlled trial.

PubMed

Picelli, Alessandro; Chemello, Elena; Castellazzi, Paola; Filippetti, Mirko; Brugnera, Annalisa; Gandolfi, Marialuisa; Waldner, Andreas; Saltuari, Leopold; Smania, Nicola

2018-01-01

Preliminary evidence showed additional effects of anodal transcranial direct current stimulation over the damaged cerebral hemisphere combined with cathodal transcutaneous spinal direct current stimulation during robot-assisted gait training in chronic stroke patients. This is consistent with the neural organization of locomotion involving cortical and spinal control. The cerebellum is crucial for locomotor control, in particular for avoidance of obstacles, and adaptation to novel conditions during walking. Despite its key role in gait control, to date the effects of transcranial direct current stimulation of the cerebellum have not been investigated on brain stroke patients treated with robot-assisted gait training. To evaluate the effects of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke. After balanced randomization, 20 chronic stroke patients received ten, 20-minute robot-assisted gait training sessions (five days a week, for two consecutive weeks) combined with central nervous system stimulation. Group 1 underwent on-line cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation. Group 2 received on-line anodal transcranial direct current stimulation over the damaged cerebral hemisphere + cathodal transcutaneous spinal direct current stimulation. The primary outcome was the 6-minute walk test performed before, after, and at follow-up at 2 and 4 weeks post-treatment. The significant differences in the 6-minute walk test noted between groups at the first post-treatment evaluation (p = 0.041) were not maintained at either the 2-week (P = 0.650) or the 4-week (P = 0.545) follow-up evaluations. Our preliminary findings support the hypothesis that cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere in combination with cathodal transcutaneous spinal direct current stimulation might be useful to boost the effects of robot-assisted gait training in chronic brain stroke patients with walking impairment.

Hardware Development for a Mobile Educational Robot.

ERIC Educational Resources Information Center

Mannaa, A. M.; And Others

1987-01-01

Describes the development of a robot whose mainframe is essentially transparent and walks on four legs. Discusses various gaits in four-legged motion. Reports on initial trials of a full-sized model without computer-control, including smoothness of motion and actual obstacle crossing features. (CW)

Human-like robots for space and hazardous environments

NASA Technical Reports Server (NTRS)

Cogley, Allen; Gustafson, David; White, Warren; Dyer, Ruth; Hampton, Tom (Editor); Freise, Jon (Editor)

1990-01-01

The three year goal for this NASA Senior Design team is to design and build a walking autonomous robotic rover. The rover should be capable of rough terrain crossing, traversing human made obstacles (such as stairs and doors), and moving through human and robot occupied spaces without collision. The rover is also to evidence considerable decision making ability, navigation and path planning skills. These goals came from the concept that the robot should have the abilities of both a planetary rover and a hazardous waste site scout.

Human-like robots for space and hazardous environments

NASA Astrophysics Data System (ADS)

Cogley, Allen; Gustafson, David; White, Warren; Dyer, Ruth; Hampton, Tom; Freise, Jon

The three year goal for this NASA Senior Design team is to design and build a walking autonomous robotic rover. The rover should be capable of rough terrain crossing, traversing human made obstacles (such as stairs and doors), and moving through human and robot occupied spaces without collision. The rover is also to evidence considerable decision making ability, navigation and path planning skills. These goals came from the concept that the robot should have the abilities of both a planetary rover and a hazardous waste site scout.

Metabolic and cardiac responses to robotic-assisted locomotion in motor-complete tetraplegia: a case report.

PubMed

Nash, Mark S; Jacobs, Patrick L; Johnson, Brad M; Field-Fote', Edelle

2004-01-01

To examine acute metabolic responses to treadmill locomotion in a participant with motor-complete tetraplegia. The participant--a woman with a chronic ASIA B C3-C4 spinal cord injury--walked on a treadmill with 40% body weight support (BWS) and robotic assistance. Oxygen consumption (VO2), minute ventilation (VE), and heart rate (HR) were measured during seated resting, supported standing, and 40 minutes of walking with stepping assistance from a Lokomat-driven gait orthosis. A resting VO2 equal to 50 milliliters per minute was predictably low, and did not change after the participant assumed an upright posture. Both VO2 and VE increased immediately upon onset of locomotion, suggesting a neurogenic rather than a humoral regulatory response to movement. VO2 averaged 2.4 metabolic units (METS) during locomotion at an average expenditure of 2.98 kilocalories per minute. HR was unaltered by standing, but during locomotion averaged 1 7 beats higher than during resting. Increases in VE but not VO2 upon standing, and decreases in VO2 but not VE immediately after walking, rule out changes in VE alone as the source for increased VO2 during walking. The data collected on this single participant show that treadmill locomotion with BWS and robotic assistance elicits a metabolic response to treadmill gaiting characterized by increased VO2, VE, HR, and caloric expenditure.

Anticipatory detection of turning in humans for intuitive control of robotic mobility assistance.

PubMed

Farkhatdinov, Ildar; Roehri, Nicolas; Burdet, Etienne

2017-09-26

Many wearable lower-limb robots for walking assistance have been developed in recent years. However, it remains unclear how they can be commanded in an intuitive and efficient way by their user. In particular, providing robotic assistance to neurologically impaired individuals in turning remains a significant challenge. The control should be safe to the users and their environment, yet yield sufficient performance and enable natural human-machine interaction. Here, we propose using the head and trunk anticipatory behaviour in order to detect the intention to turn in a natural, non-intrusive way, and use it for triggering turning movement in a robot for walking assistance. We therefore study head and trunk orientation during locomotion of healthy adults, and investigate upper body anticipatory behaviour during turning. The collected walking and turning kinematics data are clustered using the k-means algorithm and cross-validation tests and k-nearest neighbours method are used to evaluate the performance of turning detection during locomotion. Tests with seven subjects exhibited accurate turning detection. Head anticipated turning by more than 400-500 ms in average across all subjects. Overall, the proposed method detected turning 300 ms after its initiation and 1230 ms before the turning movement was completed. Using head anticipatory behaviour enabled to detect turning faster by about 100 ms, compared to turning detection using only pelvis orientation measurements. Finally, it was demonstrated that the proposed turning detection can improve the quality of human-robot interaction by improving the control accuracy and transparency.

Slow Versus Fast Robot-Assisted Locomotor Training After Severe Stroke: A Randomized Controlled Trial.

PubMed

Rodrigues, Thais Amanda; Goroso, Daniel Gustavo; Westgate, Philip M; Carrico, Cheryl; Batistella, Linamara R; Sawaki, Lumy

2017-10-01

Robot-assisted locomotor training on a bodyweight-supported treadmill is a rehabilitation intervention that compels repetitive practice of gait movements. Standard treadmill speed may elicit rhythmic movements generated primarily by spinal circuits. Slower-than-standard treadmill speed may elicit discrete movements, which are more complex than rhythmic movements and involve cortical areas. Compare effects of fast (i.e., rhythmic) versus slow (i.e., discrete) robot-assisted locomotor training on a bodyweight-supported treadmill in subjects with chronic, severe gait deficit after stroke. Subjects (N = 18) were randomized to receive 30 sessions (5 d/wk) of either fast or slow robot-assisted locomotor training on a bodyweight-supported treadmill in an inpatient setting. Functional ambulation category, time up and go, 6-min walk test, 10-m walk test, Berg Balance Scale, and Fugl-Meyer Assessment were administered at baseline and postintervention. The slow group had statistically significant improvement on functional ambulation category (first quartile-third quartile, P = 0.004), 6-min walk test (95% confidence interval [CI] = 1.8 to 49.0, P = 0.040), Berg Balance Scale (95% CI = 7.4 to 14.8, P < 0.0001), time up and go (95% CI = -79.1 to 5.0, P < 0.0030), and Fugl-Meyer Assessment (95% CI = 24.1 to 45.1, P < 0.0001). The fast group had statistically significant improvement on Berg Balance Scale (95% CI = 1.5 to 10.5, P = 0.02). In initial stages of robot-assisted locomotor training on a bodyweight-supported treadmill after severe stroke, slow training targeting discrete movement may yield greater benefit than fast training.

Ambler: Performance of a six-legged planetary rover

NASA Astrophysics Data System (ADS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1995-01-01

In this paper we quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. We present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. We document the performance of a novel dead-reckoning approach, and analyze its accuracy. We describe the results of autonomous walking experiments in terms of terrain traversed, walking speed and endurance.

From cineradiography to biorobots: an approach for designing robots to emulate and study animal locomotion.

PubMed

Karakasiliotis, K; Thandiackal, R; Melo, K; Horvat, T; Mahabadi, N K; Tsitkov, S; Cabelguen, J M; Ijspeert, A J

2016-06-01

Robots are increasingly used as scientific tools to investigate animal locomotion. However, designing a robot that properly emulates the kinematic and dynamic properties of an animal is difficult because of the complexity of musculoskeletal systems and the limitations of current robotics technology. Here, we propose a design process that combines high-speed cineradiography, optimization, dynamic scaling, three-dimensional printing, high-end servomotors and a tailored dry-suit to construct Pleurobot: a salamander-like robot that closely mimics its biological counterpart, Pleurodeles waltl Our previous robots helped us test and confirm hypotheses on the interaction between the locomotor neuronal networks of the limbs and the spine to generate basic swimming and walking gaits. With Pleurobot, we demonstrate a design process that will enable studies of richer motor skills in salamanders. In particular, we are interested in how these richer motor skills can be obtained by extending our spinal cord models with the addition of more descending pathways and more detailed limb central pattern generator networks. Pleurobot is a dynamically scaled amphibious salamander robot with a large number of actuated degrees of freedom (DOFs: 27 in total). Because of our design process, the robot can capture most of the animal's DOFs and range of motion, especially at the limbs. We demonstrate the robot's abilities by imposing raw kinematic data, extracted from X-ray videos, to the robot's joints for basic locomotor behaviours in water and on land. The robot closely matches the behaviour of the animal in terms of relative forward speeds and lateral displacements. Ground reaction forces during walking also resemble those of the animal. Based on our results, we anticipate that future studies on richer motor skills in salamanders will highly benefit from Pleurobot's design. © 2016 The Author(s).

From cineradiography to biorobots: an approach for designing robots to emulate and study animal locomotion

PubMed Central

Karakasiliotis, K.; Thandiackal, R.; Melo, K.; Horvat, T.; Mahabadi, N. K.; Tsitkov, S.; Cabelguen, J. M.; Ijspeert, A. J.

2016-01-01

Robots are increasingly used as scientific tools to investigate animal locomotion. However, designing a robot that properly emulates the kinematic and dynamic properties of an animal is difficult because of the complexity of musculoskeletal systems and the limitations of current robotics technology. Here, we propose a design process that combines high-speed cineradiography, optimization, dynamic scaling, three-dimensional printing, high-end servomotors and a tailored dry-suit to construct Pleurobot: a salamander-like robot that closely mimics its biological counterpart, Pleurodeles waltl. Our previous robots helped us test and confirm hypotheses on the interaction between the locomotor neuronal networks of the limbs and the spine to generate basic swimming and walking gaits. With Pleurobot, we demonstrate a design process that will enable studies of richer motor skills in salamanders. In particular, we are interested in how these richer motor skills can be obtained by extending our spinal cord models with the addition of more descending pathways and more detailed limb central pattern generator networks. Pleurobot is a dynamically scaled amphibious salamander robot with a large number of actuated degrees of freedom (DOFs: 27 in total). Because of our design process, the robot can capture most of the animal's DOFs and range of motion, especially at the limbs. We demonstrate the robot's abilities by imposing raw kinematic data, extracted from X-ray videos, to the robot's joints for basic locomotor behaviours in water and on land. The robot closely matches the behaviour of the animal in terms of relative forward speeds and lateral displacements. Ground reaction forces during walking also resemble those of the animal. Based on our results, we anticipate that future studies on richer motor skills in salamanders will highly benefit from Pleurobot's design. PMID:27358276

Drift-Free Humanoid State Estimation fusing Kinematic, Inertial and LIDAR Sensing

DTIC Science & Technology

2014-08-01

registration to this map and other objects in the robot’s vicinity while also contributing to direct low-level control of a Boston Dynamics Atlas robot ...requirements. I. INTRODUCTION Dynamic locomotion of legged robotic systems remains an open and challenging research problem whose solution will enable...humanoids to perform tasks and reach places inaccessible to wheeled or tracked robots . Several research institutions are developing walking and running

Development of robust behaviour recognition for an at-home biomonitoring robot with assistance of subject localization and enhanced visual tracking.

PubMed

Imamoglu, Nevrez; Dorronzoro, Enrique; Wei, Zhixuan; Shi, Huangjun; Sekine, Masashi; González, José; Gu, Dongyun; Chen, Weidong; Yu, Wenwei

2014-01-01

Our research is focused on the development of an at-home health care biomonitoring mobile robot for the people in demand. Main task of the robot is to detect and track a designated subject while recognizing his/her activity for analysis and to provide warning in an emergency. In order to push forward the system towards its real application, in this study, we tested the robustness of the robot system with several major environment changes, control parameter changes, and subject variation. First, an improved color tracker was analyzed to find out the limitations and constraints of the robot visual tracking considering the suitable illumination values and tracking distance intervals. Then, regarding subject safety and continuous robot based subject tracking, various control parameters were tested on different layouts in a room. Finally, the main objective of the system is to find out walking activities for different patterns for further analysis. Therefore, we proposed a fast, simple, and person specific new activity recognition model by making full use of localization information, which is robust to partial occlusion. The proposed activity recognition algorithm was tested on different walking patterns with different subjects, and the results showed high recognition accuracy.

Development of Robust Behaviour Recognition for an at-Home Biomonitoring Robot with Assistance of Subject Localization and Enhanced Visual Tracking

PubMed Central

Imamoglu, Nevrez; Dorronzoro, Enrique; Wei, Zhixuan; Shi, Huangjun; González, José; Gu, Dongyun; Yu, Wenwei

2014-01-01

Our research is focused on the development of an at-home health care biomonitoring mobile robot for the people in demand. Main task of the robot is to detect and track a designated subject while recognizing his/her activity for analysis and to provide warning in an emergency. In order to push forward the system towards its real application, in this study, we tested the robustness of the robot system with several major environment changes, control parameter changes, and subject variation. First, an improved color tracker was analyzed to find out the limitations and constraints of the robot visual tracking considering the suitable illumination values and tracking distance intervals. Then, regarding subject safety and continuous robot based subject tracking, various control parameters were tested on different layouts in a room. Finally, the main objective of the system is to find out walking activities for different patterns for further analysis. Therefore, we proposed a fast, simple, and person specific new activity recognition model by making full use of localization information, which is robust to partial occlusion. The proposed activity recognition algorithm was tested on different walking patterns with different subjects, and the results showed high recognition accuracy. PMID:25587560

ODYSSEUS autonomous walking robot: The leg/arm design

NASA Technical Reports Server (NTRS)

Bourbakis, N. G.; Maas, M.; Tascillo, A.; Vandewinckel, C.

1994-01-01

ODYSSEUS is an autonomous walking robot, which makes use of three wheels and three legs for its movement in the free navigation space. More specifically, it makes use of its autonomous wheels to move around in an environment where the surface is smooth and not uneven. However, in the case that there are small height obstacles, stairs, or small height unevenness in the navigation environment, the robot makes use of both wheels and legs to travel efficiently. In this paper we present the detailed hardware design and the simulated behavior of the extended leg/arm part of the robot, since it plays a very significant role in the robot actions (movements, selection of objects, etc.). In particular, the leg/arm consists of three major parts: The first part is a pipe attached to the robot base with a flexible 3-D joint. This pipe has a rotated bar as an extended part, which terminates in a 3-D flexible joint. The second part of the leg/arm is also a pipe similar to the first. The extended bar of the second part ends at a 2-D joint. The last part of the leg/arm is a clip-hand. It is used for selecting several small weight and size objects, and when it is in a 'closed' mode, it is used as a supporting part of the robot leg. The entire leg/arm part is controlled and synchronized by a microcontroller (68CH11) attached to the robot base.

A cable-driven locomotor training system for restoration of gait in human SCI.

PubMed

Wu, Ming; Hornby, T George; Landry, Jill M; Roth, Heidi; Schmit, Brian D

2011-02-01

A novel cable-driven robotic locomotor training system was developed to provide compliant assistance/resistance forces to the legs during treadmill training in patients with incomplete spinal cord injury (SCI). Eleven subjects with incomplete SCI were recruited to participate in two experiments to test the feasibility of the robotic gait training system. Specifically, 10 subjects participated in one experimental session to test the characteristics of the robotic gait training system and one subject participated in repeated testing sessions over 8 weeks with the robotic device to test improvements in locomotor function. Limb kinematics were recorded in one experiment to evaluate the system characteristics of the cable-driven locomotor trainer and the overground gait speed and 6 min walking distance were evaluated at pre, 4 and 8 weeks post treadmill training of a single subject as well. The results indicated that the cable driven robotic gait training system improved the kinematic performance of the leg during treadmill walking and had no significant impact on the variability of lower leg trajectory, suggesting a high backdrivability of the cable system. In addition, results from a patient with incomplete SCI indicated that prolonged robotic gait training using the cable robot improved overground gait speed. Results from this study suggested that a cable driven robotic gait training system is effective in improving leg kinematic performance, yet allows variability of gait kinematics. Thus, it seems feasible to improve the locomotor function in human SCI using this cable driven robotic system, warranting testing with a larger group of patients. Copyright © 2010 Elsevier B.V. All rights reserved.

Planning strategies for the Ambler walking robot

NASA Technical Reports Server (NTRS)

Wettergreen, David; Thomas, Hans; Thorpe, Chuck

1990-01-01

A hierarchy of planning strategies is proposed and explained for a walking robot called the Ambler. The hierarchy decomposes planning into levels of trajectory, gait, and footfall. An abstraction of feasible traversability allows the Ambler's trajectory planner to identify acceptable trajectories by finding paths that guarantee footfalls without specifying exactly which footfalls. Leg and body moves that achieve this trajectory can be generated by the Ambler's gait planner, which incorporates pattern constraints and measures of utility to search for the best next move. By combining constraints from the quality and details of the terrain, the Ambler's footfall planner can select footfalls that insure stability and remain within the tolerances of the gait.

Walking robot: A design project for undergraduate students

NASA Technical Reports Server (NTRS)

1990-01-01

The design and construction of the University of Maryland walking machine was completed during the 1989 to 1990 academic year. It was required that the machine be capable of completing a number of tasks including walking a straight line, turning to change direction, and manuevering over an obstacle such as a set of stairs. The machine consists of two sets of four telescoping legs that alternately support the entire structure. A gear box and crank arm assembly is connected to the leg sets to provide the power required for the translational motion of the machine. By retracting all eight legs, the robot comes to rest on a central Bigfoot support. Turning is accomplished by rotating this machine about this support. The machine can be controlled by using either a user-operated remote tether or the onboard computer for the execution of control commands. Absolute encoders are attached to all motors to provide the control computer with information regarding the status of the motors. Long and short range infrared sensors provide the computer with feedback information regarding the machine's position relative to a series of stripes and reflectors. These infrared sensors simulate how the robot might sense and gain information about the environment of Mars.

Necessity of early-stage verticalization in patients with brain and spinal cord injuries: Preliminary study.

PubMed

Daunoraviciene, Kristina; Adomaviciene, Ausra; Svirskis, Donatas; Griškevičius, Julius; Juocevicius, Alvydas

2018-05-18

Integration of the verticalization robot, Erigo, with functional electric stimulation and passive leg movements in the postacute rehabilitation of neurological patients could reduce the risk of secondary complications and improve functional outcomes (i.e. orthostatic hypotension, postural control and walking ability). The aim of this study was to estimate and quantify changes in the postacute stage, mainly related to heart rate and blood pressure in functional recovery, postural parameters, walking ability and psychoemotional reactions, during training using the verticalization robot Erigo. Six patients [three suffering from a stroke (ST) and three with spinal cord injuries (SCI)] participated in 10 sessions of physical therapy with the verticalization robot during primary inpatient rehabilitation. Functional state changes were assessed using clinical tests before and after the treatment, and the loading tolerance during Erigo training was noted. In early rehabilitation, Erigo training was safe and effective at improving orthostatic tolerance, posture and positive emotional reactions in both the ST and SCI patients (P< 0.05). In addition, advanced technologies were more effective at boosting the orthostatic tolerance in SCI patients, while they were more effective at increasing the dynamic balance and walking ability in ST patients (P< 0.05).

Physiological responses and energy cost of walking on the Gait Trainer with and without body weight support in subacute stroke patients

PubMed Central

2014-01-01

Background Robotic-assisted walking after stroke provides intensive task-oriented training. But, despite the growing diffusion of robotic devices little information is available about cardiorespiratory and metabolic responses during electromechanically-assisted repetitive walking exercise. Aim of the study was to determine whether use of an end-effector gait training (GT) machine with body weight support (BWS) would affect physiological responses and energy cost of walking (ECW) in subacute post-stroke hemiplegic patients. Methods Participants: six patients (patient group: PG) with hemiplegia due to stroke (age: 66 ± 15y; time since stroke: 8 ± 3 weeks; four men) and 6 healthy subjects as control group (CG: age, 76 ± 7y; six men). Interventions: overground walking test (OWT) and GT-assisted walking with 0%, 30% and 50% BWS (GT-BWS0%, 30% and 50%). Main Outcome Measures: heart rate (HR), pulmonary ventilation, oxygen consumption, respiratory exchange ratio (RER) and ECW. Results Intervention conditions significantly affected parameter values in steady state (HR: p = 0.005, V’E: p = 0.001, V'O2: p < 0.001) and the interaction condition per group affected ECW (p = 0.002). For PG, the most energy (V’O2 and ECW) demanding conditions were OWT and GT-BWS0%. On the contrary, for CG the least demanding condition was OWT. On the GT, increasing BWS produced a decrease in energy and cardiac demand in both groups. Conclusions In PG, GT-BWS walking resulted in less cardiometabolic demand than overground walking. This suggests that GT-BWS walking training might be safer than overground walking training in subacute stroke patients. PMID:24720844

Physiological responses and energy cost of walking on the Gait Trainer with and without body weight support in subacute stroke patients.

PubMed

Delussu, Anna Sofia; Morone, Giovanni; Iosa, Marco; Bragoni, Maura; Traballesi, Marco; Paolucci, Stefano

2014-04-10

Robotic-assisted walking after stroke provides intensive task-oriented training. But, despite the growing diffusion of robotic devices little information is available about cardiorespiratory and metabolic responses during electromechanically-assisted repetitive walking exercise. Aim of the study was to determine whether use of an end-effector gait training (GT) machine with body weight support (BWS) would affect physiological responses and energy cost of walking (ECW) in subacute post-stroke hemiplegic patients. six patients (patient group: PG) with hemiplegia due to stroke (age: 66 ± 15y; time since stroke: 8 ± 3 weeks; four men) and 6 healthy subjects as control group (CG: age, 76 ± 7y; six men). overground walking test (OWT) and GT-assisted walking with 0%, 30% and 50% BWS (GT-BWS0%, 30% and 50%). heart rate (HR), pulmonary ventilation, oxygen consumption, respiratory exchange ratio (RER) and ECW. Intervention conditions significantly affected parameter values in steady state (HR: p = 0.005, V'E: p = 0.001, V'O2: p < 0.001) and the interaction condition per group affected ECW (p = 0.002). For PG, the most energy (V'O2 and ECW) demanding conditions were OWT and GT-BWS0%. On the contrary, for CG the least demanding condition was OWT. On the GT, increasing BWS produced a decrease in energy and cardiac demand in both groups. In PG, GT-BWS walking resulted in less cardiometabolic demand than overground walking. This suggests that GT-BWS walking training might be safer than overground walking training in subacute stroke patients.

Ambler - Performance of a six-legged planetary rover

NASA Astrophysics Data System (ADS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1992-08-01

In this paper, several performance metrics are quantified for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. Power consumption measures are presented for walking on sandy terrain and for vertical lifts at different velocities. The performance of a novel dead reckoning approach is documented, and its accuracy is analyzed. The results of autonomous walking experiments are described in terms of terrain traversed, walking speed, and endurance.

Ambler - Performance of a six-legged planetary rover

NASA Technical Reports Server (NTRS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1992-01-01

In this paper, several performance metrics are quantified for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. Power consumption measures are presented for walking on sandy terrain and for vertical lifts at different velocities. The performance of a novel dead reckoning approach is documented, and its accuracy is analyzed. The results of autonomous walking experiments are described in terms of terrain traversed, walking speed, and endurance.

The metabolic cost of walking on an incline in the Peacock (Pavo cristatus).

PubMed

Wilkinson, Holly; Thavarajah, Nathan; Codd, Jonathan

2015-01-01

Altering speed and moving on a gradient can affect an animal's posture and gait, which in turn can change the energetic requirements of terrestrial locomotion. Here, the energetic and kinematic effects of locomoting on an incline were investigated in the Indian peacock, Pavo cristatus. The mass-specific metabolic rate of the Indian peacock was elevated on an incline, but this change was not dependent on the angle ascended and the cost of lifting remained similar between the two inclines (+5 and +7°). Interestingly, the Indian peacock had the highest efficiency when compared to any other previously studied avian biped, despite the presence of a large train. Duty factors were higher for birds moving on an incline, but there was no difference between +5 and +7°. Our results highlight the importance of investigating kinematic responses during energetic studies, as these may enable explanation of what is driving the underlying metabolic differences when moving on inclines. Further investigations are required to elucidate the underlying mechanical processes occurring during incline movement.

A fault tolerant gait for a hexapod robot over uneven terrain.

PubMed

Yang, J M; Kim, J H

2000-01-01

The fault tolerant gait of legged robots in static walking is a gait which maintains its stability against a fault event preventing a leg from having the support state. In this paper, a fault tolerant quadruped gait is proposed for a hexapod traversing uneven terrain with forbidden regions, which do not offer viable footholds but can be stepped over. By comparing performance of straight-line motion and crab walking over even terrain, it is shown that the proposed gait has better mobility and terrain adaptability than previously developed gaits. Based on the proposed gait, we present a method for the generation of the fault tolerant locomotion of a hexapod over uneven terrain with forbidden regions. The proposed method minimizes the number of legs on the ground during walking, and foot adjustment algorithm is used for avoiding steps on forbidden regions. The effectiveness of the proposed strategy over uneven terrain is demonstrated with a computer simulation.

Development of Live-working Robot for Power Transmission Lines

NASA Astrophysics Data System (ADS)

Yan, Yu; Liu, Xiaqing; Ren, Chengxian; Li, Jinliang; Li, Hui

2017-07-01

Dream-I, the first reconfigurable live-working robot for power transmission lines successfully developed in China, has the functions of autonomous walking on lines and accurately positioning. This paper firstly described operation task and object of the robot; then designed a general platform, an insulator replacement end and a drainage plate bolt fastening end of the robot, presented a control system of the robot, and performed simulation analysis on operation plan of the robot; and finally completed electrical field withstand voltage tests in a high voltage hall as well as online test and trial on actual lines. Experimental results show that by replacing ends of manipulators, the robot can fulfill operation tasks of live replacement of suspension insulators and live drainage plate bolt fastening.

Exploration of Planetary Terrains with a Legged Robot as a Scout Adjunct to a Rover

NASA Technical Reports Server (NTRS)

Colombano, Silvano; Kirchner, Frank; Spenneberg, Dirk; Hanratty, James

2004-01-01

The Scorpion robot is an innovative, biologically inspired 8-legged walking robot. It currently runs a novel approach to control which utilizes a central pattern generator (CPG) and local reflex action for each leg. From this starting point we are proposing to both extend the system's individual capabilities and its capacity to function as a "scout", cooperating with a larger wheeled rover. For this purpose we propose to develop a distributed system architecture that extends the system's capabilities both in the direction of high level planning and execution in collaboration with a rover, and in the direction of force-feedback based low level behaviors that will greatly enhance its ability to walk and climb in rough varied terrains. The final test of this improved ability will be a rappelling experiment where the Scorpion explores a steep cliff side in cooperation with a rover that serves as both anchor and planner/executive.

Robot-assisted gait training in multiple sclerosis: a pilot randomized trial.

PubMed

Beer, S; Aschbacher, B; Manoglou, D; Gamper, E; Kool, J; Kesselring, J

2008-03-01

To evaluate feasibility and perform an explanatory analysis of the efficacy of robot-assisted gait training (RAGT) in MS patients with severe walking disabilities (Expanded Disability Status Scale [EDSS] 6.0-7.5) in a pilot trial. Prospective, randomized, controlled clinical trial comparing RAGT with conventional walking training (CWT) in a group of stable MS patients (n = 35) during an inpatient rehabilitation stay, 15 sessions over three weeks. All patients participated additionally in a multimodal rehabilitation program. The primary outcome measure was walking velocity and secondary measures were 6-min-walking distance, stride length and knee-extensor strength. All tests were performed by an external blinded assessor at baseline after three weeks and at follow-up after six months. Additionally, Extended Barthel Index (EBI) at entry and discharge was assessed (not blinded), and acceptance/convenience of RAGT rated by patients (Visual Analogue Scale [VAS]) was recorded. Nineteen patients were randomly allocated to RAGT and 16 patients to CWT. Groups were comparable at baseline. There were 5 drop-outs (2 related directly to treatment) in the RAGT group and 1 in the CWT group, leaving 14 RAGT patients and 15 CWT patients for final analysis. Acceptance and convenience of RAGT as rated by patients were high. Effect sizes were moderate to large, although not significant, for walking velocity (0.700, 95% CI -0.089 to 1.489), walking distance (0.401, 95% CI - 0.370 to 1.172) and knee-extensor strength (right: 1.105, 95% CI 0.278 to 1.932, left 0.650, 95% CI -0.135 to 1.436) favouring RAGT. Prepost within-group analysis revealed an increase of walking velocity, walking distance and knee-extensor strength in the RAGT group, whereas in CWT group only walking velocity was improved. In both groups outcome values returned to baseline at follow-up after six months (n = 23). Robot-assisted gait training is feasible and may be an effective therapeutic option in MS patients with severe walking disabilities. Effect size calculation and prepost analysis suggest a higher benefit on walking velocity and knee-extensor strength by RAGT compared to CWT. Due to several limitations, however, our results should be regarded as preliminary. Post hoc power calculation showed that two groups of 106 patients are needed to demonstrate a significant moderate effect size of 0.4 after three weeks of RAGT. Thus, further studies with a larger number of patients are needed to investigate the impact of this new treatment option in MS patients.

Integrated system for single leg walking

NASA Astrophysics Data System (ADS)

Simmons, Reid; Krotkov, Eric; Roston, Gerry

1990-07-01

The Carnegie Mellon University Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. This report describes an integrated software system capable of navigating a single leg of the robot over rugged terrain. The leg, based on an early design of the Ambler Planetary Rover, is suspended below a carriage that slides along rails. To walk, the system creates an elevation map of the terrain from laser scanner images, plans an appropriate foothold based on terrain and geometric constraints, weaves the leg through the terrain to position it above the foothold, contacts the terrain with the foot, and applies force enough to advance the carriage along the rails. Walking both forward and backward, the system has traversed hundreds of meters of rugged terrain including obstacles too tall to step over, trenches too deep to step in, closely spaced obstacles, and sand hills. The implemented system consists of a number of task-specific processes (two for planning, two for perception, one for real-time control) and a central control process that directs the flow of communication between processes.

Relationship between magnitude of applied torque in pre-swing phase and gait change for prevention of trip in elderly people.

PubMed

Miyake, Tamon; Tsukune, Mariko; Kobayashi, Yo; Sugano, Shigeki; Fujie, Masakatsu G

2016-08-01

Elderly people are at risk of tripping because of their narrow range of articular motion. To avoid tripping, gait training that improves their range of articular motion would be beneficial. In this study we propose a gait-training robot that applies a torque during the pre-swing phase to achieve this goal. We investigated the relationship between magnitude of applied torque and change in the range of knee-articular motion while walking before and after the application of this torque. We developed a wearable robot and carried out an experiment on human participants in which a motor pulls a string embedded on the robotic frame, applying torque in the pre-swing phase for a period of 20 [s]. Before and after applying torque the participant walked normally for 15 [s] without interference from the robot. We found that knee flexion angle increased after applying the torque if the torque was within the range of approximately 6-8 [Nm]. Therefore, we were able to verify that a new range of knee articular motion can be learned through application of torque.

Human-robot interaction: kinematics and muscle activity inside a powered compliant knee exoskeleton.

PubMed

Knaepen, Kristel; Beyl, Pieter; Duerinck, Saartje; Hagman, Friso; Lefeber, Dirk; Meeusen, Romain

2014-11-01

Until today it is not entirely clear how humans interact with automated gait rehabilitation devices and how we can, based on that interaction, maximize the effectiveness of these exoskeletons. The goal of this study was to gain knowledge on the human-robot interaction, in terms of kinematics and muscle activity, between a healthy human motor system and a powered knee exoskeleton (i.e., KNEXO). Therefore, temporal and spatial gait parameters, human joint kinematics, exoskeleton kinetics and muscle activity during four different walking trials in 10 healthy male subjects were studied. Healthy subjects can walk with KNEXO in patient-in-charge mode with some slight constraints in kinematics and muscle activity primarily due to inertia of the device. Yet, during robot-in-charge walking the muscular constraints are reversed by adding positive power to the leg swing, compensating in part this inertia. Next to that, KNEXO accurately records and replays the right knee kinematics meaning that subject-specific trajectories can be implemented as a target trajectory during assisted walking. No significant differences in the human response to the interaction with KNEXO in low and high compliant assistance could be pointed out. This is in contradiction with our hypothesis that muscle activity would decrease with increasing assistance. It seems that the differences between the parameter settings of low and high compliant control might not be sufficient to observe clear effects in healthy subjects. Moreover, we should take into account that KNEXO is a unilateral, 1 degree-of-freedom device.

Development and Field Testing of the FootFall Planning System for the ATHLETE Robots

NASA Technical Reports Server (NTRS)

SunSpiral, Vytas; Wheeler, D. W.; Chavez-Clementa, Daniel; Mittman, David

2011-01-01

The FootFall Planning System is a ground-based planning and decision support system designed to facilitate the control of walking activities for the ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) family of robots. ATHLETE was developed at NASA's Jet Propulsion Laboratory (JPL) and is a large six-legged robot designed to serve multiple roles during manned and unmanned missions to the Moon; its roles include transportation, construction and exploration. Over the four years from 2006 through 2010 the FootFall Planning System was developed and adapted to two generations of the ATHLETE robots and tested at two analog field sites (the Human Robotic Systems Project's Integrated Field Test at Moses Lake, Washington, June 2008, and the Desert Research and Technology Studies (D-RATS), held at Black Point Lava Flow in Arizona, September 2010). Having 42 degrees of kinematic freedom, standing to a maximum height of just over 4 meters, and having a payload capacity of 450 kg in Earth gravity, the current version of the ATHLETE robot is a uniquely complex system. A central challenge to this work was the compliance of the high-DOF (Degree Of Freedom) robot, especially the compliance of the wheels, which affected many aspects of statically-stable walking. This paper will review the history of the development of the FootFall system, sharing design decisions, field test experiences, and the lessons learned concerning compliance and self-awareness.

Exploiting Inherent Robustness and Natural Dynamics in the Control of Bipedal Walking Robots

DTIC Science & Technology

2000-06-01

physical models of bipedal walking. The insight gained from these models is used in the development of three planar (motion only in the sagittal plane ...ground is implemented and tested in simulation. The dynamics of the sagittal plane are suffciently decoupled from the dynamics of the frontal and...transverse planes such that control of each can be treated separately. We achieve three-dimensional walking by adding lateral balance to the planar algorithms

HAL® exoskeleton training improves walking parameters and normalizes cortical excitability in primary somatosensory cortex in spinal cord injury patients.

PubMed

Sczesny-Kaiser, Matthias; Höffken, Oliver; Aach, Mirko; Cruciger, Oliver; Grasmücke, Dennis; Meindl, Renate; Schildhauer, Thomas A; Schwenkreis, Peter; Tegenthoff, Martin

2015-08-20

Reorganization in the sensorimotor cortex accompanied by increased excitability and enlarged body representations is a consequence of spinal cord injury (SCI). Robotic-assisted bodyweight supported treadmill training (BWSTT) was hypothesized to induce reorganization and improve walking function. To assess whether BWSTT with hybrid assistive limb® (HAL®) exoskeleton affects cortical excitability in the primary somatosensory cortex (S1) in SCI patients, as measured by paired-pulse somatosensory evoked potentials (ppSEP) stimulated above the level of injury. Eleven SCI patients took part in HAL® assisted BWSTT for 3 months. PpSEP were conducted before and after this training period, where the amplitude ratios (SEP amplitude following double pulses - SEP amplitude following single pulses) were assessed and compared to eleven healthy control subjects. To assess improvement in walking function, we used the 10-m walk test, timed-up-and-go test, the 6-min walk test, and the lower extremity motor score. PpSEPs were significantly increased in SCI patients as compared to controls at baseline. Following training, ppSEPs were increased from baseline and no longer significantly differed from controls. Walking parameters also showed significant improvements, yet there was no significant correlation between ppSEP measures and walking parameters. The findings suggest that robotic-assisted BWSTT with HAL® in SCI patients is capable of inducing cortical plasticity following highly repetitive, active locomotive use of paretic legs. While there was no significant correlation of excitability with walking parameters, brain areas other than S1 might reflect improvement of walking functions. EEG and neuroimaging studies may provide further information about supraspinal plastic processes and foci in SCI rehabilitation.

Pleasant to the Touch: By Emulating Nature, Scientists Hope to Find Innovative New Uses for Soft Robotics in Health-Care Technology.

PubMed

Cianchetti, Matteo; Laschi, Cecilia

2016-01-01

Open your Internet browser and search for videos showing the most advanced humanoid robots. Look at how they move and walk. Observe their motion and their interaction with the environment (the ground, users, target objects). Now, search for a video of your favorite sports player. Despite the undoubtedly great achievements of modern robotics, it will become quite evident that a lot of work still remains.

Microgravity, Mesh-Crawling Legged Robots

NASA Technical Reports Server (NTRS)

Behar, Alberto; Marzwell, Neville; Matthews, Jaret; Richardson, Krandalyn; Wall, Jonathan; Poole, Michael; Foor, David; Rodgers, Damian

2008-01-01

The design, fabrication, and microgravity flight-testing are part of a continuing development of palm-sized mobile robots that resemble spiders (except that they have six legs apiece, whereas a spider has eight legs). Denoted SpiderBots (see figure), they are prototypes of proposed product line of relatively inexpensive walking robots that could be deployed in large numbers to function cooperatively in construction, repair, exploration, search, and rescue activities in connection with exploration of outer space and remote planets.

Design of a walking robot

NASA Technical Reports Server (NTRS)

Whittaker, William; Dowling, Kevin

1994-01-01

Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

Design of a walking robot

NASA Astrophysics Data System (ADS)

Whittaker, William; Dowling, Kevin

1994-03-01

Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

Lateral Symmetry of Synergies in Lower Limb Muscles of Acute Post-stroke Patients After Robotic Intervention

PubMed Central

Tan, Chun Kwang; Kadone, Hideki; Watanabe, Hiroki; Marushima, Aiki; Yamazaki, Masashi; Sankai, Yoshiyuki; Suzuki, Kenji

2018-01-01

Gait disturbance is commonly associated with stroke, which is a serious neurological disease. With current technology, various exoskeletons have been developed to provide therapy, leading to many studies evaluating the use of such exoskeletons as an intervention tool. Although these studies report improvements in patients who had undergone robotic intervention, they are usually reported with clinical assessment, which are unable to characterize how muscle activations change in patients after robotic intervention. We believe that muscle activations can provide an objective view on gait performance of patients. To quantify improvement of lateral symmetry before and after robotic intervention, muscle synergy analysis with Non-Negative Matrix Factorization was used to evaluate patients' EMG data. Eight stroke patients in their acute phase were evaluated before and after a course of robotic intervention with the Hybrid Assistive Limb (HAL), lasting over 3 weeks. We found a significant increase in similarity between lateral synergies of patients after robotic intervention. This is associated with significant improvements in gait measures like walking speed, step cadence, stance duration percentage of gait cycle. Clinical assessments [Functional Independence Measure-Locomotion (FIM-Locomotion), FIM-Motor (General), and Fugl-Meyer Assessment-Lower Extremity (FMA-LE)] showed significant improvements as well. Our study shows that muscle synergy analysis can be a good tool to quantify the change in neuromuscular coordination of lateral symmetry during walking in stroke patients. PMID:29922121

Space_Station_Crew_Members_Walk_in_Space_to_Complete_Robotics_Upgrades

NASA Image and Video Library

2018-02-16

Outside the International Space Station, Expedition 54 Flight Engineers Mark Vande Hei of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) conducted a spacewalk to move a Latching End Effector, or hand, for the Canadarm2 robotic arm into the Quest airlock that was removed during another excursion last October and to move a degraded end effector replaced during a Jan. 23 spacewalk onto a payload attachment device on the station’s Mobile Base System railcar. The spacewalk was the 208th in station history for assembly, maintenance and upgrades, the fourth in Vande Hei’s career and the first for Kanai, who became only the fourth Japanese astronaut to walk in space.

Biomechanics and energetics of walking in powered ankle exoskeletons using myoelectric control versus mechanically intrinsic control.

PubMed

Koller, Jeffrey R; Remy, C David; Ferris, Daniel P

2018-05-25

Controllers for assistive robotic devices can be divided into two main categories: controllers using neural signals and controllers using mechanically intrinsic signals. Both approaches are prevalent in research devices, but a direct comparison between the two could provide insight into their relative advantages and disadvantages. We studied subjects walking with robotic ankle exoskeletons using two different control modes: dynamic gain proportional myoelectric control based on soleus muscle activity (neural signal), and timing-based mechanically intrinsic control based on gait events (mechanically intrinsic signal). We hypothesized that subjects would have different measures of metabolic work rate between the two controllers as we predicted subjects would use each controller in a unique manner due to one being dependent on muscle recruitment and the other not. The two controllers had the same average actuation signal as we used the control signals from walking with the myoelectric controller to shape the mechanically intrinsic control signal. The difference being the myoelectric controller allowed step-to-step variation in the actuation signals controlled by the user's soleus muscle recruitment while the timing-based controller had the same actuation signal with each step regardless of muscle recruitment. We observed no statistically significant difference in metabolic work rate between the two controllers. Subjects walked with 11% less soleus activity during mid and late stance and significantly less peak soleus recruitment when using the timing-based controller than when using the myoelectric controller. While walking with the myoelectric controller, subjects walked with significantly higher average positive and negative total ankle power compared to walking with the timing-based controller. We interpret the reduced ankle power and muscle activity with the timing-based controller relative to the myoelectric controller to result from greater slacking effects. Subjects were able to be less engaged on a muscle level when using a controller driven by mechanically intrinsic signals than when using a controller driven by neural signals, but this had no affect on their metabolic work rate. These results suggest that the type of controller (neural vs. mechanical) is likely to affect how individuals use robotic exoskeletons for therapeutic rehabilitation or human performance augmentation.

Safety and efficacy of at-home robotic locomotion therapy in individuals with chronic incomplete spinal cord injury: a prospective, pre-post intervention, proof-of-concept study.

PubMed

Rupp, Rüdiger; Schließmann, Daniel; Plewa, Harry; Schuld, Christian; Gerner, Hans Jürgen; Weidner, Norbert; Hofer, Eberhard P; Knestel, Markus

2015-01-01

The compact Motorized orthosis for home rehabilitation of Gait (MoreGait) was developed for continuation of locomotion training at home. MoreGait generates afferent stimuli of walking with the user in a semi-supine position and provides feedback about deviations from the reference walking pattern. Prospective, pre-post intervention, proof-of-concept study to test the feasibility of an unsupervised home-based application of five MoreGait prototypes in subjects with incomplete spinal cord injury (iSCI). Twenty-five (5 tetraplegia, 20 paraplegia) participants with chronic (mean time since injury: 5.8 ± 5.4 (standard deviation, SD) years) sensorimotor iSCI (7 ASIA Impairment Scale (AIS) C, 18 AIS D; Walking Index for Spinal Cord Injury (WISCI II): Interquartile range 9 to 16) completed the training (45 minutes / day, at least 4 days / week, 8 weeks). Baseline status was documented 4 and 2 weeks before and at training onset. Training effects were assessed after 4 and 8 weeks of therapy. After therapy, 9 of 25 study participants improved with respect to the dependency on walking aids assessed by the WISCI II. For all individuals, the short-distance walking velocity measured by the 10-Meter Walk Test showed significant improvements compared to baseline (100%) for both self-selected (Mean 139.4% ± 35.5% (SD)) and maximum (Mean 143.1% ± 40.6% (SD)) speed conditions as well as the endurance estimated with the six-minute walk test (Mean 166.6% ± 72.1% (SD)). One device-related adverse event (pressure sore on the big toe) occurred in over 800 training sessions. Home-based robotic locomotion training with MoreGait is feasible and safe. The magnitude of functional improvements achieved by MoreGait in individuals with iSCI is well within the range of complex locomotion robots used in hospitals. Thus, unsupervised MoreGait training potentially represents an option to prolong effective training aiming at recovery of locomotor function beyond in-patient rehabilitation. German Clinical Trials Register (DKRS) DRKS00005587.

Time-Shift Correlation Algorithm for P300 Event Related Potential Brain-Computer Interface Implementation

PubMed Central

Liu, Ju-Chi; Chou, Hung-Chyun; Chen, Chien-Hsiu; Lin, Yi-Tseng

2016-01-01

A high efficient time-shift correlation algorithm was proposed to deal with the peak time uncertainty of P300 evoked potential for a P300-based brain-computer interface (BCI). The time-shift correlation series data were collected as the input nodes of an artificial neural network (ANN), and the classification of four LED visual stimuli was selected as the output node. Two operating modes, including fast-recognition mode (FM) and accuracy-recognition mode (AM), were realized. The proposed BCI system was implemented on an embedded system for commanding an adult-size humanoid robot to evaluate the performance from investigating the ground truth trajectories of the humanoid robot. When the humanoid robot walked in a spacious area, the FM was used to control the robot with a higher information transfer rate (ITR). When the robot walked in a crowded area, the AM was used for high accuracy of recognition to reduce the risk of collision. The experimental results showed that, in 100 trials, the accuracy rate of FM was 87.8% and the average ITR was 52.73 bits/min. In addition, the accuracy rate was improved to 92% for the AM, and the average ITR decreased to 31.27 bits/min. due to strict recognition constraints. PMID:27579033

Time-Shift Correlation Algorithm for P300 Event Related Potential Brain-Computer Interface Implementation.

PubMed

Liu, Ju-Chi; Chou, Hung-Chyun; Chen, Chien-Hsiu; Lin, Yi-Tseng; Kuo, Chung-Hsien

2016-01-01

A high efficient time-shift correlation algorithm was proposed to deal with the peak time uncertainty of P300 evoked potential for a P300-based brain-computer interface (BCI). The time-shift correlation series data were collected as the input nodes of an artificial neural network (ANN), and the classification of four LED visual stimuli was selected as the output node. Two operating modes, including fast-recognition mode (FM) and accuracy-recognition mode (AM), were realized. The proposed BCI system was implemented on an embedded system for commanding an adult-size humanoid robot to evaluate the performance from investigating the ground truth trajectories of the humanoid robot. When the humanoid robot walked in a spacious area, the FM was used to control the robot with a higher information transfer rate (ITR). When the robot walked in a crowded area, the AM was used for high accuracy of recognition to reduce the risk of collision. The experimental results showed that, in 100 trials, the accuracy rate of FM was 87.8% and the average ITR was 52.73 bits/min. In addition, the accuracy rate was improved to 92% for the AM, and the average ITR decreased to 31.27 bits/min. due to strict recognition constraints.

Control of a robot dinosaur

PubMed Central

Papantoniou, V.

1999-01-01

The Palaiomation Consortium, supported by the European Commission, is building a robot Iguanodon atherfieldensis for museum display that is much more sophisticated than existing animatronic exhibits. The current half-size (2.5 m) prototype is fully autonomous, carrying its own computer and batteries. It walks around the room, choosing its own path and avoiding obstacles. A bigger version with a larger repertoire of behaviours is planned. Many design problems have had to be overcome. A real dinosaur would have had hundreds of muscles, and we have had to devise means of achieving life-like movement with a much smaller number of motors; we have limited ourselves to 20, to keep the control problems manageable. Realistic stance requires a narrower trackway and a higher centre of mass than in previous (often spider-like) legged robots, making it more difficult to maintain stability. Other important differences from previous walking robots are that the forelegs have to be shorter than the hind, and the machinery has had to be designed to fit inside a realistically shaped body shell. Battery life is about one hour, but to achieve this we have had to design the robot to have very low power consumption. Currently, this limits it to unrealistically slow movement. The control system includes a high-level instructions processor, a gait generator, a motion-coordination generator, and a kinematic model.

The Physics of a Walking Robot

ERIC Educational Resources Information Center

Guemez, J.; Fiolhais, M.

2013-01-01

The physics of walking is explored, using a toy as a concrete example and a "toy model" applied to it. Besides using Newton's second law, the problem is also discussed from the thermodynamical perspective. Once the steady state (constant velocity) is achieved, we show that the internal energy of the toy is dissipated as heat in the…

Robot-assisted gait training for stroke patients: current state of the art and perspectives of robotics.

PubMed

Morone, Giovanni; Paolucci, Stefano; Cherubini, Andrea; De Angelis, Domenico; Venturiero, Vincenzo; Coiro, Paola; Iosa, Marco

2017-01-01

In this review, we give a brief outline of robot-mediated gait training for stroke patients, as an important emerging field in rehabilitation. Technological innovations are allowing rehabilitation to move toward more integrated processes, with improved efficiency and less long-term impairments. In particular, robot-mediated neurorehabilitation is a rapidly advancing field, which uses robotic systems to define new methods for treating neurological injuries, especially stroke. The use of robots in gait training can enhance rehabilitation, but it needs to be used according to well-defined neuroscientific principles. The field of robot-mediated neurorehabilitation brings challenges to both bioengineering and clinical practice. This article reviews the state of the art (including commercially available systems) and perspectives of robotics in poststroke rehabilitation for walking recovery. A critical revision, including the problems at stake regarding robotic clinical use, is also presented.

Robot-assisted gait training for stroke patients: current state of the art and perspectives of robotics

PubMed Central

Morone, Giovanni; Paolucci, Stefano; Cherubini, Andrea; De Angelis, Domenico; Venturiero, Vincenzo; Coiro, Paola; Iosa, Marco

2017-01-01

In this review, we give a brief outline of robot-mediated gait training for stroke patients, as an important emerging field in rehabilitation. Technological innovations are allowing rehabilitation to move toward more integrated processes, with improved efficiency and less long-term impairments. In particular, robot-mediated neurorehabilitation is a rapidly advancing field, which uses robotic systems to define new methods for treating neurological injuries, especially stroke. The use of robots in gait training can enhance rehabilitation, but it needs to be used according to well-defined neuroscientific principles. The field of robot-mediated neurorehabilitation brings challenges to both bioengineering and clinical practice. This article reviews the state of the art (including commercially available systems) and perspectives of robotics in poststroke rehabilitation for walking recovery. A critical revision, including the problems at stake regarding robotic clinical use, is also presented. PMID:28553117

Algorithms exploiting ultrasonic sensors for subject classification

NASA Astrophysics Data System (ADS)

Desai, Sachi; Quoraishee, Shafik

2009-09-01

Proposed here is a series of techniques exploiting micro-Doppler ultrasonic sensors capable of characterizing various detected mammalian targets based on their physiological movements captured a series of robust features. Employed is a combination of unique and conventional digital signal processing techniques arranged in such a manner they become capable of classifying a series of walkers. These processes for feature extraction develops a robust feature space capable of providing discrimination of various movements generated from bipeds and quadrupeds and further subdivided into large or small. These movements can be exploited to provide specific information of a given signature dividing it in a series of subset signatures exploiting wavelets to generate start/stop times. After viewing a series spectrograms of the signature we are able to see distinct differences and utilizing kurtosis, we generate an envelope detector capable of isolating each of the corresponding step cycles generated during a walk. The walk cycle is defined as one complete sequence of walking/running from the foot pushing off the ground and concluding when returning to the ground. This time information segments the events that are readily seen in the spectrogram but obstructed in the temporal domain into individual walk sequences. This walking sequence is then subsequently translated into a three dimensional waterfall plot defining the expected energy value associated with the motion at particular instance of time and frequency. The value is capable of being repeatable for each particular class and employable to discriminate the events. Highly reliable classification is realized exploiting a classifier trained on a candidate sample space derived from the associated gyrations created by motion from actors of interest. The classifier developed herein provides a capability to classify events as an adult humans, children humans, horses, and dogs at potentially high rates based on the tested sample space. The algorithm developed and described will provide utility to an underused sensor modality for human intrusion detection because of the current high-rate of generated false alarms. The active ultrasonic sensor coupled in a multi-modal sensor suite with binary, less descriptive sensors like seismic devices realizing a greater accuracy rate for detection of persons of interest for homeland purposes.

Hemorrhagic versus ischemic stroke: Who can best benefit from blended conventional physiotherapy with robotic-assisted gait therapy?

PubMed

Dierick, Frédéric; Dehas, Mélanie; Isambert, Jean-Luc; Injeyan, Soizic; Bouché, Anne-France; Bleyenheuft, Yannick; Portnoy, Sigal

2017-01-01

Contrary to common belief of clinicians that hemorrhagic stroke survivors have better functional prognoses than ischemic, recent studies show that ischemic survivors could experience similar or even better functional improvements. However, the influence of stroke subtype on gait and posture outcomes following an intervention blending conventional physiotherapy with robotic-assisted gait therapy is missing. This study compared gait and posture outcome measures between ambulatory hemorrhagic patients and ischemic patients, who received a similar 4 weeks' intervention blending a conventional bottom-up physiotherapy approach and an exoskeleton top-down robotic-assisted gait training (RAGT) approach with Lokomat. Forty adult hemiparetic stroke inpatient subjects were recruited: 20 hemorrhagic and 20 ischemic, matched by age, gender, side of hemisphere lesion, stroke severity, and locomotor impairments. Functional Ambulation Category, Postural Assessment Scale for Stroke, Tinetti Performance Oriented Mobility Assessment, 6 Minutes Walk Test, Timed Up and Go and 10-Meter Walk Test were performed before and after a 4-week long intervention. Functional gains were calculated for all tests. Hemorrhagic and ischemic subjects showed significant improvements in Functional Ambulation Category (P<0.001 and P = 0.008, respectively), Postural Assessment Scale for Stroke (P<0.001 and P = 0.003), 6 Minutes Walk Test (P = 0.003 and P = 0.015) and 10-Meter Walk Test (P = 0.001 and P = 0.024). Ischemic patients also showed significant improvements in Timed Up and Go. Significantly greater mean Functional Ambulation Category and Tinetti Performance Oriented Mobility Assessment gains were observed for hemorrhagic compared to ischemic, with large (dz = 0.81) and medium (dz = 0.66) effect sizes, respectively. Overall, both groups exhibited quasi similar functional improvements and benefits from the same type, length and frequency of blended conventional physiotherapy and RAGT protocol. The use of intensive treatment plans blending top-down physiotherapy and bottom-up robotic approaches is promising for post-stroke rehabilitation.

Hemorrhagic versus ischemic stroke: Who can best benefit from blended conventional physiotherapy with robotic-assisted gait therapy?

PubMed Central

Dehas, Mélanie; Isambert, Jean-Luc; Injeyan, Soizic; Bouché, Anne-France; Bleyenheuft, Yannick; Portnoy, Sigal

2017-01-01

Background Contrary to common belief of clinicians that hemorrhagic stroke survivors have better functional prognoses than ischemic, recent studies show that ischemic survivors could experience similar or even better functional improvements. However, the influence of stroke subtype on gait and posture outcomes following an intervention blending conventional physiotherapy with robotic-assisted gait therapy is missing. Objective This study compared gait and posture outcome measures between ambulatory hemorrhagic patients and ischemic patients, who received a similar 4 weeks’ intervention blending a conventional bottom-up physiotherapy approach and an exoskeleton top-down robotic-assisted gait training (RAGT) approach with Lokomat. Methods Forty adult hemiparetic stroke inpatient subjects were recruited: 20 hemorrhagic and 20 ischemic, matched by age, gender, side of hemisphere lesion, stroke severity, and locomotor impairments. Functional Ambulation Category, Postural Assessment Scale for Stroke, Tinetti Performance Oriented Mobility Assessment, 6 Minutes Walk Test, Timed Up and Go and 10-Meter Walk Test were performed before and after a 4-week long intervention. Functional gains were calculated for all tests. Results Hemorrhagic and ischemic subjects showed significant improvements in Functional Ambulation Category (P<0.001 and P = 0.008, respectively), Postural Assessment Scale for Stroke (P<0.001 and P = 0.003), 6 Minutes Walk Test (P = 0.003 and P = 0.015) and 10-Meter Walk Test (P = 0.001 and P = 0.024). Ischemic patients also showed significant improvements in Timed Up and Go. Significantly greater mean Functional Ambulation Category and Tinetti Performance Oriented Mobility Assessment gains were observed for hemorrhagic compared to ischemic, with large (dz = 0.81) and medium (dz = 0.66) effect sizes, respectively. Conclusion Overall, both groups exhibited quasi similar functional improvements and benefits from the same type, length and frequency of blended conventional physiotherapy and RAGT protocol. The use of intensive treatment plans blending top-down physiotherapy and bottom-up robotic approaches is promising for post-stroke rehabilitation. PMID:28575054

Research on Robot Pose Control Technology Based on Kinematics Analysis Model

NASA Astrophysics Data System (ADS)

Liu, Dalong; Xu, Lijuan

2018-01-01

In order to improve the attitude stability of the robot, proposes an attitude control method of robot based on kinematics analysis model, solve the robot walking posture transformation, grasping and controlling the motion planning problem of robot kinematics. In Cartesian space analytical model, using three axis accelerometer, magnetometer and the three axis gyroscope for the combination of attitude measurement, the gyroscope data from Calman filter, using the four element method for robot attitude angle, according to the centroid of the moving parts of the robot corresponding to obtain stability inertia parameters, using random sampling RRT motion planning method, accurate operation to any position control of space robot, to ensure the end effector along a prescribed trajectory the implementation of attitude control. The accurate positioning of the experiment is taken using MT-R robot as the research object, the test robot. The simulation results show that the proposed method has better robustness, and higher positioning accuracy, and it improves the reliability and safety of robot operation.

Accelerometry-enabled measurement of walking performance with a robotic exoskeleton: a pilot study.

PubMed

Lonini, Luca; Shawen, Nicholas; Scanlan, Kathleen; Rymer, William Z; Kording, Konrad P; Jayaraman, Arun

2016-03-31

Clinical scores for evaluating walking skills with lower limb exoskeletons are often based on a single variable, such as distance walked or speed, even in cases where a host of features are measured. We investigated how to combine multiple features such that the resulting score has high discriminatory power, in particular with few patients. A new score is introduced that allows quantifying the walking ability of patients with spinal cord injury when using a powered exoskeleton. Four spinal cord injury patients were trained to walk over ground with the ReWalk™ exoskeleton. Body accelerations during use of the device were recorded by a wearable accelerometer and 4 features to evaluate walking skills were computed. The new score is the Gaussian naïve Bayes surprise, which evaluates patients relative to the features' distribution measured in 7 expert users of the ReWalk™. We compared our score based on all the features with a standard outcome measure, which is based on number of steps only. All 4 patients improved over the course of training, as their scores trended towards the expert users' scores. The combined score (Gaussian naïve surprise) was considerably more discriminative than the one using only walked distance (steps). At the end of training, 3 out of 4 patients were significantly different from the experts, according to the combined score (p < .001, Wilcoxon Signed-Rank Test). In contrast, all but one patient were scored as experts when number of steps was the only feature. Integrating multiple features could provide a more robust metric to measure patients' skills while they learn to walk with a robotic exoskeleton. Testing this approach with other features and more subjects remains as future work.

A soft robotic exosuit improves walking in patients after stroke.

PubMed

Awad, Louis N; Bae, Jaehyun; O'Donnell, Kathleen; De Rossi, Stefano M M; Hendron, Kathryn; Sloot, Lizeth H; Kudzia, Pawel; Allen, Stephen; Holt, Kenneth G; Ellis, Terry D; Walsh, Conor J

2017-07-26

Stroke-induced hemiparetic gait is characteristically slow and metabolically expensive. Passive assistive devices such as ankle-foot orthoses are often prescribed to increase function and independence after stroke; however, walking remains highly impaired despite-and perhaps because of-their use. We sought to determine whether a soft wearable robot (exosuit) designed to supplement the paretic limb's residual ability to generate both forward propulsion and ground clearance could facilitate more normal walking after stroke. Exosuits transmit mechanical power generated by actuators to a wearer through the interaction of garment-like, functional textile anchors and cable-based transmissions. We evaluated the immediate effects of an exosuit actively assisting the paretic limb of individuals in the chronic phase of stroke recovery during treadmill and overground walking. Using controlled, treadmill-based biomechanical investigation, we demonstrate that exosuits can function in synchrony with a wearer's paretic limb to facilitate an immediate 5.33 ± 0.91° increase in the paretic ankle's swing phase dorsiflexion and 11 ± 3% increase in the paretic limb's generation of forward propulsion ( P < 0.05). These improvements in paretic limb function contributed to a 20 ± 4% reduction in forward propulsion interlimb asymmetry and a 10 ± 3% reduction in the energy cost of walking, which is equivalent to a 32 ± 9% reduction in the metabolic burden associated with poststroke walking. Relatively low assistance (~12% of biological torques) delivered with a lightweight and nonrestrictive exosuit was sufficient to facilitate more normal walking in ambulatory individuals after stroke. Future work will focus on understanding how exosuit-induced improvements in walking performance may be leveraged to improve mobility after stroke. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Robotic rehabilitation of spinal cord injury individual.

PubMed

Karimi, Mohammad Taghi

2013-01-01

Various types of systems have been used for rehabilitation of Spinal cord injury (SCI) individuals, including mechanical orthoses, functional electrical stimulation (FES), hybrid system and robotic devices. Although, the use of robotic systems for rehabilitation of SCI subjects is increasing, there is not enough evidence to determine the positive and side effects of this system. Therefore, the aim of this review article is to find some evidences to support the influence of use of this system on the performance of the subjects. Furthermore, it was aimed to find the difference between the performances of paraplegic subjects while walking with robotic devices. An electronic search was done based on PubMed, Embase, Ebsco, and ISI Web of Knowledge to extract the data from 1970 to 2012. The quality of the research studies was evaluated by use of Black and Down tool. Although 250 papers have been found based on the selected key words, finally 10 papers have been selected for final analysis. There were only two clinical trials done in this regard. There are some improvements which were reported to body function and activities follow the use of robotic device. 1. Although various types of orthotic systems have been developed for paraplegic subjects for walking and rehabilitation, there is not enough research in this regard. 2. It is not easy to determine the therapeutic influence of robotic orthosis on the health status of paraplegic subjects. 3. There is a huge gap for a randomized clinical trial research to determine the effect of robotic system on the health status of the SCI subjects.

Modular ankle robotics training in early subacute stroke: a randomized controlled pilot study.

PubMed

Forrester, Larry W; Roy, Anindo; Krywonis, Amanda; Kehs, Glenn; Krebs, Hermano Igo; Macko, Richard F

2014-09-01

BACKGROUND. Modular lower extremity robotics may offer a valuable avenue for restoring neuromotor control after hemiparetic stroke. Prior studies show that visually guided and visually evoked practice with an ankle robot (anklebot) improves paretic ankle motor control that translates into improved overground walking. To assess the feasibility and efficacy of daily anklebot training during early subacute hospitalization poststroke. Thirty-four inpatients from a stroke unit were randomly assigned to anklebot (n = 18) or passive manual stretching (n = 16) treatments. All suffered a first stroke with residual hemiparesis (ankle manual muscle test grade 1/5 to 4/5), and at least trace muscle activation in plantar- or dorsiflexion. Anklebot training employed an "assist-as-needed" approach during >200 volitional targeted paretic ankle movements, with difficulty adjusted to active range of motion and success rate. Stretching included >200 daily mobilizations in these same ranges. All sessions lasted 1 hour and assessments were not blinded. Both groups walked faster at discharge; however, the robot group improved more in percentage change of temporal symmetry (P = .032) and also of step length symmetry (P = .038), with longer nonparetic step lengths in the robot (133%) versus stretching (31%) groups. Paretic ankle control improved in the robot group, with increased peak (P ≤ .001) and mean (P ≤ .01) angular speeds, and increased movement smoothness (P ≤ .01). There were no adverse events. Though limited by small sample size and restricted entry criteria, our findings suggest that modular lower extremity robotics during early subacute hospitalization is well tolerated and improves ankle motor control and gait patterning. © The Author(s) 2014.

Bio-robots automatic navigation with electrical reward stimulation.

PubMed

Sun, Chao; Zhang, Xinlu; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

2012-01-01

Bio-robots that controlled by outer stimulation through brain computer interface (BCI) suffer from the dependence on realtime guidance of human operators. Current automatic navigation methods for bio-robots focus on the controlling rules to force animals to obey man-made commands, with animals' intelligence ignored. This paper proposes a new method to realize the automatic navigation for bio-robots with electrical micro-stimulation as real-time rewards. Due to the reward-seeking instinct and trial-and-error capability, bio-robot can be steered to keep walking along the right route with rewards and correct its direction spontaneously when rewards are deprived. In navigation experiments, rat-robots learn the controlling methods in short time. The results show that our method simplifies the controlling logic and realizes the automatic navigation for rat-robots successfully. Our work might have significant implication for the further development of bio-robots with hybrid intelligence.

Autonomous Evolution of Dynamic Gaits with Two Quadruped Robots

NASA Technical Reports Server (NTRS)

Hornby, Gregory S.; Takamura, Seichi; Yamamoto, Takashi; Fujita, Masahiro

2004-01-01

A challenging task that must be accomplished for every legged robot is creating the walking and running behaviors needed for it to move. In this paper we describe our system for autonomously evolving dynamic gaits on two of Sony's quadruped robots. Our evolutionary algorithm runs on board the robot and uses the robot's sensors to compute the quality of a gait without assistance from the experimenter. First we show the evolution of a pace and trot gait on the OPEN-R prototype robot. With the fastest gait, the robot moves at over 10/min/min., which is more than forty body-lengths/min. While these first gaits are somewhat sensitive to the robot and environment in which they are evolved, we then show the evolution of robust dynamic gaits, one of which is used on the ERS-110, the first consumer version of AIBO.

Gastrocnemius Myoelectric Control of a Robotic Hip Exoskeleton Can Reduce the User's Lower-Limb Muscle Activities at Push Off

PubMed Central

Grazi, Lorenzo; Crea, Simona; Parri, Andrea; Molino Lova, Raffaele; Micera, Silvestro; Vitiello, Nicola

2018-01-01

We present a novel assistive control strategy for a robotic hip exoskeleton for assisting hip flexion/extension, based on a proportional Electromyography (EMG) strategy. The novelty of the proposed controller relies on the use of the Gastrocnemius Medialis (GM) EMG signal instead of a hip flexor muscle, to control the hip flexion torque. This strategy has two main advantages: first, avoiding the placement of the EMG electrodes at the human–robot interface can reduce discomfort issues for the user and motion artifacts of the recorded signals; second, using a powerful signal for control, such as the GM, could improve the reliability of the control system. The control strategy has been tested on eight healthy subjects, walking with the robotic hip exoskeleton on the treadmill. We evaluated the controller performance and the effect of the assistance on muscle activities. The tuning of the assistance timing in the controller was subject dependent and varied across subjects. Two muscles could benefit more from the assistive strategy, namely the Rectus Femoris (directly assisted) and the Tibialis Anterior (indirectly assisted). A significant correlation was found between the timing of the delivered assistance (i.e., synchronism with the biological hip torque), and reduction of the hip flexors muscular activity during walking; instead, no significant correlations were found for peak torque and peak power. Results suggest that the timing of the assistance is the most significant parameter influencing the effectiveness of the control strategy. The findings of this work could be important for future studies aimed at developing assistive strategies for walking assistance exoskeletons. PMID:29491830

Gastrocnemius Myoelectric Control of a Robotic Hip Exoskeleton Can Reduce the User's Lower-Limb Muscle Activities at Push Off.

PubMed

Grazi, Lorenzo; Crea, Simona; Parri, Andrea; Molino Lova, Raffaele; Micera, Silvestro; Vitiello, Nicola

2018-01-01

We present a novel assistive control strategy for a robotic hip exoskeleton for assisting hip flexion/extension, based on a proportional Electromyography (EMG) strategy. The novelty of the proposed controller relies on the use of the Gastrocnemius Medialis (GM) EMG signal instead of a hip flexor muscle, to control the hip flexion torque. This strategy has two main advantages: first, avoiding the placement of the EMG electrodes at the human-robot interface can reduce discomfort issues for the user and motion artifacts of the recorded signals; second, using a powerful signal for control, such as the GM, could improve the reliability of the control system. The control strategy has been tested on eight healthy subjects, walking with the robotic hip exoskeleton on the treadmill. We evaluated the controller performance and the effect of the assistance on muscle activities. The tuning of the assistance timing in the controller was subject dependent and varied across subjects. Two muscles could benefit more from the assistive strategy, namely the Rectus Femoris (directly assisted) and the Tibialis Anterior (indirectly assisted). A significant correlation was found between the timing of the delivered assistance (i.e., synchronism with the biological hip torque), and reduction of the hip flexors muscular activity during walking; instead, no significant correlations were found for peak torque and peak power. Results suggest that the timing of the assistance is the most significant parameter influencing the effectiveness of the control strategy. The findings of this work could be important for future studies aimed at developing assistive strategies for walking assistance exoskeletons.

Unexpected recovery after robotic locomotor training at physiologic stepping speed: a single-case design.

PubMed

Spiess, Martina R; Jaramillo, Jeffrey P; Behrman, Andrea L; Teraoka, Jeffrey K; Patten, Carolynn

2012-08-01

To investigate the effect of walking speed on the emergence of locomotor electromyogram (EMG) patterns in an individual with chronic incomplete spinal cord injury (SCI), and to determine whether central pattern generator activity during robotic locomotor training (RLT) transfers to volitional EMG activity during overground walking. Single-case (B-A-B; experimental treatment-withdrawal-experimental treatment) design. Freestanding rehabilitation research center. A 50-year-old man who was nonambulatory for 16 months after incomplete SCI (sub-T11). The participant completed two 6-week blocks of RLT, training 4 times per week for 30 minutes per session at walking speeds up to 5km/h (1.4m/s) over continuous bouts lasting up to 17 minutes. Surface EMG was recorded weekly during RLT and overground walking. The Walking Index for Spinal Cord Injury (WISCI-II) was assessed daily during training blocks. During week 4, reciprocal, patterned EMG emerged during RLT. EMG amplitude modulation revealed a curvilinear relationship over the range of walking speeds from 1.5 to 5km/h (1.4m/s). Functionally, the participant improved from being nonambulatory (WISCI-II 1/20), to walking overground with reciprocal stepping using knee-ankle-foot orthoses and a walker (WISCI-II 9/20). EMG was also observed during overground walking. These functional gains were maintained greater than 4 years after locomotor training (LT). Here we report an unexpected course of locomotor recovery in an individual with chronic incomplete SCI. Through RLT at physiologic walking speeds, it was possible to activate the central pattern generator even 16 months postinjury. Further, to a certain degree, improvements from RLT transferred to overground walking. Our results suggest that LT-induced changes affect the central pattern generator and allow supraspinal inputs to engage residual spinal pathways. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Efficacy of a hybrid assistive limb in post-stroke hemiplegic patients: a preliminary report

PubMed Central

2011-01-01

Background Robotic devices are expected to be widely used in various applications including support for the independent mobility of the elderly with muscle weakness and people with impaired motor function as well as support for nursing care that involves heavy laborious work. We evaluated the effects of a hybrid assistive limb robot suit on the gait of stroke patients undergoing rehabilitation. Methods The study group comprised 16 stroke patients with severe hemiplegia. All patients underwent gait training. Four patients required assistance, and 12 needed supervision while walking. The stride length, walking speed and physiological cost index on wearing the hybrid assistive limb suit and a knee-ankle-foot orthosis were compared. Results The hybrid assistive limb suit increased the stride length and walking speed in 4 of 16 patients. The patients whose walking speed decreased on wearing the hybrid assistive limb suit either had not received sufficient gait training or had an established gait pattern with a knee-ankle-foot orthosis using a quad cane. The physiological cost index increased after wearing the hybrid assistive limb suit in 12 patients, but removal of the suit led to a decrease in the physiological cost index values to equivalent levels prior to the use of the suit. Conclusions Although the hybrid assistive limb suit is not useful for all hemiplegic patients, it may increase the walking speed and affect the walking ability. Further investigation would clarify its indication for the possibility of gait training. PMID:21943320

Modulation of weight off-loading level over body-weight supported locomotion training.

PubMed

Wang, Ping; Low, K H; Lim, Peter A C; McGregor, A H

2011-01-01

With the evolution of robotic systems to facilitate overground walking rehabilitation, it is important to understand the effect of robotic-aided body-weight supported loading on lower limb muscle activity, if we are to optimize neuromotor recovery. To achieve this objective, we have collected and studied electromyography (EMG) data from key muscles in the lower extremity from healthy subjects walking over a wide range of body-weight off-loading levels as provided by a bespoke gait robot. By examining the impact of body-weight off-loading, it was found that muscle activation patterns were sensitive to the level of off-loading. In addition, a large off-loading might introduce disturbance of muscle activation pattern, led to a wider range of motion in terms of dorsiflexion/plantarflexion. Therefore, any future overground training machine should be enhanced to exclude unnecessary effect of body off-loading in securing the sustaining upright posture and providing assist-as-needed BWS over gait rehabilitation. © 2011 IEEE

Development of an assist controller with robot suit HAL for hemiplegic patients using motion data on the unaffected side.

PubMed

Kawamoto, Hiroaki; Kandone, Hideki; Sakurai, Takeru; Ariyasu, Ryohei; Ueno, Yukiko; Eguchi, Kiyoshi; Sankai, Yoshiyuki

2014-01-01

Among several characteristics seen in gait of hemiplegic patients after stroke, symmetry is known to be an indicator of the degree of impairment of walking ability. This paper proposes a control method for a wearable type lower limb motion assist robot to realize spontaneous symmetric gait for these individuals. This control method stores the motion of the unaffected limb during swing and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. This method is implemented on the robot suit HAL (Hybrid Assistive Limbs). Clinical tests were conducted in order to assess the feasibility of the control method. Our case study involved participation of one chronic stroke patient who was not able to flex his right knee. As a result, the walking support for hemiplegic leg provided by the HAL improved the subject's gait symmetry. The feasibility study showed promising basis for the future clinical study.

Design and evaluation of Mina: a robotic orthosis for paraplegics.

PubMed

Neuhaus, Peter D; Noorden, Jerryll H; Craig, Travis J; Torres, Tecalote; Kirschbaum, Justin; Pratt, Jerry E

2011-01-01

Mobility options for persons suffering from paraplegia or paraparesis are limited to mainly wheeled devices. There are significant health, psychological, and social consequences related to being confined to a wheelchair. We present the Mina, a robotic orthosis for assisting mobility, which offers a legged mobility option for these persons. Mina is an overground robotic device that is worn on the back and around the legs to provide mobility assistance for people suffering from paraplegia or paraparesis. Mina uses compliant actuation to power the hip and knee joints. For paralyzed users, balance is provided with the assistance of forearm crutches. This paper presents the evaluation of Mina with two paraplegics (SCI ASIA-A). We confirmed that with a few hours of training and practice, Mina is currently able to provide paraplegics walking mobility at speeds of up to 0.20 m/s. We further confirmed that using Mina is not physically taxing and requires little cognitive effort, allowing the user to converse and maintain eye contact while walking. © 2011 IEEE

Design and evaluation of NEUROBike: a neurorehabilitative platform for bedridden post-stroke patients.

PubMed

Monaco, Vito; Galardi, Giuseppe; Coscia, Martina; Martelli, Dario; Micera, Silvestro

2012-11-01

Over the past decades, a large number of robotic platforms have been developed which provide rehabilitative treatments aimed at recovering walking abilities in post-stroke patients. Unfortunately, they do not significantly influence patients' performance after three months from the accident. One of the main reasons underlying this result seems to be related to the time of intervention. Specifically, although experimental evidences suggest that early (i.e., first days after the injury) and intense neuro-rehabilitative treatments can significantly favor the functional recovery of post-stroke patients, robots require patients to be verticalized. Consequently, this does not allow them to be treated immediately after the trauma. This paper introduces a new robotic platform, named NEUROBike, designed to provide neuro-rehabilitative treatments to bedridden patients. It was designed to provide an early and well-addressed rehabilitation therapy, in terms of kinesiology, efforts, and fatigue, accounting for exercises functionally related to daily motor tasks. For this purpose, kinematic models of leg-joint angular excursions during both walking and sit-to-stand were developed and implemented in control algorithms leading both passive and active exercises. Finally, a set of pilot tests was carried out to evaluate the performance of the robotic platform on healthy subjects.

Tandem Stance Avoidance Using Adaptive and Asymmetric Admittance Control for Fall Prevention.

PubMed

Nakagawa, Shotaro; Hasegawa, Yasuhisa; Fukuda, Toshio; Kondo, Izumi; Tanimoto, Masanori; Di, Pei; Huang, Jian; Huang, Qiang

2016-05-01

Fall prevention is one of the most important functions of walking assistance devices for user's safety. It is preferable that these devices prevent the user from being in the state where the risk of falling is high rather than helping them recovering from falling motion. During turning, when the user is in the tandem stance, a state where both legs form a line along walking direction, a support base that is surrounded by two legs becomes small, and a stability margin becomes small. This paper therefore aims to prevent the tandem stance by using nonwearable robot "intelligent cane" for the elderly or physically challenged person. Generally, the behavior of the lower limb follows the upper body turning. This paper therefore introduces a cane robot control method which constrains the behavior of user's upper body. By adjusting an admittance parameter of the robot according to the positions of a support leg, the robot resists to turn while a support leg is on the same side of the turning direction. A swing leg on the turning direction side therefore freely moves to the turning direction, while a swing leg on the opposite direction side of turning hardly move to the turning direction.

Translating research into clinical practice: integrating robotics into neurorehabilitation for stroke survivors.

PubMed

Backus, Deborah; Winchester, Patricia; Tefertiller, Candace

2010-01-01

Technological advances continue to infuse the field of neurorehabilitation with both excitement and apprehension. A challenge for clinicians is to determine which of the growing number of devices or interventions available should be incorporated into their clinical practice, and when and with whom they should be offered, in order to best assist their patients in attaining the highest level of function and quality of life. Robotics is one area of technology that has seen robust growth in rehabilitation applications, so much so that the presence of robotic devices in rehabilitation centers has become an expectation among patients, their caregivers, and therapists. Although rehabilitation robotic devices afford the opportunity to provide high doses of repetitive movement in a reliable and controllable manner, the role they play in the continuum of clinical care remains uncertain. The focus of this article is on translating the empirical evidence related to the application of rehabilitation robotics for improving lower limb and walking function in a manner that the clinician, or any stakeholder, will be able to incorporate relevant findings into clinical practice. A process is outlined and applied to a recent review of the literature related to the use of robotics for the treatment of lower limb and walking function in persons with stroke. This process provides the reader with a tool that can be applied to the translation and implementation of evidence related to any intervention for any client with neurological injury or disease.

Perception, planning, and control for walking on rugged terrain

NASA Technical Reports Server (NTRS)

Simmons, Reid; Krotkov, Eric

1991-01-01

The CMU Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. To gain experience with the problems involved in walking on rugged terrain, a full-scale prototype leg was built and mounted on a carriage that rolls along overhead rails. Issues addressed in developing the software system to autonomously walk the leg through rugged terrain are described. In particular, the insights gained into perceiving and modeling rugged terrain, controlling the legged mechanism, interacting with the ground, choosing safe yet effective footfalls, and planning efficient leg moves through space are described.

Robot-Assisted Rehabilitation of Ankle Plantar Flexors Spasticity: A 3-Month Study with Proprioceptive Neuromuscular Facilitation

PubMed Central

Zhou, Zhihao; Sun, Yao; Wang, Ninghua; Gao, Fan; Wei, Kunlin; Wang, Qining

2016-01-01

In this paper, we aim to investigate the effect of proprioceptive neuromuscular facilitation (PNF)-based rehabilitation for ankle plantar flexors spasticity by using a Robotic Ankle–foot Rehabilitation System (RARS). A modified robot-assisted system was proposed, and seven poststroke patients with hemiplegic spastic ankles participated in a 3-month robotic PNF training. Their impaired sides were used as the experimental group, while their unimpaired sides as the control group. A robotic intervention for the experimental group started from a 2-min passive stretching to warming-up or relaxing the soleus and gastrocnemius muscles and also ended with the same one. Then a PNF training session including 30 trials was activated between them. The rehabilitation trainings were carried out three times a week as an addition to their regular rehabilitation exercise. Passive range of motion, resistance torque, and stiffness were measured in both ankles before and after the interventions. The changes in Achilles tendon length, walking speed, and lower limb function were also evaluated by the same physician or physiotherapist for each participant. Biomechanical measurements before interventions showed significant difference between the experimental group and the control group due to ankle spasticity. For the control group, there was no significant difference in the 3 months with no robotic intervention. But for the experimental group, passive dorsiflexion range of motion increased (p < 0.01), resistance torque under different dorsiflexion angle levels (0°, 10°, and 20°) decreased (p < 0.05, p < 0.001, and p < 0.001, respectively), and quasi-static stiffness under different dorsiflexion angle levels (0°, 10°, and 20°) also decreased (p < 0.01, p < 0.001, and p < 0.001, respectively). Achilles’s tendon length shortened (p < 0.01), while its thickness showed no significant change (p > 0.05). The robotic rehabilitation also improved the muscle strength (p < 0.01) and muscle control performance (p < 0.001). In addition, improvements were observed in clinical and functional measurements, such as Timed Up-and-Go (p < 0.05), normal walking speed (p > 0.05), and fast walking speed (p < 0.05). These results indicated that the PNF-based robotic intervention could significantly alleviate lower limb spasticity and improve the motor function in chronic stroke participant. The robotic system could potentially be used as an effective tool in poststroke rehabilitation training. PMID:27895574

Robustness of a distributed neural network controller for locomotion in a hexapod robot

NASA Technical Reports Server (NTRS)

Chiel, Hillel J.; Beer, Randall D.; Quinn, Roger D.; Espenschied, Kenneth S.

1992-01-01

A distributed neural-network controller for locomotion, based on insect neurobiology, has been used to control a hexapod robot. How robust is this controller? Disabling any single sensor, effector, or central component did not prevent the robot from walking. Furthermore, statically stable gaits could be established using either sensor input or central connections. Thus, a complex interplay between central neural elements and sensor inputs is responsible for the robustness of the controller and its ability to generate a continuous range of gaits. These results suggest that biologically inspired neural-network controllers may be a robust method for robotic control.

Algorithms of walking and stability for an anthropomorphic robot

NASA Astrophysics Data System (ADS)

Sirazetdinov, R. T.; Devaev, V. M.; Nikitina, D. V.; Fadeev, A. Y.; Kamalov, A. R.

2017-09-01

Autonomous movement of an anthropomorphic robot is considered as a superposition of a set of typical elements of movement - so-called patterns, each of which can be considered as an agent of some multi-agent system [ 1 ]. To control the AP-601 robot, an information and communication infrastructure has been created that represents some multi-agent system that allows the development of algorithms for individual patterns of moving and run them in the system as a set of independently executed and interacting agents. The algorithms of lateral movement of the anthropomorphic robot AP-601 series with active stability due to the stability pattern are presented.

Stabilization of a three-dimensional limit cycle walking model through step-to-step ankle control.

PubMed

Kim, Myunghee; Collins, Steven H

2013-06-01

Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss of active ankle control. If ankle control can contribute significantly to maintaining balance, even in the presence of active foot placement, this might provide an opportunity to improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods in a three-dimensional model of human gait that included ankle plantarflexion, ankle inversion-eversion, hip flexion-extension, and hip ad/abduction. We generated discrete feedback control laws (linear quadratic regulators) that altered nominal actuation parameters once per step. We used ankle push-off, lateral ankle stiffness and damping, fore-aft foot placement, lateral foot placement, or all of these as control inputs. We modeled environmental disturbances as random, bounded, unexpected changes in floor height, and defined balance performance as the maximum allowable disturbance value for which the model walked 500 steps without falling. Nominal walking motions were unstable, but were stabilized by all of the step-to-step control laws we tested. Surprisingly, step-by-step modulation of ankle push-off alone led to better balance performance (3.2% leg length) than lateral foot placement (1.2% leg length) for these control laws. These results suggest that appropriate control of robotic ankle-foot prosthesis push-off could make balancing during walking easier for individuals with amputation.

Robot Serviced Space Facility

NASA Technical Reports Server (NTRS)

Purves, Lloyd R. (Inventor)

1992-01-01

A robot serviced space facility includes multiple modules which are identical in physical structure, but selectively differing in function. and purpose. Each module includes multiple like attachment points which are identically placed on each module so as to permit interconnection with immediately adjacent modules. Connection is made through like outwardly extending flange assemblies having identical male and female configurations for interconnecting to and locking to a complementary side of another flange. Multiple rows of interconnected modules permit force, fluid, data and power transfer to be accomplished by redundant circuit paths. Redundant modules of critical subsystems are included. Redundancy of modules and of interconnections results in a space complex with any module being removable upon demand, either for module replacement or facility reconfiguration. without eliminating any vital functions of the complex. Module replacement and facility assembly or reconfiguration are accomplished by a computer controlled articulated walker type robotic manipulator arm assembly having two identical end-effectors in the form of male configurations which are identical to those on module flanges and which interconnect to female configurations on other flanges. The robotic arm assembly moves along a connected set or modules by successively disconnecting, moving and reconnecting alternate ends of itself to a succession of flanges in a walking type maneuver. To transport a module, the robot keeps the transported module attached to one of its end-effectors and uses another flange male configuration of the attached module as a substitute end-effector during walking.

Walking model with no energy cost.

PubMed

Gomes, Mario; Ruina, Andy

2011-03-01

We have numerically found periodic collisionless motions of a walking model consisting of linked rigid objects. Unlike previous designs, this model can walk on level ground at noninfinitesimal speed with zero energy input. The model avoids collisional losses by using an internal mode of oscillation: swaying of the upper body coupled to the legs by springs. Appropriate synchronized internal oscillations set the foot-strike collision to zero velocity. The concept might be of use for energy-efficient robots and may also help to explain aspects of human and animal locomotion efficiency.

Teaching Adult Rats Spinalized as Neonates to Walk Using Trunk Robotic Rehabilitation: Elements of Success, Failure, and Dependence

PubMed Central

Udoekwere, Ubong I.; Oza, Chintan S.

2016-01-01

Robot therapy promotes functional recovery after spinal cord injury (SCI) in animal and clinical studies. Trunk actions are important in adult rats spinalized as neonates (NTX rats) that walk autonomously. Quadrupedal robot rehabilitation was tested using an implanted orthosis at the pelvis. Trunk cortical reorganization follows such rehabilitation. Here, we test the functional outcomes of such training. Robot impedance control at the pelvis allowed hindlimb, trunk, and forelimb mechanical interactions. Rats gradually increased weight support. Rats showed significant improvement in hindlimb stepping ability, quadrupedal weight support, and all measures examined. Function in NTX rats both before and after training showed bimodal distributions, with “poor” and “high weight support” groupings. A total of 35% of rats initially classified as “poor” were able to increase their weight-supported step measures to a level considered “high weight support” after robot training, thus moving between weight support groups. Recovered function in these rats persisted on treadmill with the robot both actuated and nonactuated, but returned to pretraining levels if they were completely disconnected from the robot. Locomotor recovery in robot rehabilitation of NTX rats thus likely included context dependence and/or incorporation of models of robot mechanics that became essential parts of their learned strategy. Such learned dependence is likely a hurdle to autonomy to be overcome for many robot locomotor therapies. Notwithstanding these limitations, trunk-based quadrupedal robot rehabilitation helped the rats to visit mechanical states they would never have achieved alone, to learn novel coordinations, and to achieve major improvements in locomotor function. SIGNIFICANCE STATEMENT Neonatal spinal transected rats without any weight support can be taught weight support as adults by using robot rehabilitation at trunk. No adult control rats with neonatal spinal transections spontaneously achieve similar changes. The robot rehabilitation system can be inactivated and the skills that were learned persist. Responding rats cannot be detached from the robot altogether, a dependence develops in the skill learned. From data and analysis here, the likelihood of such rats to respond to the robot therapy can also now be predicted. These results are all novel. Understanding trunk roles in voluntary and spinal reflex integration after spinal cord injury and in recovery of function are broadly significant for basic and clinical understanding of motor function. PMID:27511008

Teaching Adult Rats Spinalized as Neonates to Walk Using Trunk Robotic Rehabilitation: Elements of Success, Failure, and Dependence.

PubMed

Udoekwere, Ubong I; Oza, Chintan S; Giszter, Simon F

2016-08-10

Robot therapy promotes functional recovery after spinal cord injury (SCI) in animal and clinical studies. Trunk actions are important in adult rats spinalized as neonates (NTX rats) that walk autonomously. Quadrupedal robot rehabilitation was tested using an implanted orthosis at the pelvis. Trunk cortical reorganization follows such rehabilitation. Here, we test the functional outcomes of such training. Robot impedance control at the pelvis allowed hindlimb, trunk, and forelimb mechanical interactions. Rats gradually increased weight support. Rats showed significant improvement in hindlimb stepping ability, quadrupedal weight support, and all measures examined. Function in NTX rats both before and after training showed bimodal distributions, with "poor" and "high weight support" groupings. A total of 35% of rats initially classified as "poor" were able to increase their weight-supported step measures to a level considered "high weight support" after robot training, thus moving between weight support groups. Recovered function in these rats persisted on treadmill with the robot both actuated and nonactuated, but returned to pretraining levels if they were completely disconnected from the robot. Locomotor recovery in robot rehabilitation of NTX rats thus likely included context dependence and/or incorporation of models of robot mechanics that became essential parts of their learned strategy. Such learned dependence is likely a hurdle to autonomy to be overcome for many robot locomotor therapies. Notwithstanding these limitations, trunk-based quadrupedal robot rehabilitation helped the rats to visit mechanical states they would never have achieved alone, to learn novel coordinations, and to achieve major improvements in locomotor function. Neonatal spinal transected rats without any weight support can be taught weight support as adults by using robot rehabilitation at trunk. No adult control rats with neonatal spinal transections spontaneously achieve similar changes. The robot rehabilitation system can be inactivated and the skills that were learned persist. Responding rats cannot be detached from the robot altogether, a dependence develops in the skill learned. From data and analysis here, the likelihood of such rats to respond to the robot therapy can also now be predicted. These results are all novel. Understanding trunk roles in voluntary and spinal reflex integration after spinal cord injury and in recovery of function are broadly significant for basic and clinical understanding of motor function. Copyright © 2016 the authors 0270-6474/16/368341-15$15.00/0.

Autonomous Motion Learning for Intra-Vehicular Activity Space Robot

NASA Astrophysics Data System (ADS)

Watanabe, Yutaka; Yairi, Takehisa; Machida, Kazuo

Space robots will be needed in the future space missions. So far, many types of space robots have been developed, but in particular, Intra-Vehicular Activity (IVA) space robots that support human activities should be developed to reduce human-risks in space. In this paper, we study the motion learning method of an IVA space robot with the multi-link mechanism. The advantage point is that this space robot moves using reaction force of the multi-link mechanism and contact forces from the wall as space walking of an astronaut, not to use a propulsion. The control approach is determined based on a reinforcement learning with the actor-critic algorithm. We demonstrate to clear effectiveness of this approach using a 5-link space robot model by simulation. First, we simulate that a space robot learn the motion control including contact phase in two dimensional case. Next, we simulate that a space robot learn the motion control changing base attitude in three dimensional case.

Ankle voluntary movement enhancement following robotic-assisted locomotor training in spinal cord injury.

PubMed

Varoqui, Deborah; Niu, Xun; Mirbagheri, Mehdi M

2014-03-31

In incomplete spinal cord injury (iSCI), sensorimotor impairments result in severe limitations to ambulation. To improve walking capacity, physical therapies using robotic-assisted locomotor devices, such as the Lokomat, have been developed. Following locomotor training, an improvement in gait capabilities-characterized by increases in the over-ground walking speed and endurance-is generally observed in patients. To better understand the mechanisms underlying these improvements, we studied the effects of Lokomat training on impaired ankle voluntary movement, known to be an important limiting factor in gait for iSCI patients. Fifteen chronic iSCI subjects performed twelve 1-hour sessions of Lokomat training over the course of a month. The voluntary movement was qualified by measuring active range of motion, maximal velocity peak and trajectory smoothness for the spastic ankle during a movement from full plantar-flexion (PF) to full dorsi-flexion (DF) at the patient's maximum speed. Dorsi- and plantar-flexor muscle strength was quantified by isometric maximal voluntary contraction (MVC). Clinical assessments were also performed using the Timed Up and Go (TUG), the 10-meter walk (10MWT) and the 6-minute walk (6MWT) tests. All evaluations were performed both before and after the training and were compared to a control group of fifteen iSCI patients. After the Lokomat training, the active range of motion, the maximal velocity, and the movement smoothness were significantly improved in the voluntary movement. Patients also exhibited an improvement in the MVC for their ankle dorsi- and plantar-flexor muscles. In terms of functional activity, we observed an enhancement in the mobility (TUG) and the over-ground gait velocity (10MWT) with training. Correlation tests indicated a significant relationship between ankle voluntary movement performance and the walking clinical assessments. The improvements of the kinematic and kinetic parameters of the ankle voluntary movement, and their correlation with the functional assessments, support the therapeutic effect of robotic-assisted locomotor training on motor impairment in chronic iSCI.

Innovative gait robot for the repetitive practice of floor walking and stair climbing up and down in stroke patients

PubMed Central

2010-01-01

Background Stair climbing up and down is an essential part of everyday's mobility. To enable wheelchair-dependent patients the repetitive practice of this task, a novel gait robot, G-EO-Systems (EO, Lat: I walk), based on the end-effector principle, has been designed. The trajectories of the foot plates are freely programmable enabling not only the practice of simulated floor walking but also stair climbing up and down. The article intended to compare lower limb muscle activation patterns of hemiparetic subjects during real floor walking and stairs climbing up, and during the corresponding simulated conditions on the machine, and secondly to demonstrate gait improvement on single case after training on the machine. Methods The muscle activation pattern of seven lower limb muscles of six hemiparetic patients during free and simulated walking on the floor and stair climbing was measured via dynamic electromyography. A non-ambulatory, sub-acute stroke patient additionally trained on the G-EO-Systems every workday for five weeks. Results The muscle activation patterns were comparable during the real and simulated conditions, both on the floor and during stair climbing up. Minor differences, concerning the real and simulated floor walking conditions, were a delayed (prolonged) onset (duration) of the thigh muscle activation on the machine across all subjects. Concerning stair climbing conditions, the shank muscle activation was more phasic and timely correct in selected patients on the device. The severely affected subject regained walking and stair climbing ability. Conclusions The G-EO-Systems is an interesting new option in gait rehabilitation after stroke. The lower limb muscle activation patterns were comparable, a training thus feasible, and the positive case report warrants further clinical studies. PMID:20584307

Innovative gait robot for the repetitive practice of floor walking and stair climbing up and down in stroke patients.

PubMed

Hesse, Stefan; Waldner, Andreas; Tomelleri, Christopher

2010-06-28

Stair climbing up and down is an essential part of everyday's mobility. To enable wheelchair-dependent patients the repetitive practice of this task, a novel gait robot, G-EO-Systems (EO, Lat: I walk), based on the end-effector principle, has been designed. The trajectories of the foot plates are freely programmable enabling not only the practice of simulated floor walking but also stair climbing up and down. The article intended to compare lower limb muscle activation patterns of hemiparetic subjects during real floor walking and stairs climbing up, and during the corresponding simulated conditions on the machine, and secondly to demonstrate gait improvement on single case after training on the machine. The muscle activation pattern of seven lower limb muscles of six hemiparetic patients during free and simulated walking on the floor and stair climbing was measured via dynamic electromyography. A non-ambulatory, sub-acute stroke patient additionally trained on the G-EO-Systems every workday for five weeks. The muscle activation patterns were comparable during the real and simulated conditions, both on the floor and during stair climbing up. Minor differences, concerning the real and simulated floor walking conditions, were a delayed (prolonged) onset (duration) of the thigh muscle activation on the machine across all subjects. Concerning stair climbing conditions, the shank muscle activation was more phasic and timely correct in selected patients on the device. The severely affected subject regained walking and stair climbing ability. The G-EO-Systems is an interesting new option in gait rehabilitation after stroke. The lower limb muscle activation patterns were comparable, a training thus feasible, and the positive case report warrants further clinical studies.

Motion and Emotional Behavior Design for Pet Robot Dog

NASA Astrophysics Data System (ADS)

Cheng, Chi-Tai; Yang, Yu-Ting; Miao, Shih-Heng; Wong, Ching-Chang

A pet robot dog with two ears, one mouth, one facial expression plane, and one vision system is designed and implemented so that it can do some emotional behaviors. Three processors (Inter® Pentium® M 1.0 GHz, an 8-bit processer 8051, and embedded soft-core processer NIOS) are used to control the robot. One camera, one power detector, four touch sensors, and one temperature detector are used to obtain the information of the environment. The designed robot with 20 DOF (degrees of freedom) is able to accomplish the walking motion. A behavior system is built on the implemented pet robot so that it is able to choose a suitable behavior for different environmental situation. From the practical test, we can see that the implemented pet robot dog can do some emotional interaction with the human.

Modular Ankle Robotics Training in Early Sub-Acute Stroke: A Randomized Controlled Pilot Study

PubMed Central

Forrester, Larry W.; Roy, Anindo; Krywonis, Amanda; Kehs, Glenn; Krebs, Hermano Igo; Macko, Richard F.

2014-01-01

Background Modular lower extremity (LE) robotics may offer a valuable avenue for restoring neuromotor control after hemiparetic stroke. Prior studies show that visually-guided and visually-evoked practice with an ankle robot (anklebot) improves paretic ankle motor control that translates into improved overground walking. Objective Assess the feasibility and efficacy of daily anklebot training during early sub-acute hospitalization post-stroke. Methods Thirty-four inpatients from a stroke unit were randomly assigned to anklebot (N=18) or passive manual stretching (N=16) treatments. All suffered a first stroke with residual hemiparesis (ankle manual muscle test grade 1/5 to 4/5), and at least trace muscle activation in plantar- or dorsiflexion. Anklebot training employed an “assist-as-needed” approach during > 200 volitional targeted paretic ankle movements, with difficulty adjusted to active range of motion and success rate. Stretching included >200 daily mobilizations in these same ranges. All sessions lasted 1 hour and assessments were not blinded. Results Both groups walked faster at discharge, however the robot group improved more in percent change of temporal symmetry (p=0.032) and also of step length symmetry (p=0.038), with longer nonparetic step lengths in the robot (133%) vs. stretching (31%) groups. Paretic ankle control improved in the robot group, with increased peak (p≤ 0.001) and mean (p≤ 0.01) angular speeds, and increased movement smoothness (p≤ 0.01). There were no adverse events. Conclusion Though limited by small sample size and restricted entry criteria, our findings suggest that modular lower extremity robotics during early sub-acute hospitalization is well tolerated and improves ankle motor control and gait patterning. PMID:24515923

Overground vs. treadmill-based robotic gait training to improve seated balance in people with motor-complete spinal cord injury: a case report.

PubMed

Chisholm, Amanda E; Alamro, Raed A; Williams, Alison M M; Lam, Tania

2017-04-11

Robotic overground gait training devices, such as the Ekso, require users to actively participate in triggering steps through weight-shifting movements. It remains unknown how much the trunk muscles are activated during these movements, and if it is possible to transfer training effects to seated balance control. This study was conducted to compare the activity of postural control muscles of the trunk during overground (Ekso) vs. treadmill-based (Lokomat) robotic gait training, and evaluate changes in seated balance control in people with high-thoracic motor-complete spinal cord injury (SCI). Three individuals with motor-complete SCI from C7-T4, assumed to have no voluntary motor function below the chest, underwent robotic gait training. The participants were randomly assigned to Ekso-Lokomat-Ekso or Lokomat-Ekso-Lokomat for 10 sessions within each intervention phase for a total of 30 sessions. We evaluated static and dynamic balance control through analysis of center of pressure (COP) movements after each intervention phase. Surface electromyography was used to compare activity of the abdominal and erector spinae muscles during Ekso and Lokomat walking. We observed improved postural stability after training with Ekso compared to Lokomat during static balance tasks, indicated by reduced COP root mean square distance and ellipse area. In addition, Ekso training increased total distance of COP movements during a dynamic balance task. The trunk muscles showed increased activation during Ekso overground walking compared to Lokomat walking. Our findings suggest that the Ekso actively recruits trunk muscles through postural control mechanisms, which may lead to improved balance during sitting. Developing effective training strategies to reactivate the trunk muscles is important to facilitate independence during seated balance activity in people with SCI.

Collaborative robotic biomechanical interactions and gait adjustments in young, non-impaired individuals.

PubMed

Dionisio, Valdeci C; Brown, David A

2016-06-16

Collaborative robots are used in rehabilitation and are designed to interact with the client so as to provide the ability to assist walking therapeutically. One such device is the KineAssist which was designed to interact, either in a self-driven mode (SDM) or in an assist mode (AM), with neurologically-impaired individuals while they are walking on a treadmill surface. To understand the level of transparency (i.e., interference with movement due to the mechanical interface) between human and robot, and to estimate and account for changes in the kinetics and kinematics of the gait pattern, we tested the KineAssist under conditions of self-drive and horizontal push assistance. The aims of this study were to compare the joint kinematics, forces and moments during walking at a fixed constant treadmill belt speed and constrained walking cadence, with and without the robotic device (OUT) and to compare the biomechanics of assistive and self-drive modes in the device. Twenty non-neurologically impaired adults participated in this study. We evaluated biomechanical parameters of walking at a fixed constant treadmill belt speed (1.0 m/s), with and without the robotic device in assistive mode. We also tested the self-drive condition, which enables the user to drive the speed and direction of a treadmill belt. Hip, knee and ankle angular displacements, ground reaction forces, hip, knee and ankle moments, and center of mass displacement were compared "in" vs "out" of the device. A repeated measures ANOVA test was applied with the three level factor of condition (OUT, AM, and SDM), and each participant was used as its own comparison. When comparing "in" and "out" of the device, we did not observe any interruptions and/or reversals of direction of the basic gait pattern trajectory, but there was increased ankle and hip angular excursions, vertical ground reaction force and hip moments and reduced center of mass displacement during the "in device" condition. Comparing assistive vs self-drive mode in device, participants had greater flexed posture and accentuated hip moments and propulsive force, but reduced braking force. Although the magnitudes and/or range of certain gait pattern components were altered by the device, we did not observe any interruption from the mechanical interface upon the advancement of the trajectories nor reversals in direction of movement which suggests that the KineAssist permits relative transparency (i.e.. lack of interference of movement by the device mechanism) to the individual's gait pattern. However, there are interactive forces to take into account, which appear to be overcome by kinematic and kinetic adjustments.

An accelerometry-based comparison of 2 robotic assistive devices for treadmill training of gait.

PubMed

Regnaux, Jean-Philippe; Saremi, Kaveh; Marehbian, Jon; Bussel, Bernard; Dobkin, Bruce H

2008-01-01

Two commercial robotic devices, the Gait Trainer (GT) and the Lokomat (LOKO), assist task-oriented practice of walking. The gait patterns induced by these motor-driven devices have not been characterized and compared. A healthy participant chose the most comfortable gait pattern on each device and for treadmill (TM) walking at 1, 2 (maximum for the GT), and 3 km/h and over ground at similar speeds. A system of accelerometers on the thighs and feet allowed the calculation of spatiotemporal features and accelerations during the gait cycle. At the 1 and 2 km/h speed settings, single-limb stance times were prolonged on the devices compared with overground walking. Differences on the LOKO were decreased by adjusting the hip and knee angles and step length. At the 3 km/h setting, the LOKO approximated the participant's overground parameters. Irregular accelerations and decelerations from toe-off to heel contact were induced by the devices, especially at slower speeds. The LOKO and GT impose mechanical constraints that may alter leg accelerations-decelerations during stance and swing phases, as well as stance duration, especially at their slower speed settings, that are not found during TM and overground walking. The potential impact of these perturbations on training to improve gait needs further study.

A New Powered Lower Limb Prosthesis Control Framework Based on Adaptive Dynamic Programming.

PubMed

Wen, Yue; Si, Jennie; Gao, Xiang; Huang, Stephanie; Huang, He Helen

2017-09-01

This brief presents a novel application of adaptive dynamic programming (ADP) for optimal adaptive control of powered lower limb prostheses, a type of wearable robots to assist the motor function of the limb amputees. Current control of these robotic devices typically relies on finite state impedance control (FS-IC), which lacks adaptability to the user's physical condition. As a result, joint impedance settings are often customized manually and heuristically in clinics, which greatly hinder the wide use of these advanced medical devices. This simulation study aimed at demonstrating the feasibility of ADP for automatic tuning of the twelve knee joint impedance parameters during a complete gait cycle to achieve balanced walking. Given that the accurate models of human walking dynamics are difficult to obtain, the model-free ADP control algorithms were considered. First, direct heuristic dynamic programming (dHDP) was applied to the control problem, and its performance was evaluated on OpenSim, an often-used dynamic walking simulator. For the comparison purposes, we selected another established ADP algorithm, the neural fitted Q with continuous action (NFQCA). In both cases, the ADP controllers learned to control the right knee joint and achieved balanced walking, but dHDP outperformed NFQCA in this application during a 200 gait cycle-based testing.

Overview of Robotic Devices for Nursing Care Project.

PubMed

Hirukawa, Hirohisa

2017-01-01

METI/AMED are conducting a project on the development and deployment of robotic devices for nursing care to enhance the autonomy of elderly persons and assist care givers. An evaluation protocol is presented and the devices developed in the project are introduced. The devices consist of transfer assist devices (wearable/non-wearable), walking assist devices (outdoor/indoor), safety surveillance sensors (nursing home/private home), bath lift and toilet assist.

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs.

PubMed

Spröwitz, Alexander T; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2-3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.

Robot-assisted gait training in multiple sclerosis patients: a randomized trial.

PubMed

Schwartz, Isabella; Sajin, Anna; Moreh, Elior; Fisher, Iris; Neeb, Martin; Forest, Adina; Vaknin-Dembinsky, Adi; Karusis, Dimitrios; Meiner, Zeev

2012-06-01

Preservation of locomotor activity in multiple sclerosis (MS) patients is of utmost importance. Robotic-assisted body weight-supported treadmill training is a promising method to improve gait functions in neurologically impaired patients, although its effectiveness in MS patients is still unknown. To compare the effectiveness of robot-assisted gait training (RAGT) with that of conventional walking treatment (CWT) on gait and generalized functions in a group of stable MS patients. A prospective randomized controlled trial of 12 sessions of RAGT or CWT in MS patients of EDSS score 5-7. Primary outcome measures were gait parameters and the secondary outcomes were functional and quality of life parameters. All tests were performed at baseline, 3 and 6 months post-treatment by a blinded rater. Fifteen and 17 patients were randomly allocated to RAGT and CWT, respectively. Both groups were comparable at baseline in all parameters. As compared with baseline, although some gait parameters improved significantly following the treatment at each time point there was no difference between the groups. Both FIM and EDSS scores improved significantly post-treatment with no difference between the groups. At 6 months, most gait and functional parameters had returned to baseline. Robot-assisted gait training is feasible and safe and may be an effective additional therapeutic option in MS patients with severe walking disabilities.

Novel actuation design of a gait trainer with shadow leg approach.

PubMed

Meuleman, Jos; Meuleman, Jos; van Asseldonk, Edwin H F; van der Kooij, Herman

2013-06-01

Robotic gait training has developed since the end of the 20(th) century, yet there is much room for improvement in the design of the robots. With the conventional exoskeleton structures, donning of patients in a gait trainer usually is a cumbersome process due to the need of joint alignments and normal walking is often hindered due to obstructed arm swing. Our goal was to design a gait training robots that overcomes these limitations. We propose a novel design in which these drawbacks are reduced to a great amount. By using a parallel structure behind the patient (shadow leg) that is connected to the patient joints with rods, little alignment is needed, the area lateral to the hip is left free, and thus arm swing is not obstructed. The construction is lightweight, because the actuators are mounted on a fixed base and the transmission of power is executed with light weight rods. An end stop in the shadow leg prevents hyper extension of the patient's knee. The relationship between motor displacement and human joint rotations is nonlinear. In this paper we derive the nonlinear relationships between motors and patient joints and verify these. calculations with a measurement. The device has been built, now tests with subjects are required to assess if subjects can indeed walk normally in the robot.

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs

PubMed Central

Spröwitz, Alexander T.; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2–3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware. PMID:24639645

Robotic gait trainer in water: development of an underwater gait-training orthosis.

PubMed

Miyoshi, Tasuku; Hiramatsu, Kazuaki; Yamamoto, Shin-Ichiro; Nakazawa, Kimitaka; Akai, Masami

2008-01-01

To develop a robotic gait trainer that can be used in water (RGTW) and achieve repetitive physiological gait patterns to improve the movement dysfunctions. The RGTW is a hip-knee-ankle-foot orthosis with pneumatic actuators; the control software was developed on the basis of the angular motions of the hip and knee joint of a healthy subject as he walked in water. Three-dimensional motions and electromyographic (EMG) activities were recorded in nine healthy subjects to evaluate the efficacy of using the RGTW while walking on a treadmill in water. The device could preserve the angular displacement patterns of the hip and knee and foot trajectories under all experimental conditions. The tibialis anterior EMG activities in the late swing phase and the biceps femoris throughout the stance phase were reduced whose joint torques were assisted by the RGTW while walking on a treadmill in water. Using the RGTW could expect not only the effect of the hydrotherapy but also the standard treadmill gait training, in particular, and may be particularly effective for treating individuals with hip joint movement dysfunction.

Planning energy-efficient bipedal locomotion on patterned terrain

NASA Astrophysics Data System (ADS)

Zamani, Ali; Bhounsule, Pranav A.; Taha, Ahmad

2016-05-01

Energy-efficient bipedal walking is essential in realizing practical bipedal systems. However, current energy-efficient bipedal robots (e.g., passive-dynamics-inspired robots) are limited to walking at a single speed and step length. The objective of this work is to address this gap by developing a method of synthesizing energy-efficient bipedal locomotion on patterned terrain consisting of stepping stones using energy-efficient primitives. A model of Cornell Ranger (a passive-dynamics inspired robot) is utilized to illustrate our technique. First, an energy-optimal trajectory control problem for a single step is formulated and solved. The solution minimizes the Total Cost Of Transport (TCOT is defined as the energy used per unit weight per unit distance travelled) subject to various constraints such as actuator limits, foot scuffing, joint kinematic limits, ground reaction forces. The outcome of the optimization scheme is a table of TCOT values as a function of step length and step velocity. Next, we parameterize the terrain to identify the location of the stepping stones. Finally, the TCOT table is used in conjunction with the parameterized terrain to plan an energy-efficient stepping strategy.

EVA Robotic Assistant Project: Platform Attitude Prediction

NASA Technical Reports Server (NTRS)

Nickels, Kevin M.

2003-01-01

The Robotic Systems Technology Branch is currently working on the development of an EVA Robotic Assistant under the sponsorship of the Surface Systems Thrust of the NASA Cross Enterprise Technology Development Program (CETDP). This will be a mobile robot that can follow a field geologist during planetary surface exploration, carry his tools and the samples that he collects, and provide video coverage of his activity. Prior experiments have shown that for such a robot to be useful it must be able to follow the geologist at walking speed over any terrain of interest. Geologically interesting terrain tends to be rough rather than smooth. The commercial mobile robot that was recently purchased as an initial testbed for the EVA Robotic Assistant Project, an ATRV Jr., is capable of faster than walking speed outside but it has no suspension. Its wheels with inflated rubber tires are attached to axles that are connected directly to the robot body. Any angular motion of the robot produced by driving over rough terrain will directly affect the pointing of the on-board stereo cameras. The resulting image motion is expected to make tracking of the geologist more difficult. This will either require the tracker to search a larger part of the image to find the target from frame to frame or to search mechanically in pan and tilt whenever the image motion is large enough to put the target outside the image in the next frame. This project consists of the design and implementation of a Kalman filter that combines the output of the angular rate sensors and linear accelerometers on the robot to estimate the motion of the robot base. The motion of the stereo camera pair mounted on the robot that results from this motion as the robot drives over rough terrain is then straightforward to compute. The estimates may then be used, for example, to command the robot s on-board pan-tilt unit to compensate for the camera motion induced by the base movement. This has been accomplished in two ways: first, a standalone head stabilizer has been implemented and second, the estimates have been used to influence the search algorithm of the stereo tracking algorithm. Studies of the image motion of a tracked object indicate that the image motion of objects is suppressed while the robot crossing rough terrain. This work expands the range of speed and surface roughness over which the robot should be able to track and follow a field geologist and accept arm gesture commands from the geologist.

Biomimetics and the Development of Humanlike Robots as the Ultimate Challenge

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2011-01-01

Evolution led to effective solutions to nature's challenges and they were improved over millions of years. Humans have always made efforts to use nature as a model for innovation and problems solving. These efforts became more intensive in recent years where systematic studies of nature are being made towards better understanding and applying more sophisticated capabilities. Making humanlike robots, including the appearance, functions and intelligence, poses the ultimate challenges to biomimetics. For many years, making such robots was considered science fiction, but as a result of significant advances in biologically inspired technologies, such robots are increasingly becoming an engineering reality. There are already humanlike robots that walk, talk, interpret speech, make eye-contact and facial expressions, as well as perform many other humanlike functions. In this paper, the state-of-the-art of humanlike robots, potential applications and issues of concern will be reviewed.

Intelligent control and adaptive systems; Proceedings of the Meeting, Philadelphia, PA, Nov. 7, 8, 1989

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor)

1990-01-01

Various papers on intelligent control and adaptive systems are presented. Individual topics addressed include: control architecture for a Mars walking vehicle, representation for error detection and recovery in robot task plans, real-time operating system for robots, execution monitoring of a mobile robot system, statistical mechanics models for motion and force planning, global kinematics for manipulator planning and control, exploration of unknown mechanical assemblies through manipulation, low-level representations for robot vision, harmonic functions for robot path construction, simulation of dual behavior of an autonomous system. Also discussed are: control framework for hand-arm coordination, neural network approach to multivehicle navigation, electronic neural networks for global optimization, neural network for L1 norm linear regression, planning for assembly with robot hands, neural networks in dynamical systems, control design with iterative learning, improved fuzzy process control of spacecraft autonomous rendezvous using a genetic algorithm.

2014 NASA Centennial Challenges Sample Return Robot Challenge

NASA Image and Video Library

2014-06-10

A pair of Worcester Polytechnic Institute (WPI) students walk past a pair of team KuuKulgur's robots on the campus quad, during a final tuneup before the start of competition at the 2014 NASA Centennial Challenges Sample Return Robot Challenge, Tuesday, June 10, 2014, at the Worcester Polytechnic Institute (WPI) in Worcester, Mass. Team KuuKulgur is one of eighteen teams competing for a $1.5 million NASA prize purse. Teams will be required to demonstrate autonomous robots that can locate and collect samples from a wide and varied terrain, operating without human control. The objective of this NASA-WPI Centennial Challenge is to encourage innovations in autonomous navigation and robotics technologies. Innovations stemming from the challenge may improve NASA's capability to explore a variety of destinations in space, as well as enhance the nation's robotic technology for use in industries and applications on Earth. Photo Credit: (NASA/Joel Kowsky)

Effects of unilateral robotic limb loading on gait characteristics in subjects with chronic stroke.

PubMed

Khanna, Ira; Roy, Anindo; Rodgers, Mary M; Krebs, Hermano I; Macko, Richard M; Forrester, Larry W

2010-05-21

Hemiparesis after stroke often leads to impaired ankle motor control that impacts gait function. In recent studies, robotic devices have been developed to address this impairment. While capable of imparting forces to assist during training and gait, these devices add mass to the paretic leg which might encumber patients' gait pattern. The purpose of this study was to assess the effects of the added mass of one of these robots, the MIT's Anklebot, while unpowered, on gait of chronic stroke survivors during overground and treadmill walking. Nine chronic stroke survivors walked overground and on a treadmill with and without the anklebot mounted on the paretic leg. Gait parameters, interlimb symmetry, and joint kinematics were collected for the four conditions. Repeated-measures analysis of variance (ANOVA) tests were conducted to examine for possible differences across four conditions for the paretic and nonparetic leg. The added inertia and friction of the unpowered anklebot had no statistically significant effect on spatio-temporal parameters of gait, including paretic and nonparetic step time and stance percentage, in both overground and treadmill conditions. Noteworthy, interlimb symmetry as characterized by relative stance duration was greater on the treadmill than overground regardless of loading conditions. The presence of the unpowered robot loading reduced the nonparetic knee peak flexion on the treadmill and paretic peak dorsiflexion overground (p < 0.05). Our results suggest that for these subjects the added inertia and friction of this backdriveable robot did not significantly alter their gait pattern.

Robot-Assisted Training for People With Spinal Cord Injury: A Meta-Analysis.

PubMed

Cheung, Eddy Y Y; Ng, Thomas K W; Yu, Kevin K K; Kwan, Rachel L C; Cheing, Gladys L Y

2017-11-01

To investigate the effects of robot-assisted training on the recovery of people with spinal cord injury (SCI). Randomized controlled trials (RCTs) or quasi-RCTs involving people with SCI that compared robot-assisted upper limbs or lower limbs training with a control of other treatment approach or no treatment. We included studies involving people with complete or incomplete SCIs. We searched MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials (Cochrane Library), and Embase to August 2016. Bibliographies of relevant articles on the effect of body-weight-supported treadmill training on subjects with SCI were screened to avoid missing relevant articles from the search of databases. All kinds of objective assessments concerning physical ability, mobility, and/or functional ability were included. Assessments could be clinical tests (ie, 6-minute walk test, FIM) or laboratory tests (ie, gait analysis). Subjective outcome measures were excluded from this review. Eleven RCT studies involving 443 subjects were included in the study. Meta-analysis was performed on the included studies. Walking independence (3.73; 95% confidence interval [CI], -4.92 to -2.53; P<.00001; I 2 =38%) and endurance (53.32m; 95% CI, -73.15 to -33.48; P<.00001; I 2 =0%) were found to have better improvement in robot-assisted training groups. Lower limb robot-assisted training was also found to be as effective as other types of body-weight-supported training. There is a lack of upper limb robot-assisted training studies; therefore, performing a meta-analysis was not possible. Robot-assisted training is an adjunct therapy for physical and functional recovery for patients with SCI. Future high-quality studies are warranted to investigate the effects of robot-assisted training on functional and cardiopulmonary recovery of patients with SCI. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Gait performance and foot pressure distribution during wearable robot-assisted gait in elderly adults.

PubMed

Lee, Su-Hyun; Lee, Hwang-Jae; Chang, Won Hyuk; Choi, Byung-Ok; Lee, Jusuk; Kim, Jeonghun; Ryu, Gyu-Ha; Kim, Yun-Hee

2017-11-28

A robotic exoskeleton device is an intelligent system designed to improve gait performance and quality of life for the wearer. Robotic technology has developed rapidly in recent years, and several robot-assisted gait devices were developed to enhance gait function and activities of daily living in elderly adults and patients with gait disorders. In this study, we investigated the effects of the Gait-enhancing Mechatronic System (GEMS), a new wearable robotic hip-assist device developed by Samsung Electronics Co, Ltd., Korea, on gait performance and foot pressure distribution in elderly adults. Thirty elderly adults who had no neurological or musculoskeletal abnormalities affecting gait participated in this study. A three-dimensional (3D) motion capture system, surface electromyography and the F-Scan system were used to collect data on spatiotemporal gait parameters, muscle activity and foot pressure distribution under three conditions: free gait without robot assistance (FG), robot-assisted gait with zero torque (RAG-Z) and robot-assisted gait (RAG). We found increased gait speed, cadence, stride length and single support time in the RAG condition. Reduced rectus femoris and medial gastrocnemius muscle activity throughout the terminal stance phase and reduced effort of the medial gastrocnemius muscle throughout the pre-swing phase were also observed in the RAG condition. In addition, walking with the assistance of GEMS resulted in a significant increase in foot pressure distribution, specifically in maximum force and peak pressure of the total foot, medial masks, anterior masks and posterior masks. The results of the present study reveal that GEMS may present an alternative way of restoring age-related changes in gait such as gait instability with muscle weakness, reduced step force and lower foot pressure in elderly adults. In addition, GEMS improved gait performance by improving push-off power and walking speed and reducing muscle activity in the lower extremities. NCT02843828 .

Vision-based semi-autonomous outdoor robot system to reduce soldier workload

NASA Astrophysics Data System (ADS)

Richardson, Al; Rodgers, Michael H.

2001-09-01

Sensors and computational capability have not reached the point to enable small robots to navigate autonomously in unconstrained outdoor environments at tactically useful speeds. This problem is greatly reduced, however, if a soldier can lead the robot through terrain that he knows it can traverse. An application of this concept is a small pack-mule robot that follows a foot soldier over outdoor terrain. The solder would be responsible to avoid situations beyond the robot's limitations when encountered. Having learned the route, the robot could autonomously retrace the path carrying supplies and munitions. This would greatly reduce the soldier's workload under normal conditions. This paper presents a description of a developmental robot sensor system using low-cost commercial 3D vision and inertial sensors to address this application. The robot moves at fast walking speed and requires only short-range perception to accomplish its task. 3D-feature information is recorded on a composite route map that the robot uses to negotiate its local environment and retrace the path taught by the soldier leader.

A survey on dielectric elastomer actuators for soft robots.

PubMed

Gu, Guo-Ying; Zhu, Jian; Zhu, Li-Min; Zhu, Xiangyang

2017-01-23

Conventional industrial robots with the rigid actuation technology have made great progress for humans in the fields of automation assembly and manufacturing. With an increasing number of robots needing to interact with humans and unstructured environments, there is a need for soft robots capable of sustaining large deformation while inducing little pressure or damage when maneuvering through confined spaces. The emergence of soft robotics offers the prospect of applying soft actuators as artificial muscles in robots, replacing traditional rigid actuators. Dielectric elastomer actuators (DEAs) are recognized as one of the most promising soft actuation technologies due to the facts that: i) dielectric elastomers are kind of soft, motion-generating materials that resemble natural muscle of humans in terms of force, strain (displacement per unit length or area) and actuation pressure/density; ii) dielectric elastomers can produce large voltage-induced deformation. In this survey, we first introduce the so-called DEAs emphasizing the key points of working principle, key components and electromechanical modeling approaches. Then, different DEA-driven soft robots, including wearable/humanoid robots, walking/serpentine robots, flying robots and swimming robots, are reviewed. Lastly, we summarize the challenges and opportunities for the further studies in terms of mechanism design, dynamics modeling and autonomous control.

Human motion behavior while interacting with an industrial robot.

PubMed

Bortot, Dino; Ding, Hao; Antonopolous, Alexandros; Bengler, Klaus

2012-01-01

Human workers and industrial robots both have specific strengths within industrial production. Advantageously they complement each other perfectly, which leads to the development of human-robot interaction (HRI) applications. Bringing humans and robots together in the same workspace may lead to potential collisions. The avoidance of such is a central safety requirement. It can be realized with sundry sensor systems, all of them decelerating the robot when the distance to the human decreases alarmingly and applying the emergency stop, when the distance becomes too small. As a consequence, the efficiency of the overall systems suffers, because the robot has high idle times. Optimized path planning algorithms have to be developed to avoid that. The following study investigates human motion behavior in the proximity of an industrial robot. Three different kinds of encounters between the two entities under three robot speed levels are prompted. A motion tracking system is used to capture the motions. Results show, that humans keep an average distance of about 0,5m to the robot, when the encounter occurs. Approximation of the workbenches is influenced by the robot in ten of 15 cases. Furthermore, an increase of participants' walking velocity with higher robot velocities is observed.

Applying the System Component and Operationally Relevant Evaluation (SCORE) Framework to Evaluate Advanced Military Technologies

DTIC Science & Technology

2010-03-01

and charac- terize the actions taken by the soldier (e.g., running, walking, climbing stairs ). Real-time image capture and exchange N The ability of...multimedia information sharing among soldiers in the field, two-way speech translation systems, and autonomous robotic platforms. Key words: Emerging...soldiers in the field, two-way speech translation systems, and autonomous robotic platforms. It has been the foundation for 10 technology evaluations

Brain-machine interfaces for controlling lower-limb powered robotic systems.

PubMed

He, Yongtian; Eguren, David; Azorín, José M; Grossman, Robert G; Luu, Trieu Phat; Contreras-Vidal, Jose L

2018-04-01

Lower-limb, powered robotics systems such as exoskeletons and orthoses have emerged as novel robotic interventions to assist or rehabilitate people with walking disabilities. These devices are generally controlled by certain physical maneuvers, for example pressing buttons or shifting body weight. Although effective, these control schemes are not what humans naturally use. The usability and clinical relevance of these robotics systems could be further enhanced by brain-machine interfaces (BMIs). A number of preliminary studies have been published on this topic, but a systematic understanding of the experimental design, tasks, and performance of BMI-exoskeleton systems for restoration of gait is lacking. To address this gap, we applied standard systematic review methodology for a literature search in PubMed and EMBASE databases and identified 11 studies involving BMI-robotics systems. The devices, user population, input and output of the BMIs and robot systems respectively, neural features, decoders, denoising techniques, and system performance were reviewed and compared. Results showed BMIs classifying walk versus stand tasks are the most common. The results also indicate that electroencephalography (EEG) is the only recording method for humans. Performance was not clearly presented in most of the studies. Several challenges were summarized, including EEG denoising, safety, responsiveness and others. We conclude that lower-body powered exoskeletons with automated gait intention detection based on BMIs open new possibilities in the assistance and rehabilitation fields, although the current performance, clinical benefits and several key challenging issues indicate that additional research and development is required to deploy these systems in the clinic and at home. Moreover, rigorous EEG denoising techniques, suitable performance metrics, consistent trial reporting, and more clinical trials are needed to advance the field.

Brain-machine interfaces for controlling lower-limb powered robotic systems

NASA Astrophysics Data System (ADS)

He, Yongtian; Eguren, David; Azorín, José M.; Grossman, Robert G.; Phat Luu, Trieu; Contreras-Vidal, Jose L.

2018-04-01

Objective. Lower-limb, powered robotics systems such as exoskeletons and orthoses have emerged as novel robotic interventions to assist or rehabilitate people with walking disabilities. These devices are generally controlled by certain physical maneuvers, for example pressing buttons or shifting body weight. Although effective, these control schemes are not what humans naturally use. The usability and clinical relevance of these robotics systems could be further enhanced by brain-machine interfaces (BMIs). A number of preliminary studies have been published on this topic, but a systematic understanding of the experimental design, tasks, and performance of BMI-exoskeleton systems for restoration of gait is lacking. Approach. To address this gap, we applied standard systematic review methodology for a literature search in PubMed and EMBASE databases and identified 11 studies involving BMI-robotics systems. The devices, user population, input and output of the BMIs and robot systems respectively, neural features, decoders, denoising techniques, and system performance were reviewed and compared. Main results. Results showed BMIs classifying walk versus stand tasks are the most common. The results also indicate that electroencephalography (EEG) is the only recording method for humans. Performance was not clearly presented in most of the studies. Several challenges were summarized, including EEG denoising, safety, responsiveness and others. Significance. We conclude that lower-body powered exoskeletons with automated gait intention detection based on BMIs open new possibilities in the assistance and rehabilitation fields, although the current performance, clinical benefits and several key challenging issues indicate that additional research and development is required to deploy these systems in the clinic and at home. Moreover, rigorous EEG denoising techniques, suitable performance metrics, consistent trial reporting, and more clinical trials are needed to advance the field.

Electromechanical-assisted training for walking after stroke.

PubMed

Mehrholz, Jan; Elsner, Bernhard; Werner, Cordula; Kugler, Joachim; Pohl, Marcus

2013-07-25

Electromechanical and robotic-assisted gait training devices are used in rehabilitation and might help to improve walking after stroke. This is an update of a Cochrane Review first published in 2007. To investigate the effects of automated electromechanical and robotic-assisted gait training devices for improving walking after stroke. We searched the Cochrane Stroke Group Trials Register (last searched April 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 2), MEDLINE (1966 to November 2012), EMBASE (1980 to November 2012), CINAHL (1982 to November 2012), AMED (1985 to November 2012), SPORTDiscus (1949 to September 2012), the Physiotherapy Evidence Database (PEDro, searched November 2012) and the engineering databases COMPENDEX (1972 to November 2012) and INSPEC (1969 to November 2012). We handsearched relevant conference proceedings, searched trials and research registers, checked reference lists and contacted authors in an effort to identify further published, unpublished and ongoing trials. We included all randomised and randomised cross-over trials consisting of people over 18 years old diagnosed with stroke of any severity, at any stage, or in any setting, evaluating electromechanical and robotic-assisted gait training versus normal care. Two review authors independently selected trials for inclusion, assessed methodological quality and extracted the data. The primary outcome was the proportion of participants walking independently at follow-up. In this update of our review, we included 23 trials involving 999 participants. Electromechanical-assisted gait training in combination with physiotherapy increased the odds of participants becoming independent in walking (odds ratio (OR) (random effects) 2.39, 95% confidence interval (CI) 1.67 to 3.43; P < 0.00001; I² = 0%) but did not significantly increase walking velocity (mean difference (MD) = 0.04 metres/s, 95% CI -0.03 to 0.11; P = 0.26; I² = 73%) or walking capacity (MD = 3 metres walked in six minutes, 95% CI -29 to 35; P = 0.86; I² = 70%). The results must be interpreted with caution because (1) some trials investigated people who were independent in walking at the start of the study, (2) we found variations between the trials with respect to devices used and duration and frequency of treatment, and (3) some trials included devices with functional electrical stimulation. Our planned subgroup analysis suggests that people in the acute phase may benefit but people in the chronic phase may not benefit from electromechanical-assisted gait training. Post hoc analysis showed that people who are non-ambulatory at intervention onset may benefit but ambulatory people may not benefit from this type of training. Post hoc analysis showed no differences between the types of devices used in studies regarding ability to walk, but significant differences were found between devices in terms of walking velocity. People who receive electromechanical-assisted gait training in combination with physiotherapy after stroke are more likely to achieve independent walking than people who receive gait training without these devices. Specifically, people in the first three months after stroke and those who are not able to walk seem to benefit most from this type of intervention. The role of the type of device is still not clear. Further research should consist of a large definitive, pragmatic, phase III trial undertaken to address specific questions such as the following: What frequency or duration of electromechanical-assisted gait training might be most effective? How long does the benefit last?

Comparison between the robo-horse and real horse movements for hippotherapy.

PubMed

Park, Ji H; Shurtleff, Timothy; Engsberg, Jack; Rafferty, Sandy; You, Joshua Y; You, Isaac Y; You, Sung H

2014-01-01

While the novel robotic hippotherapy system has gradually gained clinical application for therapeutic intervention on postural and locomotor control in individuals with neurological or musculoskeletal impairments, the system's validity and reliability for the robotic hippotherapy system has not been well established. The objective of the current study was to investigate the validity and test-retest reliability of the robotic hippotherapy system by comparing with real horse movements. The 3-axis accelerometer sensors attached on the robotic and real horse saddles were used to collect 3-dimensional acceleration data at a preferred walking velocity. Linear regression analysis showed an excellent correlation in the time-to-peak acceleration (TPA) (R(2)=0.997), but little correlation in X-axis acceleration between the real and robotic horses (R(2)=0.177), thus confirming consistent time control and a certain degree of variability between the robotic and real horse movements. The mean resultant accelerations for a real horse and robotic horse were 3.22 m/s(2) and 0.67 m/s(2), respectively, accounting for almost five times greater acceleration in the real horse than the robotic horse.

Multisensor-based human detection and tracking for mobile service robots.

PubMed

Bellotto, Nicola; Hu, Huosheng

2009-02-01

One of fundamental issues for service robots is human-robot interaction. In order to perform such a task and provide the desired services, these robots need to detect and track people in the surroundings. In this paper, we propose a solution for human tracking with a mobile robot that implements multisensor data fusion techniques. The system utilizes a new algorithm for laser-based leg detection using the onboard laser range finder (LRF). The approach is based on the recognition of typical leg patterns extracted from laser scans, which are shown to also be very discriminative in cluttered environments. These patterns can be used to localize both static and walking persons, even when the robot moves. Furthermore, faces are detected using the robot's camera, and the information is fused to the legs' position using a sequential implementation of unscented Kalman filter. The proposed solution is feasible for service robots with a similar device configuration and has been successfully implemented on two different mobile platforms. Several experiments illustrate the effectiveness of our approach, showing that robust human tracking can be performed within complex indoor environments.

Ankle voluntary movement enhancement following robotic-assisted locomotor training in spinal cord injury

PubMed Central

2014-01-01

Background In incomplete spinal cord injury (iSCI), sensorimotor impairments result in severe limitations to ambulation. To improve walking capacity, physical therapies using robotic-assisted locomotor devices, such as the Lokomat, have been developed. Following locomotor training, an improvement in gait capabilities—characterized by increases in the over-ground walking speed and endurance—is generally observed in patients. To better understand the mechanisms underlying these improvements, we studied the effects of Lokomat training on impaired ankle voluntary movement, known to be an important limiting factor in gait for iSCI patients. Methods Fifteen chronic iSCI subjects performed twelve 1-hour sessions of Lokomat training over the course of a month. The voluntary movement was qualified by measuring active range of motion, maximal velocity peak and trajectory smoothness for the spastic ankle during a movement from full plantar-flexion (PF) to full dorsi-flexion (DF) at the patient’s maximum speed. Dorsi- and plantar-flexor muscle strength was quantified by isometric maximal voluntary contraction (MVC). Clinical assessments were also performed using the Timed Up and Go (TUG), the 10-meter walk (10MWT) and the 6-minute walk (6MWT) tests. All evaluations were performed both before and after the training and were compared to a control group of fifteen iSCI patients. Results After the Lokomat training, the active range of motion, the maximal velocity, and the movement smoothness were significantly improved in the voluntary movement. Patients also exhibited an improvement in the MVC for their ankle dorsi- and plantar-flexor muscles. In terms of functional activity, we observed an enhancement in the mobility (TUG) and the over-ground gait velocity (10MWT) with training. Correlation tests indicated a significant relationship between ankle voluntary movement performance and the walking clinical assessments. Conclusions The improvements of the kinematic and kinetic parameters of the ankle voluntary movement, and their correlation with the functional assessments, support the therapeutic effect of robotic-assisted locomotor training on motor impairment in chronic iSCI. PMID:24684813

A Biomechanical Comparison of Proportional Electromyography Control to Biological Torque Control Using a Powered Hip Exoskeleton.

PubMed

Young, Aaron J; Gannon, Hannah; Ferris, Daniel P

2017-01-01

Despite a large increase in robotic exoskeleton research, there are few studies that have examined human performance with different control strategies on the same exoskeleton device. Direct comparison studies are needed to determine how users respond to different types of control. The purpose of this study was to compare user performance using a robotic hip exoskeleton with two different controllers: a controller that targeted a biological hip torque profile and a proportional myoelectric controller. We tested both control approaches on 10 able-bodied subjects using a pneumatically powered hip exoskeleton. The state machine controller targeted a biological hip torque profile. The myoelectric controller used electromyography (EMG) of lower limb muscles to produce a proportional control signal for the hip exoskeleton. Each subject performed two 30-min exoskeleton walking trials (1.0 m/s) using each controller and a 10-min trial with the exoskeleton unpowered. During each trial, we measured subjects' metabolic cost of walking, lower limb EMG profiles, and joint kinematics and kinetics (torques and powers) using a force treadmill and motion capture. Compared to unassisted walking in the exoskeleton, myoelectric control significantly reduced metabolic cost by 13% ( p  = 0.005) and biological hip torque control reduced metabolic cost by 7% ( p  = 0.261). Subjects reduced muscle activity relative to the unpowered condition for a greater number of lower limb muscles using myoelectric control compared to the biological hip torque control. More subjects subjectively preferred the myoelectric controller to the biological hip torque control. Myoelectric control had more advantages (metabolic cost and muscle activity reduction) compared to a controller that targeted a biological torque profile for walking with a robotic hip exoskeleton. However, these results were obtained with a single exoskeleton device with specific control configurations while level walking at a single speed. Further testing on different exoskeleton hardware and with more varied experimental protocols, such as testing over multiple types of terrain, is needed to fully elucidate the potential benefits of myoelectric control for exoskeleton technology.

UT Austin Villa 2011: 3D Simulation Team Report

DTIC Science & Technology

2011-01-01

inverted pendulum model omnidirectional walk engine based on one that was originally designed for the real Nao robot [7]. The omnidirectional walk is...using a double linear inverted pendulum , where the center of mass is swinging over the stance foot. In addition, as in Graf et al.’s work [7], we use...between the inverted pendulums formed by the respective stance feet. Notation Description maxStep∗i Maximum step sizes allowed for x, y, and θ y

A biologically-inspired autonomous robot

NASA Astrophysics Data System (ADS)

Beer, Randall D.

1993-12-01

A treadmill has been developed to support our cockroach locomotion studies. We have developed a small treadmill with a transparent belt for studying leg joint movements along with EMG's as the animal walks or runs at various speeds. This allows us to match the electrical activity in muscles with the kinematics of joint movement. Along with intracellular stimulation studies performed previously, the tools are now in place to make major advances in understanding how the insect's walking movements are actually accomplished.

A six-legged rover for planetary exploration

NASA Technical Reports Server (NTRS)

Simmons, Reid; Krotkov, Eric; Bares, John

1991-01-01

To survive the rigors and isolation of planetary exploration, an autonomous rover must be competent, reliable, and efficient. This paper presents the Ambler, a six-legged robot featuring orthogonal legs and a novel circulating gait, which has been designed for traversal of rugged, unknown environments. An autonomous software system that integrates perception, planning, and real-time control has been developed to walk the Ambler through obstacle strewn terrain. The paper describes the information and control flow of the walking system, and how the design of the mechanism and software combine to achieve competent walking, reliable behavior in the face of unexpected failures, and efficient utilization of time and power.

Autonomous planetary rover

NASA Astrophysics Data System (ADS)

Krotkov, Eric; Simmons, Reid; Whittaker, William

1992-02-01

This report describes progress in research on an autonomous robot for planetary exploration performed during 1991 at the Robotics Institute, Carnegie Mellon University. The report summarizes the achievements during calendar year 1991, and lists personnel and publications. In addition, it includes several papers resulting from the research. Research in 1991 focused on understanding the unique capabilities of the Ambler mechanism and on autonomous walking in rough, natural terrain. We also designed a sample acquisition system, and began to configure a successor to the Ambler.

An integrated neuro-robotic interface for stroke rehabilitation using the NASA X1 powered lower limb exoskeleton.

PubMed

He, Yongtian; Nathan, Kevin; Venkatakrishnan, Anusha; Rovekamp, Roger; Beck, Christopher; Ozdemir, Recep; Francisco, Gerard E; Contreras-Vidal, Jose L

2014-01-01

Stroke remains a leading cause of disability, limiting independent ambulation in survivors, and consequently affecting quality of life (QOL). Recent technological advances in neural interfacing with robotic rehabilitation devices are promising in the context of gait rehabilitation. Here, the X1, NASA's powered robotic lower limb exoskeleton, is introduced as a potential diagnostic, assistive, and therapeutic tool for stroke rehabilitation. Additionally, the feasibility of decoding lower limb joint kinematics and kinetics during walking with the X1 from scalp electroencephalographic (EEG) signals--the first step towards the development of a brain-machine interface (BMI) system to the X1 exoskeleton--is demonstrated.

Optimal powering schemes for legged robotics

NASA Astrophysics Data System (ADS)

Muench, Paul; Bednarz, David; Czerniak, Gregory P.; Cheok, Ka C.

2010-04-01

Legged Robots have tremendous mobility, but they can also be very inefficient. These inefficiencies can be due to suboptimal control schemes, among other things. If your goal is to get from point A to point B in the least amount of time, your control scheme will be different from if your goal is to get there using the least amount of energy. In this paper, we seek a balance between these extremes by looking at both efficiency and speed. We model a walking robot as a rimless wheel, and, using Pontryagin's Maximum Principle (PMP), we find an "on-off" control for the model, and describe the switching curve between these control extremes.

Modelisation of an unspecialized quadruped walking mammal.

PubMed

Neveu, P; Villanova, J; Gasc, J P

2001-12-01

Kinematics and structural analyses were used as basic data to elaborate a dynamic quadruped model that may represent an unspecialized mammal. Hedgehogs were filmed on a treadmill with a cinefluorographic system providing trajectories of skeletal elements during locomotion. Body parameters such as limb segments mass and length, and segments centre of mass were checked from cadavers. These biological parameters were compiled in order to build a virtual quadruped robot. The robot locomotor behaviour was compared with the actual hedgehog to improve the model and to disclose the necessary changes. Apart from use in robotics, the resulting model may be useful to simulate the locomotion of extinct mammals.

Biological Soft Robotics.

PubMed

Feinberg, Adam W

2015-01-01

In nature, nanometer-scale molecular motors are used to generate force within cells for diverse processes from transcription and transport to muscle contraction. This adaptability and scalability across wide temporal, spatial, and force regimes have spurred the development of biological soft robotic systems that seek to mimic and extend these capabilities. This review describes how molecular motors are hierarchically organized into larger-scale structures in order to provide a basic understanding of how these systems work in nature and the complexity and functionality we hope to replicate in biological soft robotics. These span the subcellular scale to macroscale, and this article focuses on the integration of biological components with synthetic materials, coupled with bioinspired robotic design. Key examples include nanoscale molecular motor-powered actuators, microscale bacteria-controlled devices, and macroscale muscle-powered robots that grasp, walk, and swim. Finally, the current challenges and future opportunities in the field are addressed.

Human pair walking behavior: evaluation of cooperation strategies

NASA Astrophysics Data System (ADS)

Dobramysl, Ulrich; Bodova, Katarina; Kollar, Richard; Erban, Radek

2015-03-01

Human walkers are notoriously poor at keeping a direction without external cues: Experimental work by Souman et al. with blindfolded subjects told to walk in a straight line revealed intriguing circular and spiraling trajectories, which can be approximated by a stochastic process. In this work, motivated by pair walking experiments by Miglierini et al., we introduce an analysis of various strategies employed by a pair of blindfolded walkers, who are communicating via auditory cues, to maximize their efficiency at walking straight. To this end, we characterize pairs of strategies such as free walking, side-by-side walking and unconditional following from data generated by robot pair walking experiments (using computer vision techniques) and numerical simulations. We extract the mean exit distances of walker pairs from a corridor with finite width to construct phase portraits of the walking performance. We find intriguing cooperative effects leading to non-trivial enhancements of the efficiency at walking straight. The research leading to these results has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC Grant Agreement No. 239870; and from the Royal Society through a Research Grant.

Robonaut: a robot designed to work with humans in space

NASA Technical Reports Server (NTRS)

Bluethmann, William; Ambrose, Robert; Diftler, Myron; Askew, Scott; Huber, Eric; Goza, Michael; Rehnmark, Fredrik; Lovchik, Chris; Magruder, Darby

2003-01-01

The Robotics Technology Branch at the NASA Johnson Space Center is developing robotic systems to assist astronauts in space. One such system, Robonaut, is a humanoid robot with the dexterity approaching that of a suited astronaut. Robonaut currently has two dexterous arms and hands, a three degree-of-freedom articulating waist, and a two degree-of-freedom neck used as a camera and sensor platform. In contrast to other space manipulator systems, Robonaut is designed to work within existing corridors and use the same tools as space walking astronauts. Robonaut is envisioned as working with astronauts, both autonomously and by teleoperation, performing a variety of tasks including, routine maintenance, setting up and breaking down worksites, assisting crew members while outside of spacecraft, and serving in a rapid response capacity.

Robonaut: a robot designed to work with humans in space.

PubMed

Bluethmann, William; Ambrose, Robert; Diftler, Myron; Askew, Scott; Huber, Eric; Goza, Michael; Rehnmark, Fredrik; Lovchik, Chris; Magruder, Darby

2003-01-01

The Robotics Technology Branch at the NASA Johnson Space Center is developing robotic systems to assist astronauts in space. One such system, Robonaut, is a humanoid robot with the dexterity approaching that of a suited astronaut. Robonaut currently has two dexterous arms and hands, a three degree-of-freedom articulating waist, and a two degree-of-freedom neck used as a camera and sensor platform. In contrast to other space manipulator systems, Robonaut is designed to work within existing corridors and use the same tools as space walking astronauts. Robonaut is envisioned as working with astronauts, both autonomously and by teleoperation, performing a variety of tasks including, routine maintenance, setting up and breaking down worksites, assisting crew members while outside of spacecraft, and serving in a rapid response capacity.

Motion Tracking and Identification of Unrestraint Gait Rehabilitation by Use of Elderly Support Robot

NASA Astrophysics Data System (ADS)

Nokata, Makoto; Hirai, Wataru; Itatani, Ryosuke

This paper presents a robotic training system that can exercise the user without bodily restraint, neither markers nor sensors are attached to the trainee. We developed the robot system that has a total of four mounted components: a laser sensor, a camera, a cushion, and an electric motor. This paper have showed the method used for determining whether the trainee was bending forward or backward while walking, and the extent of the tilt, using the recorded image of the back of the trainee's head. A characteristic of our software algorithms has been that the image was divided into 9 quadrants, and each quadrant undergoes Hough transformation. We have verified experimentally that by using our algorithms for the four patterns of forward, backward, diagonally, and crouching, the tilt of the trainee's body have been accurately determined. We created a flowchart for determining the direction of movement according to experimental results. By adjusting the values used to make the distinction according to the position and the angle of the camera, and the width of the back of the trainee's head, we were able to accurately determine the walking condition of the trainee, and achieve early detection of the start of a fall.

Small-scale soft-bodied robot with multimodal locomotion.

PubMed

Hu, Wenqi; Lum, Guo Zhan; Mastrangeli, Massimo; Sitti, Metin

2018-02-01

Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly, in bioengineering such as single-cell manipulation and biosensing, and in healthcare such as targeted drug delivery and minimally invasive surgery. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.

Small-scale soft-bodied robot with multimodal locomotion

NASA Astrophysics Data System (ADS)

Hu, Wenqi; Lum, Guo Zhan; Mastrangeli, Massimo; Sitti, Metin

2018-02-01

Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly, in bioengineering such as single-cell manipulation and biosensing, and in healthcare such as targeted drug delivery and minimally invasive surgery. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.

The effects of gait training using powered lower limb exoskeleton robot on individuals with complete spinal cord injury.

PubMed

Wu, Cheng-Hua; Mao, Hui-Fen; Hu, Jwu-Sheng; Wang, Ting-Yun; Tsai, Yi-Jeng; Hsu, Wei-Li

2018-03-05

Powered exoskeleton can improve the mobility for people with movement deficits by providing mechanical support and facilitate the gait training. This pilot study evaluated the effect of gait training using a newly developed powered lower limb exoskeleton robot for individuals with complete spinal cord injury (SCI). Two participants with a complete SCI were recruited for this clinical study. The powered exoskeleton gait training was 8 weeks, 1 h per session, and 2 sessions per week. The evaluation was performed before and after the training for (1) the time taken by the user to don and doff the powered exoskeleton independently, (2) the level of exertion perceived by participants while using the powered exoskeleton, and (3) the mobility performance included the timed up-and-go test, 10-m walk test, and 6-min walk test with the powered exoskeleton. The safety of the powered exoskeleton was evaluated on the basis of injury reports and the incidence of falls or imbalance while using the device. The results indicated that the participants were donning and doffing the powered lower limb exoskeleton robot independently with a lower level of exertion and walked faster and farther without any injury or fall incidence when using the powered exoskeleton than when using a knee-ankle-foot orthosis. Bone mineral densities was also increased after the gait training. No adverse effects, such as skin abrasions, or discomfort were reported while using the powered exoskeleton. The findings demonstrated that individuals with complete SCI used the powered lower limb exoskeleton robot independently without any assistance after 8 weeks of powered exoskeleton gait training. Trial registration: National Taiwan University Hospital. 201210051RIB . Name of registry: Hui-Fen Mao. URL of registry: Not available. Date of registration: December 12th, 2012. Date of enrolment of the first participant to the trial: January 3rd, 2013.

Mental models for cognitive control

NASA Astrophysics Data System (ADS)

Schilling, Malte; Cruse, Holk; Schmitz, Josef

2007-05-01

Even so called "simple" organisms as insects are able to fastly adapt to changing conditions of their environment. Their behaviour is affected by many external influences and only its variability and adaptivity permits their survival. An intensively studied example concerns hexapod walking. 1,2 Complex walking behaviours in stick insects have been analysed and the results were used to construct a reactive model that controls walking in a robot. This model is now extended by higher levels of control: as a bottom-up approach the low-level reactive behaviours are modulated and activated through a medium level. In addition, the system grows up to an upper level for cognitive control of the robot: Cognition - as the ability to plan ahead - and cognitive skills involve internal representations of the subject itself and its environment. These representations are used for mental simulations: In difficult situations, for which neither motor primitives, nor whole sequences of these exist, available behaviours are varied and applied in the internal model while the body itself is decoupled from the controlling modules. The result of the internal simulation is evaluated. Successful actions are learned and applied to the robot. This constitutes a level for planning. Its elements (movements, behaviours) are embodied in the lower levels, whereby their meaning arises directly from these levels. The motor primitives are situation models represented as neural networks. The focus of this work concerns the general architecture of the framework as well as the reactive basic layer of the bottom-up architecture and its connection to higher level functions and its application on an internal model.

Sliding GAIT Algorithm for the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE)

NASA Technical Reports Server (NTRS)

Townsend, Julie; Biesiadecki, Jeffrey

2012-01-01

The design of a surface robotic system typically involves a trade between the traverse speed of a wheeled rover and the terrain-negotiating capabilities of a multi-legged walker. The ATHLETE mobility system, with both articulated limbs and wheels, is uniquely capable of both driving and walking, and has the flexibility to employ additional hybrid mobility modes. This paper introduces the Sliding Gait, an intermediate mobility algorithm faster than walking with better terrain-handling capabilities than wheeled mobility.

Human-Robot Interaction: Intention Recognition and Mutual Entrainment

DTIC Science & Technology

2012-08-18

A 3D model and its controller proposed by Shih et al. [35] guarantee the input-to-state stability during turning, but the model has point feet and...Music Research, vol. 30, no. 2, pp. 159-171, 2001. [21] Y. Shiu, N. Cho, P.-C. Chang, and C.-C. Kuo , “Robust On-Line Beat Tracking with Kalman...2009. [35] C.-L. Shih , J.W. Grizzle, and C. Chevallereau, “From Stable Walking to Steering of a 3D Bipedal Robot with Passive Point Feet,” Robotica

Influence of a Locomotor Training Approach on Walking Speed and Distance in People With Chronic Spinal Cord Injury: A Randomized Clinical Trial

PubMed Central

Roach, Kathryn E.

2011-01-01

Background Impaired walking limits function after spinal cord injury (SCI), but training-related improvements are possible even in people with chronic motor incomplete SCI. Objective The objective of this study was to compare changes in walking speed and distance associated with 4 locomotor training approaches. Design This study was a single-blind, randomized clinical trial. Setting This study was conducted in a rehabilitation research laboratory. Participants Participants were people with minimal walking function due to chronic SCI. Intervention Participants (n=74) trained 5 days per week for 12 weeks with the following approaches: treadmill-based training with manual assistance (TM), treadmill-based training with stimulation (TS), overground training with stimulation (OG), and treadmill-based training with robotic assistance (LR). Measurements Overground walking speed and distance were the primary outcome measures. Results In participants who completed the training (n=64), there were overall effects for speed (effect size index [d]=0.33) and distance (d=0.35). For speed, there were no significant between-group differences; however, distance gains were greatest with OG. Effect sizes for speed and distance were largest with OG (d=0.43 and d=0.40, respectively). Effect sizes for speed were the same for TM and TS (d=0.28); there was no effect for LR. The effect size for distance was greater with TS (d=0.16) than with TM or LR, for which there was no effect. Ten participants who improved with training were retested at least 6 months after training; walking speed at this time was slower than that at the conclusion of training but remained faster than before training. Limitations It is unknown whether the training dosage and the emphasis on training speed were optimal. Robotic training that requires active participation would likely yield different results. Conclusions In people with chronic motor incomplete SCI, walking speed improved with both overground training and treadmill-based training; however, walking distance improved to a greater extent with overground training. PMID:21051593

Neuromechanical adaptations during a robotic powered exoskeleton assisted walking session.

PubMed

Ramanujam, Arvind; Cirnigliaro, Christopher M; Garbarini, Erica; Asselin, Pierre; Pilkar, Rakesh; Forrest, Gail F

2017-04-20

To evaluate gait parameters and neuromuscular profiles of exoskeleton-assisted walking under Max Assist condition during a single-session for; (i) able bodied (AB) individuals walking assisted with (EXO) and without (non-EXO) a powered exoskeleton, (ii) non-ambulatory SCI individuals walking assisted with a powered exoskeleton. Single-session. Motion analysis laboratory. Four AB individuals and four individuals with SCI. Powered lower extremity exoskeleton. Temporal-spatial parameters, kinematics, walking velocity and electromyography data. AB individuals in exoskeleton showed greater stance time and a significant reduction in walking velocity (P < 0.05) compared to non-EXO walking. Interestingly, when the AB individuals voluntarily assisted the exoskeleton movements, they walked with an increased velocity and lowered stance time to resemble that of slow walking. For SCI individuals, mean percent stance time was higher and walking velocity was lower compared to all AB walking conditions (P < 0.05). There was muscle activation in several lower limb muscles for SCI group. For AB individuals, there were similarities among EXO and non-EXO walking conditions however there were differences in several lower limb EMGs for phasing of muscle activation. The data suggests that our AB individuals experienced reduction in walking velocity and muscle activation amplitudes while walking in the exoskeleton and moreover with voluntary control there is a greater temporal-spatial response of the lower limbs. Also, there are neuromuscular phasic adaptions for both AB and SCI groups while walking in the exoskeleton that are inconsistent to non-EXO gait muscle activation.

Mechanical analysis of infant carrying in hominoids

PubMed Central

2007-01-01

In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair–hair friction coefficient, and body angle exists. The hair–hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here. PMID:18030438

Fault-tolerant locomotion of the hexapod robot.

PubMed

Yang, J M; Kim, J H

1998-01-01

In this paper, we propose a scheme for fault detection and tolerance of the hexapod robot locomotion on even terrain. The fault stability margin is defined to represent potential stability which a gait can have in case a sudden fault event occurs to one leg. Based on this, the fault-tolerant quadruped periodic gaits of the hexapod walking over perfectly even terrain are derived. It is demonstrated that the derived quadruped gait is the optimal one the hexapod can have maintaining fault stability margin nonnegative and a geometric condition should be satisfied for the optimal locomotion. By this scheme, when one leg is in failure, the hexapod robot has the modified tripod gait to continue the optimal locomotion.

Model-Based Experimental Development of Passive Compliant Robot Legs from Fiberglass Composites

PubMed Central

Lin, Shang-Chang; Hu, Chia-Jui; Lin, Pei-Chun

2015-01-01

We report on the methodology of developing compliant, half-circular, and composite robot legs with designable stiffness. First, force-displacement experiments on flat cantilever composites made by one or multifiberglass cloths are executed. By mapping the cantilever mechanics to the virtual spring model, the equivalent elastic moduli of the composites can be derived. Next, by using the model that links the curved beam mechanics back to the virtual spring, the resultant stiffness of the composite in a half-circular shape can be estimated without going through intensive experimental tryouts. The overall methodology has been experimentally validated, and the fabricated composites were used on a hexapod robot to perform walking and leaping behaviors. PMID:27065748

An Open-Structure Treadmill Gait Trainer: From Research to Application.

PubMed

Li, Jian; Chen, Diansheng; Fan, Yubo

2017-01-01

Lower limb rehabilitation robots are designed to enhance gait function in individuals with motor impairments. Although numerous rehabilitation robots have been developed, only few of these robots have been used in practical health care, particularly in China. The objective of this study is to construct a lower limb rehabilitation robot and bridge the gap between research and application. Open structure to facilitate practical application was created for the whole robot. Three typical movement patterns of a single leg were adopted in designing the exoskeletons, and force models for patient training were established and analyzed under three different conditions, respectively, and then a control system and security strategy were introduced. After establishing the robot, a preliminary experiment on the actual use of a prototype by patients was conducted to validate the functionality of the robot. The experiment showed that different patients and stages displayed different performances, and results on the trend variations across patients and across stages confirmed the validity of the robot and suggested that the design may lead to a system that could be successful in the treatment of patients with walking disorders in China. Furthermore, this study could provide a reference for a similar application design.

Gym-based exoskeleton walking: A preliminary exploration of non-ambulatory end-user perspectives.

PubMed

Cahill, Aoife; Ginley, Orna Mc; Bertrand, Courtney; Lennon, Olive

2018-07-01

Robotic walking devices (RWD) have shown many physical benefits in Spinal Cord Injury (SCI) rehabilitation. No study to date has explored end-user perceptions of these devices or gained insight into the use of these devices in a gym-based setting. This preliminary study explores the perspectives of four non-ambulatory individuals with SCI on using an exoskeleton walking device in a gym-based community setting. In-depth, semi-structured interviews were conducted with four SCI individuals living in the community. Interviews were audio-recorded and transcribed verbatim. Inductive thematic analysis established common overarching themes and subthemes. Four primary themes emerged addressing "The Psychological Adjustments Around Using RWDs with Respect to Disability", "Perceived Physical, Social and Psychological Benefits of Using an Exoskeleton", "The Role of External Influences", and "A Wellness Model to Health". A fully integrated gym setting was found to provide a positive and encouraging space to utilise the device. In addition, both the ability to set training goals and the positive attitude of robotic trainers were deemed to be important factors. This preliminary study provides detailed perspectives of four non-ambulatory individuals with SCI on utilising an exoskeleton walking device in a community setting. It suggests that gym-based RWDs impact positively on the users' lives and enhance their perceived wellbeing and sense of community integration. Enabling access to similar, community-based facilities should be prioritised for those with longstanding SCI disability. Copyright © 2018 Elsevier Inc. All rights reserved.

Electromechanical-assisted training for walking after stroke.

PubMed

Mehrholz, Jan; Thomas, Simone; Werner, Cordula; Kugler, Joachim; Pohl, Marcus; Elsner, Bernhard

2017-05-10

Electromechanical- and robotic-assisted gait-training devices are used in rehabilitation and might help to improve walking after stroke. This is an update of a Cochrane Review first published in 2007. To investigate the effects of automated electromechanical- and robotic-assisted gait-training devices for improving walking after stroke. We searched the Cochrane Stroke Group Trials Register (last searched 9 August 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 8), MEDLINE in Ovid (1950 to 15 August 2016), Embase (1980 to 15 August 2016), CINAHL (1982 to 15 August 2016), AMED (1985 to 15 August 2016), Web of Science (1899 to 16 August 2016), SPORTDiscus (1949 to 15 September 2012), the Physiotherapy Evidence Database (PEDro) (searched 16 August 2016), and the engineering databases COMPENDEX (1972 to 16 November 2012) and Inspec (1969 to 26 August 2016). We handsearched relevant conference proceedings, searched trials and research registers, checked reference lists, and contacted authors in an effort to identify further published, unpublished, and ongoing trials. We included all randomised controlled trials and randomised controlled cross-over trials in people over the age of 18 years diagnosed with stroke of any severity, at any stage, in any setting, evaluating electromechanical- and robotic-assisted gait training versus normal care. Two review authors independently selected trials for inclusion, assessed methodological quality and risk of bias, and extracted the data. The primary outcome was the proportion of participants walking independently at follow-up. We included 36 trials involving 1472 participants in this review update. Electromechanical-assisted gait training in combination with physiotherapy increased the odds of participants becoming independent in walking (odds ratio (random effects) 1.94, 95% confidence interval (CI) 1.39 to 2.71; P < 0.001; I² = 8%; moderate-quality evidence) but did not significantly increase walking velocity (mean difference (MD) 0.04 m/s, 95% CI 0.00 to 0.09; P = 0.08; I² = 65%; low-quality evidence) or walking capacity (MD 5.84 metres walked in 6 minutes, 95% CI -16.73 to 28.40; P = 0.61; I² = 53%; very low-quality evidence). The results must be interpreted with caution because 1) some trials investigated people who were independent in walking at the start of the study, 2) we found variations between the trials with respect to devices used and duration and frequency of treatment, and 3) some trials included devices with functional electrical stimulation. Our planned subgroup analysis suggested that people in the acute phase may benefit, but people in the chronic phase may not benefit from electromechanical-assisted gait training. Post hoc analysis showed that people who are non-ambulatory at intervention onset may benefit, but ambulatory people may not benefit from this type of training. Post hoc analysis showed no differences between the types of devices used in studies regarding ability to walk, but significant differences were found between devices in terms of walking velocity. People who receive electromechanical-assisted gait training in combination with physiotherapy after stroke are more likely to achieve independent walking than people who receive gait training without these devices. We concluded that seven patients need to be treated to prevent one dependency in walking. Specifically, people in the first three months after stroke and those who are not able to walk seem to benefit most from this type of intervention. The role of the type of device is still not clear. Further research should consist of large definitive pragmatic phase III trials undertaken to address specific questions about the most effective frequency and duration of electromechanical-assisted gait training as well as how long any benefit may last.

Adaptive Control Strategies for Interlimb Coordination in Legged Robots: A Review

PubMed Central

Aoi, Shinya; Manoonpong, Poramate; Ambe, Yuichi; Matsuno, Fumitoshi; Wörgötter, Florentin

2017-01-01

Walking animals produce adaptive interlimb coordination during locomotion in accordance with their situation. Interlimb coordination is generated through the dynamic interactions of the neural system, the musculoskeletal system, and the environment, although the underlying mechanisms remain unclear. Recently, investigations of the adaptation mechanisms of living beings have attracted attention, and bio-inspired control systems based on neurophysiological findings regarding sensorimotor interactions are being developed for legged robots. In this review, we introduce adaptive interlimb coordination for legged robots induced by various factors (locomotion speed, environmental situation, body properties, and task). In addition, we show characteristic properties of adaptive interlimb coordination, such as gait hysteresis and different time-scale adaptations. We also discuss the underlying mechanisms and control strategies to achieve adaptive interlimb coordination and the design principle for the control system of legged robots. PMID:28878645

Autonomous navigation method for substation inspection robot based on travelling deviation

NASA Astrophysics Data System (ADS)

Yang, Guoqing; Xu, Wei; Li, Jian; Fu, Chongguang; Zhou, Hao; Zhang, Chuanyou; Shao, Guangting

2017-06-01

A new method of edge detection is proposed in substation environment, which can realize the autonomous navigation of the substation inspection robot. First of all, the road image and information are obtained by using an image acquisition device. Secondly, the noise in the region of interest which is selected in the road image, is removed with the digital image processing algorithm, the road edge is extracted by Canny operator, and the road boundaries are extracted by Hough transform. Finally, the distance between the robot and the left and the right boundaries is calculated, and the travelling distance is obtained. The robot's walking route is controlled according to the travel deviation and the preset threshold. Experimental results show that the proposed method can detect the road area in real time, and the algorithm has high accuracy and stable performance.

Robot Swarms

NASA Technical Reports Server (NTRS)

Morring, Frank, Jr.

2005-01-01

Engineers and interns at this NASA field center are building the prototype of a robotic rover that could go where no wheeled rover has gone before-into the dark cold craters at the lunar poles and across the Moon s rugged highlands-like a walking tetrahedron. With NASA pushing to meet President Bush's new exploration objectives, the robots taking shape here today could be on the Moon in a decade. In the longer term, the concept could lead to shape-shifting robot swarms designed to explore distant planetary surfaces in advance of humans. "If you look at all of NASA s projections of the future, anyone s projections of the space program, they re all rigid-body architecture," says Steven Curtis, principal investigator on the effort. "This is not rigid-body. The whole key here is flexibility and reconfigurability with a capital R."

Experimental Evaluation of Energy Efficiency for a Soft Wearable Robotic Suit.

PubMed

Jin, Shanhai; Iwamoto, Noriyasu; Hashimoto, Kazunobu; Yamamoto, Motoji

2016-10-12

This paper presents a new soft wearable robotic suit for energy-efficient walking in daily activities for elderly persons. The presented robotic suit provides a small yet effective assistive force for hip flexion through winding belts that include elastic elements. In addition, it does not restrict the range of movement in the lower limbs. Moreover, its structure is simple and lightweight, and thus wearers can easily take the device on and off by themselves. Experimental results on nine elderly subjects (age = 74.23.7 years) show that the robotic suit worn and powered on (PON) significantly reduced energy expenditure by an average of 5.9 % compared with the condition of worn but powered off (POFF). Furthermore, compared with the POFF condition, there was a significant improvement in gait characteristics in the PON condition for all subjects.

Evolutionary Initial Poses of Reduced D.O.F’s Quadruped Robot

NASA Astrophysics Data System (ADS)

Iida, Ken-Ichi; Nakata, Yoshitaka; Hira, Toshio; Kamano, Takuya; Suzuki, Takayuki

In this paper, an application of genetic algorithm for generation of evolutionary initial poses of a quadrupedal robot which reduced degrees of freedom is described. To reduce degree of freedom, each leg of the robot has a slider-crank mechanism and is driven by an actuator. Furthermore we introduced the forward movement mode and the rotating mode because the omnidirection movement should be made possible. To generate the suitable initial pose, the initial angle of four legs are coded under gray code and tuned by an estimation function in each mode with the genetic algorithm. As a result of generation, the cooperation of the legs is realized to move toward the omnidirection. The experimental results demonstrate that the proposed scheme is effective for generation of the suitable initial poses and the robot can walk smoothly with the generated patterns.

Development and Training of a Neural Controller for Hind Leg Walking in a Dog Robot

PubMed Central

Hunt, Alexander; Szczecinski, Nicholas; Quinn, Roger

2017-01-01

Animals dynamically adapt to varying terrain and small perturbations with remarkable ease. These adaptations arise from complex interactions between the environment and biomechanical and neural components of the animal's body and nervous system. Research into mammalian locomotion has resulted in several neural and neuro-mechanical models, some of which have been tested in simulation, but few “synthetic nervous systems” have been implemented in physical hardware models of animal systems. One reason is that the implementation into a physical system is not straightforward. For example, it is difficult to make robotic actuators and sensors that model those in the animal. Therefore, even if the sensorimotor circuits were known in great detail, those parameters would not be applicable and new parameter values must be found for the network in the robotic model of the animal. This manuscript demonstrates an automatic method for setting parameter values in a synthetic nervous system composed of non-spiking leaky integrator neuron models. This method works by first using a model of the system to determine required motor neuron activations to produce stable walking. Parameters in the neural system are then tuned systematically such that it produces similar activations to the desired pattern determined using expected sensory feedback. We demonstrate that the developed method successfully produces adaptive locomotion in the rear legs of a dog-like robot actuated by artificial muscles. Furthermore, the results support the validity of current models of mammalian locomotion. This research will serve as a basis for testing more complex locomotion controllers and for testing specific sensory pathways and biomechanical designs. Additionally, the developed method can be used to automatically adapt the neural controller for different mechanical designs such that it could be used to control different robotic systems. PMID:28420977

Acute Cardiorespiratory and Metabolic Responses During Exoskeleton-Assisted Walking Overground Among Persons with Chronic Spinal Cord Injury.

PubMed

Evans, Nicholas; Hartigan, Clare; Kandilakis, Casey; Pharo, Elizabeth; Clesson, Ismari

2015-01-01

Lower extremity robotic exoskeleton technology is being developed with the promise of affording people with spinal cord injury (SCI) the opportunity to stand and walk. The mobility benefits of exoskeleton-assisted walking can be realized immediately, however the cardiorespiratory and metabolic benefits of this technology have not been thoroughly investigated. The purpose of this pilot study was to evaluate the acute cardiorespiratory and metabolic responses associated with exoskeleton-assisted walking overground and to determine the degree to which these responses change at differing walking speeds. Five subjects (4 male, 1 female) with chronic SCI (AIS A) volunteered for the study. Expired gases were collected during maximal graded exercise testing and two, 6-minute bouts of exoskeleton-assisted walking overground. Outcome measures included peak oxygen consumption (V̇O2peak), average oxygen consumption (V̇O2avg), peak heart rate (HRpeak), walking economy, metabolic equivalent of tasks for SCI (METssci), walk speed, and walk distance. Significant differences were observed between walk-1 and walk-2 for walk speed, total walk distance, V̇O2avg, and METssci. Exoskeleton-assisted walking resulted in %V̇O2peak range of 51.5% to 63.2%. The metabolic cost of exoskeleton-assisted walking ranged from 3.5 to 4.3 METssci. Persons with motor-complete SCI may be limited in their capacity to perform physical exercise to the extent needed to improve health and fitness. Based on preliminary data, cardiorespiratory and metabolic demands of exoskeleton-assisted walking are consistent with activities performed at a moderate intensity.

Acute Cardiorespiratory and Metabolic Responses During Exoskeleton-Assisted Walking Overground Among Persons with Chronic Spinal Cord Injury

PubMed Central

Hartigan, Clare; Kandilakis, Casey; Pharo, Elizabeth; Clesson, Ismari

2015-01-01

Background: Lower extremity robotic exoskeleton technology is being developed with the promise of affording people with spinal cord injury (SCI) the opportunity to stand and walk. The mobility benefits of exoskeleton-assisted walking can be realized immediately, however the cardiorespiratory and metabolic benefits of this technology have not been thoroughly investigated. Objective: The purpose of this pilot study was to evaluate the acute cardiorespiratory and metabolic responses associated with exoskeleton-assisted walking overground and to determine the degree to which these responses change at differing walking speeds. Methods: Five subjects (4 male, 1 female) with chronic SCI (AIS A) volunteered for the study. Expired gases were collected during maximal graded exercise testing and two, 6-minute bouts of exoskeleton-assisted walking overground. Outcome measures included peak oxygen consumption (V̇O2peak), average oxygen consumption (V̇O2avg), peak heart rate (HRpeak), walking economy, metabolic equivalent of tasks for SCI (METssci), walk speed, and walk distance. Results: Significant differences were observed between walk-1 and walk-2 for walk speed, total walk distance, V̇O2avg, and METssci. Exoskeleton-assisted walking resulted in %V̇O2peak range of 51.5% to 63.2%. The metabolic cost of exoskeleton-assisted walking ranged from 3.5 to 4.3 METssci. Conclusion: Persons with motor-complete SCI may be limited in their capacity to perform physical exercise to the extent needed to improve health and fitness. Based on preliminary data, cardiorespiratory and metabolic demands of exoskeleton-assisted walking are consistent with activities performed at a moderate intensity. PMID:26364281

Elastic coupling of limb joints enables faster bipedal walking

PubMed Central

Dean, J.C.; Kuo, A.D.

2008-01-01

The passive dynamics of bipedal limbs alone are sufficient to produce a walking motion, without need for control. Humans augment these dynamics with muscles, actively coordinated to produce stable and economical walking. Present robots using passive dynamics walk much slower, perhaps because they lack elastic muscles that couple the joints. Elastic properties are well known to enhance running gaits, but their effect on walking has yet to be explored. Here we use a computational model of dynamic walking to show that elastic joint coupling can help to coordinate faster walking. In walking powered by trailing leg push-off, the model's speed is normally limited by a swing leg that moves too slowly to avoid stumbling. A uni-articular spring about the knee allows faster but uneconomical walking. A combination of uni-articular hip and knee springs can speed the legs for improved speed and economy, but not without the swing foot scuffing the ground. Bi-articular springs coupling the hips and knees can yield high economy and good ground clearance similar to humans. An important parameter is the knee-to-hip moment arm that greatly affects the existence and stability of gaits, and when selected appropriately can allow for a wide range of speeds. Elastic joint coupling may contribute to the economy and stability of human gait. PMID:18957360

Complete low-cost implementation of a teleoperated control system for a humanoid robot.

PubMed

Cela, Andrés; Yebes, J Javier; Arroyo, Roberto; Bergasa, Luis M; Barea, Rafael; López, Elena

2013-01-24

Humanoid robotics is a field of a great research interest nowadays. This work implements a low-cost teleoperated system to control a humanoid robot, as a first step for further development and study of human motion and walking. A human suit is built, consisting of 8 sensors, 6 resistive linear potentiometers on the lower extremities and 2 digital accelerometers for the arms. The goal is to replicate the suit movements in a small humanoid robot. The data from the sensors is wirelessly transmitted via two ZigBee RF configurable modules installed on each device: the robot and the suit. Replicating the suit movements requires a robot stability control module to prevent falling down while executing different actions involving knees flexion. This is carried out via a feedback control system with an accelerometer placed on the robot's back. The measurement from this sensor is filtered using Kalman. In addition, a two input fuzzy algorithm controlling five servo motors regulates the robot balance. The humanoid robot is controlled by a medium capacity processor and a low computational cost is achieved for executing the different algorithms. Both hardware and software of the system are based on open platforms. The successful experiments carried out validate the implementation of the proposed teleoperated system.

Complete Low-Cost Implementation of a Teleoperated Control System for a Humanoid Robot

PubMed Central

Cela, Andrés; Yebes, J. Javier; Arroyo, Roberto; Bergasa, Luis M.; Barea, Rafael; López, Elena

2013-01-01

Humanoid robotics is a field of a great research interest nowadays. This work implements a low-cost teleoperated system to control a humanoid robot, as a first step for further development and study of human motion and walking. A human suit is built, consisting of 8 sensors, 6 resistive linear potentiometers on the lower extremities and 2 digital accelerometers for the arms. The goal is to replicate the suit movements in a small humanoid robot. The data from the sensors is wirelessly transmitted via two ZigBee RF configurable modules installed on each device: the robot and the suit. Replicating the suit movements requires a robot stability control module to prevent falling down while executing different actions involving knees flexion. This is carried out via a feedback control system with an accelerometer placed on the robot's back. The measurement from this sensor is filtered using Kalman. In addition, a two input fuzzy algorithm controlling five servo motors regulates the robot balance. The humanoid robot is controlled by a medium capacity processor and a low computational cost is achieved for executing the different algorithms. Both hardware and software of the system are based on open platforms. The successful experiments carried out validate the implementation of the proposed teleoperated system. PMID:23348029

`An observational report of intensive robotic and manual gait training in sub-acute stroke

PubMed Central

2012-01-01

Background The use of automated electromechanical devices for gait training in neurological patients is increasing, yet the functional outcomes of well-defined training programs using these devices and the characteristics of patients that would most benefit are seldom reported in the literature. In an observational study of functional outcomes, we aimed to provide a benchmark for expected change in gait function in early stroke patients, from an intensive inpatient rehabilitation program including both robotic and manual gait training. Methods We followed 103 sub-acute stroke patients who met the clinical inclusion criteria for Body Weight Supported Robotic Gait Training (BWSRGT). Patients completed an intensive 8-week gait-training program comprising robotic gait training (weeks 0-4) followed by manual gait training (weeks 4-8). A change in clinical function was determined by the following assessments taken at 0, 4 and 8 weeks (baseline, mid-point and end-point respectively): Functional Ambulatory Categories (FAC), 10 m Walking Test (10 MWT), and Tinetti Gait and Balance Scales. Results Over half of the patients made a clinically meaningful improvement on the Tinetti Gait Scale (> 3 points) and Tinetti Balance Scale (> 5 points), while over 80% of the patients increased at least 1 point on the FAC scale (0-5) and improved walking speed by more than 0.2 m/s. Patients responded positively in gait function regardless of variables gender, age, aetiology (hemorrhagic/ischemic), and affected hemisphere. The most robust and significant change was observed for patients in the FAC categories two and three. The therapy was well tolerated and no patients withdrew for factors related to the type or intensity of training. Conclusions Eight-weeks of intensive rehabilitation including robotic and manual gait training was well tolerated by early stroke patients, and was associated with significant gains in function. Patients with mid-level gait dysfunction showed the most robust improvement following robotic training. PMID:22329866

Insect-controlled Robot: A Mobile Robot Platform to Evaluate the Odor-tracking Capability of an Insect.

PubMed

Ando, Noriyasu; Emoto, Shuhei; Kanzaki, Ryohei

2016-12-19

Robotic odor source localization has been a challenging area and one to which biological knowledge has been expected to contribute, as finding odor sources is an essential task for organism survival. Insects are well-studied organisms with regard to odor tracking, and their behavioral strategies have been applied to mobile robots for evaluation. This "bottom-up" approach is a fundamental way to develop biomimetic robots; however, the biological analyses and the modeling of behavioral mechanisms are still ongoing. Therefore, it is still unknown how such a biological system actually works as the controller of a robotic platform. To answer this question, we have developed an insect-controlled robot in which a male adult silkmoth (Bombyx mori) drives a robot car in response to odor stimuli; this can be regarded as a prototype of a future insect-mimetic robot. In the cockpit of the robot, a tethered silkmoth walked on an air-supported ball and an optical sensor measured the ball rotations. These rotations were translated into the movement of the two-wheeled robot. The advantage of this "hybrid" approach is that experimenters can manipulate any parameter of the robot, which enables the evaluation of the odor-tracking capability of insects and provides useful suggestions for robotic odor-tracking. Furthermore, these manipulations are non-invasive ways to alter the sensory-motor relationship of a pilot insect and will be a useful technique for understanding adaptive behaviors.

A Novel Approach to Apply Gait Synchronized External Forces on the Pelvis using A-TPAD to Reduce Walking Effort

PubMed Central

Vashista, Vineet; Khan, Moiz; Agrawal, Sunil K.

2017-01-01

In this paper, we develop an intervention to apply external gait synchronized forces on the pelvis to reduce the user’s effort during walking. A cable-driven robot was used to apply the external forces and an adaptive frequency oscillator scheme was developed to adapt the timing of force actuation to the gait frequency during walking. The external forces were directed in the sagittal plane to assist the trailing leg during the forward propulsion and vertical deceleration of the pelvis during the gait cycle. A pilot experiment with five healthy subjects was conducted. The results showed that the subjects applied lower ground reaction forces in the vertical and anterior-posterior directions during the late stance phase. In summary, the current work provides a novel approach to study the role of external pelvic forces in altering the walking effort. These studies can provide better understanding for designing exoskeletons and prosthetic devices to reduce the overall walking effort. PMID:29623294

Reaching for the Unreachable: Reorganization of Reaching with Walking

PubMed Central

Grzyb, Beata J.; Smith, Linda B.; del Pobil, Angel P.

2015-01-01

Previous research suggests that reaching and walking behaviors may be linked developmentally as reaching changes at the onset of walking. Here we report new evidence on an apparent loss of the distinction between the reachable and nonreachable distances as children start walking. The experiment compared nonwalkers, walkers with help, and independent walkers in a reaching task to targets at varying distances. Reaching attempts, contact, leaning, and communication behaviors were recorded. Most of the children reached for the unreachable objects the first time it was presented. Nonwalkers, however, reached less on the subsequent trials showing clear adjustment of their reaching decisions with the failures. On the contrary, walkers consistently attempted reaches to targets at unreachable distances. We suggest that these reaching errors may result from inappropriate integration of reaching and locomotor actions, attention control and near/far visual space. We propose a reward-mediated model implemented on a NAO humanoid robot that replicates the main results from our study showing an increase in reaching attempts to nonreachable distances after the onset of walking. PMID:26110046

Concurrent validity of Physiological Cost Index in walking over ground and during robotic training in subacute stroke patients.

PubMed

Delussu, Anna Sofia; Morone, Giovanni; Iosa, Marco; Bragoni, Maura; Paolucci, Stefano; Traballesi, Marco

2014-01-01

Physiological Cost Index (PCI) has been proposed to assess gait demand. The purpose of the study was to establish whether PCI is a valid indicator in subacute stroke patients of energy cost of walking in different walking conditions, that is, over ground and on the Gait Trainer (GT) with body weight support (BWS). The study tested if correlations exist between PCI and ECW, indicating validity of the measure and, by implication, validity of PCI. Six patients (patient group (PG)) with subacute stroke and 6 healthy age- and size-matched subjects as control group (CG) performed, in a random sequence in different days, walking tests overground and on the GT with 0, 30, and 50% BWS. There was a good to excellent correlation between PCI and ECW in the observed walking conditions: in PG Pearson correlation was 0.919 (p < 0.001); in CG Pearson correlation was 0.852 (p < 0.001). In conclusion, the high significant correlations between PCI and ECW, in all the observed walking conditions, suggest that PCI is a valid outcome measure in subacute stroke patients.

Robot-aided gait training in an individual with chronic spinal cord injury: a case study.

PubMed

Bishop, Lauri; Stein, Joel; Wong, Christopher Kevin

2012-09-01

Traditional physical therapy is beneficial in restoring mobility in individuals who have sustained spinal cord injury (SCI), but residual limitations often persist. Robotic technologies may offer opportunities for further gains. The purpose of this case study was to document the use and practicality of gait training for an individual with chronic, incomplete SCI with asymmetric lower limb motor deficits using a novel robotic knee orthosis (RKO). The participant was a 22-year-old woman who sustained fractures of the odontoid process and C5-C6 vertebrae from a motor vehicle accident resulting in incomplete SCI with asymmetric tetraparesis, right side more severe than left side. She required supervised assistance with gait and balance tasks, minimal assistance to ascend/descend steps using a handrail, and upper extremity assistance for sit-to-stand tasks. The participant underwent 7 one-hour sessions of mobility training, using a novel RKO. Her primary goal was to increase independence and endurance with mobility. Functional measures included the 6-Minute Walk Test, the Berg Balance Scale, the Timed Up & Go Test, and the 10-Meter Walk Test. Outcomes were assessed and recorded at baseline and on completion of 7 hours of training with the device over a 2-week period. No adverse events occurred. The RKO was well received by both the participant and the treating therapist. The participant demonstrated improvements in the 6-Minute Walk Test and Berg Balance Scale after RKO-training intervention. Outcomes suggest that the use of this device during a physical therapy program for an individual with incomplete SCI is practical and this device may be a useful adjunct to standard training.

Robot-assisted vs. sensory integration training in treating gait and balance dysfunctions in patients with multiple sclerosis: a randomized controlled trial

PubMed Central

Gandolfi, Marialuisa; Geroin, Christian; Picelli, Alessandro; Munari, Daniele; Waldner, Andreas; Tamburin, Stefano; Marchioretto, Fabio; Smania, Nicola

2014-01-01

Background: Extensive research on both healthy subjects and patients with central nervous damage has elucidated a crucial role of postural adjustment reactions and central sensory integration processes in generating and “shaping” locomotor function, respectively. Whether robotic-assisted gait devices might improve these functions in Multiple sclerosis (MS) patients is not fully investigated in literature. Purpose: The aim of this study was to compare the effectiveness of end-effector robot-assisted gait training (RAGT) and sensory integration balance training (SIBT) in improving walking and balance performance in patients with MS. Methods: Twenty-two patients with MS (EDSS: 1.5–6.5) were randomly assigned to two groups. The RAGT group (n = 12) underwent end-effector system training. The SIBT group (n = 10) underwent specific balance exercises. Each patient received twelve 50-min treatment sessions (2 days/week). A blinded rater evaluated patients before and after treatment as well as 1 month post treatment. Primary outcomes were walking speed and Berg Balance Scale. Secondary outcomes were the Activities-specific Balance Confidence Scale, Sensory Organization Balance Test, Stabilometric Assessment, Fatigue Severity Scale, cadence, step length, single and double support time, Multiple Sclerosis Quality of Life-54. Results: Between groups comparisons showed no significant differences on primary and secondary outcome measures over time. Within group comparisons showed significant improvements in both groups on the Berg Balance Scale (P = 0.001). Changes approaching significance were found on gait speed (P = 0.07) only in the RAGT group. Significant changes in balance task-related domains during standing and walking conditions were found in the SIBT group. Conclusion: Balance disorders in patients with MS may be ameliorated by RAGT and by SIBT. PMID:24904361

Walking in the uncanny valley: importance of the attractiveness on the acceptance of a robot as a working partner.

PubMed

Destephe, Matthieu; Brandao, Martim; Kishi, Tatsuhiro; Zecca, Massimiliano; Hashimoto, Kenji; Takanishi, Atsuo

2015-01-01

The Uncanny valley hypothesis, which tells us that almost-human characteristics in a robot or a device could cause uneasiness in human observers, is an important research theme in the Human Robot Interaction (HRI) field. Yet, that phenomenon is still not well-understood. Many have investigated the external design of humanoid robot faces and bodies but only a few studies have focused on the influence of robot movements on our perception and feelings of the Uncanny valley. Moreover, no research has investigated the possible relation between our uneasiness feeling and whether or not we would accept robots having a job in an office, a hospital or elsewhere. To better understand the Uncanny valley, we explore several factors which might have an influence on our perception of robots, be it related to the subjects, such as culture or attitude toward robots, or related to the robot such as emotions and emotional intensity displayed in its motion. We asked 69 subjects (N = 69) to rate the motions of a humanoid robot (Perceived Humanity, Eeriness, and Attractiveness) and state where they would rather see the robot performing a task. Our results suggest that, among the factors we chose to test, the attitude toward robots is the main influence on the perception of the robot related to the Uncanny valley. Robot occupation acceptability was affected only by Attractiveness, mitigating any Uncanny valley effect. We discuss the implications of these findings for the Uncanny valley and the acceptability of a robotic worker in our society.

Walking in the uncanny valley: importance of the attractiveness on the acceptance of a robot as a working partner

PubMed Central

Destephe, Matthieu; Brandao, Martim; Kishi, Tatsuhiro; Zecca, Massimiliano; Hashimoto, Kenji; Takanishi, Atsuo

2015-01-01

The Uncanny valley hypothesis, which tells us that almost-human characteristics in a robot or a device could cause uneasiness in human observers, is an important research theme in the Human Robot Interaction (HRI) field. Yet, that phenomenon is still not well-understood. Many have investigated the external design of humanoid robot faces and bodies but only a few studies have focused on the influence of robot movements on our perception and feelings of the Uncanny valley. Moreover, no research has investigated the possible relation between our uneasiness feeling and whether or not we would accept robots having a job in an office, a hospital or elsewhere. To better understand the Uncanny valley, we explore several factors which might have an influence on our perception of robots, be it related to the subjects, such as culture or attitude toward robots, or related to the robot such as emotions and emotional intensity displayed in its motion. We asked 69 subjects (N = 69) to rate the motions of a humanoid robot (Perceived Humanity, Eeriness, and Attractiveness) and state where they would rather see the robot performing a task. Our results suggest that, among the factors we chose to test, the attitude toward robots is the main influence on the perception of the robot related to the Uncanny valley. Robot occupation acceptability was affected only by Attractiveness, mitigating any Uncanny valley effect. We discuss the implications of these findings for the Uncanny valley and the acceptability of a robotic worker in our society. PMID:25762967

A robotic exoskeleton to treat crouch gait from cerebral palsy: Initial kinematic and neuromuscular evaluation.

PubMed

Lerner, Zachary F; Damiano, Diane L; Bulea, Thomas C

2016-08-01

A robotic exoskeleton was designed for individuals with crouch gait caused by cerebral palsy with the intent to supplement existing muscle function during walking. The aim of this study was to evaluate how powered knee extension assistance provided during stance and swing phases of the gait cycle affect knee kinematics, and knee flexor and extensor muscle activity. Muscle activity and kinematic data were collected from four individuals with crouch gait from cerebral palsy during their normal walking condition and while walking with the exoskeleton under stance, swing, and stance & swing assistance. The exoskeleton was effective in reducing crouch by an average of 13.8° in three of the four participants when assistance was provided during the stance phase; assistance during the swing phase alone was ineffective. Peak knee extensor activity was maintained for all of the conditions during the stance and swing phases. Integrated (i.e. area under the curve) knee extensor activity decreased in two of the subjects indicating a more well-modulated activation pattern. Modest increases in peak and integrated antagonist knee flexor activity were exhibited in all participants; the subject without kinematic improvement had the greatest increase. While the exoskeleton was well tolerated, additional training with a focus on reducing knee flexor activity may lead to further improvements in crouch gait reduction.

The second me: Seeing the real body during humanoid robot embodiment produces an illusion of bi-location.

PubMed

Aymerich-Franch, Laura; Petit, Damien; Ganesh, Gowrishankar; Kheddar, Abderrahmane

2016-11-01

Whole-body embodiment studies have shown that synchronized multi-sensory cues can trick a healthy human mind to perceive self-location outside the bodily borders, producing an illusion that resembles an out-of-body experience (OBE). But can a healthy mind also perceive the sense of self in more than one body at the same time? To answer this question, we created a novel artificial reduplication of one's body using a humanoid robot embodiment system. We first enabled individuals to embody the humanoid robot by providing them with audio-visual feedback and control of the robot head movements and walk, and then explored the self-location and self-identification perceived by them when they observed themselves through the embodied robot. Our results reveal that, when individuals are exposed to the humanoid body reduplication, they experience an illusion that strongly resembles heautoscopy, suggesting that a healthy human mind is able to bi-locate in two different bodies simultaneously. Copyright © 2016 Elsevier Inc. All rights reserved.

The influence of speed and size on avian terrestrial locomotor biomechanics: Predicting locomotion in extinct theropod dinosaurs.

PubMed

Bishop, P J; Graham, D F; Lamas, L P; Hutchinson, J R; Rubenson, J; Hancock, J A; Wilson, R S; Hocknull, S A; Barrett, R S; Lloyd, D G; Clemente, C J

2018-01-01

How extinct, non-avian theropod dinosaurs moved is a subject of considerable interest and controversy. A better understanding of non-avian theropod locomotion can be achieved by better understanding terrestrial locomotor biomechanics in their modern descendants, birds. Despite much research on the subject, avian terrestrial locomotion remains little explored in regards to how kinematic and kinetic factors vary together with speed and body size. Here, terrestrial locomotion was investigated in twelve species of ground-dwelling bird, spanning a 1,780-fold range in body mass, across almost their entire speed range. Particular attention was devoted to the ground reaction force (GRF), the force that the feet exert upon the ground. Comparable data for the only other extant obligate, striding biped, humans, were also collected and studied. In birds, all kinematic and kinetic parameters examined changed continuously with increasing speed, while in humans all but one of those same parameters changed abruptly at the walk-run transition. This result supports previous studies that show birds to have a highly continuous locomotor repertoire compared to humans, where discrete 'walking' and 'running' gaits are not easily distinguished based on kinematic patterns alone. The influences of speed and body size on kinematic and kinetic factors in birds are developed into a set of predictive relationships that may be applied to extinct, non-avian theropods. The resulting predictive model is able to explain 79-93% of the observed variation in kinematics and 69-83% of the observed variation in GRFs, and also performs well in extrapolation tests. However, this study also found that the location of the whole-body centre of mass may exert an important influence on the nature of the GRF, and hence some caution is warranted, in lieu of further investigation.

Self-evaluation on Motion Adaptation for Service Robots

NASA Astrophysics Data System (ADS)

Funabora, Yuki; Yano, Yoshikazu; Doki, Shinji; Okuma, Shigeru

We suggest self motion evaluation method to adapt to environmental changes for service robots. Several motions such as walking, dancing, demonstration and so on are described with time series patterns. These motions are optimized with the architecture of the robot and under certain surrounding environment. Under unknown operating environment, robots cannot accomplish their tasks. We propose autonomous motion generation techniques based on heuristic search with histories of internal sensor values. New motion patterns are explored under unknown operating environment based on self-evaluation. Robot has some prepared motions which realize the tasks under the designed environment. Internal sensor values observed under the designed environment with prepared motions show the interaction results with the environment. Self-evaluation is composed of difference of internal sensor values between designed environment and unknown operating environment. Proposed method modifies the motions to synchronize the interaction results on both environment. New motion patterns are generated to maximize self-evaluation function without external information, such as run length, global position of robot, human observation and so on. Experimental results show that the possibility to adapt autonomously patterned motions to environmental changes.

Systematic Review of Appropriate Robotic Intervention for Gait Function in Subacute Stroke Patients

PubMed Central

Yoo, Jun Sang; Kim, Kyoung Eun; Cho, Sung Tae; Jang, Woo Seok

2018-01-01

The purpose of this study was to critically evaluate the effects of robot-assisted gait training (RAGT) on gait-related function in patients with acute/subacute stroke. We conducted a systematic review of randomized controlled trials published between May 2012 and April 2016. This search included 334 articles (Cochrane, 51 articles; Embase, 175 articles; PubMed, 108 articles). Based on the inclusion and exclusion criteria, 7 studies were selected for this review. We performed a quality evaluation using the PEDro scale. In this review, 3 studies used an exoskeletal robot, and 4 studies used an end-effector robot as interventions. As a result, RAGT was found to be effective in improving walking ability in subacute stroke patients. Significant improvements in gait speed, functional ambulatory category, and Rivermead mobility index were found with RAGT compared with conventional physical therapy (p < 0.05). Therefore, aggressive weight support and gait training at an early stage using a robotic device are helpful, and robotic intervention should be applied according to the patient's functional level and onset time of stroke. PMID:29546057

Psychological state estimation from physiological recordings during robot-assisted gait rehabilitation.

PubMed

Koenig, Alexander; Omlin, Ximena; Zimmerli, Lukas; Sapa, Mark; Krewer, Carmen; Bolliger, Marc; Müller, Friedemann; Riener, Robert

2011-01-01

Robot-assisted treadmill training is an established intervention used to improve walking ability in patients with neurological disorders. Although it has been shown that attention to the task is a key factor for successful rehabilitation, the psychological state of patients during robot-assisted gait therapy is often neglected. We presented 17 nondisabled subjects and 10 patients with neurological disorders a virtual-reality task with varying difficulty levels to induce feelings of being bored, excited, and overstressed. We developed an approach to automatically estimate and classify a patient's psychological state, i.e., his or her mental engagement, in real time during gait training. We used psychophysiological measurements to obtain an objective measure of the current psychological state. Automatic classification was performed by a neural network. We found that heart rate, skin conductance responses, and skin temperature can be used as markers for psychological states in the presence of physical effort induced by walking. The classifier achieved a classification error of 1.4% for nondisabled subjects and 2.1% for patients with neurological disorders. Using our new method, we processed the psychological state data in real time. Our method is a first step toward real-time auto-adaptive gait training with potential to improve rehabilitation results by optimally challenging patients at all times during exercise.

Proceeding of human exoskeleton technology and discussions on future research

NASA Astrophysics Data System (ADS)

Li, Zhiqiang; Xie, Hanxing; Li, Weilin; Yao, Zheng

2014-05-01

After more than half a century of intense efforts, the development of exoskeleton has seen major advances, and several remarkable achievements have been made. Reviews of developing history of exoskeleton are presented, both in active and passive categories. Major models are introduced, and typical technologies are commented on. Difficulties in control algorithm, driver system, power source, and man-machine interface are discussed. Current researching routes and major developing methods are mapped and critically analyzed, and in the process, some key problems are revealed. First, the exoskeleton is totally different from biped robot, and relative studies based on the robot technologies are considerably incorrect. Second, biomechanical studies are only used to track the motion of the human body, the interaction between human and machines are seldom studied. Third, the traditional developing ways which focused on servo-controlling have inborn deficiency from making portable systems. Research attention should be shifted to the human side of the coupling system, and the human ability to learn and adapt should play a more significant role in the control algorithms. Having summarized the major difficulties, possible future works are discussed. It is argued that, since a distinct boundary cannot be drawn in such strong-coupling human-exoskeleton system, the more complex the control system gets, the more difficult it is for the user to learn to use. It is suggested that the exoskeleton should be treated as a simple wearable tool, and downgrading its automatic level may be a change toward a brighter research outlook. This effort at simplification is definitely not easy, as it necessitates theoretical supports from fields such as biomechanics, ergonomics, and bionics.

Simultaneous estimation of human and exoskeleton motion: A simplified protocol.

PubMed

Alvarez, M T; Torricelli, D; Del-Ama, A J; Pinto, D; Gonzalez-Vargas, J; Moreno, J C; Gil-Agudo, A; Pons, J L

2017-07-01

Adequate benchmarking procedures in the area of wearable robots is gaining importance in order to compare different devices on a quantitative basis, improve them and support the standardization and regulation procedures. Performance assessment usually focuses on the execution of locomotion tasks, and is mostly based on kinematic-related measures. Typical drawbacks of marker-based motion capture systems, gold standard for measure of human limb motion, become challenging when measuring limb kinematics, due to the concomitant presence of the robot. This work answers the question of how to reliably assess the subject's body motion by placing markers over the exoskeleton. Focusing on the ankle joint, the proposed methodology showed that it is possible to reconstruct the trajectory of the subject's joint by placing markers on the exoskeleton, although foot flexibility during walking can impact the reconstruction accuracy. More experiments are needed to confirm this hypothesis, and more subjects and walking conditions are needed to better characterize the errors of the proposed methodology, although our results are promising, indicating small errors.

Design of a high-mobility multi-terrain robot based on eccentric paddle mechanism.

PubMed

Sun, Yi; Yang, Yang; Ma, Shugen; Pu, Huayan

Gaining high mobility on versatile terrains is a crucial target for designing a mobile robot toward tasks such as search and rescue, scientific exploration, and environment monitoring. Inspired by dextrous limb motion of animals, a novel form of locomotion has been established in our previous study, by proposing an eccentric paddle mechanism (ePaddle) for integrating paddling motion into a traditional wheeled mechanism. In this paper, prototypes of an ePaddle mechanism and an ePaddle-based quadruped robot are presented. Several locomotion modes, including wheeled rolling, legged crawling, legged race-walking, rotational paddling, oscillating paddling, and paddle-aided rolling, are experimentally verified on testbeds with fabricated prototypes. Experimental results confirm that paddle's motion is useful in all the locomotion modes.

Generation of Adaptive Gait Patterns for Quadruped Robot with CPG Network including Motor Dynamic Model

NASA Astrophysics Data System (ADS)

Son, Yurak; Kamano, Takuya; Yasuno, Takashi; Suzuki, Takayuki; Harada, Hironobu

This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environment. The CPGs act as the flexible oscillators of the joints and make the desired angle of the joints. The CPGs are mutually connected each other, and the sets of their coupling parameters are adjusted by genetic algorithm so that the quadruped robot can realize the stable and adequate gait patterns. As a result of generation, the suitable CPG networks for not only a walking straight gait pattern but also rotation gait patterns are obtained. Experimental results demonstrate that the proposed CPG networks are effective to automatically adjust the adaptive gait patterns for the tested quadruped robot under various environment. Furthermore, the target tracking control based on image processing is achieved by combining the generated gait patterns.

Data management for biofied building

NASA Astrophysics Data System (ADS)

Matsuura, Kohta; Mita, Akira

2015-03-01

Recently, Smart houses have been studied by many researchers to satisfy individual demands of residents. However, they are not feasible yet as they are very costly and require many sensors to be embedded into houses. Therefore, we suggest "Biofied Building". In Biofied Building, sensor agent robots conduct sensing, actuation, and control in their house. The robots monitor many parameters of human lives such as walking postures and emotion continuously. In this paper, a prototype network system and a data model for practical application for Biofied Building is pro-posed. In the system, functions of robots and servers are divided according to service flows in Biofield Buildings. The data model is designed to accumulate both the building data and the residents' data. Data sent from the robots and data analyzed in the servers are automatically registered into the database. Lastly, feasibility of this system is verified through lighting control simulation performed in an office space.

A miniature surface tension-driven robot using spatially elliptical moving legs to mimic a water strider's locomotion.

PubMed

Yan, J H; Zhang, X B; Zhao, J; Liu, G F; Cai, H G; Pan, Q M

2015-08-04

The highly agile and efficient water-surface locomotion of the water strider has stimulated substantial interest in biomimetic research. In this paper, we propose a new miniature surface tension-driven robot inspired by the water strider. A key feature of this robot is that its actuating leg possesses an ellipse-like spatial trajectory similar to that of a water strider by using a cam-link mechanism. Simplified models are presented to discuss the leg-water interactions as well as critical conditions for a leg penetrating the water surface, and simulations are performed on the robot's dynamic properties. The final fabricated robot weighs about 3.9 g, and can freely and stably walk on water at different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm s(-1) and 23°/s, respectively. Furthermore, a similarity analysis with Bond number and Weber number demonstrates that the locomotion of this robot is quite analogous to that of a real water strider: the surface tension force dominates the lifting force and plays a major role in the propulsion force. This miniature surface tension-driven robot might have potential applications in many areas such as water quality monitoring and aquatic search and rescue.

Tactile surface classification for limbed robots using a pressure sensitive robot skin.

PubMed

Shill, Jacob J; Collins, Emmanuel G; Coyle, Eric; Clark, Jonathan

2015-02-02

This paper describes an approach to terrain identification based on pressure images generated through direct surface contact using a robot skin constructed around a high-resolution pressure sensing array. Terrain signatures for classification are formulated from the magnitude frequency responses of the pressure images. The initial experimental results for statically obtained images show that the approach yields classification accuracies [Formula: see text]. The methodology is extended to accommodate the dynamic pressure images anticipated when a robot is walking or running. Experiments with a one-legged hopping robot yield similar identification accuracies [Formula: see text]. In addition, the accuracies are independent with respect to changing robot dynamics (i.e., when using different leg gaits). The paper further shows that the high-resolution capabilities of the sensor enables similarly textured surfaces to be distinguished. A correcting filter is developed to accommodate for failures or faults that inevitably occur within the sensing array with continued use. Experimental results show using the correcting filter can extend the effective operational lifespan of a high-resolution sensing array over 6x in the presence of sensor damage. The results presented suggest this methodology can be extended to autonomous field robots, providing a robot with crucial information about the environment that can be used to aid stable and efficient mobility over rough and varying terrains.

Decrease of spasticity after hybrid assistive limb® training for a patient with C4 quadriplegia due to chronic SCI.

PubMed

Ikumi, Akira; Kubota, Shigeki; Shimizu, Yukiyo; Kadone, Hideki; Marushima, Aiki; Ueno, Tomoyuki; Kawamoto, Hiroaki; Hada, Yasushi; Matsumura, Akira; Sankai, Yoshiyuki; Yamazaki, Masashi

2017-09-01

Recently, locomotor training with robotic assistance has been found effective in treating spinal cord injury (SCI). Our case report examined locomotor training using the robotic suit hybrid assistive limb (HAL) in a patient with complete C4 quadriplegia due to chronic SCI. This is the first report examining HAL in complete C4 quadriplegia. The patient was a 19-year-old man who dislocated C3/4 during judo 4 years previously. Following the injury, he underwent C3/4 posterior spinal fusion but remained paralyzed despite rehabilitation. There was muscle atrophy under C5 level and no sensation around the anus, but partial sensation of pressure remained in the limbs. The American Spinal Injury Association impairment scale was Grade A (complete motor C4 lesion). HAL training was administered in 10 sessions (twice per week). The training sessions consisted of treadmill walking with HAL. For safety, 2 physicians and 1 therapist supported the subject for balance and weight-bearing. The device's cybernic autonomous control mode provides autonomic physical support based on predefined walking patterns. We evaluated the adverse events, walking time and distance, and the difference in muscle spasticity before and after HAL-training using a modified Ashworth scale (mAs). No adverse events were observed that required discontinuation of rehabilitation. Walking distance and time increased from 25.2 meters/7.6 minutes to 148.3 meter/15 minutes. The mAs score decreased after HAL training. Our case report indicates that HAL training is feasible and effective for complete C4 quadriplegia in chronic SCI.

Research on the inspection robot for cable tunnel

NASA Astrophysics Data System (ADS)

Xin, Shihao

2017-03-01

Robot by mechanical obstacle, double end communication, remote control and monitoring software components. The mechanical obstacle part mainly uses the tracked mobile robot mechanism, in order to facilitate the design and installation of the robot, the other auxiliary swing arm; double side communication part used a combination of communication wire communication with wireless communication, great improve the communication range of the robot. When the robot is controlled by far detection range, using wired communication control, on the other hand, using wireless communication; remote control part mainly completes the inspection robot walking, navigation, positioning and identification of cloud platform control. In order to improve the reliability of its operation, the preliminary selection of IPC as the control core the movable body selection program hierarchical structure as a design basis; monitoring software part is the core part of the robot, which has a definite diagnosis Can be instead of manual simple fault judgment, instead the robot as a remote actuators, staff as long as the remote control can be, do not have to body at the scene. Four parts are independent of each other but are related to each other, the realization of the structure of independence and coherence, easy maintenance and coordination work. Robot with real-time positioning function and remote control function, greatly improves the IT operation. Robot remote monitor, to avoid the direct contact with the staff and line, thereby reducing the accident casualties, for the safety of the inspection work has far-reaching significance.

Improved walking ability with wearable robot-assisted training in patients suffering chronic stroke.

PubMed

Li, Lifang; Ding, Li; Chen, Na; Mao, Yurong; Huang, Dongfeng; Li, Le

2015-01-01

Wearable robotic devices provide safe and intensive rehabilitation, enabling repeated motions for motor function recovery in stroke patients. The aim of this small case series was to demonstrate the training effects of a three-week robotic leg orthosis, and to investigate possible mechanisms of the sensory-motor alterations and improvements by using gait analysis and EMG. Three survivors of chronic strokes participated in robot-assisted gait therapy for three weeks. EMG signals from the rectus femoris (RF), tibialis anterior (TA), biceps femoris (BF), and medial gastrocnemius (MG), as well as kinetics and kinematics data of the lower limb, were recorded before and after the training. The normalized root mean squared (RMS) values of the muscles, the joint moments, joint angles, and the results of two clinical scales (Berg Balance scale, BBS, and the lower extremity subscale of Fugl-Meyer assessment, LE-FMA) were used for analysis. All participants experienced improved balance and functional performances and increased BBS and LE-FMA scores. The EMG results showed there was an increase of the normalized RMS values of the MG and BF on the affected side. Additionally, EMG activities of the agonist and antagonist pair (i.e. RF and BF) appeared to return to similar levels after training. The peak moment of hip flexor, knee extensor, and plantar flexor, which all contributed to push-off power, were found to have increased after training. In summary, the three-week training period using the wearable RLO improved the three participants' gait performance by regaining push-off power and improved muscle activation and walking speed.

KENNEDY SPACE CENTER, FLA. - Workers walk with the suspended backshell/ Mars Exploration Rover 1 (MER-1) as it travels across the floor of the Payload Hazardous Servicing Facility. The backshell will be attached to the lower heat shield. NASA's twin Mars Exploration Rovers are designed to study the history of water on Mars. These robotic geologists are equipped with a robotic arm, a drilling tool, three spectrometers, and four pairs of cameras that allow them to have a human-like, 3D view of the terrain. Each rover could travel as far as 100 meters in one day to act as Mars scientists' eyes and hands, exploring an environment where humans can't yet go. MER-1 is scheduled to launch June 25 as MER-B aboard a Delta II rocket from Cape Canaveral Air Force Station.

NASA Image and Video Library

2003-05-15

KENNEDY SPACE CENTER, FLA. - Workers walk with the suspended backshell/ Mars Exploration Rover 1 (MER-1) as it travels across the floor of the Payload Hazardous Servicing Facility. The backshell will be attached to the lower heat shield. NASA's twin Mars Exploration Rovers are designed to study the history of water on Mars. These robotic geologists are equipped with a robotic arm, a drilling tool, three spectrometers, and four pairs of cameras that allow them to have a human-like, 3D view of the terrain. Each rover could travel as far as 100 meters in one day to act as Mars scientists' eyes and hands, exploring an environment where humans can't yet go. MER-1 is scheduled to launch June 25 as MER-B aboard a Delta II rocket from Cape Canaveral Air Force Station.

Phylogenetic relationships among amphisbaenian reptiles based on complete mitochondrial genomic sequences.

PubMed

Macey, J Robert; Papenfuss, Theodore J; Kuehl, Jennifer V; Fourcade, H Mathew; Boore, Jeffrey L

2004-10-01

Complete mitochondrial genomic sequences are reported from 12 members in the four families of the reptile group Amphisbaenia. Analysis of 11,946 aligned nucleotide positions (5797 informative) produces a robust phylogenetic hypothesis. The family Rhineuridae is basal and Bipedidae is the sister taxon to the Amphisbaenidae plus Trogonophidae. Amphisbaenian reptiles are surprisingly old, predating the breakup of Pangaea 200 million years before present, because successive basal taxa (Rhineuridae and Bipedidae) are situated in tectonic regions of Laurasia and nested taxa (Amphisbaenidae and Trogonophidae) are found in Gondwanan regions. Thorough sampling within the Bipedidae shows that it is not tectonic movement of Baja California away from the Mexican mainland that is primary in isolating Bipes species, but rather that primary vicariance occurred between northern and southern groups. Amphisbaenian families show parallel reduction in number of limbs and Bipes species exhibit parallel reduction in number of digits. A measure is developed for comparing the phylogenetic information content of various genes. A synapomorphic trait defining the Bipedidae is a shift from the typical vertebrate mitochondrial gene arrangement to the derived state of trnE and nad6. In addition, a tandem duplication of trnT and trnP is observed in Bipes biporus with a pattern of pseudogene formation that varies among populations. The first case of convergent rearrangement of the mitochondrial genome among animals demonstrated by complete genomic sequences is reported. Relative to most vertebrates, the Rhineuridae has the block nad6, trnE switched in order with the block cob, trnT, trnP, as they are in birds.

An intermittent control model of flexible human gait using a stable manifold of saddle-type unstable limit cycle dynamics

PubMed Central

Fu, Chunjiang; Suzuki, Yasuyuki; Kiyono, Ken; Morasso, Pietro; Nomura, Taishin

2014-01-01

Stability of human gait is the ability to maintain upright posture during walking against external perturbations. It is a complex process determined by a number of cross-related factors, including gait trajectory, joint impedance and neural control strategies. Here, we consider a control strategy that can achieve stable steady-state periodic gait while maintaining joint flexibility with the lowest possible joint impedance. To this end, we carried out a simulation study of a heel-toe footed biped model with hip, knee and ankle joints and a heavy head-arms-trunk element, working in the sagittal plane. For simplicity, the model assumes a periodic desired joint angle trajectory and joint torques generated by a set of feed-forward and proportional-derivative feedback controllers, whereby the joint impedance is parametrized by the feedback gains. We could show that a desired steady-state gait accompanied by the desired joint angle trajectory can be established as a stable limit cycle (LC) for the feedback controller with an appropriate set of large feedback gains. Moreover, as the feedback gains are decreased for lowering the joint stiffness, stability of the LC is lost only in a few dimensions, while leaving the remaining large number of dimensions quite stable: this means that the LC becomes saddle-type, with a low-dimensional unstable manifold and a high-dimensional stable manifold. Remarkably, the unstable manifold remains of low dimensionality even when the feedback gains are decreased far below the instability point. We then developed an intermittent neural feedback controller that is activated only for short periods of time at an optimal phase of each gait stride. We characterized the robustness of this design by showing that it can better stabilize the unstable LC with small feedback gains, leading to a flexible gait, and in particular we demonstrated that such an intermittent controller performs better if it drives the state point to the stable manifold, rather than directly to the LC. The proposed intermittent control strategy might have a high affinity for the inverted pendulum analogy of biped gait, providing a dynamic view of how the step-to-step transition from one pendular stance to the next can be achieved stably in a robust manner by a well-timed neural intervention that exploits the stable modes embedded in the unstable dynamics. PMID:25339687

An intermittent control model of flexible human gait using a stable manifold of saddle-type unstable limit cycle dynamics.

PubMed

Fu, Chunjiang; Suzuki, Yasuyuki; Kiyono, Ken; Morasso, Pietro; Nomura, Taishin

2014-12-06

Stability of human gait is the ability to maintain upright posture during walking against external perturbations. It is a complex process determined by a number of cross-related factors, including gait trajectory, joint impedance and neural control strategies. Here, we consider a control strategy that can achieve stable steady-state periodic gait while maintaining joint flexibility with the lowest possible joint impedance. To this end, we carried out a simulation study of a heel-toe footed biped model with hip, knee and ankle joints and a heavy head-arms-trunk element, working in the sagittal plane. For simplicity, the model assumes a periodic desired joint angle trajectory and joint torques generated by a set of feed-forward and proportional-derivative feedback controllers, whereby the joint impedance is parametrized by the feedback gains. We could show that a desired steady-state gait accompanied by the desired joint angle trajectory can be established as a stable limit cycle (LC) for the feedback controller with an appropriate set of large feedback gains. Moreover, as the feedback gains are decreased for lowering the joint stiffness, stability of the LC is lost only in a few dimensions, while leaving the remaining large number of dimensions quite stable: this means that the LC becomes saddle-type, with a low-dimensional unstable manifold and a high-dimensional stable manifold. Remarkably, the unstable manifold remains of low dimensionality even when the feedback gains are decreased far below the instability point. We then developed an intermittent neural feedback controller that is activated only for short periods of time at an optimal phase of each gait stride. We characterized the robustness of this design by showing that it can better stabilize the unstable LC with small feedback gains, leading to a flexible gait, and in particular we demonstrated that such an intermittent controller performs better if it drives the state point to the stable manifold, rather than directly to the LC. The proposed intermittent control strategy might have a high affinity for the inverted pendulum analogy of biped gait, providing a dynamic view of how the step-to-step transition from one pendular stance to the next can be achieved stably in a robust manner by a well-timed neural intervention that exploits the stable modes embedded in the unstable dynamics.

Obstacle negotiation control for a mobile robot suspended on overhead ground wires by optoelectronic sensors

NASA Astrophysics Data System (ADS)

Zheng, Li; Yi, Ruan

2009-11-01

Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

Computer visualizations in engineering applications

NASA Astrophysics Data System (ADS)

Bills, K. C.

The use of computerized simulations of various robotic tasks via IGRIP software is reported. The projects include underwater activities demonstrating clean up of a quarry; time study of methods to store waste drums inside a facility; design walk-through of a new facility; plant layout flyover; and conceptual development and layout of new mechanisms.

Dante's Volcano

NASA Technical Reports Server (NTRS)

1994-01-01

This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

KSC-99pp0401

NASA Image and Video Library

1999-04-08

KENNEDY SPACE CENTER, FLA. -- Part of the Robot Scouts exhibit in the $13 million expansion to KSC's Visitor Complex, this display offers a view of how data from robotic probes might be used to build a human habitat for Mars. Visitors witness a simulated Martian sunset. Other new additions include and information center, a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. The KSC Visitor Complex was inaugurated three decades ago and is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge

Cooperative Exploration of Rough Martian Terrains with the "Scorpion" Legged Robot as an Adjunct to a Rover.

NASA Technical Reports Server (NTRS)

Colombano, Silvano P.; Kirchner, Frank; Spenneberg, Dirk; Starman, Jared; Hanratty, James; Kovsmeyer, David (Technical Monitor)

2003-01-01

NASA needs autonomous robotic exploration of difficult (rough and/or steep) scientifically interesting Martian terrains. Concepts involving distributed autonomy for cooperative robotic exploration are key to enabling new scientific objectives in robotic missions. We propose to utilize a legged robot as an adjunct scout to a rover for access to difficult - scientifically interesting - terrains (rocky areas, slopes, cliffs). Our final mission scenario involves the Ames rover platform "K9" and Scorpion acting together to explore a steep cliff, with the Scorpion robot rappelling down using the K9 as an anchor as well as mission planner and executive. Cooperation concepts, including wheeled rappelling robots have been proposed before. Now we propose to test the combined advantages of a wheeled vehicle with a legged scout as well as the advantages of merging of high level planning and execution with biologically inspired, behavior based robotics. We propose to use the 8-legged, multifunctional autonomous robot platform Scorpion that is currently capable of: Walking on different terrains (rocks, sand, grass, ...). Perceiving its environment and modifying its behavioral pattern accordingly. These capabilities would be extended to enable the Scorpion to: communicate and cooperate with a partner robot; climb over rocks, rubble piles, and objects with structural features. This will be done in the context of exploration of rough terrains in the neighborhood of the rover, but inaccessible to it, culminating in the added capability of rappelling down a steep cliff for both vertical and horizontal terrain observation.

Powered lower limb orthoses for gait rehabilitation

PubMed Central

Ferris, Daniel P.; Sawicki, Gregory S.; Domingo, Antoinette

2006-01-01

Bodyweight supported treadmill training has become a prominent gait rehabilitation method in leading rehabilitation centers. This type of locomotor training has many functional benefits but the labor costs are considerable. To reduce therapist effort, several groups have developed large robotic devices for assisting treadmill stepping. A complementary approach that has not been adequately explored is to use powered lower limb orthoses for locomotor training. Recent advances in robotic technology have made lightweight powered orthoses feasible and practical. An advantage to using powered orthoses as rehabilitation aids is they allow practice starting, turning, stopping, and avoiding obstacles during overground walking. PMID:16568153

Robot-assisted walking training for individuals with Parkinson’s disease: a pilot randomized controlled trial

PubMed Central

2013-01-01

Background Over the last years, the introduction of robotic technologies into Parkinson’s disease rehabilitation settings has progressed from concept to reality. However, the benefit of robotic training remains elusive. This pilot randomized controlled observer trial is aimed at investigating the feasibility, the effectiveness and the efficacy of new end-effector robot training in people with mild Parkinson’s disease. Methods Design. Pilot randomized controlled trial. Setting. Robot assisted gait training (EG) compared to treadmill training (CG). Participants. Twenty cognitively intact participants with mild Parkinson’s disease and gait disturbance. Interventions. The EG underwent a rehabilitation programme of robot assisted walking for 40 minutes, 5 times a week for 4 weeks. The CG received a treadmill training programme for 40 minutes, 5 times a week for 4 weeks. Main outcome measures. The outcome measure of efficacy was recorded by gait analysis laboratory. The assessments were performed at the beginning (T0) and at the end of the treatment (T1). The main outcome was the change in velocity. The feasibility of the intervention was assessed by recording exercise adherence and acceptability by specific test. Results Robot training was feasible, acceptable, safe, and the participants completed 100% of the prescribed training sessions. A statistically significant improvement in gait index was found in favour of the EG (T0 versus T1). In particular, the statistical analysis of primary outcome (gait speed) using the Friedman test showed statistically significant improvements for the EG (p = 0,0195). The statistical analysis performed by Friedman test of Step length left (p = 0,0195) and right (p = 0,0195) and Stride length left (p = 0,0078) and right (p = 0,0195) showed a significant statistical gain. No statistically significant improvements on the CG were found. Conclusions Robot training is a feasible and safe form of rehabilitative exercise for cognitively intact people with mild PD. This original approach can contribute to increase a short time lower limb motor recovery in idiopathic PD patients. The focus on the gait recovery is a further characteristic that makes this research relevant to clinical practice. On the whole, the simplicity of treatment, the lack of side effects, and the positive results from patients support the recommendation to extend the use of this treatment. Further investigation regarding the long-time effectiveness of robot training is warranted. Trial registration ClinicalTrials.gov NCT01668407 PMID:23706025

Analysis on the Load Carrying Mechanism Integrated as Heterogeneous Co-operative Manipulator in a Walking Wheelchair

NASA Astrophysics Data System (ADS)

Rajay Vedaraj, I. S.; Jain, Ritika; Rao, B. V. A.

2014-07-01

After industrial robots came into existence during 1960, the technology of robotics with the design and analysis of robots in various forms in industries as well as in domestic applications were developed. Nowadays, along with the automotive sector the robots are producing a great impact in the form of quality and production rate to register their existence reliable in various other sectors also. Robotic technology has undergone various phase translations from being tortured as humanoids to the present day manipulators. Depending upon the various forms of its existence, robot manipulators are designed as serial manipulators and parallel manipulators. Individually both types can be proved effective though both have various drawbacks in design and the kinematic analysis. The versatility of robots can be increased by making them work in an environment where the same work volume is shared by more than one manipulator. This work volume can be identified as co-operative work volume of those manipulators. Here the interference of manipulators in the work volume of other manipulators is possible and is made obstacle free. The main advantage of co-operative manipulators is that when a number of independent manipulators are put together in a cooperative work envelope the efficiency and ability to perform tasks is greatly enhanced. The main disadvantage of the co-operative manipulators lies in the complication of its design even for a simple application, in almost all fields. In this paper, a cooperative design of robot manipulators to work in co-operative work environment is done and analysed for its efficacy. In the industrial applications when robotic manipulators are put together in more numbers, the trajectory planning becomes the tough task in the work cell. Proper design can remove the design defects of the cooperative manipulators and can be utilized in a more efficient way. In the proposed research paper an analysis is made on such a type of cooperative manipulator used for climbing stairs with three leg design and anlaysis were also done on the mechanism integrated to the system. Kinematics of the legs are analysed separately and the legs are designed to carry a maximum of 175kgs, which is sustained by the center leg and shared by the dual wing legs equally during the walking phase. In the proposed design, screwjack mechanism is used as the central leg to share the load and thus the analysis on the load sharing capability of the whole system is analysed and concluded in terms of failure modes.

Lower extremity robotic exoskeleton training: Case studies for complete spinal cord injury walking.

PubMed

Lemaire, Edward D; Smith, Andrew J; Herbert-Copley, Andrew; Sreenivasan, Vidya

2017-01-01

Recent advances in exoskeleton technology has made lower extremity powered exoskeletons (LEPE) a viable treatment tool to restore upright walking mobility to persons with spinal cord injury (SCI). Evaluate ARKE exoskeleton training within a rehabilitation centre environment. Case studies are presented for two male participants, age 41 and 30, motor complete SCI at T6 (N01) and T12 (N02), respectively, as they progress from new LEPE users to independent walking. The ARKE 2.0 LEPE (Bionik Laboratories Inc., Toronto, Canada) was used for all training (hip and knee powered, forearm crutches, control tablet). Data were collected on session times, activity metrics from ARKE system logs, and qualitative questionnaire feedback. N01 required 18, 30-minute training sessions to achieve independent walking. N01 walked independently within the 12 session target. Foot strikes were frequently before the end of the programmed swing phase, which were handled by the ARKE control system. Subjective ratings of LEPE learning, comfort, pain, fatigue, and overall experience were high for sitting-standing and moderate to high for walking. This reflected the complexity of learning to safely walk. Qualitative feedback supported the continuation of LEPE use in rehabilitation settings based on end-user desire for upright mobility.

Kinematic and EMG Responses to Pelvis and Leg Assistance Force during Treadmill Walking in Children with Cerebral Palsy

PubMed Central

Kim, Janis; Arora, Pooja; Zhang, Yunhui

2016-01-01

Treadmill training has been used for improving locomotor function in children with cerebral palsy (CP), but the functional gains are relatively small, suggesting a need to improve current paradigms. The understanding of the kinematic and EMG responses to forces applied to the body of subjects during treadmill walking is crucial for improving current paradigms. The objective of this study was to determine the kinematics and EMG responses to the pelvis and/or leg assistance force. Ten children with spastic CP were recruited to participate in this study. A controlled assistance force was applied to the pelvis and/or legs during stance and swing phase of gait through a custom designed robotic system during walking. Muscle activities and spatial-temporal gait parameters were measured at different loading conditions during walking. In addition, the spatial-temporal gait parameters during overground walking before and after treadmill training were also collected. Applying pelvis assistance improved step height and applying leg assistance improved step length during walking, but applying leg assistance also reduced muscle activation of ankle flexor during the swing phase of gait. In addition, step length and self-selected walking speed significantly improved after one session of treadmill training with combined pelvis and leg assistance. PMID:27651955

Psychophysiological response to cognitive workload during symmetrical, asymmetrical and dual-task walking.

PubMed

Knaepen, Kristel; Marusic, Uros; Crea, Simona; Rodríguez Guerrero, Carlos D; Vitiello, Nicola; Pattyn, Nathalie; Mairesse, Olivier; Lefeber, Dirk; Meeusen, Romain

2015-04-01

Walking with a lower limb prosthesis comes at a high cognitive workload for amputees, possibly affecting their mobility, safety and independency. A biocooperative prosthesis which is able to reduce the cognitive workload of walking could offer a solution. Therefore, we wanted to investigate whether different levels of cognitive workload can be assessed during symmetrical, asymmetrical and dual-task walking and to identify which parameters are the most sensitive. Twenty-four healthy subjects participated in this study. Cognitive workload was assessed through psychophysiological responses, physical and cognitive performance and subjective ratings. The results showed that breathing frequency and heart rate significantly increased, and heart rate variability significantly decreased with increasing cognitive workload during walking (p<.05). Performance measures (e.g., cadence) only changed under high cognitive workload. As a result, psychophysiological measures are the most sensitive to identify changes in cognitive workload during walking. These parameters reflect the cognitive effort necessary to maintain performance during complex walking and can easily be assessed regardless of the task. This makes them excellent candidates to feed to the control loop of a biocooperative prosthesis in order to detect the cognitive workload. This information can then be used to adapt the robotic assistance to the patient's cognitive abilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Multi Sensor Fusion Framework for Indoor-Outdoor Localization of Limited Resource Mobile Robots

PubMed Central

Marín, Leonardo; Vallés, Marina; Soriano, Ángel; Valera, Ángel; Albertos, Pedro

2013-01-01

This paper presents a sensor fusion framework that improves the localization of mobile robots with limited computational resources. It employs an event based Kalman Filter to combine the measurements of a global sensor and an inertial measurement unit (IMU) on an event based schedule, using fewer resources (execution time and bandwidth) but with similar performance when compared to the traditional methods. The event is defined to reflect the necessity of the global information, when the estimation error covariance exceeds a predefined limit. The proposed experimental platforms are based on the LEGO Mindstorm NXT, and consist of a differential wheel mobile robot navigating indoors with a zenithal camera as global sensor, and an Ackermann steering mobile robot navigating outdoors with a SBG Systems GPS accessed through an IGEP board that also serves as datalogger. The IMU in both robots is built using the NXT motor encoders along with one gyroscope, one compass and two accelerometers from Hitecnic, placed according to a particle based dynamic model of the robots. The tests performed reflect the correct performance and low execution time of the proposed framework. The robustness and stability is observed during a long walk test in both indoors and outdoors environments. PMID:24152933

Multi sensor fusion framework for indoor-outdoor localization of limited resource mobile robots.

PubMed

Marín, Leonardo; Vallés, Marina; Soriano, Ángel; Valera, Ángel; Albertos, Pedro

2013-10-21

This paper presents a sensor fusion framework that improves the localization of mobile robots with limited computational resources. It employs an event based Kalman Filter to combine the measurements of a global sensor and an inertial measurement unit (IMU) on an event based schedule, using fewer resources (execution time and bandwidth) but with similar performance when compared to the traditional methods. The event is defined to reflect the necessity of the global information, when the estimation error covariance exceeds a predefined limit. The proposed experimental platforms are based on the LEGO Mindstorm NXT, and consist of a differential wheel mobile robot navigating indoors with a zenithal camera as global sensor, and an Ackermann steering mobile robot navigating outdoors with a SBG Systems GPS accessed through an IGEP board that also serves as datalogger. The IMU in both robots is built using the NXT motor encoders along with one gyroscope, one compass and two accelerometers from Hitecnic, placed according to a particle based dynamic model of the robots. The tests performed reflect the correct performance and low execution time of the proposed framework. The robustness and stability is observed during a long walk test in both indoors and outdoors environments.

Robotic Technologies and Rehabilitation: New Tools for Stroke Patients' Therapy

PubMed Central

Poli, Patrizia; Morone, Giovanni; Rosati, Giulio; Masiero, Stefano

2013-01-01

Introduction. The role of robotics in poststroke patients' rehabilitation has been investigated intensively. This paper presents the state-of-the-art and the possible future role of robotics in poststroke rehabilitation, for both upper and lower limbs. Materials and Methods. We performed a comprehensive search of PubMed, Cochrane, and PeDRO databases using as keywords “robot AND stroke AND rehabilitation.” Results and Discussion. In upper limb robotic rehabilitation, training seems to improve arm function in activities of daily living. In addition, electromechanical gait training after stroke seems to be effective. It is still unclear whether robot-assisted arm training may improve muscle strength, and which electromechanical gait-training device may be the most effective for walking training implementation. Conclusions. In the field of robotic technologies for stroke patients' rehabilitation we identified currently relevant growing points and areas timely for developing research. Among the growing points there is the development of new easily transportable, wearable devices that could improve rehabilitation also after discharge, in an outpatient or home-based setting. For developing research, efforts are being made to establish the ideal type of treatment, the length and amount of training protocol, and the patient's characteristics to be successfully enrolled to this treatment. PMID:24350244

Novel compliant actuator for wearable robotics applications.

PubMed

Claros, M; Soto, R; Rodríguez, J J; Cantú, C; Contreras-Vidal, José L

2013-01-01

In the growing fields of wearable robotics, rehabilitation robotics, prosthetics, and walking robots, variable impedance and force actuators are being designed and implemented because of their ability to dynamically modulate the intrinsic viscoelastic properties such as stiffness and damping. This modulation is crucial to achieve an efficient and safe human-robot interaction that could lead to electronically generate useful emergent dynamical behaviors. In this work we propose a novel actuation system in which is implemented a control scheme based on equilibrium forces for an active joint capable to provide assistance/resistance as needed and also achieve minimal mechanical impedance when tracking the movement of the user limbs. The actuation system comprises a DC motor with a built in speed reducer, two force-sensing resistors (FSR), a mechanism which transmits to the FSRs the torque developed in the joint and a controller which regulate the amount of energy that is delivered to the DC motor. The proposed system showed more impedance reduction, by the effect of the controlled contact forces, compared with the ones in the reviewed literature.

Design and development of biomimetic quadruped robot for behavior studies of rats and mice.

PubMed

Ishii, Hiroyuki; Masuda, Yuichi; Miyagishima, Syunsuke; Fumino, Shogo; Takanishi, Atsuo; Laschi, Cecilia; Mazzolai, Barbara; Mattoli, Virgilio; Dario, Paolo

2009-01-01

This paper presents the design and development of a novel biomimetic quadruped robot for behavior studies of rats and mice. Many studies have been performed using these animals for the purpose of understanding human mind in psychology, pharmacology and brain science. In these fields, several experiments on social interactions have been performed using rats as basic studies of mental disorders or social learning. However, some researchers mention that the experiments on social interactions using animals are poorly-reproducible. Therefore, we consider that reproducibility of these experiments can be improved by using a robotic agent that interacts with an animal subject. Thus, we developed a small quadruped robot WR-2 (Waseda Rat No. 2) that behaves like a real rat. Proportion and DOF arrangement of WR-2 are designed based on those of a mature rat. This robot has four 3-DOF legs, a 2-DOF waist and a 1-DOF neck. A microcontroller and a wireless communication module are implemented on it. A battery is also implemented. Thus, it can walk, rear by limbs and groom its body.

Semi-autonomous exploration of multi-floor buildings with a legged robot

NASA Astrophysics Data System (ADS)

Wenger, Garrett J.; Johnson, Aaron M.; Taylor, Camillo J.; Koditschek, Daniel E.

2015-05-01

This paper presents preliminary results of a semi-autonomous building exploration behavior using the hexapedal robot RHex. Stairwells are used in virtually all multi-floor buildings, and so in order for a mobile robot to effectively explore, map, clear, monitor, or patrol such buildings it must be able to ascend and descend stairwells. However most conventional mobile robots based on a wheeled platform are unable to traverse stairwells, motivating use of the more mobile legged machine. This semi-autonomous behavior uses a human driver to provide steering input to the robot, as would be the case in, e.g., a tele-operated building exploration mission. The gait selection and transitions between the walking and stair climbing gaits are entirely autonomous. This implementation uses an RGBD camera for stair acquisition, which offers several advantages over a previously documented detector based on a laser range finder, including significantly reduced acquisition time. The sensor package used here also allows for considerable expansion of this behavior. For example, complete automation of the building exploration task driven by a mapping algorithm and higher level planner is presently under development.

Influence of virtual reality soccer game on walking performance in robotic assisted gait training for children.

PubMed

Brütsch, Karin; Schuler, Tabea; Koenig, Alexander; Zimmerli, Lukas; -Koeneke, Susan Mérillat; Lünenburger, Lars; Riener, Robert; Jäncke, Lutz; Meyer-Heim, Andreas

2010-04-22

Virtual reality (VR) offers powerful therapy options within a functional, purposeful and motivating context. Several studies have shown that patients' motivation plays a crucial role in determining therapy outcome. However, few studies have demonstrated the potential of VR in pediatric rehabilitation. Therefore, we developed a VR-based soccer scenario, which provided interactive elements to engage patients during robotic assisted treadmill training (RAGT). The aim of this study was to compare the immediate effect of different supportive conditions (VR versus non-VR conditions) on motor output in patients and healthy control children during training with the driven gait orthosis Lokomat*. A total of 18 children (ten patients with different neurological gait disorders, eight healthy controls) took part in this study. They were instructed to walk on the Lokomat in four different, randomly-presented conditions: (1) walk normally without supporting assistance, (2) with therapists' instructions to promote active participation, (3) with VR as a motivating tool to walk actively and (4) with the VR tool combined with therapists' instructions. The Lokomat gait orthosis is equipped with sensors at hip and knee joint to measure man-machine interaction forces. Additionally, subjects' acceptance of the RAGT with VR was assessed using a questionnaire. The mixed ANOVA revealed significant main effects for the factor CONDITIONS (p < 0.001) and a significant interaction CONDITIONS x GROUP (p = 0.01). Tests of between-subjects effects showed no significant main effect for the GROUP (p = 0.592). Active participation in patients and control children increased significantly when supported and motivated either by therapists' instructions or by a VR scenario compared with the baseline measurement "normal walking" (p < 0.001). The VR scenario used here induces an immediate effect on motor output to a similar degree as the effect resulting from verbal instructions by the therapists. Further research needs to focus on the implementation of interactive design elements, which keep motivation high across and beyond RAGT sessions, especially in pediatric rehabilitation.

Gait speed using powered robotic exoskeletons after spinal cord injury: a systematic review and correlational study.

PubMed

Louie, Dennis R; Eng, Janice J; Lam, Tania

2015-10-14

Powered robotic exoskeletons are an emerging technology of wearable orthoses that can be used as an assistive device to enable non-ambulatory individuals with spinal cord injury (SCI) to walk, or as a rehabilitation tool to improve walking ability in ambulatory individuals with SCI. No studies to date have systematically reviewed the literature on the efficacy of powered exoskeletons on restoring walking function. Our objective was to systematically review the literature to determine the gait speed attained by individuals with SCI when using a powered exoskeleton to walk, factors influencing this speed, and characteristics of studies involving a powered exoskeleton (e.g. inclusion criteria, screening, and training processes). A systematic search in computerized databases was conducted to identify articles that reported on walking outcomes when using a powered exoskeleton. Individual gait speed data from each study was extracted. Pearson correlations were performed between gait speed and 1) age, 2) years post-injury, 3) injury level, and 4) number of training sessions. Fifteen articles met inclusion criteria, 14 of which investigated the powered exoskeleton as an assistive device for non-ambulatory individuals and one which used it as a training intervention for ambulatory individuals with SCI. The mean gait speed attained by non-ambulatory participants (n = 84) while wearing a powered exoskeleton was 0.26 m/s, with the majority having a thoracic-level motor-complete injury. Twelve articles reported individual data for the non-ambulatory participants, from which a positive correlation was found between gait speed and 1) age (r = 0.27, 95 % CI 0.02-0.48, p = 0.03, 63 participants), 2) injury level (r = 0.27, 95 % CI 0.02-0.48, p = 0.03, 63 participants), and 3) training sessions (r = 0.41, 95 % CI 0.16-0.61, p = 0.002, 55 participants). In conclusion, powered exoskeletons can provide non-ambulatory individuals with thoracic-level motor-complete SCI the ability to walk at modest speeds. This speed is related to level of injury as well as training time.

Towards more effective robotic gait training for stroke rehabilitation: a review

PubMed Central

2012-01-01

Background Stroke is the most common cause of disability in the developed world and can severely degrade walking function. Robot-driven gait therapy can provide assistance to patients during training and offers a number of advantages over other forms of therapy. These potential benefits do not, however, seem to have been fully realised as of yet in clinical practice. Objectives This review determines ways in which robot-driven gait technology could be improved in order to achieve better outcomes in gait rehabilitation. Methods The literature on gait impairments caused by stroke is reviewed, followed by research detailing the different pathways to recovery. The outcomes of clinical trials investigating robot-driven gait therapy are then examined. Finally, an analysis of the literature focused on the technical features of the robot-based devices is presented. This review thus combines both clinical and technical aspects in order to determine the routes by which robot-driven gait therapy could be further developed. Conclusions Active subject participation in robot-driven gait therapy is vital to many of the potential recovery pathways and is therefore an important feature of gait training. Higher levels of subject participation and challenge could be promoted through designs with a high emphasis on robotic transparency and sufficient degrees of freedom to allow other aspects of gait such as balance to be incorporated. PMID:22953989

A Comparison of Locomotor Therapy Interventions: Partial-Body Weight-Supported Treadmill, Lokomat, and G-EO Training in People With Traumatic Brain Injury.

PubMed

Esquenazi, Alberto; Lee, Stella; Wikoff, Amanda; Packel, Andrew; Toczylowski, Theresa; Feeley, John

2017-09-01

Literature in the application of gait training techniques in persons with traumatic brain injury (TBI) is limited. Current techniques require multiple staff and are physically demanding. The use of a robotic locomotor training may provide improved training capacity for this population. To examine the impact of 3 different modes of locomotor therapy on gait velocity and spatiotemporal symmetry using an end effector robot (G-EO); a robotic exoskeleton (Lokomat), and manual assisted partial-body weight-supported treadmill training (PBWSTT) in participants with traumatic brain injury. Randomized, prospective study. Tertiary rehabilitation hospital. A total of 22 individuals with ≥12 months chronic TBI with hemiparetic pattern able to walk overground without assistance at velocities between 0.2 and 0.6 m/s. Eighteen sessions of 45 minutes of assigned locomotor training. Overground walking self-selected velocity (SSV), maximal velocity (MV), spatiotemporal asymmetry ratio, 6-Minute Walk Test (6MWT), and mobility domain of Stroke Impact Scale (MSIS). Severity in walking dysfunction was similar across groups as determined by walking velocity data. At baseline, participants in the Lokomat group had a baseline velocity that was slightly slower compared with the other groups. Training elicited a statistically significant median increase in SSV for all groups compared with pretraining (Lokomat, P = .04; G-EO, P = .03; and PBWSTT, P = .02) and MV excluding the G-EO group (Lokomat, P = .04; PBWSTT, P = .03 and G-EO, P = .15). There were no pre-post significant differences in swing time, stance time, and step length asymmetry ratios at SSV or MV for any of the interventions. Mean rank in the change of SSV and MV was not statistically significantly different between groups. Participants in the G-EO and PBWSTT groups significantly improved their 6MWT posttraining (P = .04 and .03, respectively). The MSIS significantly improved only for the Lokomat group (P = .04 and .03). The data did not elicit between-groups significant differences for 6MWT and MSIS. There was less use of staff for Lokomat than G-EO. Locomotor therapy using G-EO, Lokomat, or PBWSTT in individuals with chronic TBI increased SSV and MV without significant changes in gait symmetry. Staffing needed for therapy provision was the least for the Lokomat. A larger study may further elucidate changes in gait symmetry and other training parameters. II. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

BigDog

NASA Astrophysics Data System (ADS)

Playter, R.; Buehler, M.; Raibert, M.

2006-05-01

BigDog's goal is to be the world's most advanced quadruped robot for outdoor applications. BigDog is aimed at the mission of a mechanical mule - a category with few competitors to date: power autonomous quadrupeds capable of carrying significant payloads, operating outdoors, with static and dynamic mobility, and fully integrated sensing. BigDog is about 1 m tall, 1 m long and 0.3 m wide, and weighs about 90 kg. BigDog has demonstrated walking and trotting gaits, as well as standing up and sitting down. Since its creation in the fall of 2004, BigDog has logged tens of hours of walking, climbing and running time. It has walked up and down 25 & 35 degree inclines and trotted at speeds up to 1.8 m/s. BigDog has walked at 0.7 m/s over loose rock beds and carried over 50 kg of payload. We are currently working to expand BigDog's rough terrain mobility through the creation of robust locomotion strategies and terrain sensing capabilities.

KineAssist: design and development of a robotic overground gait and balance therapy device.

PubMed

Patton, James; Brown, David A; Peshkin, Michael; Santos-Munné, Julio J; Makhlin, Alex; Lewis, Ela; Colgate, Edward J; Schwandt, Doug

2008-01-01

Balance and mobility training consists of activities that carry a high risk for falling. The purpose of this article is to describe a novel robotic system for allowing challenging, yet safe, balance and mobility training in persons at high risk for falls. With no initial preconceptions of what device we would build, a user-needs analysis led us to focus on increasing the level of challenge to a patient's ability to maintain balance during gait training and also on maintaining direct involvement of a physical therapist (rather than attempting robotic replacement). The KineAssist is a robotic device for gait and balance training that has emerged from a unique design process of a start-up product of a small company and a team of therapists, engineers, mechanical design experts, and rehabilitation scientists. The KineAssist provides partial body weight support and postural control on the torso; allows many axes of motion of the trunk and pelvis; leaves the patient's legs accessible to a physical therapist's manipulation during walking; follows a patient's walking motions overground in forward, rotation, and sidestepping directions; and catches an individual who loses balance and begins to fall. Design and development of the KineAssist proceeded more rapidly in the context of a small company than would have been possible in most institutional research contexts. A prototype KineAssist has been constructed and has received US Food and Drug Administration (FDA) classification and institutional review board clearance for initial human studies. The acceptance of KineAssist will ultimately depend on improved patient outcomes, the use of this new tool by therapists, the ease of use of the system, and the recognition of the unique value it brings to therapeutic recovery.

Limb contribution to increased self-selected walking speeds during body weight support in individuals poststroke.

PubMed

Hurt, Christopher P; Burgess, Jamie K; Brown, David A

2015-03-01

Individuals poststroke walk at faster self-selected speeds under some nominal level of body weight support (BWS) whereas nonimpaired individuals walk slower after adding BWS. The purpose of this study was to determine whether increases in self-selected overground walking speed under BWS conditions of individuals poststroke can be explained by changes in their paretic and nonparetic ground reaction forces (GRF). We hypothesize that increased self-selected walking speed, recorded at some nominal level of BWS, will relate to decreased braking GRFs by the paretic limb. We recruited 10 chronic (>12 months post-ictus, 57.5±9.6 y.o.) individuals poststroke and eleven nonimpaired participants (53.3±4.1 y.o.). Participants walked overground in a robotic device, the KineAssist Walking and Balance Training System that provided varying degrees of BWS (0-20% in 5% increments) while individuals self-selected their walking speed. Self-selected walking speed and braking and propulsive GRF impulses were quantified. Out of 10 poststroke individuals, 8 increased their walking speed 13% (p=0.004) under some level of BWS (5% n=2, 10% n=3, 20% n=3) whereas nonimpaired controls did not change speed (p=0.470). In individuals poststroke, changes to self-selected walking speed were correlated with changes in paretic propulsive impulses (r=0.68, p=0.003) and nonparetic braking impulses (r=-0.80, p=0.006), but were not correlated with decreased paretic braking impulses (r=0.50 p=0.14). This investigation demonstrates that when individuals poststroke are provided with BWS and allowed to self-select their overground walking speed, they are capable of achieving faster speeds by modulating braking impulses on the nonparetic limb and propulsive impulses of the paretic limb. Copyright © 2015 Elsevier B.V. All rights reserved.

Autoregressive-moving-average hidden Markov model for vision-based fall prediction-An application for walker robot.

PubMed

Taghvaei, Sajjad; Jahanandish, Mohammad Hasan; Kosuge, Kazuhiro

2017-01-01

Population aging of the societies requires providing the elderly with safe and dependable assistive technologies in daily life activities. Improving the fall detection algorithms can play a major role in achieving this goal. This article proposes a real-time fall prediction algorithm based on the acquired visual data of a user with walking assistive system from a depth sensor. In the lack of a coupled dynamic model of the human and the assistive walker a hybrid "system identification-machine learning" approach is used. An autoregressive-moving-average (ARMA) model is fitted on the time-series walking data to forecast the upcoming states, and a hidden Markov model (HMM) based classifier is built on the top of the ARMA model to predict falling in the upcoming time frames. The performance of the algorithm is evaluated through experiments with four subjects including an experienced physiotherapist while using a walker robot in five different falling scenarios; namely, fall forward, fall down, fall back, fall left, and fall right. The algorithm successfully predicts the fall with a rate of 84.72%.

Approximate analytical solutions to the double-stance dynamics of the lossy spring-loaded inverted pendulum.

PubMed

Shahbazi, Mohammad; Saranlı, Uluç; Babuška, Robert; Lopes, Gabriel A D

2016-12-05

This paper introduces approximate time-domain solutions to the otherwise non-integrable double-stance dynamics of the 'bipedal' spring-loaded inverted pendulum (B-SLIP) in the presence of non-negligible damping. We first introduce an auxiliary system whose behavior under certain conditions is approximately equivalent to the B-SLIP in double-stance. Then, we derive approximate solutions to the dynamics of the new system following two different methods: (i) updated-momentum approach that can deal with both the lossy and lossless B-SLIP models, and (ii) perturbation-based approach following which we only derive a solution to the lossless case. The prediction performance of each method is characterized via a comprehensive numerical analysis. The derived representations are computationally very efficient compared to numerical integrations, and, hence, are suitable for online planning, increasing the autonomy of walking robots. Two application examples of walking gait control are presented. The proposed solutions can serve as instrumental tools in various fields such as control in legged robotics and human motion understanding in biomechanics.

ATHLETE's Feet: Mu1ti-Resolution Planning for a Hexapod Robot

NASA Technical Reports Server (NTRS)

Smith, Tristan B.; Barreiro, Javier; Smith, David E.; SunSpiral, Vytas; Chavez-Clemente, Daniel

2008-01-01

ATHLETE is a large six-legged tele-operated robot. Each foot is a wheel; travel can be achieved by walking, rolling, or some combination of the two. Operators control ATHLETE by selecting parameterized commands from a command dictionary. While rolling can be done efficiently with a single command, any motion involving steps is cumbersome - walking a few meters through difficult terrain can take hours. Our goal is to improve operator efficiency by automatically generating sequences of motion commands. There is increasing uncertainty regarding ATHLETE s actual configuration over time and decreasing quality of terrain data farther away from the current position. This, combined with the complexity that results from 36 degrees of kinematic freedom, led to an architecture that interleaves planning and execution at multiple levels, ranging from traditional configuration space motion planning algorithms for immediate moves to higher level task and path planning algorithms for overall travel. The modularity of the architecture also simplifies the development process and allows the operator to interact with and control the system at varying levels of autonomy depending on terrain and need.

Robot-assisted gait training versus treadmill training in patients with Parkinson's disease: a kinematic evaluation with gait profile score.

PubMed

Galli, M; Cimolin, V; De Pandis, M F; Le Pera, D; Sova, I; Albertini, G; Stocchi, F; Franceschini, M

2016-01-01

The purpose of this study was to quantitatively compare the effects, on walking performance, of end-effector robotic rehabilitation locomotor training versus intensive training with a treadmill in Parkinson's disease (PD). Fifty patients with PD were randomly divided into two groups: 25 were assigned to the robot-assisted therapy group (RG) and 25 to the intensive treadmill therapy group (IG). They were evaluated with clinical examination and 3D quantitative gait analysis [gait profile score (GPS) and its constituent gait variable scores (GVSs) were calculated from gait analysis data] at the beginning (T0) and at the end (T1) of the treatment. In the RG no differences were found in the GPS, but there were significant improvements in some GVSs (Pelvic Obl and Hip Ab-Add). The IG showed no statistically significant changes in either GPS or GVSs. The end-effector robotic rehabilitation locomotor training improved gait kinematics and seems to be effective for rehabilitation in patients with mild PD.

Hydrogel Walkers with Electro-Driven Motility for Cargo Transport.

PubMed

Yang, Chao; Wang, Wei; Yao, Chen; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

2015-08-28

In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two "legs" for walking. The hydrogel walkers can reversibly bend and stretch via repeated "on/off" electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers can move their two "legs" to achieve one-directional walking motion on a rough surface via repeated "on/off" electro-triggering cycles. Moreover, the hydrogel walkers loaded with very heavy cargo also exhibit excellent walking motion for cargo transport. Such hydrogel systems create new opportunities for developing electro-controlled soft systems with simple design/fabrication strategies in the soft robotic field for remote manipulation and transportation.

Conway Morris: Extraterrestrials: Aliens like us?

NASA Astrophysics Data System (ADS)

Morris, Simon Conway

2005-08-01

So what are they going to be like, those long-expected extraterrestrials? Hideous hydrocarbon arachnoids, waving laser cannons as they chase screaming humans, repulsively surveying the scene through empathy-free compound eyes? Or maybe laughing bipeds, chatting away, holding a glass of wine, a bit like us?

The newly expanded KSC Visitors Complex features a new ticket plaza, information center, exhibits an

NASA Technical Reports Server (NTRS)

1999-01-01

Part of the Robot Scouts exhibit in the $13 million expansion to KSC's Visitor Complex, this display offers a view of how data from robotic probes might be used to build a human habitat for Mars. Visitors witness a simulated Martian sunset. Other new additions include and information center, a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station- themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. The KSC Visitor Complex was inaugurated three decades ago and is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge.

Robotic complex for the development of thick steeply-inclined coal seams and ore deposits

NASA Astrophysics Data System (ADS)

Nikitenko, M. S.; Malakhov, Yu V.; Neogi, Biswarup; Chakraborty, Pritam; Banerjee, Dipesu

2017-09-01

Proposal for the formulation of robotic complexes for steeply inclined coal seams as a basis of the supportive-enclosing walking module and power support with a controlled outlet for mining industry has been represented in this literature. In mining industry, the available resource base reserves and mineral deposits are concentrated deep down the earth crust leading towards a complicated geological condition i.e. abrupt ore bedding and steeply inclined strata with the high gas content and fire hazard of thick coal stratum, heading against an unfavorable and sometimes human labor life risk during subversive mining. Prevailing towards the development of effective robotic complexes based on the means of “unmanned technologies” for extraction of minerals from hard-to-reach deposits and make sure the safety of underground staff during sublevel mining technology.

Locomotion control of hybrid cockroach robots

PubMed Central

Sanchez, Carlos J.; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M.; Vinson, S. Bradleigh; Liang, Hong

2015-01-01

Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%. PMID:25740855

CPG-inspired workspace trajectory generation and adaptive locomotion control for quadruped robots.

PubMed

Liu, Chengju; Chen, Qijun; Wang, Danwei

2011-06-01

This paper deals with the locomotion control of quadruped robots inspired by the biological concept of central pattern generator (CPG). A control architecture is proposed with a 3-D workspace trajectory generator and a motion engine. The workspace trajectory generator generates adaptive workspace trajectories based on CPGs, and the motion engine realizes joint motion imputes. The proposed architecture is able to generate adaptive workspace trajectories online by tuning the parameters of the CPG network to adapt to various terrains. With feedback information, a quadruped robot can walk through various terrains with adaptive joint control signals. A quadruped platform AIBO is used to validate the proposed locomotion control system. The experimental results confirm the effectiveness of the proposed control architecture. A comparison by experiments shows the superiority of the proposed method against the traditional CPG-joint-space control method.

Real-time physics-based 3D biped character animation using an inverted pendulum model.

PubMed

Tsai, Yao-Yang; Lin, Wen-Chieh; Cheng, Kuangyou B; Lee, Jehee; Lee, Tong-Yee

2010-01-01

We present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real time. Our approach utilizes an inverted pendulum model to online adjust the desired motion trajectory from the input motion capture data. This online adjustment produces a physically plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to track in dynamics simulation. Rather than using Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion tracking adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically correct full-body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that tracking motion capture data with real-time response animation can be achieved easily. In addition, physically plausible motion style editing, automatic motion transition, and motion adaptation to different limb sizes can also be generated without difficulty.

Method for six-legged robot stepping on obstacles by indirect force estimation

NASA Astrophysics Data System (ADS)

Xu, Yilin; Gao, Feng; Pan, Yang; Chai, Xun

2016-07-01

Adaptive gaits for legged robots often requires force sensors installed on foot-tips, however impact, temperature or humidity can affect or even damage those sensors. Efforts have been made to realize indirect force estimation on the legged robots using leg structures based on planar mechanisms. Robot Octopus III is a six-legged robot using spatial parallel mechanism(UP-2UPS) legs. This paper proposed a novel method to realize indirect force estimation on walking robot based on a spatial parallel mechanism. The direct kinematics model and the inverse kinematics model are established. The force Jacobian matrix is derived based on the kinematics model. Thus, the indirect force estimation model is established. Then, the relation between the output torques of the three motors installed on one leg to the external force exerted on the foot tip is described. Furthermore, an adaptive tripod static gait is designed. The robot alters its leg trajectory to step on obstacles by using the proposed adaptive gait. Both the indirect force estimation model and the adaptive gait are implemented and optimized in a real time control system. An experiment is carried out to validate the indirect force estimation model. The adaptive gait is tested in another experiment. Experiment results show that the robot can successfully step on a 0.2 m-high obstacle. This paper proposes a novel method to overcome obstacles for the six-legged robot using spatial parallel mechanism legs and to avoid installing the electric force sensors in harsh environment of the robot's foot tips.

STS-109 MS Grunsfeld and Linnehan stow old solar array from payload bay

NASA Image and Video Library

2002-03-04

STS109-E-5246 (4 March 2002) --- Astronaut John M. Grunsfeld (foreground), payload commander, is seen at one end of stowed solar panels in the cargo bay of the Space Shuttle Columbia while astronaut Richard M. Linnehan, mission specialist, uses the Remote Manipulator System's robotic arm to move around at the other end. The two, participating in the first of their assigned STS-109 space walks to perform work on the Hubble Space Telescope (HST), went on to replace the giant telescope’s starboard solar array. Their seven-hour space walk ended at 7:38 a.m. (CST) or 13:38 GMT March 4, 2002.

MS Currie at RMS controls on aft flight deck

NASA Image and Video Library

2002-03-07

STS109-E-5685 (7 March 2002) --- Astronaut Nancy J. Currie, mission specialist, works the controls for Columbia's Remote Manipulator System (RMS) on the crew cabin's aft flight deck. On a week with one lengthy space walk per day, Currie has had her hands full with RMS duties to support the space walks of four crewmates. Astronauts James H. Newman and Michael J. Massimino had just begin EVA-4, during which the duo required the services of Currie to control the robotic arm to maneuver them around the various workstations on the Hubble Space Telescope (HST). The image was recorded with a digital still camera.

MS Currie on aft flight deck with checklist

NASA Image and Video Library

2002-03-07

STS109-E-5681 (7 March 2002) --- Astronaut Nancy J. Currie, mission specialist, remains very near the controls (upper left) for Columbia's Remote Manipulator System (RMS). On a week with one lengthy space walk per day, Currie has had her hands full with RMS duties to support the space walks of four crewmates. A short time later on this day, astronauts James H. Newman and Michael J. Massimino began EVA-4 and the duo required the services of Currie to control the robotic arm to maneuver them around the various work stations on the Hubble Space Telescope (HST). The image was recorded with a digital still camera.

It's how you get there: walking down a virtual alley activates premotor and parietal areas.

PubMed

Wagner, Johanna; Solis-Escalante, Teodoro; Scherer, Reinhold; Neuper, Christa; Müller-Putz, Gernot

2014-01-01

Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE) feedback task on the EEG patterns during robot assisted walking. We compared walking in the VE modality to two control conditions: walking with a visual attention paradigm, in which visual stimuli were unrelated to the motor task; and walking with mirror feedback, in which participants observed their own movements. Eleven healthy participants were considered. Application of independent component analysis to the EEG revealed three independent component clusters in premotor and parietal areas showing increased activity during walking with the adaptive VE training paradigm compared to the control conditions. During the interactive VE walking task spectral power in frequency ranges 8-12, 15-20, and 23-40 Hz was significantly (p ≤ 0.05) decreased. This power decrease is interpreted as a correlate of an active cortical area. Furthermore activity in the premotor cortex revealed gait cycle related modulations significantly different (p ≤ 0.05) from baseline in the frequency range 23-40 Hz during walking. These modulations were significantly (p ≤ 0.05) reduced depending on gait cycle phases in the interactive VE walking task compared to the control conditions. We demonstrate that premotor and parietal areas show increased activity during walking with the adaptive VE training paradigm, when compared to walking with mirror- and movement unrelated feedback. Previous research has related a premotor-parietal network to motor planning and motor intention. We argue that movement related interactive feedback enhances motor planning and motor intention. We hypothesize that this might improve gait recovery during rehabilitation.

Restoration of gait for spinal cord injury patients using HAL with intention estimator for preferable swing speed.

PubMed

Tsukahara, Atsushi; Hasegawa, Yasuhisa; Eguchi, Kiyoshi; Sankai, Yoshiyuki

2015-03-01

This paper proposes a novel gait intention estimator for an exoskeleton-wearer who needs gait support owing to walking impairment. The gait intention estimator not only detects the intention related to the start of the swing leg based on the behavior of the center of ground reaction force (CoGRF), but also infers the swing speed depending on the walking velocity. The preliminary experiments categorized into two stages were performed on a mannequin equipped with the exoskeleton robot [Hybrid Assistive Limb: (HAL)] including the proposed estimator. The first experiment verified that the gait support system allowed the mannequin to walk properly and safely. In the second experiment, we confirmed the differences in gait characteristics attributed to the presence or absence of the proposed swing speed profile. As a feasibility study, we evaluated the walking capability of a severe spinal cord injury patient supported by the system during a 10-m walk test. The results showed that the system enabled the patient to accomplish a symmetrical walk from both spatial and temporal standpoints while adjusting the speed of the swing leg. Furthermore, the critical differences of gait between our system and a knee-ankle-foot orthosis were obtained from the CoGRF distribution and the walking time. Through the tests, we demonstrated the effectiveness and practical feasibility of the gait support algorithms.

Golden Gait: An Optimization Theory Perspective on Human and Humanoid Walking

PubMed Central

Iosa, Marco; Morone, Giovanni; Paolucci, Stefano

2017-01-01

Human walking is a complex task which includes hundreds of muscles, bones and joints working together to deliver harmonic movements with the need of finding equilibrium between moving forward and maintaining stability. Many different computational approaches have been used to explain human walking mechanisms, from pendular model to fractal approaches. A new perspective can be gained from using the principles developed in the field of Optimization theory and in particularly the branch of Game Theory. In particular we provide a new insight into human walking showing as the trade-off between advancement and equilibrium managed during walking has the same solution of the Ultimatum game, one of the most famous paradigms of game theory, and this solution is the golden ratio. The golden ratio is an irrational number that was found in many biological and natural systems self-organized in a harmonic, asymmetric, and fractal structure. Recently, the golden ratio has also been found as the equilibrium point between two players involved into the Ultimatum Game. It has been suggested that this result can be due to the fact that the golden ratio is perceived as the fairest asymmetric solution by the two players. The golden ratio is also the most common proportion between stance and swing phase of human walking. This approach may explain the importance of harmony in human walking, and provide new perspectives for developing quantitative assessment of human walking, efficient humanoid robotic walkers, and effective neurorobots for rehabilitation. PMID:29311890

The effectiveness of Robot-Assisted Gait Training versus conventional therapy on mobility in severely disabled progressIve MultiplE sclerosis patients (RAGTIME): study protocol for a randomized controlled trial.

PubMed

Straudi, Sofia; Manfredini, Fabio; Lamberti, Nicola; Zamboni, Paolo; Bernardi, Francesco; Marchetti, Giovanna; Pinton, Paolo; Bonora, Massimo; Secchiero, Paola; Tisato, Veronica; Volpato, Stefano; Basaglia, Nino

2017-02-27

Gait and mobility impairments affect the quality of life (QoL) of patients with progressive multiple sclerosis (MS). Robot-assisted gait training (RAGT) is an effective rehabilitative treatment but evidence of its superiority compared to other options is lacking. Furthermore, the response to rehabilitation is multidimensional, person-specific and possibly involves functional reorganization processes. The aims of this study are: (1) to test the effectiveness on gait speed, mobility, balance, fatigue and QoL of RAGT compared to conventional therapy (CT) in progressive MS and (2) to explore changes of clinical and circulating biomarkers of neural plasticity. This will be a parallel-group, randomized controlled trial design with the assessor blinded to the group allocation of participants. Ninety-eight (49 per arm) progressive MS patients (EDSS scale 6-7) will be randomly assigned to receive twelve 2-h training sessions over a 4-week period (three sessions/week) of either: (1) RAGT intervention on a robotic-driven gait orthosis (Lokomat, Hocoma, Switzerland). The training parameters (torque of the knee and hip drives, treadmill speed, body weight support) are set during the first session and progressively adjusted during training progression or (2) individual conventional physiotherapy focusing on over-ground walking training performed with the habitual walking device. The same assessors will perform outcome measurements at four time points: baseline (before the first intervention session); intermediate (after six training sessions); end of treatment (after the completion of 12 sessions); and follow-up (after 3 months from the end of the training program). The primary outcome is gait speed, assessed by the Timed 25-Foot Walk Test. We will also assess walking endurance, balance, depression, fatigue and QoL as well as instrumental laboratory markers (muscle metabolism, cerebral venous hemodynamics, cortical activation) and circulating laboratory markers (rare circulating cell populations pro and anti-inflammatory cytokines/chemokines, growth factors, neurotrophic factors, coagulation factors, other plasma proteins suggested by transcriptomic analysis and metabolic parameters). The RAGT training is expected to improve mobility compared to the active control intervention in progressive MS. Unique to this study is the analysis of various potential markers of plasticity in relation with clinical outcomes. ClinicalTrials.gov, identifier: NCT02421731 . Registered on 19 January 2015 (retrospectively registered).

Obstacle traversal and self-righting of bio-inspired robots reveal the physics of multi-modal locomotion

NASA Astrophysics Data System (ADS)

Li, Chen; Fearing, Ronald; Full, Robert

Most animals move in nature in a variety of locomotor modes. For example, to traverse obstacles like dense vegetation, cockroaches can climb over, push across, reorient their bodies to maneuver through slits, or even transition among these modes forming diverse locomotor pathways; if flipped over, they can also self-right using wings or legs to generate body pitch or roll. By contrast, most locomotion studies have focused on a single mode such as running, walking, or jumping, and robots are still far from capable of life-like, robust, multi-modal locomotion in the real world. Here, we present two recent studies using bio-inspired robots, together with new locomotion energy landscapes derived from locomotor-environment interaction physics, to begin to understand the physics of multi-modal locomotion. (1) Our experiment of a cockroach-inspired legged robot traversing grass-like beam obstacles reveals that, with a terradynamically ``streamlined'' rounded body like that of the insect, robot traversal becomes more probable by accessing locomotor pathways that overcome lower potential energy barriers. (2) Our experiment of a cockroach-inspired self-righting robot further suggests that body vibrations are crucial for exploring locomotion energy landscapes and reaching lower barrier pathways. Finally, we posit that our new framework of locomotion energy landscapes holds promise to better understand and predict multi-modal biological and robotic movement.

Continuous sweep versus discrete step protocols for studying effects of wearable robot assistance magnitude.

PubMed

Malcolm, Philippe; Rossi, Denise Martineli; Siviy, Christopher; Lee, Sangjun; Quinlivan, Brendan Thomas; Grimmer, Martin; Walsh, Conor J

2017-07-12

Different groups developed wearable robots for walking assistance, but there is still a need for methods to quickly tune actuation parameters for each robot and population or sometimes even for individual users. Protocols where parameters are held constant for multiple minutes have traditionally been used for evaluating responses to parameter changes such as metabolic rate or walking symmetry. However, these discrete protocols are time-consuming. Recently, protocols have been proposed where a parameter is changed in a continuous way. The aim of the present study was to compare effects of continuously varying assistance magnitude with a soft exosuit against discrete step conditions. Seven participants walked on a treadmill wearing a soft exosuit that assists plantarflexion and hip flexion. In Continuous-up, peak exosuit ankle moment linearly increased from approximately 0 to 38% of biological moment over 10 min. Continuous-down was the opposite. In Discrete, participants underwent five periods of 5 min with steady peak moment levels distributed over the same range as Continuous-up and Continuous-down. We calculated metabolic rate for the entire Continuous-up and Continuous-down conditions and the last 2 min of each Discrete force level. We compared kinematics, kinetics and metabolic rate between conditions by curve fitting versus peak moment. Reduction in metabolic rate compared to Powered-off was smaller in Continuous-up than in Continuous-down at most peak moment levels, due to physiological dynamics causing metabolic measurements in Continuous-up and Continuous-down to lag behind the values expected during steady-state testing. When evaluating the average slope of metabolic reduction over the entire peak moment range there was no significant difference between Continuous-down and Discrete. Attempting to correct the lag in metabolics by taking the average of Continuous-up and Continuous-down removed all significant differences versus Discrete. For kinematic and kinetic parameters, there were no differences between all conditions. The finding that there were no differences in biomechanical parameters between all conditions suggests that biomechanical parameters can be recorded with the shortest protocol condition (i.e. single Continuous directions). The shorter time and higher resolution data of continuous sweep protocols hold promise for the future study of human interaction with wearable robots.

A stability-based mechanism for hysteresis in the walk–trot transition in quadruped locomotion

PubMed Central

Aoi, Shinya; Katayama, Daiki; Fujiki, Soichiro; Tomita, Nozomi; Funato, Tetsuro; Yamashita, Tsuyoshi; Senda, Kei; Tsuchiya, Kazuo

2013-01-01

Quadrupeds vary their gaits in accordance with their locomotion speed. Such gait transitions exhibit hysteresis. However, the underlying mechanism for this hysteresis remains largely unclear. It has been suggested that gaits correspond to attractors in their dynamics and that gait transitions are non-equilibrium phase transitions that are accompanied by a loss in stability. In the present study, we used a robotic platform to investigate the dynamic stability of gaits and to clarify the hysteresis mechanism in the walk–trot transition of quadrupeds. Specifically, we used a quadruped robot as the body mechanical model and an oscillator network for the nervous system model to emulate dynamic locomotion of a quadruped. Experiments using this robot revealed that dynamic interactions among the robot mechanical system, the oscillator network, and the environment generate walk and trot gaits depending on the locomotion speed. In addition, a walk–trot transition that exhibited hysteresis was observed when the locomotion speed was changed. We evaluated the gait changes of the robot by measuring the locomotion of dogs. Furthermore, we investigated the stability structure during the gait transition of the robot by constructing a potential function from the return map of the relative phase of the legs and clarified the physical characteristics inherent to the gait transition in terms of the dynamics. PMID:23389894

Biologically inspired intelligent robots

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph; Breazeal, Cynthia

2003-07-01

Humans throughout history have always sought to mimic the appearance, mobility, functionality, intelligent operation, and thinking process of biological creatures. This field of biologically inspired technology, having the moniker biomimetics, has evolved from making static copies of human and animals in the form of statues to the emergence of robots that operate with realistic behavior. Imagine a person walking towards you where suddenly you notice something weird about him--he is not real but rather he is a robot. Your reaction would probably be "I can't believe it but this robot looks very real" just as you would react to an artificial flower that is a good imitation. You may even proceed and touch the robot to check if your assessment is correct but, as oppose to the flower case, the robot may be programmed to respond physical and verbally. This science fiction scenario could become a reality as the current trend continues in developing biologically inspired technologies. Technology evolution led to such fields as artificial muscles, artificial intelligence, and artificial vision as well as biomimetic capabilities in materials science, mechanics, electronics, computing science, information technology and many others. This paper will review the state of the art and challenges to biologically-inspired technologies and the role that EAP is expected to play as the technology evolves.

Optimal Design of Cable-Driven Manipulators Using Particle Swarm Optimization.

PubMed

Bryson, Joshua T; Jin, Xin; Agrawal, Sunil K

2016-08-01

The design of cable-driven manipulators is complicated by the unidirectional nature of the cables, which results in extra actuators and limited workspaces. Furthermore, the particular arrangement of the cables and the geometry of the robot pose have a significant effect on the cable tension required to effect a desired joint torque. For a sufficiently complex robot, the identification of a satisfactory cable architecture can be difficult and can result in multiply redundant actuators and performance limitations based on workspace size and cable tensions. This work leverages previous research into the workspace analysis of cable systems combined with stochastic optimization to develop a generalized methodology for designing optimized cable routings for a given robot and desired task. A cable-driven robot leg performing a walking-gait motion is used as a motivating example to illustrate the methodology application. The components of the methodology are described, and the process is applied to the example problem. An optimal cable routing is identified, which provides the necessary controllable workspace to perform the desired task and enables the robot to perform that task with minimal cable tensions. A robot leg is constructed according to this routing and used to validate the theoretical model and to demonstrate the effectiveness of the resulting cable architecture.

Practical Recommendations for Robot-Assisted Treadmill Therapy (Lokomat) in Children with Cerebral Palsy: Indications, Goal Setting, and Clinical Implementation within the WHO-ICF Framework.

PubMed

Aurich-Schuler, Tabea; Warken, Birgit; Graser, Judith V; Ulrich, Thilo; Borggraefe, Ingo; Heinen, Florian; Meyer-Heim, Andreas; van Hedel, Hubertus J A; Schroeder, A Sebastian

2015-08-01

Active participation and the highest level of independence during daily living are primary goals in neurorehabilitation. Therefore, standing and walking are key factors in many rehabilitation programs. Despite inconclusive evidence considering the best application and efficacy of robotic tools in the field of pediatric neurorehabilitation, robotic technologies have been implemented to complement conventional therapies in recent years. A group of experienced therapists and physicians joined in an "expert panel." They compared their clinical application protocols, discussed recurring open questions, and developed experience-based recommendations for robot-assisted treadmill therapy (exemplified by the Lokomat, Hocoma, Volketswil, Switzerland) with a focus on children with cerebral palsy. Specific indications and therapeutic goals were defined considering the severity of motor impairments and the International Classification of Functioning, Disability and Health framework (ICF). After five meetings, consensus was found and recommendations for the implementation of robot-assisted treadmill therapy including postsurgery rehabilitation were proposed. This article aims to provide a comprehensive overview on therapeutical applications in a fast developing field of medicine, where scientific evidence is still scarce. These recommendations can help physicians and therapists to plan the child's individual therapy protocol of robot-assisted treadmill therapy. Georg Thieme Verlag KG Stuttgart · New York.

Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

PubMed

Geva, Ronny; Orr, Edna

2016-01-01

Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9) for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p < .005), along with increases, counter to the general reduction trend, in skills that serve recruitment of external resources [socio-communication bids before speech (r = -.696, p < .01), and speech bids before walking; r = .729, p < .01)]. Integration of these proactive changes using a computational approach yielded an even stronger link, underscoring internal resource reallocation as a facilitator of walking initiation (r = .901, p<0.001). These preliminary data suggest that representational capacities, symbolic object use, language and social developments, form an integrated adaptable composite, which possibly enables proactive internal resource reallocation, designed to support the emergence of new developmental milestones, such as walking.

Novel locomotion via biological inspiration

NASA Astrophysics Data System (ADS)

Quinn, Roger D.; Boxerbaum, Alexander; Palmer, Luther; Chiel, Hillel; Diller, Eric; Hunt, Alexander; Bachmann, Richard

2011-05-01

Animal behavioral, physiological and neurobiological studies are providing a wealth of inspirational data for robot design and control. Several very different biologically inspired mobile robots will be reviewed. A robot called DIGbot is being developed that moves independent of the direction of gravity using Distributed Inward Gripping (DIG) as a rapid and robust attachment mechanism observed in climbing animals. DIGbot is an 18 degree of freedom hexapod with onboard power and control systems. Passive compliance in its feet, which is inspired by the flexible tarsus of the cockroach, increases the robustness of the adhesion strategy and enables DIGbot to execute large steps and stationary turns while walking on mesh screens. A Whegs™ robot, inspired by insect locomotion principles, is being developed that can be rapidly reconfigured between tracks and wheel-legs and carry GeoSystems Zipper Mast. The mechanisms that cause it to passively change its gait on irregular terrain have been integrated into its hubs for a compact and modular design. The robot is designed to move smoothly on moderately rugged terrain using its tracks and run on irregular terrain and stairs using its wheel-legs. We are also developing soft bodied robots that use peristalsis, the same method of locomotion earthworms use. We present a technique of using a braided mesh exterior to produce fluid waves of motion along the body of the robot that increase the robot's speed relative to previous designs. The concept is highly scalable, for endoscopes to water, oil or gas line inspection.

A novel device for studying weight supported, quadrupedal overground locomotion in spinal cord injured rats.

PubMed

Hamlin, Marvin; Traughber, Terence; Reinkensmeyer, David J; de Leon, Ray D

2015-05-15

Providing weight support facilitates locomotion in spinal cord injured animals. To control weight support, robotic systems have been developed for treadmill stepping and more recently for overground walking. We developed a novel device, the body weight supported ambulatory rodent trainer (i.e. BART). It has a small pneumatic cylinder that moves along a linear track above the rat. When air is supplied to the cylinder, the rats are lifted as they perform overground walking. We tested the BART device in rats that received a moderate spinal cord contusion injury and in normal rats. Locomotor training with the BART device was not performed. All of the rats learned to walk in the BART device. In the contused rats, significantly greater paw dragging and dorsal stepping occurred in the hindlimbs compared to normal. Providing weight support significantly raised hip position and significantly reduced locomotor deficits. Hindlimb stepping was tightly coupled to forelimb stepping but only when the contused rats stepped without weight support. Three weeks after the contused rats received a complete spinal cord transection, significantly fewer hindlimb steps were performed. Relative to rodent robotic systems, the BART device is a simpler system for studying overground locomotion. The BART device lacks sophisticated control and sensing capability, but it can be assembled relatively easily and cheaply. These findings suggest that the BART device is a useful tool for assessing quadrupedal, overground locomotion which is a more natural form of locomotion relative to treadmill locomotion. Published by Elsevier B.V.