Science.gov

Sample records for actuated parallel robot

  1. Design of a series elastic actuator for a compliant parallel wrist rehabilitation robot.

    PubMed

    Sergi, Fabrizio; Lee, Melissa M; O'Malley, Marcia K

    2013-06-01

    This paper presents the design of a novel linear series elastic actuator purposely designed to match the requirements of robots for wrist rehabilitation: backdriveability, intrinsic compliance, and capability to be controlled as ideal force/torque sources. An existing rehabilitation robot is adapted to include intrinsic compliance in the design. A novel linear compliant element is designed to meet dimensional and force/stiffness requirements; a force sensing scheme involving a Hall-effect sensor is optimized in FEM simulations and developed. Linearity tests of the compliant sensing element show a maximum of 4.5% of FSO combined nonlinearity and hysteresis errors. Characterization experiments show that the developed system introduces physical compliance, still guaranteeing accurate force control in a frequency range largely compatible with that required for wrist assistance during rehabilitation.

  2. Development of a 3D parallel mechanism robot arm with three vertical-axial pneumatic actuators combined with a stereo vision system.

    PubMed

    Chiang, Mao-Hsiung; Lin, Hao-Ting

    2011-01-01

    This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot's end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H(∞) tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to

  3. Parallel Robot for Lower Limb Rehabilitation Exercises

    PubMed Central

    Saadat, Mozafar; Borboni, Alberto

    2016-01-01

    The aim of this study is to investigate the capability of a 6-DoF parallel robot to perform various rehabilitation exercises. The foot trajectories of twenty healthy participants have been measured by a Vicon system during the performing of four different exercises. Based on the kinematics and dynamics of a parallel robot, a MATLAB program was developed in order to calculate the length of the actuators, the actuators' forces, workspace, and singularity locus of the robot during the performing of the exercises. The calculated length of the actuators and the actuators' forces were used by motion analysis in SolidWorks in order to simulate different foot trajectories by the CAD model of the robot. A physical parallel robot prototype was built in order to simulate and execute the foot trajectories of the participants. Kinect camera was used to track the motion of the leg's model placed on the robot. The results demonstrate the robot's capability to perform a full range of various rehabilitation exercises. PMID:27799727

  4. Parallel Robot for Lower Limb Rehabilitation Exercises.

    PubMed

    Rastegarpanah, Alireza; Saadat, Mozafar; Borboni, Alberto

    2016-01-01

    The aim of this study is to investigate the capability of a 6-DoF parallel robot to perform various rehabilitation exercises. The foot trajectories of twenty healthy participants have been measured by a Vicon system during the performing of four different exercises. Based on the kinematics and dynamics of a parallel robot, a MATLAB program was developed in order to calculate the length of the actuators, the actuators' forces, workspace, and singularity locus of the robot during the performing of the exercises. The calculated length of the actuators and the actuators' forces were used by motion analysis in SolidWorks in order to simulate different foot trajectories by the CAD model of the robot. A physical parallel robot prototype was built in order to simulate and execute the foot trajectories of the participants. Kinect camera was used to track the motion of the leg's model placed on the robot. The results demonstrate the robot's capability to perform a full range of various rehabilitation exercises.

  5. Bi-directional series-parallel elastic actuator and overlap of the actuation layers.

    PubMed

    Furnémont, Raphaël; Mathijssen, Glenn; Verstraten, Tom; Lefeber, Dirk; Vanderborght, Bram

    2016-01-27

    Several robotics applications require high torque-to-weight ratio and energy efficient actuators. Progress in that direction was made by introducing compliant elements into the actuation. A large variety of actuators were developed such as series elastic actuators (SEAs), variable stiffness actuators and parallel elastic actuators (PEAs). SEAs can reduce the peak power while PEAs can reduce the torque requirement on the motor. Nonetheless, these actuators still cannot meet performances close to humans. To combine both advantages, the series parallel elastic actuator (SPEA) was developed. The principle is inspired from biological muscles. Muscles are composed of motor units, placed in parallel, which are variably recruited as the required effort increases. This biological principle is exploited in the SPEA, where springs (layers), placed in parallel, can be recruited one by one. This recruitment is performed by an intermittent mechanism. This paper presents the development of a SPEA using the MACCEPA principle with a self-closing mechanism. This actuator can deliver a bi-directional output torque, variable stiffness and reduced friction. The load on the motor can also be reduced, leading to a lower power consumption. The variable recruitment of the parallel springs can also be tuned in order to further decrease the consumption of the actuator for a given task. First, an explanation of the concept and a brief description of the prior work done will be given. Next, the design and the model of one of the layers will be presented. The working principle of the full actuator will then be given. At the end of this paper, experiments showing the electric consumption of the actuator will display the advantage of the SPEA over an equivalent stiff actuator.

  6. Series Elastic Actuators for legged robots

    NASA Astrophysics Data System (ADS)

    Pratt, Jerry E.; Krupp, Benjamin T.

    2004-09-01

    Series Elastic Actuators provide many benefits in force control of robots in unconstrained environments. These benefits include high force fidelity, extremely low impedance, low friction, and good force control bandwidth. Series Elastic Actuators employ a novel mechanical design architecture which goes against the common machine design principal of "stiffer is better." A compliant element is placed between the gear train and driven load to intentionally reduce the stiffness of the actuator. A position sensor measures the deflection, and the force output is accurately calculated using Hooke"s Law (F=Kx). A control loop then servos the actuator to the desired output force. The resulting actuator has inherent shock tolerance, high force fidelity and extremely low impedance. These characteristics are desirable in many applications including legged robots, exoskeletons for human performance amplification, robotic arms, haptic interfaces, and adaptive suspensions. We describe several variations of Series Elastic Actuators that have been developed using both electric and hydraulic components.

  7. Serpentine Robot Arm Contains Electromagnetic Actuators

    NASA Technical Reports Server (NTRS)

    Moya, Israel A.; Studer, Philip A.

    1994-01-01

    Identical modules assembled into flexible robot arm configured in serpentlike fashion to manipulate objects while avoiding obstacles. Each module includes integral electromagnetic actuators energized selectively to produce variety of motions, stationary configurations, and combinations thereof.

  8. Parallel-coupled micro-macro actuators

    SciTech Connect

    Morrell, J.B.; Salisbury, J.K.

    1998-07-01

    This paper presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the parallel-coupled micro-macro actuator, or PaCMMA. In this system, the micro-actuator is capable of high-bandwidth force control owing to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft, and increases the dynamic range of force. Performance improvement over single-actuator systems was expected in force control, impedance control, force distortion, and transient impact force reduction. Several theoretical performance limits are derived from the saturation limits of the system. A control law is presented. A prototype test bed was built and an experimental comparison was performed between this actuator concept and two single-actuator systems. A set of quantitative measures is proposed and the actuator system is evaluated against them with the following results: force bandwidth of 56 Hz, torque dynamic range of 800:1, peak torque of 1,040 mNm, and minimum torque of 1.3 mNm. Peak impact force, force distortion, and back-driven impedance of the PaCMMA system are shown to be better than either of the single-actuator configurations considered.

  9. MRI-powered Actuators for Robotic Interventions

    PubMed Central

    Vartholomeos, Panagiotis; Qin, Lei; Dupont, Pierre E.

    2012-01-01

    This paper presents a novel actuation technology for robotically assisted MRI-guided interventional procedures. Compact and wireless, the actuators are both powered and controlled by the MRI scanner. The design concept and performance limits are described and derived analytically. Simulation and experiments in a clinical MR scanner are used to validate the analysis and to demonstrate the capability of the approach for needle biopsies. The concepts of actuator locking mechanisms and multi-axis control are also introduced. PMID:22287082

  10. Parallel Architecture For Robotics Computation

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Bejczy, Antal K.

    1990-01-01

    Universal Real-Time Robotic Controller and Simulator (URRCS) is highly parallel computing architecture for control and simulation of robot motion. Result of extensive algorithmic study of different kinematic and dynamic computational problems arising in control and simulation of robot motion. Study led to development of class of efficient parallel algorithms for these problems. Represents algorithmically specialized architecture, in sense capable of exploiting common properties of this class of parallel algorithms. System with both MIMD and SIMD capabilities. Regarded as processor attached to bus of external host processor, as part of bus memory.

  11. Nylon-muscle-actuated robotic finger

    NASA Astrophysics Data System (ADS)

    Wu, Lianjun; Jung de Andrade, Monica; Rome, Richard S.; Haines, Carter; Lima, Marcio D.; Baughman, Ray H.; Tadesse, Yonas

    2015-04-01

    This paper describes the design and experimental analysis of novel artificial muscles, made of twisted and coiled nylon fibers, for powering a biomimetic robotic hand. The design is based on circulating hot and cold water to actuate the artificial muscles and obtain fast finger movements. The actuation system consists of a spring and a coiled muscle within a compliant silicone tube. The silicone tube provides a watertight, expansible compartment within which the coiled muscle contracts when heated and expands when cooled. The fabrication and characterization of the actuating system are discussed in detail. The performance of the coiled muscle fiber in embedded conditions and the related characteristics of the actuated robotic finger are described.

  12. Soft Actuators for Small-Scale Robotics.

    PubMed

    Hines, Lindsey; Petersen, Kirstin; Lum, Guo Zhan; Sitti, Metin

    2017-04-01

    This review comprises a detailed survey of ongoing methodologies for soft actuators, highlighting approaches suitable for nanometer- to centimeter-scale robotic applications. Soft robots present a special design challenge in that their actuation and sensing mechanisms are often highly integrated with the robot body and overall functionality. When less than a centimeter, they belong to an even more special subcategory of robots or devices, in that they often lack on-board power, sensing, computation, and control. Soft, active materials are particularly well suited for this task, with a wide range of stimulants and a number of impressive examples, demonstrating large deformations, high motion complexities, and varied multifunctionality. Recent research includes both the development of new materials and composites, as well as novel implementations leveraging the unique properties of soft materials.

  13. 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.

  14. Experimental characterization of a binary actuated parallel manipulator

    NASA Astrophysics Data System (ADS)

    Giuseppe, Carbone

    2016-05-01

    This paper describes the BAPAMAN (Binary Actuated Parallel MANipulator) series of parallel manipulators that has been conceived at Laboratory of Robotics and Mechatronics (LARM). Basic common characteristics of BAPAMAN series are described. In particular, it is outlined the use of a reduced number of active degrees of freedom, the use of design solutions with flexural joints and Shape Memory Alloy (SMA) actuators for achieving miniaturization, cost reduction and easy operation features. Given the peculiarities of BAPAMAN architecture, specific experimental tests have been proposed and carried out with the aim to validate the proposed design and to evaluate the practical operation performance and the characteristics of a built prototype, in particular, in terms of operation and workspace characteristics.

  15. Robotic insects: Manufacturing, actuation, and power considerations

    NASA Astrophysics Data System (ADS)

    Wood, Robert

    2015-12-01

    As the characteristic size of a flying robot decreases, the challenges for successful flight revert to basic questions of fabrication, actuation, fluid mechanics, stabilization, and power - whereas such questions have in general been answered for larger aircraft. When developing a robot on the scale of a housefly, all hardware must be developed from scratch as there is nothing "off-the-shelf" which can be used for mechanisms, sensors, or computation that would satisfy the extreme mass and power limitations. With these challenges in mind, this talk will present progress in the essential technologies for insect-like robots with an emphasis on multi-scale manufacturing methods, high power density actuation, and energy-efficient power distribution.

  16. Pneumatic artificial muscle actuators for compliant robotic manipulators

    NASA Astrophysics Data System (ADS)

    Robinson, Ryan Michael

    Robotic systems are increasingly being utilized in applications that require interaction with humans. In order to enable safe physical human-robot interaction, light weight and compliant manipulation are desirable. These requirements are problematic for many conventional actuation systems, which are often heavy, and typically use high stiffness to achieve high performance, leading to large impact forces upon collision. However, pneumatic artificial muscles (PAMs) are actuators that can satisfy these safety requirements while offering power-to-weight ratios comparable to those of conventional actuators. PAMs are extremely lightweight actuators that produce force in response to pressurization. These muscles demonstrate natural compliance, but have a nonlinear force-contraction profile that complicates modeling and control. This body of research presents solutions to the challenges associated with the implementation of PAMs as actuators in robotic manipulators, particularly with regard to modeling, design, and control. An existing PAM force balance model was modified to incorporate elliptic end geometry and a hyper-elastic constitutive relationship, dramatically improving predictions of PAM behavior at high contraction. Utilizing this improved model, two proof-of-concept PAM-driven manipulators were designed and constructed; design features included parallel placement of actuators and a tendon-link joint design. Genetic algorithm search heuristics were employed to determine an optimal joint geometry; allowing a manipulator to achieve a desired torque profile while minimizing the required PAM pressure. Performance of the manipulators was evaluated in both simulation and experiment employing various linear and nonlinear control strategies. These included output feedback techniques, such as proportional-integral-derivative (PID) and fuzzy logic, a model-based control for computed torque, and more advanced controllers, such as sliding mode, adaptive sliding mode, and

  17. Dynamic stiffness model of spherical parallel robots

    NASA Astrophysics Data System (ADS)

    Cammarata, Alessandro; Caliò, Ivo; D`Urso, Domenico; Greco, Annalisa; Lacagnina, Michele; Fichera, Gabriele

    2016-12-01

    A novel approach to study the elastodynamics of Spherical Parallel Robots is described through an exact dynamic model. Timoshenko arches are used to simulate flexible curved links while the base and mobile platforms are modelled as rigid bodies. Spatial joints are inherently included into the model without Lagrangian multipliers. At first, the equivalent dynamic stiffness matrix of each leg, made up of curved links joined by spatial joints, is derived; then these matrices are assembled to obtain the Global Dynamic Stiffness Matrix of the robot at a given pose. Actuator stiffness is also included into the model to verify its influence on vibrations and modes. The latter are found by applying the Wittrick-Williams algorithm. Finally, numerical simulations and direct comparison to commercial FE results are used to validate the proposed model.

  18. 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.

  19. Low-Stroke Actuation for a Serial Robot

    NASA Technical Reports Server (NTRS)

    Gao, Dalong (Inventor); Ihrke, Chris A. (Inventor)

    2014-01-01

    A serial robot includes a base, first and second segments, a proximal joint joining the base to the first segment, and a distal joint. The distal joint that joins the segments is serially arranged and distal with respect to the proximal joint. The robot includes first and second actuators. A first tendon extends from the first actuator to the proximal joint and is selectively moveable via the first actuator. A second tendon extends from the second actuator to the distal joint and is selectively moveable via the second actuator. The robot includes a transmission having at least one gear element which assists rotation of the distal joint when an input force is applied to the proximal and/or distal joints by the first and/or second actuators. A robotic hand having the above robot is also disclosed, as is a robotic system having a torso, arm, and the above-described hand.

  20. Pneumatic squirming robot based on flexible pneumatic actuator

    NASA Astrophysics Data System (ADS)

    Yang, Qinghua; Zhang, Libin; Bao, Guanjun; Ruan, Jian

    2005-12-01

    The design of a kind of pneumatic squirming robot is presented. It is based on the use of flexible pneumatic actuator. The flexible pneumatic actuator was made of caoutchouc. Its working principle is described. The structure, working principle, pneumatic and electrical control system of the pneumatic squirming robot are designed. All of the actuator's driving and squirming parts are composed of pneumatic elements. The vacuum osculums, which act as feet, are connected to the flexible pneumatic actuator. When the vacuum pumps operate, vacuum will be produced in the corresponding osculums, which can adsorb on the contacting surface and orient the robot. The actuator, operating under air pressure, drives the robot. By controlling the vacuum pumps and the actuator, straight and bending squirming of this robot can be obtained.

  1. Cruise and turning performance of an improved fish robot actuated by piezoceramic actuators

    NASA Astrophysics Data System (ADS)

    Nguyen, Quang Sang; Heo, Seok; Park, Hoon Cheol; Goo, Nam Seo; Byun, Doyoung

    2009-03-01

    The purpose of this study is improvement of a fish robot actuated by four light-weight piezocomposite actuators (LIPCAs). In the fish robot, we developed a new actuation mechanism working without any gear and thus the actuation mechanism was simple in fabrication. By using the new actuation mechanism, cross section of the fish robot became 30% smaller than that of the previous model. Performance tests of the fish robot in water were carried out to measure tail-beat angle, thrust force, swimming speed and turning radius for tail-beat frequencies from 1Hz to 5Hz. The maximum swimming speed of the fish robot was 7.7 cm/s at 3.9Hz tail-beat frequency. Turning experiment showed that swimming direction of the fish robot could be controlled with 0.41 m turning radius by controlling tail-beat angle.

  2. Bionic robot arm with compliant actuators

    NASA Astrophysics Data System (ADS)

    Moehl, Bernhard

    2000-10-01

    Traditional robotics uses non-compliant materials for all components involved in the production of movement. Elasticity is avoided as far as possible, because it leads to hazardous oscillations and makes control of precise movements very difficult. Due to this deliberate stiffness, robots are typically heavy and clumsy structures in comparison to their living counterparts (i.e. man and animals). Yet, moving systems in nature cope not only with the difficulties introduced by compliant materials, they also take advantage of the elasticity in muscles and tendons to produce smooth and even rapid movements. It is understood, that elasticity in a multi-jointed moving system requires sophisticated control mechanisms- as provided by a nervous system or a suitably programmed computer. In this contribution I shall describe a two-jointed robot with purpose-built elasticity in its actuators. This is accomplished by spiral springs places in series with a conventional electric motor and a tendon to the arm. It is shown that, with sufficiently soft elasticity, oscillations can be avoided by active oscillation damping. (Such active oscillation damping presumably also governs movement control in man and animals.) Furthermore, once the major problem has been overcome, elasticity is found to offer a wide spectrum of valuable advantages, as far as the most serious problems in traditional robotics are concerned. They are summarized by terms such as less dangerous, position tolerant, lightweight construction, controlled forces, and ballistic movements. These will be explained in detail and presented for discussion.

  3. 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.

  4. A soft creeping robot actuated by dielectric elastomer

    NASA Astrophysics Data System (ADS)

    Zhao, Jianwen; Niu, Junyang; Liu, Liwu; Yu, Jiangcheng

    2014-03-01

    Dielectric elastomer actuator showed significant advantages at high energy density, large deformation with comparing to other artificial muscle. The robot actuated by dielectric elastomer will be more lightweight and have lower cost, which shows great potential in field of future planetary exploration based on a group of micro-robot. In this context, a quite simple structure for creeping was designed to make the robot more lightweight. The actuation unit of the robot is made of an ellipse frame which can expand and contract with membrane under electric field. After joining four actuation units, the robot can move forward in a cooperative manner. Fabrication and some preliminary experiments of the robot were presented and the proposed motion principle was demonstrated.

  5. Performance evaluation of an improved fish robot actuated by piezoceramic actuators

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. S.; Heo, S.; Park, H. C.; Byun, D.

    2010-03-01

    This paper presents an improved fish robot actuated by four lightweight piezocomposite actuators. Our newly developed actuation mechanism is simple to fabricate because it works without gears. With the new actuation mechanism, the fish robot has a 30% smaller cross section than our previous model. Performance tests of the fish robot in water were carried out to measure the tail-beat angle, the thrust force, the swimming speed for various tail-beat frequencies from 1 to 5 Hz and the turning radius at the optimal frequency. The maximum swimming speed of the fish robot is 7.7 cm s - 1 at a tail-beat frequency of 3.9 Hz. A turning experiment shows that the swimming direction of the fish robot can be controlled by changing the duty ratio of the driving voltage; the fish robot has a turning radius of 0.41 m for a left turn and 0.68 m for a right turn.

  6. Electroactive Polymer (EAP) Actuators for Future Humanlike Robots

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph

    2009-01-01

    Human-like robots are increasingly becoming an engineering reality thanks to recent technology advances. These robots, which are inspired greatly by science fiction, were originated from the desire to reproduce the human appearance, functions and intelligence and they may become our household appliance or even companion. The development of such robots is greatly supported by emerging biologically inspired technologies. Potentially, electroactive polymer (EAP) materials are offering actuation capabilities that allow emulating the action of our natural muscles for making such machines perform lifelike. There are many technical issues related to making such robots including the need for EAP materials that can operate as effective actuators. Beside the technology challenges these robots also raise concerns that need to be addressed prior to forming super capable robots. These include the need to prevent accidents, deliberate harm, or their use in crimes. In this paper, the potential EAP actuators and the challenges that these robots may pose will be reviewed.

  7. Development of soft robots using dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Godaba, Hareesh; Wang, Yuzhe; Cao, Jiawei; Zhu, Jian

    2016-04-01

    Soft robots are gaining in popularity due to their unique attributes such as low weight, compliance, flexibility and diverse range in motion types. This paper illustrates soft robots and actuators which are developed using dielectric elastomer. These developments include a jellyfish robot, a worm like robot and artificial muscle actuators for jaw movement in a robotic skull. The jellyfish robot which employs a bulged dielectric elastomer membrane has been demonstrated too generate thrust and buoyant forces and can move effectively in water. The artificial muscle for jaw movement employs a pure shear configuration and has been shown to closely mimic the jaw motion while chewing or singing a song. Thee inchworm robot, powered by dielectric elastomer actuator can demonstrate stable movement in one-direction.

  8. A small and fast piezo-actuated legged robot

    NASA Astrophysics Data System (ADS)

    Yumaryanto, Abdul A.; An, Jaebum; Lee, Sangyoon

    2007-04-01

    In this paper we present the development of a small and fast LIPCA-actuated mobile robot. LIPCA (Lightweight Piezoceramic Composite curved Actuator) is a piezo-composite actuator that uses a PZT layer sandwiched between composite materials of carbon/epoxy and glass/epoxy layers to amplify the displacement. Three versions of LIPCA robots have been developed thus far to implement a small and autonomous robot. The design of the first prototype was inspired by a six-legged insect like a cockroach. Its maximum speed is 173 mm/sec with the voltage input of 400 Vpp at 40 Hz frequency. As the result of a slight modification in the design, a faster LIPCA robot was developed. However their structures are not strong enough to carry a load heavier than 20 gram, which can be a major obstacle to implementing autonomous robots. By several changes in the mechanism, the LIPCA-actuated robot has been improved such that it is able to carry a weight as much as 60 gram. For all the prototypes we used two LIPCA strips that are placed oppositely in the middle of the robot body. The LIPCA strips are driven by a square signal function of high AC voltage with the phase difference of 180°. All the experimental results show a possibility of a small and fast walking robot actuated by LIPCA without using any conventional electromagnetic actuator.

  9. A MODULAR ACTUATOR ARCHITECTURE FOR ROBOTIC APPLICATIONS

    SciTech Connect

    2001-07-01

    .'s (ARM) modular robotic manipulator technology developed for DOE EM operations, which addresses many of the issues discussed in the previous section. This manipulator system has the capability of custom configurations, which accommodate common glovebox tasks such as materials repackaging. The modular nature and quick connects of this system simplify installations into ''hot'' boxes and any potential modifications or repair therein. In the field of automation and robotics, a very common element is one used to generate motion for precise positioning of loads. One example of such an automation component would be an individual joint within an industrial robotic manipulator. This component consists of a tightly integrated package containing an electric motor, gear train, output support bearings, position sensors, brake, servo-amplifier and communications controller. Within the context of this paper, this key building block is referred to as an actuator module. With regard to the needs of the EM, [8] and [9] have shown that while each focus area has unique requirements for robotic automation at a system or manipulator level, their requirements at the actuator level are very similar. Thereby, a modular approach to automation which utilizes a small set of versatile actuator modules can be used to construct a broad range of robotic systems and automation cells suited to EM applications. By providing a pre-engineered, pre-integrated motion system to different robotics users within the DOE, new automation systems can be more quickly created without extensive expertise in motion control or the expense of building custom equipment.

  10. Three d.o.f. Robotic Wrist Actuator Redesign

    NASA Technical Reports Server (NTRS)

    Bonner, Tom; Tamasi, Gabor

    1997-01-01

    This paper describes the efforts to redesign, fabricate, assemble and test the wrist actuators on the Automated Tile Processing System (ATPS). The ATPS is a robotic system being developed at Kennedy Space Center to inspect and rewaterproof thermal protection tiles on the space shuttle orbiter prior to launch. The objective of the redesign was to eliminate backlash and provide adequate pitch and yaw actuator force. The wrist actuators have been successfully redesigned, fabricated, tested, and installed. The redesigned wrist actuators meet or exceed all design requirements. The wrist has been reinstalled on the tile processing robot and will be further evaluated during operational testing of the system.

  11. Computed torque control of an under-actuated service robot platform modeled by natural coordinates

    NASA Astrophysics Data System (ADS)

    Zelei, Ambrus; Kovács, László L.; Stépán, Gábor

    2011-05-01

    The paper investigates the motion planning of a suspended service robot platform equipped with ducted fan actuators. The platform consists of an RRT robot and a cable suspended swinging actuator that form a subsequent parallel kinematic chain and it is equipped with ducted fan actuators. In spite of the complementary ducted fan actuators, the system is under-actuated. The method of computed torques is applied to control the motion of the robot. The under-actuated systems have less control inputs than degrees of freedom. We assume that the investigated under-actuated system has desired outputs of the same number as inputs. In spite of the fact that the inverse dynamical calculation leads to the solution of a system of differential-algebraic equations (DAE), the desired control inputs can be determined uniquely by the method of computed torques. We use natural (Cartesian) coordinates to describe the configuration of the robot, while a set of algebraic equations represents the geometric constraints. In this modeling approach the mathematical model of the dynamical system itself is also a DAE. The paper discusses the inverse dynamics problem of the complex hybrid robotic system. The results include the desired actuator forces as well as the nominal coordinates corresponding to the desired motion of the carried payload. The method of computed torque control with a PD controller is applied to under-actuated systems described by natural coordinates, while the inverse dynamics is solved via the backward Euler discretization of the DAE system for which a general formalism is proposed. The results are compared with the closed form results obtained by simplified models of the system. Numerical simulation and experiments demonstrate the applicability of the presented concepts.

  12. Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics.

    PubMed

    Pourghodrat, Abolfazl; Nelson, Carl A

    2017-03-01

    Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electric-motor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the in-vivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications.

  13. A Parallel Wire Robot for Epicardial Interventions

    PubMed Central

    Costanza, Adam D.; Wood, Nathan A.; Passineau, Michael J.; Moraca, Robert J.; Bailey, Stephen H.; Yoshizumi, Tomo; Riviere, Cameron N.

    2015-01-01

    This paper describes the design and preliminary testing of a planar parallel wire robot that adheres to the surface of the beating heart and provides a stable platform for minimally invasive epicardial therapies. The device is deployed through a small subxiphoid skin incision and attaches to the heart using suction. This methodology obviates mechanical stabilization and lung deflation, which are typically required during minimally invasive beating-heart surgery. The prototype design involves three vacuum chambers connected by two flexible arms. The chambers adhere to the epicardium, forming the vertices of a triangular base structure. Three cables connect a movable end-effector head to the three bases; the cables then pass out of the body to external actuators. The surgical tool moves within the triangular workspace to perform injections, ablation, or other tasks on the beating heart. Tests in vitro and in vivo were conducted to demonstrate the capabilities of the system. Tests in vivo successfully demonstrated the ability to deploy through a subxiphoid incision, adhere to the surface of the beating heart, move the surgical tool head within the robot’s workspace, and perform injections into the myocardium. PMID:25571402

  14. Progress toward EAP actuators for biomimetic social robots

    NASA Astrophysics Data System (ADS)

    Hanson, D.

    2013-04-01

    Social robotics and artificial intelligence have progressed steadily in recent years, appearing in a variety of useful applications and products as well as breakthrough research. However, limitations in conventional motors continue to limit the possibilities of bio-inspired robotics. Such motors are needed for locomotion, grasping and manipulation, and social expressions and gestures. EAP actuators, being more like biological muscle in key regards, could revolutionize the hardware for such robots, if made robust, powerful, and manufacturable at reasonable prices. The author presents a survey of the progress and opportunities for EAP actuators in these fields, and discusses the latest work of his team in developing and manufacturing social robots that could benefit from EAP actuators.

  15. Design and demonstration of a fish robot actuated by a SMA-driven actuation system

    NASA Astrophysics Data System (ADS)

    Le, Chan H.; Nguyen, Quang S.; Park, Hoon C.

    2010-04-01

    This paper presents a concept of a fish robot actuated by an SMA-based actuator. The bending-type actuator system is composed of a 0.1mm diameter SMA wire and a 0.5mm thick glass/epoxy strip. The SMA wire is installed to the bent composite strip. The actuator can produce about 200gf of blocking force and 3.5mm displacement at the center of the glass/epoxy strip. The bending motion of the actuator is converted into the tail-beat motion of a fish robot through a linkage system. The fish robot is evaluated by measuring the tail-beat angle, swimming speed and thrust produced by the fish robot. The tail-beat angle is about 20° and the maximum swimming speed is about 1.6cm/s. The measured thrust is about 0.4gf when the fish robot is operated at 0.9Hz.

  16. 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.

  17. Actuation redundancy in a closed-chain robot mechanism

    NASA Astrophysics Data System (ADS)

    Ropponen, Timo

    1993-03-01

    A method that solves the control of actuation redundancy in a closed chain robot manipulator is presented and verified by experiments and simulations. A closed chain direct drive robot with actuation redundancy is designed and constructed for the experiments. The control scheme of the actuation redundancy is implemented for the direct drive robot. The characteristics of two model based control methods, feedforward control and computed torque control, are evaluated and compared. The experiments verify that the proposed control scheme performs successfully and no algorithmic singularity is found. In dynamic load cases, the advantage achieved by the chosen redundant motor is not significant. However, in the stationary load case, the simulation indicates that the redundant actuator increases the maximum end point forces. The low net effect in dynamic motions is a consequence of the increased inertia induced by the redundant motor, and the low torque-weight ratio of the additional motor. To improve the effect of the redundant actuator, its location should be optimized in order to decrease the inertia torque. Also, a more efficient torque weight ratio of the motor would improve the redundant performance. The results show that the computed torque control is capable of greater and prompter position tracking than feedforward control. Similarly, the positioning accuracy in steady state is more precise for computed torque. The experiments verify that the new redundant actuation control distributes the joint torques correctly in real time. The study indicates that actuation redundancy benefits most in stationary situations, where large exerting end point forces are needed. This implies that the actuation redundancy offers potential for force control applications.

  18. Bio-inspired annelid robot: a dielectric elastomer actuated soft robot.

    PubMed

    Xu, Liang; Chen, Han-Qing; Zou, Jiang; Dong, Wan-Ting; Gu, Guo-Ying; Zhu, Li-Min; Zhu, Xiang-Yang

    2017-01-31

    Biologically inspired robots with inherent softness and body compliance increasingly attract attention in the field of robotics. Aimed at solving existing problems with soft robots, regarding actuation technology and biological principles, this paper presents a soft bio-inspired annelid robot driven by dielectric elastomer actuators (DEAs) that can advance on flat rigid surfaces. The DEA, a kind of soft functional actuator, is designed and fabricated to mimic the axial elongation and differential friction of a single annelid body segment. Several (at least three) DEAs are connected together into a movable multi-segment robot. Bristles are attached at the bottom of some DEAs to achieve differential friction for imitating the setae of annelids. The annelid robot is controlled by periodic square waves, propagating from the posterior to the anterior, which imitate the peristaltic waves of annelids. Controlled by these waves, each DEA, one-by-one from tail to head, anchors to the ground by circumferential distention and pushes the front DEAs forward by axial elongation, enabling the robot to advance. Preliminary tests demonstrate that a 3-segment robot can reach an average speed of 5.3 mm s(-1) (1.871 body lengths min(-1)) on flat rigid surfaces and can functionally mimic the locomotion of annelids. Compared to the existing robots that imitate terrestrial annelids our annelid robot shows advantages in terms of speed and bionics.

  19. Development of a novel soft parallel robot equipped with polymeric artificial muscles

    NASA Astrophysics Data System (ADS)

    Amiri Moghadam, Amir Ali; Kouzani, Abbas; Torabi, Keivan; Kaynak, Akif; Shahinpoor, Mohsen

    2015-03-01

    This paper presents the design, analysis and fabrication of a novel low-cost soft parallel robot for biomedical applications, including bio-micromanipulation devices. The robot consists of two active flexible polymer actuator-based links, which are connected to two rigid links by means of flexible joints. A mathematical model is established between the input voltage to the polymer actuators and the robot’s end effector position. The robot has two degrees-of-freedom, making it suitable for handling planar micromanipulation tasks. Moreover, a number of robots can be configured to operate in a cooperative manner for increasing micromanipulation dexterity. Finally, the experimental results demonstrate two main motion modes of the robot.

  20. Sonic Actuation of Small-Scale Robots in a Fluidic Environment

    DTIC Science & Technology

    2014-05-09

    DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Sonic Actuation of Small-Scale Robots in a Fluidic...based actuation methods but this project focusses on an alternative method of actuation in which acoustic waves would excite the robot structure to...resonance, thus propelling and steering the robot . The actuation focuses on the development of a double-jointed, flagella-like, flapper designed for non

  1. Bio-inspired aquatic robotics by untethered piezohydroelastic actuation.

    PubMed

    Cen, L; Erturk, A

    2013-03-01

    This paper investigates fish-like aquatic robotics using flexible bimorphs made of macro-fiber composite (MFC) piezoelectric laminates for carangiform locomotion. In addition to noiseless and efficient actuation over a range of frequencies, geometric scalability, and simple design, bimorph propulsors made of MFCs offer a balance between the actuation force and velocity response for performance enhancement in bio-inspired swimming. The experimental component of the presented work focuses on the characterization of an elastically constrained MFC bimorph propulsor for thrust generation in quiescent water as well as the development of a robotic fish prototype combining a microcontroller and a printed-circuit-board amplifier to generate high actuation voltage for untethered locomotion. From the theoretical standpoint, a distributed-parameter electroelastic model including the hydrodynamic effects and actuator dynamics is coupled with the elongated-body theory for predicting the mean thrust in quiescent water. In-air and underwater experiments are performed to verify the incorporation of hydrodynamic effects in the linear actuation regime. For electroelastically nonlinear actuation levels, experimentally obtained underwater vibration response is coupled with the elongated-body theory to predict the thrust output. The measured mean thrust levels in quiescent water (on the order of ∼10 mN) compare favorably with thrust levels of biological fish. An untethered robotic fish prototype that employs a single bimorph fin (caudal fin) for straight swimming and turning motions is developed and tested in free locomotion. A swimming speed of 0.3 body-length/second (7.5 cm s⁻¹ swimming speed for 24.3 cm body length) is achieved at 5 Hz for a non-optimized main body-propulsor bimorph combination under a moderate actuation voltage level.

  2. Multi-objective optimization of a parallel ankle rehabilitation robot using modified differential evolution algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Congzhe; Fang, Yuefa; Guo, Sheng

    2015-07-01

    Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution(DE) algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.

  3. An Intelligent Actuator Fault Reconstruction Scheme for Robotic Manipulators.

    PubMed

    Xiao, Bing; Yin, Shen

    2017-01-16

    This paper investigates a difficult problem of reconstructing actuator faults for robotic manipulators. An intelligent approach with fast reconstruction property is developed. This is achieved by using observer technique. This scheme is capable of precisely reconstructing the actual actuator fault. It is shown by Lyapunov stability analysis that the reconstruction error can converge to zero after finite time. A perfect reconstruction performance including precise and fast properties can be provided for actuator fault. The most important feature of the scheme is that, it does not depend on control law, dynamic model of actuator, faults' type, and also their time-profile. This super reconstruction performance and capability of the proposed approach are further validated by simulation and experimental results.

  4. Parallel kinematic mechanisms for distributed actuation of future structures

    NASA Astrophysics Data System (ADS)

    Lai, G.; Plummer, A. R.; Cleaver, D. J.; Zhou, H.

    2016-09-01

    Future machines will require distributed actuation integrated with load-bearing structures, so that they are lighter, move faster, use less energy, and are more adaptable. Good examples are shape-changing aircraft wings which can adapt precisely to the ideal aerodynamic form for current flying conditions, and light but powerful robotic manipulators which can interact safely with human co-workers. A 'tensegrity structure' is a good candidate for this application due to its potentially excellent stiffness and strength-to-weight ratio and a multi-element structure into which actuators could be embedded. This paper presents results of an analysis of an example practical actuated tensegrity structure consisting of 3 ‘unit cells’. A numerical method is used to determine the stability of the structure with varying actuator length, showing how four actuators can be used to control movement in three degrees of freedom as well as simultaneously maintaining the structural pre-load. An experimental prototype has been built, in which 4 pneumatic artificial muscles (PAMs) are embedded in one unit cell. The PAMs are controlled antagonistically, by high speed switching of on-off valves, to achieve control of position and structure pre-load. Experimental and simulation results are presented, and future prospects for the approach are discussed.

  5. Multi-imager compatible actuation principles in surgical robotics

    PubMed Central

    Stoianovici, D

    2011-01-01

    Today’s most successful surgical robots are perhaps surgeon-driven systems, such as the daVinci (Intuitive Surgical Inc., USA, www.intuitivesurgical.com). These have already enabled surgery that was unattainable with classic instrumentation; however, at their present level of development, they have limited utility. The drawback of these systems is that they are independent self-contained units, and as such, they do not directly take advantage of patient data. The potential of these new surgical tools lies much further ahead. Integration with medical imaging and information are needed for these devices to achieve their true potential. Surgical robots and especially their subclass of image-guided systems require special design, construction and control compared to industrial types, due to the special requirements of the medical and imaging environments. Imager compatibility raises significant engineering challenges for the development of robotic manipulators with respect to imager access, safety, ergonomics, and above all the non-interference with the functionality of the imager. These apply to all known medical imaging types, but are especially challenging for achieving compatibility with the class of MRI systems. Even though a large majority of robotic components may be redesigned to be constructed of MRI compatible materials, for other components such as the motors used in actuation, prescribing MRI compatible materials alone is not sufficient. The electromagnetic motors most commonly used in robotic actuation, for example, are incompatible by principle. As such, alternate actuation principles using “intervention friendly” energy should be adopted and/or devised for these special surgical and radiological interventions. This paper defines the new concept of Multi-imager Compatibility of surgical manipulators and describes its requirements. Subsequently, the paper gives several recommendations and proposes new actuation principles for this concept. Several

  6. Multi-imager compatible actuation principles in surgical robotics.

    PubMed

    Stoianovici, D

    2005-01-01

    Today's most successful surgical robots are perhaps surgeon-driven systems, such as the daVinci (Intuitive Surgical Inc., USA, www.intuitivesurgical.com). These have already enabled surgery that was unattainable with classic instrumentation; however, at their present level of development, they have limited utility. The drawback of these systems is that they are independent self-contained units, and as such, they do not directly take advantage of patient data. The potential of these new surgical tools lies much further ahead. Integration with medical imaging and information are needed for these devices to achieve their true potential. Surgical robots and especially their subclass of image-guided systems require special design, construction and control compared to industrial types, due to the special requirements of the medical and imaging environments. Imager compatibility raises significant engineering challenges for the development of robotic manipulators with respect to imager access, safety, ergonomics, and above all the non-interference with the functionality of the imager. These apply to all known medical imaging types, but are especially challenging for achieving compatibility with the class of MRI systems. Even though a large majority of robotic components may be redesigned to be constructed of MRI compatible materials, for other components such as the motors used in actuation, prescribing MRI compatible materials alone is not sufficient. The electromagnetic motors most commonly used in robotic actuation, for example, are incompatible by principle. As such, alternate actuation principles using "intervention friendly" energy should be adopted and/or devised for these special surgical and radiological interventions. This paper defines the new concept of Multi-Imager Compatibility of surgical manipulators and describes its requirements. Subsequently, the paper gives several recommendations and proposes new actuation principles for this concept. Several

  7. Development of robot hand with pneumatic actuator and construct of master-slave system.

    PubMed

    Nishino, Shinya; Tsujiuchi, Nobutaka; Koizumi, Takayuki; Komatsubara, Hiroyuki; Kudawara, Tatuwo; Shimizu, Mikio

    2007-01-01

    Recently, research has concentrated on robots that can coexist with people and be of use to them. Such a robot needs to be both safe and flexible. Here, we use a pneumatic actuator as the driving source of a robot hand. We develop a pneumatic actuator driven by low pressure because we consider that the conventional pneumatic actuator is inadequate for the driving source of a robot hand. First, we examine the characteristics of our new pneumatic actuator. Next, we develop a five-fingered robot hand using this pneumatic actuator. The robot hand produced is both safe and flexible. We construct a master-slave system to enable the robot hand to perform the same operations as a human hand. Next, we make a joint model that has one degree of freedom using a pneumatic actuator. We construct a control system for the joint model and verify its control performance.

  8. Robot Arm with Tendon Connector Plate and Linear Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Bridgwater, Lyndon (Inventor); Nguyen, Vienny (Inventor); Millerman, Alexander (Inventor)

    2014-01-01

    A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

  9. Design of a biped robot actuated by pneumatic artificial muscles.

    PubMed

    Liu, Yixiang; Zang, Xizhe; Liu, Xinyu; Wang, Lin

    2015-01-01

    High compliant legs are essential for the efficient versatile locomotion and shock absorbency of humans. This study proposes a biped robot actuated by pneumatic artificial muscles to mimic human locomotion. On the basis of the musculoskeletal architecture of human lower limbs, each leg of the biped robot is modeled as a system of three segments, namely, hip joint, knee joint, and ankle joint, and eleven muscles, including both monoarticular and biarticular muscles. Each rotational joint is driven by a pair of antagonistic muscles, enabling joint compliance to be tuned by operating the pressure inside the muscles. Biarticular muscles play an important role in transferring power between joints. Walking simulations verify that biarticular muscles contribute to joint compliance and can absorb impact energy when the robot makes an impact upon ground contact.

  10. Fast bender actuators for fish-like aquatic robots

    NASA Astrophysics Data System (ADS)

    McGovern, S. T.; Spinks, G. M.; Xi, B.; Alici, G.; Truong, V.; Wallace, G. G.

    2008-03-01

    Small, highly-mobile "swimming" robots are desired for underwater monitoring operations, including pollution detection, video mapping and other tasks. Actuator materials of all types are of interest for any application where space is limited. This constraint certainly applies to the small-scale swimming robot, where multiple small actuators are needed for forward/backward propulsion, steering and diving/surfacing. A number of previous studies have demonstrated propulsion of floating objects using IPMC type polymer actuators [1-3] or piezoceramic actuators [4, 5]. Here, we show how propulsion is also possible using a multi-layer polypyrrole bimorph actuator. The actuator is based on our previously published work showing very fast resonance actuation in polypyrrole bending-type actuators [6]. The bending actuator is a tri-layer structure, in which the gold-PVDF (porous poly(vinylidene fluoride) membrane) substrate was coated on both sides with polypyrrole layers to form an electrochemical cell. Polypyrrole films on gold coated PVDF were grown galvanostatically at a current density of 0.10 mA/cm2 for 12 hours from propylene carbonate (PC) solution containing 0.1 M Li+TFSI-, 0.1 M pyrrole and 1% (w/w) water. The polypyrrole deposited PVDF was thoroughly rinsed with acetone and stored in 0.1 M Li+TFSI- / PC solution. The edges of the bulk film were trimmed off and the bending actuators were prepared as rectangular strips typically 2mm wide and 25 mm long. These actuators gave fast operation in air (to 90 Hz), and were utilised as active flexural joints on the tail fin of a fishshaped floating "boat". The actuators were attached to a simple truncated shaped fin and the deflection angle was analysed in both air and liquid for excitation with +/- 1V square wave at a range of frequencies. The mechanical resonance of the fin was seen to be 4.5 Hz in air and 0.45 Hz in PC, which gave deflection angles of approximately 60° and 55° respectively. The boat contained a battery

  11. The Effect of the Elastic Compliance of Actuator Components on the Dynamics of a Robot

    NASA Astrophysics Data System (ADS)

    Gulyaev, Valerii Ivanovich; Zavrazhina, Tat'yana Viktorovna

    2003-02-01

    Kinematic and dynamic control problems for a pedestal-mounted robot with a multilink arm are formulated. The robot is considered a system of perfectly rigid bodies controlled by a combined actuating system. The mathematical model of robot dynamics accounts for the elastic properties of actuator components based on the formalism of Lagrange equations of the second kind. The effect of the elastic compliance of the actuator components on the dynamics of manipulator links and actuator motors is discussed. A robot with a two-link arm is considered as an example

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

    SciTech Connect

    Mazumdar, Anirban; Spencer, Steven J.; Hobart, Clinton; Salton, Jonathan; Quigley, Morgan; Wu, Tingfan; Bertrand, Sylvain; Pratt, Jerry; Buerger, Stephen P.

    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 actuated 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.

  13. Kinematics of an in-parallel actuated manipulator based on the Stewart platform mechanism

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., II

    1992-01-01

    This paper presents kinematic equations and solutions for an in-parallel actuated robotic mechanism based on Stewart's platform. These equations are required for inverse position and resolved rate (inverse velocity) platform control. NASA LaRC has a Vehicle Emulator System (VES) platform designed by MIT which is based on Stewart's platform. The inverse position solution is straight-forward and computationally inexpensive. Given the desired position and orientation of the moving platform with respect to the base, the lengths of the prismatic leg actuators are calculated. The forward position solution is more complicated and theoretically has 16 solutions. The position and orientation of the moving platform with respect to the base is calculated given the leg actuator lengths. Two methods are pursued in this paper to solve this problem. The resolved rate (inverse velocity) solution is derived. Given the desired Cartesian velocity of the end-effector, the required leg actuator rates are calculated. The Newton-Raphson Jacobian matrix resulting from the second forward position kinematics solution is a modified inverse Jacobian matrix. Examples and simulations are given for the VES.

  14. Dynamics and control of cable-suspended parallel robots for giant telescopes

    NASA Astrophysics Data System (ADS)

    Zhuang, Peng; Yao, Zhengqiu

    2006-06-01

    A cable-suspended parallel robot utilizes the basic idea of Stewart platform but replaces parallel links with cables and linear actuators with winches. It has many advantages over a conventional crane. The concept of applying a cable-suspended parallel robot into the construction and maintenance of giant telescope is presented in this paper. Compared with the mass and travel of the moving platform of the robot, the mass and deformation of the cables can be disregarded. Based on the premises, the kinematic and dynamic models of the robot are built. Through simulation, the inertia and gravity of moving platform are found to have dominant effect on the dynamic characteristic of the robot, while the dynamics of actuators can be disregarded, so a simplified dynamic model applicable to real-time control is obtained. Moreover, according to control-law partitioning approach and optimization theory, a workspace model-based controller is proposed considering the characteristic that the cables can only pull but not push. The simulation results indicate that the controller possesses good accuracy in pose and speed tracking, and keeps the cables in reliable tension by maintaining the minimum strain above a certain given value, thus ensures smooth motion and accurate localization for moving platform.

  15. A biomimetic robotic jellyfish (Robojelly) actuated by shape memory alloy composite actuators.

    PubMed

    Villanueva, Alex; Smith, Colin; Priya, Shashank

    2011-09-01

    An analysis is conducted on the design, fabrication and performance of an underwater vehicle mimicking the propulsion mechanism and physical appearance of a medusa (jellyfish). The robotic jellyfish called Robojelly mimics the morphology and kinematics of the Aurelia aurita species. Robojelly actuates using bio-inspired shape memory alloy composite actuators. A systematic fabrication technique was developed to replicate the essential structural features of A. aurita. Robojelly's body was fabricated from RTV silicone having a total mass of 242 g and bell diameter of 164 mm. Robojelly was able to generate enough thrust in static water conditions to propel itself and achieve a proficiency of 0.19 s(-1) while the A. aurita achieves a proficiency of around 0.25 s(-1). A thrust analysis based on empirical measurements for a natural jellyfish was used to compare the performance of the different robotic configurations. The configuration with best performance was a Robojelly with segmented bell and a passive flap structure. Robojelly was found to consume an average power on the order of 17 W with the actuators not having fully reached a thermal steady state.

  16. Preliminary results on noncollocated torque control of space robot actuators

    NASA Technical Reports Server (NTRS)

    Tilley, Scott W.; Francis, Colin M.; Emerick, Ken; Hollars, Michael G.

    1989-01-01

    In the Space Station era, more operations will be performed robotically in space in the areas of servicing, assembly, and experiment tending among others. These robots may have various sets of requirements for accuracy, speed, and force generation, but there will be design constraints such as size, mass, and power dissipation limits. For actuation, a leading motor candidate is a dc brushless type, and there are numerous potential drive trains each with its own advantages and disadvantages. This experiment uses a harmonic drive and addresses some inherent limitations, namely its backdriveability and low frequency structural resonances. These effects are controlled and diminished by instrumenting the actuator system with a torque transducer on the output shaft. This noncollocated loop is closed to ensure that the commanded torque is accurately delivered to the manipulator link. The actuator system is modelled and its essential parameters identified. The nonlinear model for simulations will include inertias, gearing, stiction, flexibility, and the effects of output load variations. A linear model is extracted and used for designing the noncollocated torque and position feedback loops. These loops are simulated with the structural frequency encountered in the testbed system. Simulation results are given for various commands in position. The use of torque feedback is demonstrated to yield superior performance in settling time and positioning accuracy. An experimental setup being finished consists of a bench mounted motor and harmonic drive actuator system. A torque transducer and two position encoders, each with sufficient resolution and bandwidth, will provide sensory information. Parameters of the physical system are being identified and matched to analytical predictions. Initial feedback control laws will be incorporated in the bench test equipment and various experiments run to validate the designs. The status of these experiments is given.

  17. Experimental parametric study of a biomimetic fish robot actuated by piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Wiguna, T.; Park, Hoon C.; Heo, S.; Goo, Nam S.

    2007-04-01

    This paper presents an experiment and parametric study of a biomimetic fish robot actuated by the Lightweight Piezocomposite Actuator (LIPCA). The biomimetic aspects in this work are the oscillating tail beat motion and shape of caudal fin. Caudal fins that resemble fins of BCF (Body and Caudal Fin) mode fish were made in order to perform parametric study concerning the effect of caudal fin characteristics on thrust production at an operating frequency range. The observed caudal fin characteristics are the shape, stiffness, area, and aspect ratio. It is found that a high aspect ratio caudal fin contributes to high swimming speed. The robotic fish propelled by artificial caudal fins shaped after thunniform-fish and mackerel caudal fins, which have relatively high aspect ratio, produced swimming speed as high as 2.364 cm/s and 2.519 cm/s, respectively, for a 300 V p-p input voltage excited at 0.9 Hz. Thrust performance of the biomimetic fish robot is examined by calculating Strouhal number, Froude number, Reynolds number, and power consumption.

  18. Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water.

    PubMed

    Yuk, Hyunwoo; Lin, Shaoting; Ma, Chu; Takaffoli, Mahdi; Fang, Nicolas X; Zhao, Xuanhe

    2017-02-01

    Sea animals such as leptocephali develop tissues and organs composed of active transparent hydrogels to achieve agile motions and natural camouflage in water. Hydrogel-based actuators that can imitate the capabilities of leptocephali will enable new applications in diverse fields. However, existing hydrogel actuators, mostly osmotic-driven, are intrinsically low-speed and/or low-force; and their camouflage capabilities have not been explored. Here we show that hydraulic actuations of hydrogels with designed structures and properties can give soft actuators and robots that are high-speed, high-force, and optically and sonically camouflaged in water. The hydrogel actuators and robots can maintain their robustness and functionality over multiple cycles of actuations, owing to the anti-fatigue property of the hydrogel under moderate stresses. We further demonstrate that the agile and transparent hydrogel actuators and robots perform extraordinary functions including swimming, kicking rubber-balls and even catching a live fish in water.

  19. Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water

    NASA Astrophysics Data System (ADS)

    Yuk, Hyunwoo; Lin, Shaoting; Ma, Chu; Takaffoli, Mahdi; Fang, Nicolas X.; Zhao, Xuanhe

    2017-02-01

    Sea animals such as leptocephali develop tissues and organs composed of active transparent hydrogels to achieve agile motions and natural camouflage in water. Hydrogel-based actuators that can imitate the capabilities of leptocephali will enable new applications in diverse fields. However, existing hydrogel actuators, mostly osmotic-driven, are intrinsically low-speed and/or low-force; and their camouflage capabilities have not been explored. Here we show that hydraulic actuations of hydrogels with designed structures and properties can give soft actuators and robots that are high-speed, high-force, and optically and sonically camouflaged in water. The hydrogel actuators and robots can maintain their robustness and functionality over multiple cycles of actuations, owing to the anti-fatigue property of the hydrogel under moderate stresses. We further demonstrate that the agile and transparent hydrogel actuators and robots perform extraordinary functions including swimming, kicking rubber-balls and even catching a live fish in water.

  20. Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water

    PubMed Central

    Yuk, Hyunwoo; Lin, Shaoting; Ma, Chu; Takaffoli, Mahdi; Fang, Nicolas X.; Zhao, Xuanhe

    2017-01-01

    Sea animals such as leptocephali develop tissues and organs composed of active transparent hydrogels to achieve agile motions and natural camouflage in water. Hydrogel-based actuators that can imitate the capabilities of leptocephali will enable new applications in diverse fields. However, existing hydrogel actuators, mostly osmotic-driven, are intrinsically low-speed and/or low-force; and their camouflage capabilities have not been explored. Here we show that hydraulic actuations of hydrogels with designed structures and properties can give soft actuators and robots that are high-speed, high-force, and optically and sonically camouflaged in water. The hydrogel actuators and robots can maintain their robustness and functionality over multiple cycles of actuations, owing to the anti-fatigue property of the hydrogel under moderate stresses. We further demonstrate that the agile and transparent hydrogel actuators and robots perform extraordinary functions including swimming, kicking rubber-balls and even catching a live fish in water. PMID:28145412

  1. Modeling and Implementation of Solder-activated Joints for Single Actuator, Centimeter-Scale Robotic Mechanisms

    DTIC Science & Technology

    2010-06-01

    mechanisms may be built and actuated to perform a multiplicity of tasks using PCM-activated joints. The robot was developed under the Chemical Robots DARPA ...components. 4.1.1 Chemical Robots Program The Chemical Robots (ChemBots) program is funded by the DARPA Defense Sciences Office. The goal of the program...perform tasks in these hostile and hard to reach spaces safely, covertly, and efficiently [26]. To develop this new class of robots, DARPA asked for

  2. The application of polypyrrole trilayer actuators in microfluidics and robotics

    NASA Astrophysics Data System (ADS)

    Kiefer, Rudolf; Mandviwalla, Xerxes; Archer, Rosalind; Tjahyono, Sungkono Surya; Wang, Han; MacDonald, Bruce; Bowmaker, Graham A.; Kilmartin, Paul A.; Travas-Sejdic, Jadranka

    2008-03-01

    Trilayer actuators were constructed using polypyrrole (PPy) films doped with dodecylbenzene sulfonate (DBS). Identical 5-20 μm PPy/DBS films were grown on either side of a 110 μm poly(vinylidene fluoride) (PVDF) membrane to serve as working and counter electrodes with respect to each other. The performance of the trilayer actuator was tested using potential step experiments between -0.8 and +0.8 V at different frequencies (0.03 to 10 Hz) and trilayer lengths (1 to 2.5 cm), and the extent of deflection was measured using a CCD camera. Satisfactory deflections in the range of 1-3 mm were observed for 10 μm thick PPy layers on trilayers 1.5 to 2.5 cm in length when operated at 1-5 Hz for over 40,000 cycles. The trilayer actuators were examined in a fluidics channels, and mathematical modelling using finite element analysis was used to predict overall fluid movement and flow rates. The trilayers were also used to construct a 'fish-tail' positioned at the back of a self-driven robotic fish.

  3. 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

  4. Towards compliant and wearable robotic orthoses: A review of current and emerging actuator technologies.

    PubMed

    Veale, Allan Joshua; Xie, Shane Quan

    2016-04-01

    Robotic orthoses, or exoskeletons, have the potential to provide effective rehabilitation while overcoming the availability and cost constraints of therapists. However, current orthosis actuation systems use components designed for industrial applications, not specifically for interacting with humans. This can limit orthoses' capabilities and, if their users' needs are not adequately considered, contribute to their abandonment. Here, a user centered review is presented on: requirements for orthosis actuators; the electric, hydraulic, and pneumatic actuators currently used in orthoses and their advantages and limitations; the potential of new actuator technologies, including smart materials, to actuate orthoses; and the future of orthosis actuator research.

  5. Soft robotics: a review and progress towards faster and higher torque actuators (presentation video)

    NASA Astrophysics Data System (ADS)

    Shepherd, Robert

    2014-03-01

    Last year, nearly 160,000 industrial robots were shipped worldwide—into a total market valued at 26 Bn (including hardware, software, and peripherals).[1] Service robots for professional (e.g., defense, medical, agriculture) and personal (e.g., household, handicap assistance, toys, and education) use accounted for 16,000 units, 3.4 Bn and 3,000,000 units, $1.2 Bn respectively.[1] The vast majority of these robotic systems use fully actuated, rigid components that take little advantage of passive dynamics. Soft robotics is a field that is taking advantage of compliant actuators and passive dynamics to achieve several goals: reduced design, manufacturing and control complexity, improved energy efficiency, more sophisticated motions, and safe human-machine interactions to name a few. The potential for societal impact is immense. In some instances, soft actuators have achieved commercial success; however, large scale adoption will require improved methods of controlling non-linear systems, greater reliability in their function, and increased utility from faster and more forceful actuation. In my talk, I will describe efforts from my work in the Whitesides group at Harvard to prove sophisticated motions in these machines using simple controls, as well capabilities unique to soft machines. I will also describe the potential for combinations of different classes of soft actuators (e.g., electrically and pneumatically actuated systems) to improve the utility of soft robots. 1. World Robotics - Industrial Robots 2013, 2013, International Federation of Robotics.

  6. Motion capability analysis of a quadruped robot as a parallel manipulator

    NASA Astrophysics Data System (ADS)

    Yu, Jingjun; Lu, Dengfeng; Zhang, Zhongxiang; Pei, Xu

    2014-12-01

    This paper presents the forward and inverse displacement analysis of a quadruped robot MANA as a parallel manipulator in quadruple stance phase, which is used to obtain the workspace and control the motion of the body. The robot MANA designed on the basis of the structure of quadruped mammal is able to not only walk and turn in the uneven terrain, but also accomplish various manipulating tasks as a parallel manipulator in quadruple stance phase. The latter will be the focus of this paper, however. For this purpose, the leg kinematics is primarily analyzed, which lays the foundation on the gait planning in terms of locomotion and body kinematics analysis as a parallel manipulator. When all four feet of the robot contact on the ground, by assuming there is no slipping at the feet, each contacting point is treated as a passive spherical joint and the kinematic model of parallel manipulator is established. The method for choosing six non-redundant actuated joints for the parallel manipulator from all twelve optional joints is elaborated. The inverse and forward displacement analysis of the parallel manipulator is carried out using the method of coordinate transformation. Finally, based on the inverse and forward kinematic model, two issues on obtaining the reachable workspace of parallel manipulator and planning the motion of the body are implemented and verified by ADAMS simulation.

  7. Tool actuation and force feedback on robot-assisted microsurgery system

    NASA Technical Reports Server (NTRS)

    Das, Hari (Inventor); Ohm, Tim R. (Inventor); Boswell, Curtis D. (Inventor); Steele, Robert D. (Inventor)

    2002-01-01

    An input control device with force sensors is configured to sense hand movements of a surgeon performing a robot-assisted microsurgery. The sensed hand movements actuate a mechanically decoupled robot manipulator. A microsurgical manipulator, attached to the robot manipulator, is activated to move small objects and perform microsurgical tasks. A force-feedback element coupled to the robot manipulator and the input control device provides the input control device with an amplified sense of touch in the microsurgical manipulator.

  8. Using Voice Coils to Actuate Modular Soft Robots: Wormbot, an Example.

    PubMed

    Nemitz, Markus P; Mihaylov, Pavel; Barraclough, Thomas W; Ross, Dylan; Stokes, Adam A

    2016-12-01

    In this study, we present a modular worm-like robot, which utilizes voice coils as a new paradigm in soft robot actuation. Drive electronics are incorporated into the actuators, providing a significant improvement in self-sufficiency when compared with existing soft robot actuation modes such as pneumatics or hydraulics. The body plan of this robot is inspired by the phylum Annelida and consists of three-dimensional printed voice coil actuators, which are connected by flexible silicone membranes. Each electromagnetic actuator engages with its neighbor to compress or extend the membrane of each segment, and the sequence in which they are actuated results in an earthworm-inspired peristaltic motion. We find that a minimum of three segments is required for locomotion, but due to our modular design, robots of any length can be quickly and easily assembled. In addition to actuation, voice coils provide audio input and output capabilities. We demonstrate transmission of data between segments by high-frequency carrier waves and, using a similar mechanism, we note that the passing of power between coupled coils in neighboring modules-or from an external power source-is also possible. Voice coils are a convenient multifunctional alternative to existing soft robot actuators. Their self-contained nature and ability to communicate with each other are ideal for modular robotics, and the additional functionality of sound input/output and power transfer will become increasingly useful as soft robots begin the transition from early proof-of-concept systems toward fully functional and highly integrated robotic systems.

  9. Using Voice Coils to Actuate Modular Soft Robots: Wormbot, an Example

    PubMed Central

    Nemitz, Markus P.; Mihaylov, Pavel; Barraclough, Thomas W.; Ross, Dylan

    2016-01-01

    Abstract In this study, we present a modular worm-like robot, which utilizes voice coils as a new paradigm in soft robot actuation. Drive electronics are incorporated into the actuators, providing a significant improvement in self-sufficiency when compared with existing soft robot actuation modes such as pneumatics or hydraulics. The body plan of this robot is inspired by the phylum Annelida and consists of three-dimensional printed voice coil actuators, which are connected by flexible silicone membranes. Each electromagnetic actuator engages with its neighbor to compress or extend the membrane of each segment, and the sequence in which they are actuated results in an earthworm-inspired peristaltic motion. We find that a minimum of three segments is required for locomotion, but due to our modular design, robots of any length can be quickly and easily assembled. In addition to actuation, voice coils provide audio input and output capabilities. We demonstrate transmission of data between segments by high-frequency carrier waves and, using a similar mechanism, we note that the passing of power between coupled coils in neighboring modules—or from an external power source—is also possible. Voice coils are a convenient multifunctional alternative to existing soft robot actuators. Their self-contained nature and ability to communicate with each other are ideal for modular robotics, and the additional functionality of sound input/output and power transfer will become increasingly useful as soft robots begin the transition from early proof-of-concept systems toward fully functional and highly integrated robotic systems. PMID:28078195

  10. Autonomous Soft Robotic Fish Capable of Escape Maneuvers Using Fluidic Elastomer Actuators.

    PubMed

    Marchese, Andrew D; Onal, Cagdas D; Rus, Daniela

    2014-03-01

    In this work we describe an autonomous soft-bodied robot that is both self-contained and capable of rapid, continuum-body motion. We detail the design, modeling, fabrication, and control of the soft fish, focusing on enabling the robot to perform rapid escape responses. The robot employs a compliant body with embedded actuators emulating the slender anatomical form of a fish. In addition, the robot has a novel fluidic actuation system that drives body motion and has all the subsystems of a traditional robot onboard: power, actuation, processing, and control. At the core of the fish's soft body is an array of fluidic elastomer actuators. We design the fish to emulate escape responses in addition to forward swimming because such maneuvers require rapid body accelerations and continuum-body motion. These maneuvers showcase the performance capabilities of this self-contained robot. The kinematics and controllability of the robot during simulated escape response maneuvers are analyzed and compared with studies on biological fish. We show that during escape responses, the soft-bodied robot has similar input-output relationships to those observed in biological fish. The major implication of this work is that we show soft robots can be both self-contained and capable of rapid body motion.

  11. Autonomous Soft Robotic Fish Capable of Escape Maneuvers Using Fluidic Elastomer Actuators

    PubMed Central

    Onal, Cagdas D.; Rus, Daniela

    2014-01-01

    Abstract In this work we describe an autonomous soft-bodied robot that is both self-contained and capable of rapid, continuum-body motion. We detail the design, modeling, fabrication, and control of the soft fish, focusing on enabling the robot to perform rapid escape responses. The robot employs a compliant body with embedded actuators emulating the slender anatomical form of a fish. In addition, the robot has a novel fluidic actuation system that drives body motion and has all the subsystems of a traditional robot onboard: power, actuation, processing, and control. At the core of the fish's soft body is an array of fluidic elastomer actuators. We design the fish to emulate escape responses in addition to forward swimming because such maneuvers require rapid body accelerations and continuum-body motion. These maneuvers showcase the performance capabilities of this self-contained robot. The kinematics and controllability of the robot during simulated escape response maneuvers are analyzed and compared with studies on biological fish. We show that during escape responses, the soft-bodied robot has similar input–output relationships to those observed in biological fish. The major implication of this work is that we show soft robots can be both self-contained and capable of rapid body motion. PMID:27625912

  12. Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators

    NASA Astrophysics Data System (ADS)

    Thummala, P.; Zhang, Z.; Andersen, M. A. E.; Rahimullah, S.

    2014-03-01

    Dielectric electroactive polymer (DEAP) actuators are capacitive devices which provide mechanical motions when charged electrically. The charging characteristics of a DEAP actuator depends on its size, voltage applied to its electrodes, and its operating frequency. The main idea of this paper is to design and implement driving circuits for the DEAP actuators for their use in various applications. This paper presents implementation of parallel input, parallel output, high voltage (~2.5 kV) bi-directional DC-DC converters for driving the DEAP actuators. The topology is a bidirectional flyback DC-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design. This enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results with both film capacitive load and the DEAP actuator are shown for a maximum charging voltage of 2 kV.

  13. A novel traveling wave piezoelectric actuated tracked mobile robot utilizing friction effect

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Shu, Chengyou; Jin, Jiamei; Zhang, Jianhui

    2017-03-01

    A novel traveling wave piezoelectric-actuated tracked mobile robot with potential application to robotic rovers was proposed and investigated in this study. The proposed tracked mobile robot is composed of a parallelogram-frame-structure piezoelectric transducer with four rings and a metal track. Utilizing the converse piezoelectric and friction effects, traveling waves were propagated in the rings and then the metal track was actuated by the piezoelectric transducer. Compared with traditional tracked mechanisms, the proposed tracked mobile robot has a simpler and more compact structure without lubricant, which eliminates the problem of lubricant volatilization and deflation, thus, it could be operated in the vacuum environment. Dynamic characteristics were simulated and measured to reveal the mechanism of actuating track of the piezoelectric transducer. Experimental investigations of the traveling wave piezoelectric-actuated tracked mobile robot were then carried out, and the results indicated that the robot prototype with a pair of exciting voltages of 460 Vpp is able to achieve a maximum velocity of 57 mm s‑1 moving on the foam plate and possesses the obstacle crossing capability with a maximum height of 27 mm. The proposed tracked mobile robot exhibits potential to be the driving system of robotic rovers.

  14. Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems.

    PubMed

    Zheng, Hao; Shen, Xiangrong

    2013-11-25

    This paper presents a new type of muscle-like actuator, namely double-acting (DA) sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc.). Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert at the center. With the insert occupying the central portion of the internal volume, this new actuator enjoys multiple advantages relative to the traditional pneumatic muscle, including a consistent increase of force capacity over the entire range of motion, and a significant decrease of energy consumption in operation. Furthermore, the insert encompasses an additional chamber, which generates an extension force when pressurized. As such, this new actuator provides a unique bi-directional actuation capability, and, thus, has a potential to significantly simplify the design of a muscle actuator-powered robotic system. To demonstrate this new actuator concept, a prototype has been designed and fabricated, and experiments conducted on this prototype demonstrated the enhanced force capacity and the unique bi-directional actuation capability.

  15. UMD Workshop on Distributed Sensing, Actuation, and Control for Bio-Inspired Soft Robotics

    DTIC Science & Technology

    2014-10-01

    include: tissue                           engineering/biology (incorporating tissues , cells into soft robotics, conversion of tissue ...SECURITY CLASSIFICATION OF: The UMD Workshop on Distributed Sensing, Actuation, and Control for Bio­inspired Soft Robotics was held at the...and Control for Bio-inspired Soft Robotics The views, opinions and/or findings contained in this report are those of the author(s) and should not

  16. Modeling and simulation of a Stewart platform type parallel structure robot

    NASA Technical Reports Server (NTRS)

    Lim, Gee Kwang; Freeman, Robert A.; Tesar, Delbert

    1989-01-01

    The kinematics and dynamics of a Stewart Platform type parallel structure robot (NASA's Dynamic Docking Test System) were modeled using the method of kinematic influence coefficients (KIC) and isomorphic transformations of system dependence from one set of generalized coordinates to another. By specifying the end-effector (platform) time trajectory, the required generalized input forces which would theoretically yield the desired motion were determined. It was found that the relationship between the platform motion and the actuators motion was nonlinear. In addition, the contribution to the total generalized forces, required at the actuators, from the acceleration related terms were found to be more significant than the velocity related terms. Hence, the curve representing the total required actuator force generally resembled the curve for the acceleration related force. Another observation revealed that the acceleration related effective inertia matrix I sub dd had the tendency to decouple, with the elements on the main diagonal of I sub dd being larger than the off-diagonal elements, while the velocity related inertia power array P sub ddd did not show such tendency. This tendency results in the acceleration related force curve of a given actuator resembling the acceleration profile of that particular actuator. Furthermore, it was indicated that the effective inertia matrix for the legs is more decoupled than that for the platform. These observations provide essential information for further research to develop an effective control strategy for real-time control of the Dynamic Docking Test System.

  17. Flytrap-inspired robot using structurally integrated actuation based on bistability and a developable surface.

    PubMed

    Kim, Seung-Won; Koh, Je-Sung; Lee, Jong-Gu; Ryu, Junghyun; Cho, Maenghyo; Cho, Kyu-Jin

    2014-09-01

    The Venus flytrap uses bistability, the structural characteristic of its leaf, to actuate the leaf's rapid closing motion for catching its prey. This paper presents a flytrap-inspired robot and novel actuation mechanism that exploits the structural characteristics of this structure and a developable surface. We focus on the concept of exploiting structural characteristics for actuation. Using shape memory alloy (SMA), the robot actuates artificial leaves made from asymmetrically laminated carbon fiber reinforced prepregs. We exploit two distinct structural characteristics of the leaves. First, the bistability acts as an implicit actuator enabling rapid morphing motion. Second, the developable surface has a kinematic constraint that constrains the curvature of the artificial leaf. Due to this constraint, the curved artificial leaf can be unbent by bending the straight edge orthogonal to the curve. The bending propagates from one edge to the entire surface and eventually generates an overall shape change. The curvature change of the artificial leaf is 18 m(-1) within 100 ms when closing. Experiments show that these actuation mechanisms facilitate the generation of a rapid and large morphing motion of the flytrap robot by one-way actuation of the SMA actuators at a local position.

  18. Fish-inspired robots: design, sensing, actuation, and autonomy--a review of research.

    PubMed

    Raj, Aditi; Thakur, Atul

    2016-04-13

    Underwater robot designs inspired by the behavior, physiology, and anatomy of fishes can provide enhanced maneuverability, stealth, and energy efficiency. Over the last two decades, robotics researchers have developed and reported a large variety of fish-inspired robot designs. The purpose of this review is to report different types of fish-inspired robot designs based upon their intended locomotion patterns. We present a detailed comparison of various design features like sensing, actuation, autonomy, waterproofing, and morphological structure of fish-inspired robots reported in the past decade. We believe that by studying the existing robots, future designers will be able to create new designs by adopting features from the successful robots. The review also summarizes the open research issues that need to be taken up for the further advancement of the field and also for the deployment of fish-inspired robots in practice.

  19. Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator.

    PubMed

    Kim, Sung Hoon; Shin, Kyoosik; Hashi, Shuichiro; Ishiyama, Kazushi

    2012-09-01

    This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities.

  20. PARASURG hybrid parallel robot for minimally invasive surgery.

    PubMed

    Pisla, D; Gherman, B; Plitea, N; Gyurka, B; Vaida, C; Vlad, L; Graur, F; Radu, C; Suciu, M; Szilaghi, A; Stoica, A

    2011-01-01

    This paper presents the parallel hybrid robot, PARASURG 9M, for robotically assisted surgery, a robot which was entirely designed and produced in Romania. It is a versatile robot, being composed of a positioning and orientation module, PARASURG 5M with five degrees of freedom, having the possibility of attaching at its end either a laparoscope or an active surgical instrument for cutting/grasping, PARASIM, with four degrees of freedom. Based on its mathematical modelling, the first low-cost experimental model of the surgical robot has been built. The robot is part of the surgical robotic system, PARAMIS, with three arms, one used as a laparoscope holder, and other two for manipulating active instruments. When it is used as a manipulator of the camera, the user has the possibility to give commands in a large area for the positioning of the laparoscope using different interfaces: joystick, microphone, keyboard & mouse and haptic device. If the active surgical instrument, PARASIM, is attached, the robot commands are given through a haptic device. The main features that make the PARASURG 9M surgical robot suited for minimally invasive surgery are: precision, the elimination of the natural tremor of the surgeon, direct control over a smooth, precise, stable view of the internal surgical field for the surgeon. It also eliminates the need of a second surgeon to be present for the entire procedure (in the case of using the robot as a camera holder). In addition, there is improvement of surgeon dexterity in the case of using the PARASIM active instrument and better ergonomics in using the robot (in the case of the classic laparoscopy, the surgeon must adopt a difficult position for a long period of time, while the robot never gets tired). Having a relatively easy to understand, intuitive commanding system, the surgeons can rapidly adapt to the use of the PARASURG 9M robot in surgical procedures.

  1. Linear quadratic optimal controller for cable-driven parallel robots

    NASA Astrophysics Data System (ADS)

    Abdolshah, Saeed; Shojaei Barjuei, Erfan

    2015-12-01

    In recent years, various cable-driven parallel robots have been investigated for their advantages, such as low structural weight, high acceleration, and large work-space, over serial and conventional parallel systems. However, the use of cables lowers the stiffness of these robots, which in turn may decrease motion accuracy. A linear quadratic (LQ) optimal controller can provide all the states of a system for the feedback, such as position and velocity. Thus, the application of such an optimal controller in cable-driven parallel robots can result in more efficient and accurate motion compared to the performance of classical controllers such as the proportional- integral-derivative controller. This paper presents an approach to apply the LQ optimal controller on cable-driven parallel robots. To employ the optimal control theory, the static and dynamic modeling of a 3-DOF planar cable-driven parallel robot (Feriba-3) is developed. The synthesis of the LQ optimal control is described, and the significant experimental results are presented and discussed.

  2. Frequency-dependent stability of parallel-plate electrostatic actuators in conductive fluids

    NASA Astrophysics Data System (ADS)

    Sounart, T. L.; Panchawagh, H. V.; Mahajan, R. L.

    2010-05-01

    We present an electromechanical stability analysis of passivated parallel-plate electrostatic actuators in conductive dielectric media and show that the pull-in instability can be eliminated by tuning the applied frequency below a design-dependent stability limit. A partial instability region is also obtained, where the actuator jumps from the pull-in displacement to another stable position within the gap. The results predict that the stability limit is always greater than the critical actuation frequency, and therefore any device that is feasible to actuate in a conductive fluid can be operated with stability over the full range of motion.

  3. Cerebellar-inspired adaptive control of a robot eye actuated by pneumatic artificial muscles.

    PubMed

    Lenz, Alexander; Anderson, Sean R; Pipe, A G; Melhuish, Chris; Dean, Paul; Porrill, John

    2009-12-01

    In this paper, a model of cerebellar function is implemented and evaluated in the control of a robot eye actuated by pneumatic artificial muscles. The investigated control problem is stabilization of the visual image in response to disturbances. This is analogous to the vestibuloocular reflex (VOR) in humans. The cerebellar model is structurally based on the adaptive filter, and the learning rule is computationally analogous to least-mean squares, where parameter adaptation at the parallel fiber/Purkinje cell synapse is driven by the correlation of the sensory error signal (carried by the climbing fiber) and the motor command signal. Convergence of the algorithm is first analyzed in simulation on a model of the robot and then tested online in both one and two degrees of freedom. The results show that this model of neural function successfully works on a real-world problem, providing empirical evidence for validating: 1) the generic cerebellar learning algorithm; 2) the function of the cerebellum in the VOR; and 3) the signal transmission between functional neural components of the VOR.

  4. Transparent actuators and robots based on single-layer superaligned carbon nanotube sheet and polymer composites.

    PubMed

    Chen, Luzhuo; Weng, Mingcen; Zhang, Wei; Zhou, Zhiwei; Zhou, Yi; Xia, Dan; Li, Jiaxin; Huang, Zhigao; Liu, Changhong; Fan, Shoushan

    2016-03-28

    Transparent actuators have been attracting emerging interest recently, as they demonstrate potential applications in the fields of invisible robots, tactical displays, variable-focus lenses, and flexible cellular phones. However, previous technologies did not simultaneously realize macroscopic transparent actuators with advantages of large-shape deformation, low-voltage-driven actuation and fast fabrication. Here, we develop a fast approach to fabricate a high-performance transparent actuator based on single-layer superaligned carbon nanotube sheet and polymer composites. Various advantages of single-layer nanotube sheets including high transparency, considerable conductivity, and ultra-thin dimensions together with selected polymer materials completely realize all the above required advantages. Also, this is the first time that a single-layer nanotube sheet has been used to fabricate actuators with high transparency, avoiding the structural damage to the single-layer nanotube sheet. The transparent actuator shows a transmittance of 72% at the wavelength of 550 nm and bends remarkably with a curvature of 0.41 cm(-1) under a DC voltage for 5 s, demonstrating a significant advance in technological performances compared to previous conventional actuators. To illustrate their great potential usage, a transparent wiper and a humanoid robot "hand" were elaborately designed and fabricated, which initiate a new direction in the development of high-performance invisible robotics and other intelligent applications with transparency.

  5. Centrifugal forming and mechanical properties of silicone-based elastomers for soft robotic actuators

    NASA Astrophysics Data System (ADS)

    Kulkarni, Parth

    This thesis describes the centrifugal forming and resulting mechanical properties of silicone-based elastomers for the manufacture of soft robotic actuators. This process is effective at removing bubbles that get entrapped within 3D-printed, enclosed molds. Conventional methods for rapid prototyping of soft robotic actuators to remove entrapped bubbles typically involve degassing under vacuum, with open-faced molds that limit the layout of formed parts to raised 2D geometries. As the functionality and complexity of soft robots increase, there is a need to mold complete 3D structures with controlled thicknesses or curvatures on multiples surfaces. In addition, characterization of the mechanical properties of common elastomers for these soft robots has lagged the development of new designs. As such, relationships between resulting material properties and processing parameters are virtually non-existent. One of the goals of this thesis is to provide guidelines and physical insights to relate the design, processing conditions, and resulting properties of soft robotic components to each other. Centrifugal forming with accelerations on the order of 100 g's is capable of forming bubble-free, true 3D components for soft robotic actuators, and resulting demonstrations in this work include an aquatic locomotor, soft gripper, and an actuator that straightens when pressurized. Finally, this work shows that the measured mechanical properties of 3D geometries fabricated within enclosed molds through centrifugal forming possess comparable mechanical properties to vacuumed materials formed from open-faced molds with raised 2D features.

  6. Hydrodynamic performance of a biomimetic robotic swimmer actuated by ionic polymer-metal composite

    NASA Astrophysics Data System (ADS)

    Shen, Qi; Wang, Tiammiao; Liang, Jianhong; Wen, Li

    2013-07-01

    In this paper, we study the thrust performance of a biomimetic robotic swimmer that uses ionic polymer-metal composite (IPMC) as a flexible actuator in viscous and inertial flow, for a comprehensive understanding of IPMC swimmers at different scales. A hydrodynamic model based on the elongated body theory was developed. Based on image analysis, the parameters of the model were identified and simulation results were obtained. To obtain the hydrodynamic thrust performance of the robotic swimmer, we implemented a novel experimental apparatus. Systematic tests were conducted in the servo towing system to measure the self-propelled speed and thrust efficiency under different actuation of IPMC. The undulatory motions of the IPMC swimmer were identified. Experimental results demonstrated that the theoretical model can accurately predict the speed and thrust efficiency of the robotic swimmer. When the Reynolds number of the robotic swimmer was reduced to approximately 0.1%, its speed and thrust efficiency were reduced by 95.22% and 87.33% respectively. It was concluded that the robotic swimmer has a low speed and thrust efficiency when it swims in a viscous flow. Generally, the thrust performance of the robotic swimmer is determined by the kinematics and Reynolds number. In addition, the optimal actuation frequency for the thrust efficiency is greater in a viscous fluid. These results may contribute to a better understanding of the swimming performance of IPMC actuated swimmers in a distinct flow regime (viscous and inertial regime).

  7. Design and analysis on the dynamics of ICPF actuated tortoise-like flexible micro-robot

    NASA Astrophysics Data System (ADS)

    Nie, Lin; Li, Desheng; Guo, Shuxiang

    2006-11-01

    In the paper, we present a novel tortoise-like flexible micro-robot with four legs which can crawl and swim underwater. These legs are actuated by ICPF (Ionic Conducting Polymer Film) which is a kind of smart film and has the characteristics of flexibility, good response and being driven by a low voltage. For improving the robot's reliability and feasibility, we establish the micro-robot's dynamic model by applying Pseudo-Rigid-Body-Dynamic-Model (PRBDM). The model is established by considering the dynamic effect of the robot, which is based on statics and kinematics. Then, the frequency analysis of a micro-robot based on PRBDM is investigated. Based on the PRBDM, the relation between the robot's structure parameters and its natural frequency is theoretically derived and a numerical computation of the robot is performed.

  8. The behavior of dielectric elastomer actuators connected in series and parallel

    NASA Astrophysics Data System (ADS)

    Li, Guorui; Liang, Yiming; Yang, Xuxu; Cheng, Tingyu; Huang, Zhilong; Li, Tiefeng

    2016-04-01

    Dielectric elastomer membrane has the ability of shrinking the thickness and expanding surface area when a voltage is applied through its thickness. Dielectric elastomer has been widely studied and used as dielectric elastomer actuator (DEA), dielectric elastomer generator (DEG) and dielectric elastomer sensor (DES). We study the behavior of several DEAs connected in series and parallel, and find that the different connecting models can achieve different responses of the DEAs. DEAs connected in series can enhance the actuation, while DEA connected in parallel can enhance the actuation force. In our experiment, DEAs connected in series and parallel are loaded in actuation direction under a dead load providing pre-stretch. We discuss the results of the experiments and give the conclusions.

  9. CARAPACE: a novel composite advanced robotic actuator powering assistive compliant exoskeleton: preliminary design.

    PubMed

    Masia, Lorenzo; Cappello, Leonardo; Morasso, Pietro; Lachenal, Xavier; Pirrera, Alberto; Weaver, Paul; Mattioni, Filippo

    2013-06-01

    A novel actuator is introduced that combines an elastically compliant composite structure with conventional electromechanical elements. The proposed design is analogous to that used in Series Elastic Actuators, its distinctive feature being that the compliant composite part offers different stable configurations. In other words, its elastic potential presents points of local minima that correspond to robust stable positions (multistability). This potential is known a priori as a function of the structural geometry, thus providing tremendous benefits in terms of control implementation. Such knowledge enables the complexities arising from the additional degrees of freedom associated with link deformations to be overcome and uncover challenges that extends beyond those posed by standard rigidlink robot dynamics. It is thought that integrating a multistable elastic element in a robotic transmission can provide new scenarios in the field of assistive robotics, as the system may help a subject to stand or carry a load without the need for an active control effort by the actuators.

  10. A fuzzy-based shared controller for brain-actuated simulated robotic system.

    PubMed

    Liu, Rong; Xue, Kuang-Zheng; Wang, Yong-Xuan; Yang, Le

    2011-01-01

    The primary problems of brain-computer interface (BCI) are the low channel capacity and high error rate. Therefore, an assistive motion control method is important for the brain-actuated robot to realize real-time and reliable control. To make the brain-actuated robot respond to the external environments with more flexibility, a shared control method based on fuzzy logic is proposed. Experimental results obtained with ten healthy voluntary subjects show that the proposed fuzzy-based shared controller has improved performance compared with direct control approach.

  11. System and Method for Tensioning a Robotically Actuated Tendon

    NASA Technical Reports Server (NTRS)

    Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor)

    2013-01-01

    A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

  12. Piezoelectrically Actuated Robotic System for MRI-Guided Prostate Percutaneous Therapy.

    PubMed

    Su, Hao; Shang, Weijian; Cole, Gregory; Li, Gang; Harrington, Kevin; Camilo, Alexander; Tokuda, Junichi; Tempany, Clare M; Hata, Nobuhiko; Fischer, Gregory S

    2015-08-01

    This paper presents a fully-actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intra-operative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple piezoelectric motor drivers provides precision closed-loop control of piezoelectric motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a 3-Tesla MRI scanner using standard imaging sequences and the signal-to-noise ratio (SNR) loss is limited to 15%. The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated 0.87 mm root mean square (RMS) error in 3D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure.

  13. Piezoelectrically Actuated Robotic System for MRI-Guided Prostate Percutaneous Therapy

    PubMed Central

    Su, Hao; Shang, Weijian; Cole, Gregory; Li, Gang; Harrington, Kevin; Camilo, Alexander; Tokuda, Junichi; Tempany, Clare M.; Hata, Nobuhiko; Fischer, Gregory S.

    2014-01-01

    This paper presents a fully-actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intra-operative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple piezoelectric motor drivers provides precision closed-loop control of piezoelectric motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a 3-Tesla MRI scanner using standard imaging sequences and the signal-to-noise ratio (SNR) loss is limited to 15%. The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated 0.87 mm root mean square (RMS) error in 3D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure. PMID:26412962

  14. Transparent actuators and robots based on single-layer superaligned carbon nanotube sheet and polymer composites

    NASA Astrophysics Data System (ADS)

    Chen, Luzhuo; Weng, Mingcen; Zhang, Wei; Zhou, Zhiwei; Zhou, Yi; Xia, Dan; Li, Jiaxin; Huang, Zhigao; Liu, Changhong; Fan, Shoushan

    2016-03-01

    Transparent actuators have been attracting emerging interest recently, as they demonstrate potential applications in the fields of invisible robots, tactical displays, variable-focus lenses, and flexible cellular phones. However, previous technologies did not simultaneously realize macroscopic transparent actuators with advantages of large-shape deformation, low-voltage-driven actuation and fast fabrication. Here, we develop a fast approach to fabricate a high-performance transparent actuator based on single-layer superaligned carbon nanotube sheet and polymer composites. Various advantages of single-layer nanotube sheets including high transparency, considerable conductivity, and ultra-thin dimensions together with selected polymer materials completely realize all the above required advantages. Also, this is the first time that a single-layer nanotube sheet has been used to fabricate actuators with high transparency, avoiding the structural damage to the single-layer nanotube sheet. The transparent actuator shows a transmittance of 72% at the wavelength of 550 nm and bends remarkably with a curvature of 0.41 cm-1 under a DC voltage for 5 s, demonstrating a significant advance in technological performances compared to previous conventional actuators. To illustrate their great potential usage, a transparent wiper and a humanoid robot ``hand'' were elaborately designed and fabricated, which initiate a new direction in the development of high-performance invisible robotics and other intelligent applications with transparency.Transparent actuators have been attracting emerging interest recently, as they demonstrate potential applications in the fields of invisible robots, tactical displays, variable-focus lenses, and flexible cellular phones. However, previous technologies did not simultaneously realize macroscopic transparent actuators with advantages of large-shape deformation, low-voltage-driven actuation and fast fabrication. Here, we develop a fast approach to

  15. Towards a Dynamic Actuator Model for a Hexapod Robot

    DTIC Science & Technology

    2005-01-01

    pronking [7][8][9] and stair climbing [10][11][12]. Currently, each behaviour exploits proportional-derivative control of the legs to track...34 Proprioception Based Behavioral Advances in Hexapod Robot", 2001 IEEE Int. Conf. on Robotics and Automation (ICRA), pp 3650 - 3655, Seoul, Korea, May 21-26... Stair Climbing in a Simple Hexapod", 4th Int. Conf. on Climbing and Walking Robots, Karlsruhe, Germany, September 24 - 26 , 2001. [11] E. Z. Moore, D

  16. Trajectory tracking control of parallel robots in the presence of joint drive flexibility

    NASA Astrophysics Data System (ADS)

    Ider, S. Kemal; Korkmaz, Ozan

    2009-01-01

    Trajectory tracking control of parallel manipulators is aimed in the presence of flexibility at the joint drives. Joint structural damping is also considered in the dynamic model. The system is first converted into an open-tree structure by disconnecting a sufficient number of unactuated joints. The closed loops are then expressed by constraint equations. It is shown that, in a parallel robot with flexible joint drives, the acceleration level inverse dynamics equations are singular because the control torques do not have an instantaneous effect on the end-effector accelerations due to the elastic media. Eliminating the Lagrange multipliers and the intermediate variables, a fourth-order input-output relation is obtained between the actuator torques and the end-effector position variables. The proposed control law decouples and linearizes the system and achieves asymptotic stability by feedback of positions and velocities of the actuated joints and rotors. As a case study, a three degree of freedom, two legged planar parallel manipulator is simulated to illustrate the performance of the method. The end-effector desired trajectory is chosen such that the kinematic and drive singular positions are avoided.

  17. Noninvasive brain-actuated control of a mobile robot by human EEG.

    PubMed

    Millán, José del R; Renkens, Frédéric; Mouriño, Josep; Gerstner, Wulfram

    2004-06-01

    Brain activity recorded noninvasively is sufficient to control a mobile robot if advanced robotics is used in combination with asynchronous electroencephalogram (EEG) analysis and machine learning techniques. Until now brain-actuated control has mainly relied on implanted electrodes, since EEG-based systems have been considered too slow for controlling rapid and complex sequences of movements. We show that two human subjects successfully moved a robot between several rooms by mental control only, using an EEG-based brain-machine interface that recognized three mental states. Mental control was comparable to manual control on the same task with a performance ratio of 0.74.

  18. Stable visual PID control of a planar parallel robot

    NASA Astrophysics Data System (ADS)

    Garrido Moctezuma, Ruben; Soria López, Alberto; Trujano Cabrera, Miguel

    2008-11-01

    In this paper, we study an image-based PID control of a redundant planar parallel robot using a fixed camera configuration. The control objective is to move the robot end effector to the desired image reference position. The control law has a PD term plus an integral term with a nonlinear function of the position error. The proportional and integral actions use image loop information whereas the derivative action adds task space damping using joint level measurements. The Lyapunov method and the LaSalle invariance principle allow assessing asymptotic closed loop stability. Experiments show the feasibility of the proposed approach.

  19. Design, development, and evaluation of an MRI-guided SMA spring-actuated neurosurgical robot

    PubMed Central

    Ho, Mingyen; Kim, Yeongjin; Cheng, Shing Shin; Gullapalli, Rao; Desai, Jaydev P.

    2015-01-01

    In this paper, we present our work on the development of a magnetic resonance imaging (MRI)-compatible Minimally Invasive Neurosurgical Intracranial Robot (MINIR) comprising of shape memory alloy (SMA) spring actuators and tendon-sheath mechanism. We present the detailed modeling and analysis along with experimental results of the characterization of SMA spring actuators. Furthermore, to demonstrate image-feedback control, we used the images obtained from a camera to control the motion of the robot so that eventually continuous MR images could be used in the future to control the robot motion. Since the image tracking algorithm may fail in some situations, we also developed a temperature feedback control scheme which served as a backup controller for the robot. Experimental results demonstrated that both image feedback and temperature feedback can be used to control the motion of MINIR. A series of MRI compatibility tests were performed on the robot and the experimental results demonstrated that the robot is MRI compatible and no significant visual image distortion was observed in the MR images during robot operation. PMID:26622075

  20. The application of SMA spring actuators to a lightweight modular compliant surface bioinspired robot

    NASA Astrophysics Data System (ADS)

    Stone, David L.; Cranney, John; Liang, Robert; Taya, Minoru

    2004-07-01

    The DARPA Sponsored Compliant Surface Robotics (CSR) program pursues development of a high mobility, lightweight, modular, morph-able robot for military forces in the field and for other industrial uses. The USTLAB and University of Washington Center for Intelligent Materials and Systems (CIMS) effort builds on USTLAB proof of concept feasibility studies and demonstration of a 4, 6, or 8 wheeled modular vehicle with articulated leg-wheel assemblies. A collaborative effort between USTLAB and UW-CIMS explored the application of Shape Memory Alloy Nickel Titanium Alloy springs to a leg extension actuator capable of actuating with 4.5 Newton force over a 50 mm stroke. At the completion of Phase II, we have completed mechanical and electronics engineering design and achieved conventional actuation which currently enable active articulation, enabling autonomous reconfiguration for a wide variety of terrains, including upside down operations (in case of flip over), have developed a leg extension actuator demonstration model, and we have positioned our team to pursue a small vehicle with leg extension actuators in follow on work. The CSR vehicle's modular spider-like configuration facilitates adaptation to many uses and compliance over rugged terrain. The developmental process, actuator and vehicle characteristics will be discussed.

  1. Saturated Nussbaum Function Based Approach for Robotic Systems With Unknown Actuator Dynamics.

    PubMed

    Chen, Ci; Liu, Zhi; Zhang, Yun; Chen, C L Philip; Xie, Shengli

    2016-10-01

    This paper presents a saturated Nussbaum function based approach for robotic systems with unknown actuator dynamics. To eliminate the effect of the control shock from the traditional Nussbaum function, a new type of the saturated Nussbaum function is developed with the idea of time-elongation. Moreover, by exploiting properties of the proposed Nussbaum function, a promising theorem is established to deal with unknown multiple actuator nonlinearities. In what follows, the proposed theorem is integrated with the adaptive control technique such that the stability analysis of the robotic system is completed. It thus guarantees that the state of the robotic system asymptotically converges to the desired trajectory. Finally, comparative studies are carried out to validate the effectiveness and the superiority of the proposed approach.

  2. Neural Network Identification For a C5 Parallel Robot

    SciTech Connect

    Daachi, M. E.; Chikouche, D.; Achili, B.; Daachi, B.

    2008-06-12

    This paper presents the design and analysis of a neural network-based identification of the inverse dynamic model of a C5 parallel robot. The identification structure is designed using the black box form (the dynamic model is completely unknown). This identification uses real data acquired on the C5 parallel robot by applying a nominal control scheme (PD). The desired trajectories of this scheme are based on Fourier series and the coefficients are chosen in a heuristic way. We have used this type of desired trajectories to obtain exciting trajectories for identification procedure. Three identification schemes are tested and compared. The comparison is performed based on the number of parameters used in each architecture and the quality of the generalization error. The used neural network is of MLP type and composed of one hidden layer.

  3. MRI compatibility of robot actuation techniques--a comparative study.

    PubMed

    Fischer, Gregory S; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L; Gabor, Fichtinger

    2008-01-01

    This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRJ images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cylinders function with no loss of SNR with controller both inside and outside of the scanner room. The Nanomotion motor performs with moderate loss of SNR when moving during imaging. The Shinsei is unsuitable for motion during imaging. All may be used when motion is appropriately interleaved with imaging cycles.

  4. Stingray-inspired robot with simply actuated intermediate motion

    NASA Astrophysics Data System (ADS)

    Neely, Lincoln; Gaiennie, Jack; Noble, Nick; Erickson, Jonathan C.

    2016-04-01

    Batoids, or rays, utilize unique forms of locomotion that may offer more efficient techniques of motorized propulsion in various marine environments. We present a novel biomimetic engineering design and assembly of a stingray-inspired robot swimmer. The robots locomotion mimics the Dasyatis americana, or southern stingray, whose distinction among rays is its intermediate motion, characterized by sweeping strokes that propagate between 1/2-1 wavelength of the fin profile in the posterior direction. Though oscillatory (<1/2 wavelength) and undulatory (> wavelengths) ray-based robots have been created, this project demonstrates new engineering possibilities in what is, to the best of our knowledge, the first intermediately propelled batoid-based robot. The robots fins were made of silicone rubber, cast in a 3-D printed mold, with wingspan of 42 cm (1/2 - 1/5 scale for males and females, respectively, scale of model organism). Two anteriorly placed servomotors per fin were used, all controlled by one wirelessly enabled Arduino microcontroller. Each servomotor oscillated a flexible rod with cylindrical joint, whose frequency, speed, and front-back phase delay were user-programmed over wireless connection. During free-swimming tests, the fin profile developed about 0.8 wavelength, qualifying for successful mimicry of its biological inspiration. The robot satisfactorily maintained straight-line motion, reaching average peak velocity of 9.4+/-1.0 cm/s (0.27-0.03 body lengths/second) at its optimum flapping frequency of 1.4 Hz. This is in the same order of magnitude of speed normalized to body length achieved by others in two recent batoid-based projects. In summary, our robot performed intermediate stingray locomotion with relatively fewer components, which reveals robust potential for innovation of the simple intermediate batoid-based robot swimmer.

  5. Towards a Meso-Scale SMA-Actuated MRI-Compatible Neurosurgical Robot

    PubMed Central

    Ho, Mingyen; McMillan, Alan; Simard, J. Marc; Gullapalli, Rao; Desai, Jaydev P.

    2011-01-01

    Brain tumors are the most feared complications of cancer. Their treatment is challenging due to the lack of good imaging modality and the inability to remove the complete tumor. Facilitating tumor removal by accessing regions outside the “line-of-sight” will require a highly dexterous and MRI compatible robot. We present our work towards the development of a MRI-compatible neurosurgical robot. We used two antagonistic shape memory alloy (SMA) wires as actuators for each joint. Due to the size limitation of the device, we rely on temperature feedback to control the joint motion of the robot. We have developed a theoretical model based on Tanaka’s model to characterize the joint motion with the change in SMA wire temperature. The results demonstrated that the SMA wire temperature can be used reliably to predict the motion of the robot. We then used a PWM scheme and switching circuit to control the temperature of multiple SMA wires. Experimental results showed that we can actuate the robot reliably and observe joint motion in a gelatin medium. MR images also showed that the robot is fully MRI-compatible and creates no significant image distortion. PMID:22267960

  6. A force compliant surgical robotic tool with IPMC actuator and integrated sensing

    NASA Astrophysics Data System (ADS)

    Fu, Lixue; McDaid, Andrew J.; Aw, Kean C.

    2013-08-01

    A robotic surgical device, actuated by Ionic Polymer-metal Composite (IPMC), integrated with a strain gauge to achieve force control is proposed. Test results have proved the capabilities of this device to conduct surgical procedures. The recent growth of patient acceptance and demand for robotic aided surgery has stimulated the progress of research where in many applications the performance has been proven to surpass human surgeons. A new area which uses the inherently force compliant and back-drivable properties of polymers, IPMC in this case, has shown its potential to undertake precise surgical procedures in delicate environments of medical practice. This is because IPMCs have similar actuation characteristics to real biological systems ensuring the safety of the practice. Nevertheless, little has been done in developing IPMCs as a rotary joint actuators used as functional surgical devices. This research demonstrates the design of a single degree of freedom (1DOF) robotic surgical instrument with one joint mechanism actuated by IPMC with an embedded strain gauge as a feedback unit, and controlled by a scheduled gain PI controller. With the simplicity of the system it was proven to be able to cut to the desired controlled force and hence depth.

  7. Position Measurement/Tracking Comparison of the Instrumentation in a Droplet-Actuated-Robotic Platform

    PubMed Central

    Casier, Renaud; Lenders, Cyrille; Lhernould, Marion Sausse; Gauthier, Michaël; Lambert, Pierre

    2013-01-01

    This paper reports our work on developing a surface tension actuated micro-robotic platform supported by three bubbles (liquid environment) or droplets (gaseous environment). The actuation principle relies on the force developed by surface tension below a millimeter, which benefits from scaling laws, and is used to actuate this new type of compliant robot. By separately controlling the pressure inside each bubble, three degrees of freedom can be actuated. We investigated three sensing solutions to measure the platform attitude in real-time (z-position of each droplet, leading to the knowledge of the z position and Θx and Θy tilts of the platform). The comparison between optical, resistive, and capacitive measurement principles is hereafter reported. The optical technique uses SFH-9201 components. The resistive technique involves measuring the electrical resistance of a path flowing through two droplets and the platform. This innovative technique for sensing table position combines three pairs of resistances, from which the resistance in each drop can be deduced, thus determining the platform position. The third solution is a more usual high frequency (∼200 MHz) capacitive measurement. The resistive method has been proven reliable and is simple to implement. This work opens perspectives toward an interesting sensing solution for micro-robotic platforms. PMID:23653053

  8. Modeling and design of a tendon actuated soft robotic exoskeleton for hemiparetic upper limb rehabilitation.

    PubMed

    Nycz, Christopher J; Delph, Michael A; Fischer, Gregory S

    2015-01-01

    Robotic technology has recently been explored as a means to rehabilitate and assist individuals suffering from hemiparesis of their upper limbs. Robotic approaches allow for targeted rehabilitation routines which are more personalized and adaptable while providing quantitative measurements of patient outcomes. Development of these technologies into inherently safe and portable devices has the potential to extend the therapy outside of the clinical setting and into the patient's home with benefits to the cost and accessibility of care. To this end, a soft, cable actuated robotic glove and sleeve was designed, modeled, and constructed to provide assistance of finger and elbow movements in a way that mimics the biological function of the tendons. The resulting design increases safety through greater compliance as well as greater tolerance for misalignment with the user's skeletal frame over traditional rigid exoskeletons. Overall this design provides a platform to expand and study the concepts around soft robotic rehabilitation.

  9. Research regarding stiffness optimization of wires used for joints actuation from an elephant's trunk robotic arm

    NASA Astrophysics Data System (ADS)

    Ciofu, C.; Stan, G.

    2016-11-01

    Elephant's trunk robotic arms driven by wires and pulley mechanisms have issues with wires stiffness because of the entailed elastic deformations that is causing errors of positioning. Static and dynamic loads from each joint of the robotic arm affect the stiffness of driving wires and precision positioning. The influence of wires elastic deformation on precision positioning decreases with the increasing of wires stiffness by using different pre-tensioning devices. In this paper, we analyze the variation of driving wires stiffness particularly to each wire driven joint. We obtain optimum wires stiffness variation by using an analytical method that highlights the efficiency of pre-tensioning mechanism. The analysis of driving wires stiffness is necessary for taking appropriate optimization measures of robotic arm dynamic behavior and, thus, for decreasing positioning errors of the elephant's trunk robotic arm with inner actuation through wires/cables.

  10. Note: Position/torque control of antagonistic robot joint with high-compliant twisted string actuators (TSAs).

    PubMed

    Park, Jihyuk; Kim, Ji-Chul; Kim, Kyung-Soo; Kim, Soohyun

    2016-12-01

    A tendon-driven robot joint that has a low inertia compared with a conventional drive system is proposed. The robot joint displaces the drive system toward the robot base, and it is driven by twisted string actuators (TSAs), which are a substitute for the conventional heavy drive system. The design of the proposed robot joint is based on an antagonistic scheme that is actuated by two motors. The torques from the motors are transmitted to the robot joint through the TSAs. Based on the geometric analysis of TSAs, strategies for position and torque control are proposed for an antagonistic robot joint driven by TSAs. To verify the proposed control strategies, several control experiments are conducted using a developed prototype of a robot joint.

  11. A Concentric Tube Continuum Robot with Piezoelectric Actuation for MRI-Guided Closed-Loop Targeting.

    PubMed

    Su, Hao; Li, Gang; Rucker, D Caleb; Webster Iii, Robert J; Fischer, Gregory S

    2016-10-01

    This paper presents the design, modeling and experimental evaluation of a magnetic resonance imaging (MRI)-compatible concentric tube continuum robotic system. This system enables MRI-guided deployment of a precurved and steerable concentric tube continuum mechanism, and is suitable for clinical applications where a curved trajectory is needed. This compact 6 degree-of-freedom (DOF) robotic system is piezoelectrically-actuated, and allows simultaneous robot motion and imaging with no visually observable image artifact. The targeting accuracy is evaluated with optical tracking system and gelatin phantom under live MRI-guidance with Root Mean Square (RMS) errors of 1.94 and 2.17 mm respectively. Furthermore, we demonstrate that the robot has kinematic redundancy to reach the same target through different paths. This was evaluated in both free space and MRI-guided gelatin phantom trails, with RMS errors of 0.48 and 0.59 mm respectively. As the first of its kind, MRI-guided targeted concentric tube needle placements with ex vivo porcine liver are demonstrated with 4.64 mm RMS error through closed-loop control of the piezoelectrically-actuated robot.

  12. DEA for soft robotics: 1-gram actuator picks up a 60-gram egg

    NASA Astrophysics Data System (ADS)

    Shintake, Jun; Rosset, Samuel; Schubert, Bryan; Mintchev, Stefano; Floreano, Dario; Shea, Herbert

    2015-04-01

    We introduce a soft actuator for grippers using DEA capable of bending actuation. The actuator is also able to generate the electro-adhesion by the fringe field formed at the edges of the electrodes. The adhesion improves the holding force and ensures the conformation of the structure to the object. After the characterization of the actuator, we develop a 2-finger soft gripper capable of holding various objects. The gripper has a mass of around 1 g, and consists of a few cm long actuation parts, realizing simple open-close movement. The compliance of the gripper leads to conformation of the structure against the object surface, which is proven by successful handling of objects with different geometries such as a toothbrush, a flat paper, and a ping pong ball. The effect of the electro-adhesion is visible when the paper is held with its flat shape meaning that an adhesion force against gravity exists. Also, by the fact that the conformed structure increases the contact area, the holding force is improved while avoiding damaging the object, which is highlighted by the ability to hold a raw egg weighing around 60 g. This soft gripper, combining both actuation and electro-adhesion, illustrates the potential use of DEA for soft robotics.

  13. Multifunctional electroelastomer roll actuators and their application for biomimetic walking robots

    NASA Astrophysics Data System (ADS)

    Pei, Qibing; Rosenthal, Marcus A.; Pelrine, Ron; Stanford, Scott; Kornbluh, Roy D.

    2003-07-01

    Dielectric elastomer artificial muscles (electroelastomers) have been shown to exhibit excellent performance in a variety of actuator configurations. By rolling highly prestrained electroelastomer films onto a central compression spring, we have demonstrated multifunctional electroelastomer rolls (MERs) that combine load bearing, actuation, and sensing functions. The rolls are compact, have a potentially high electroelastomer-to-structure weight ratio, and can be configured to actuate in several ways including axial extension and bending, and as multiple degree-of-freedom (DOF) actuators that combine both extension and bending. 1-DOF, 2-DOF, and 3-DOF MERs have all been demonstrated through suitable electrode patterning on a single monolithic substrate. The bending MER actuators can act as leg and knee joints to produce biomimetic walking that is adaptable to many environments. Results of animation and the fabrications of a robot model of a synthetic bug or animal based on the MERs are presented. A new concept for an antagonist actuator for more precise control is introduced.

  14. An adaptive actuator failure compensation scheme for two linked 2WD mobile robots

    NASA Astrophysics Data System (ADS)

    Ma, Yajie; Al-Dujaili, Ayad; Cocquempot, Vincent; El Badaoui El Najjar, Maan

    2017-01-01

    This paper develops a new adaptive compensation control scheme for two linked mobile robots with actuator failurs. A configuration with two linked two-wheel drive (2WD) mobile robots is proposed, and the modelling of its kinematics and dynamics are given. An adaptive failure compensation scheme is developed to compensate actuator failures, consisting of a kinematic controller and a multi-design integration based dynamic controller. The kinematic controller is a virtual one, and based on which, multiple adaptive dynamic control signals are designed which covers all possible failure cases. By combing these dynamic control signals, the dynamic controller is designed, which ensures system stability and asymptotic tracking properties. Simulation results verify the effectiveness of the proposed adaptive failure compensation scheme.

  15. Single actuator wave-like robot (SAW): design, modeling, and experiments.

    PubMed

    Zarrouk, David; Mann, Moshe; Degani, Nir; Yehuda, Tal; Jarbi, Nissan; Hess, Amotz

    2016-07-01

    In this paper, we present a single actuator wave-like robot, a novel bioinspired robot which can move forward or backward by producing a continuously advancing wave. The robot has a unique minimalistic mechanical design and produces an advancing sine wave, with a large amplitude, using only a single motor but with no internal straight spine. Over horizontal surfaces, the robot does not slide relative to the surface and its direction of locomotion is determined by the direction of rotation of the motor. We developed a kinematic model of the robot that accounts for the two-dimensional mechanics of motion and yields the speed of the links relative to the motor. Based on the optimization of the kinematic model, and accounting for the mechanical constraints, we have designed and built multiple versions of the robot with different sizes and experimentally tested them (see movie). The experimental results were within a few percentages of the expectations. The larger version attained a top speed of 57 cm s(-1) over a horizontal surface and is capable of climbing vertically when placed between two walls. By optimizing the parameters, we succeeded in making the robot travel by 13% faster than its own wave speed.

  16. Control of Speed and Power in a Humanoid Robot Arm Using Pneumatic Actuators for Human-Robot Coexisting Environment

    NASA Astrophysics Data System (ADS)

    Hoshino, Kiyoshi

    A new type of humanoid robot arm which can coexist and be interactive with human beings are looked for. For the purpose of implementation of human smooth and fast movement to a pneumatic robot, the author used a humanoid robot arm with pneumatic agonist-antagonist actuators as endoskeletons which has control mechanism in the stiffness of each joint, and the controllability was experimentally discussed. Using Kitamori's method to experimentally decide the control gains and using I-PD controller, three joints of the humanoid robot arm were experimentally controlled. The damping control algorithm was also adopted to the wrist joint, to modify the speed in accordance with the power. The results showed that the controllability to step-wise input was less than one degree in error to follow the target angles, and the time constant was less than one second. The simultaneous input of command to three joints was brought about the overshoot of about ten percent increase in error. The humanoid robot arm can generate the calligraphic motions, moving quickly at some times but slowly at other times, or particularly softly on some occasions but stiffly on other occasions at high accuracy.

  17. A robotic finger driven by twisted and coiled polymer actuator

    NASA Astrophysics Data System (ADS)

    Cho, Kyeong Ho; Song, Min Geun; Jung, Hosang; Park, Jungwoo; Moon, Hyungpil; Koo, Ja Choon; Nam, Jae-Do; Choi, Hyouk Ryeol

    2016-04-01

    Previous studies reported that a twisted and coiled polymer actuator (TCA) generates strong force and large stroke by heating. Nylon 6,6 is known to be the most suitable polymer material for TCA because it has high thermal expansion ratio, high softening point and high toughness which is able to sustain gigantic twisting. In order to find the optimal structure of TCA fabricated with silver-coated nylon sewing threads, an equipment for twist-insertion (structuralization), composed of single DC motor, a slider fabricated by 3D printer and a body frame, is developed. It can measure the behaviors of TCAs as well as fabricate TCAs with desired characteristics by structuralizing fibers with controlled rotation per minutes (RPM) and turns. Comparing performances of diverse structures of TCAs, the optimal structure for TCA is found. For the verification of the availability of the optimal TCA, a TCA-driven biomimetic finger is developed. Finally, we successfully demonstrate the flexion/extension of the finger by using the actuation of TCAs.

  18. Design and energetic evaluation of a prosthetic knee joint actuator with a lockable parallel spring.

    PubMed

    Geeroms, J; Flynn, L; Jimenez-Fabian, R; Vanderborght, B; Lefeber, D

    2017-02-03

    There are disadvantages to existing damping knee prostheses which cause an asymmetric gait and higher metabolic cost during level walking compared to non-amputees. Most existing active knee prostheses which could benefit the amputees use a significant amount of energy and require a considerable motor. In this work, a novel semi-active actuator with a lockable parallel spring for a prosthetic knee joint has been developed and tested. This actuator is able to provide an approximation of the behavior of a healthy knee during most of the gait cycle of level walking. This actuator is expanded with a series-elastic actuator to mimic the full gait cycle and enable its use in other functional tasks like stair climbing and sit-to-stance. The proposed novel actuator reduces the energy consumption for the same trajectory with respect to a compliant or directly-driven prosthetic active knee joint and improves the approximation of healthy knee behavior during level walking compared to passive or variable damping knee prostheses.

  19. A Parallel Approach To Optimum Actuator Selection With a Genetic Algorithm

    NASA Technical Reports Server (NTRS)

    Rogers, James L.

    2000-01-01

    Recent discoveries in smart technologies have created a variety of aerodynamic actuators which have great potential to enable entirely new approaches to aerospace vehicle flight control. For a revolutionary concept such as a seamless aircraft with no moving control surfaces, there is a large set of candidate locations for placing actuators, resulting in a substantially larger number of combinations to examine in order to find an optimum placement satisfying the mission requirements. The placement of actuators on a wing determines the control effectiveness of the airplane. One approach to placement Maximizes the moments about the pitch, roll, and yaw axes, while minimizing the coupling. Genetic algorithms have been instrumental in achieving good solutions to discrete optimization problems, such as the actuator placement problem. As a proof of concept, a genetic has been developed to find the minimum number of actuators required to provide uncoupled pitch, roll, and yaw control for a simplified, untapered, unswept wing model. To find the optimum placement by searching all possible combinations would require 1,100 hours. Formulating the problem and as a multi-objective problem and modifying it to take advantage of the parallel processing capabilities of a multi-processor computer, reduces the optimization time to 22 hours.

  20. An FDES-Based Shared Control Method for Asynchronous Brain-Actuated Robot.

    PubMed

    Liu, Rong; Wang, Yong-Xuan; Zhang, Lin

    2016-06-01

    The asynchronous brain-computer interface (BCI) offers more natural human-machine interaction. However, it is still considered insufficient to control rapid and complex sequences of movements for a robot without any advanced control method. This paper proposes a new shared controller based on the supervisory theory of fuzzy discrete event system (FDES) for brain-actuated robot control. The developed supervisory theory allows the more reliable control mode to play a dominant role in the robot control which is beneficial to reduce misoperation and improve the robustness of the system. The experimental procedures consist of real-time direct manual control and BCI control tests from ten volunteers. Both tests have shown that the proposed method significantly improves the performance and robustness of the robotic control. In an online BCI experiment, eight of the participants successfully controlled the robot to circumnavigate obstacles and reached the target with a three mental states asynchronous BCI while the other two participants failed in all the BCI control sessions. Furthermore, the FDES-based shared control method also helps to reduce the workload. It can be stated that the asynchronous BCI, in combination with FDES-based shared controller, is feasible for the real-time and robust control of robotics.

  1. A bio-inspired bell kinematics design of a jellyfish robot using ionic polymer metal composites actuators

    NASA Astrophysics Data System (ADS)

    Najem, Joseph; Leo, Donald J.

    2012-04-01

    This paper presents the re-creation of the bell deformation cycle of the Aequorea victoria jellyfish. It focuses on the design, fabrication, and characterization of the bio-inspired bell kinematics of an IPMC actuated robotic jellyfish. The shape and bell kinematics of this underwater vehicle are based on the Aequorea victoria jellyfish. This medusa is chosen as a model system based on a comparative bell kinematics study that is conducted among different jellyfish species. Aequorea victoria is known by its low swimming frequency, small bell deformation, and high Froude efficiency (95%). Different methods of implementing the actuators underneath the bell with smaller IPMC actuators are investigated to replicate the natural jellyfish's bell deformation. Results demonstrates that proper placement of the IPMC actuators results in bell configuration that more accurately represents the deformation properties of the natural jellyfish. Smaller IPMC actuators are used to achieve the desired deformation and thus the power consumption is reduced by 70% compared to previous generations. A biomimetic jellyfish robot prototype is built, and its ability to swim and produce thrust with smaller IPMC actuators is shown. The robot swam with four actuators swam at an average speed 0.77 mm/s and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm/s with a power consumption of 1.14 W.

  2. 1999 IEEE international conference on robotics and automation

    SciTech Connect

    1999-07-01

    Topics covered in this conference include: biped robots; underwater vehicles; robot planning and programming for assembly; discrete event control of mobile robot maneuvering; navigation in unknown environment; biped robots; underwater vehicles; robot planning and programming for assembly; discrete event control of manufacturing systems; motion planning; robot control; actuator; teleoperation; force and position control; contact and grasping control; visual servo control; tactile sensing; mobile robots and applications; sensor-based navigation; underwater robotics; sensing, navigation and control; flexible manipulators; task scheduling; actuators and joint actuation; teleoperation; sensor-based teleoperation; contact geometry; sonar-based sensing; mobile robot-environment interaction; mobile robot motion planning; biology-inspired methods; service and underwater robots; manufacturing planning and scheduling; constraint and nonholonomic system; fault-tolerant robots; parallel manipulators; dexterous manipulation; computer vision in manufacturing; contact sensing; mobile robot field applications; flexible robots; fuzzy control; and more.

  3. Electromagnetic micro-actuators, micro-motors, and micro-robots

    NASA Astrophysics Data System (ADS)

    Feldmann, M.; Waldschik, A.; Büttgenbach, S.

    2007-12-01

    Due to the development of new technologies, more and more complex MEMS applications can be realized. Especially electromagnetic micro actuators have reached a growing interest in micro technology in addition to commercial applications during the last years. Their basic construction exists of electric conductors and coil systems as well as of soft-magnetic and/or hard-magnetic materials that were fabricated in additive technology via UV-depth lithography and electroplating. For UV-depth lithography, photo resists like Epon SU-8, AZ9260, Intervia-3D-N and CAR44 were applied and optimized. Layer thickness up to 1 mm and aspect ratios over 60 were achieved. Special micro composites were developed. This allowed the fabrication of micro magnets with arbitrary shape and properties, revealing a complete compatibility to existing process chains. With these potential technologies, several complex 3-D micro actuators like micro motors and micro robots were developed and successfully tested. These developments include in detail: linear and rotatory reluctance micro stepper motors with compensated attraction force as well as a special "Lorentz force actuator", which was used for micro robots and micro motors. The micro robots were deployed for assembling and for micro-/nano positioning. Furthermore "plunger coil actuators" were realized based on a voice coil principle, which were used e.g. for a micro switch or a micro mirror. Moreover, rotatory synchronous motors were developed and successfully tested. All these devices have been realized by outstanding fabrication technologies and can be used for a wide range of applications.

  4. An Analytic Model for the Success Rate of a Robotic Actuator System in Hitting Random Targets.

    PubMed

    Bradley, Stuart

    2015-11-20

    Autonomous robotic systems are increasingly being used in a wide range of applications such as precision agriculture, medicine, and the military. These systems have common features which often includes an action by an "actuator" interacting with a target. While simulations and measurements exist for the success rate of hitting targets by some systems, there is a dearth of analytic models which can give insight into, and guidance on optimization, of new robotic systems. The present paper develops a simple model for estimation of the success rate for hitting random targets from a moving platform. The model has two main dimensionless parameters: the ratio of actuator spacing to target diameter; and the ratio of platform distance moved (between actuator "firings") to the target diameter. It is found that regions of parameter space having specified high success are described by simple equations, providing guidance on design. The role of a "cost function" is introduced which, when minimized, provides optimization of design, operating, and risk mitigation costs.

  5. Supinator Extender (SUE): a pneumatically actuated robot for forearm/wrist rehabilitation after stroke.

    PubMed

    Allington, James; Spencer, Steven J; Klein, Julius; Buell, Meghan; Reinkensmeyer, David J; Bobrow, James

    2011-01-01

    The robot described in this paper, SUE (Supinator Extender), adds forearm/wrist rehabilitation functionality to the UCI BONES exoskeleton robot and to the ArmeoSpring rehabilitation device. SUE is a 2-DOF serial chain that can measure and assist forearm supination-pronation and wrist flexion-extension. The large power to weight ratio of pneumatic actuators allows SUE to achieve the forces needed for rehabilitation therapy while remaining lightweight enough to be carried by BONES and ArmeoSpring. Each degree of freedom has a range of 90 degrees, and a nominal torque of 2 ft-lbs. The cylinders are mounted away from the patient's body on the lateral aspect of the arm. This is to prevent the danger of a collision and maximize the workspace of the arm robot. The rotation axis used for supination-pronation is a small bearing just below the subject's wrist. The flexion-extension motion is actuated by a cantilevered pneumatic cylinder, which allows the palm of the hand to remain open. Data are presented that demonstrate the ability of SUE to measure and cancel forearm/wrist passive tone, thereby extending the active range of motion for people with stroke.

  6. Dynamic pull-in of parallel plate and torsional electrostatic MEMS actuators.

    SciTech Connect

    Nielson, Gregory N.; Barbastathis, George

    2005-02-01

    An analysis of the dynamic characteristics of pull-in for parallel-plate and torsional electrostatic actuators is presented. Traditionally, the analysis for pull-in has been done using quasi-static assumptions. However, it was recently shown experimentally that a step input can cause a decrease in the voltage required for pull-in to occur. We propose an energy-based solution for the step voltage required for pull-in that predicts the experimentally observed decrease in the pull-in voltage. We then use similar energy techniques to explore pull-in due to an actuation signal that is modulated depending on the sign of the velocity of the plate (i.e., modulated at the instantaneous mechanical resonant frequency). For this type of actuation signal, significant reductions in the pull-in voltage can theoretically be achieved without changing the stiffness of the structure. This analysis is significant to both parallel-plate and torsional electrostatic microelectromechanical systems (MEMS) switching structures where a reduced operating voltage without sacrificing stiffness is desired, as well as electrostatic MEMS oscillators where pull-in due to dynamic effects needs to be avoided.

  7. Establishment of a fabrication method for a long-term actuated hybrid cell robot.

    PubMed

    Kim, Jinseok; Park, Jungyul; Yang, Sungwook; Baek, Jeongeun; Kim, Byungkyu; Lee, Sang Ho; Yoon, Eui-Sung; Chun, Kukjin; Park, Sukho

    2007-11-01

    We developed a novel method to fabricate a crab-like microrobot that can actuate for a long period in a physiological condition. The microrobot backbone was built with a biocompatible and elastic material-polydimethylsiloxane (PDMS)-by using a specially designed 3D molding aligner, and consisted of three strips of PDMS "legs" connected across a "body." Cardiomyocytes were then plated on the grooved top surface of the backbone, resulting in a high concentration of pulsating cells. These key techniques enabled the microrobot to walk continuously for over ten days. The performance of our crab-like microrobot was measured at an average velocity of 100 microm s(-1), and the estimated total distance it travelled was 50 m over a one-week period. Thus, we have demonstrated for the first time a walking robot that exhibited reliable and long-term actuation performances.

  8. On-chip magnetically actuated robot with ultrasonic vibration for single cell manipulations.

    PubMed

    Hagiwara, Masaya; Kawahara, Tomohiro; Yamanishi, Yoko; Masuda, Taisuke; Feng, Lin; Arai, Fumihito

    2011-06-21

    This paper presents an innovative driving method for an on-chip robot actuated by permanent magnets in a microfluidic chip. A piezoelectric ceramic is applied to induce ultrasonic vibration to the microfluidic chip and the high-frequency vibration reduces the effective friction on the MMT significantly. As a result, we achieved 1.1 micrometre positioning accuracy of the microrobot, which is 100 times higher accuracy than without vibration. The response speed is also improved and the microrobot can be actuated with a speed of 5.5 mm s(-1) in 3 degrees of freedom. The novelty of the ultrasonic vibration appears in the output force as well. Contrary to the reduction of friction on the microrobot, the output force increased twice as much by the ultrasonic vibration. Using this high accuracy, high speed, and high power microrobot, swine oocyte manipulations are presented in a microfluidic chip.

  9. A fully actuated robotic assistant for MRI-guided prostate biopsy and brachytherapy

    NASA Astrophysics Data System (ADS)

    Li, Gang; Su, Hao; Shang, Weijian; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M.; Fischer, Gregory S.

    2013-03-01

    Intra-operative medical imaging enables incorporation of human experience and intelligence in a controlled, closed-loop fashion. Magnetic resonance imaging (MRI) is an ideal modality for surgical guidance of diagnostic and therapeutic procedures, with its ability to perform high resolution, real-time, high soft tissue contrast imaging without ionizing radiation. However, for most current image-guided approaches only static pre-operative images are accessible for guidance, which are unable to provide updated information during a surgical procedure. The high magnetic field, electrical interference, and limited access of closed-bore MRI render great challenges to developing robotic systems that can perform inside a diagnostic high-field MRI while obtaining interactively updated MR images. To overcome these limitations, we are developing a piezoelectrically actuated robotic assistant for actuated percutaneous prostate interventions under real-time MRI guidance. Utilizing a modular design, the system enables coherent and straight forward workflow for various percutaneous interventions, including prostate biopsy sampling and brachytherapy seed placement, using various needle driver configurations. The unified workflow compromises: 1) system hardware and software initialization, 2) fiducial frame registration, 3) target selection and motion planning, 4) moving to the target and performing the intervention (e.g. taking a biopsy sample) under live imaging, and 5) visualization and verification. Phantom experiments of prostate biopsy and brachytherapy were executed under MRI-guidance to evaluate the feasibility of the workflow. The robot successfully performed fully actuated biopsy sampling and delivery of simulated brachytherapy seeds under live MR imaging, as well as precise delivery of a prostate brachytherapy seed distribution with an RMS accuracy of 0.98mm.

  10. A Fully Actuated Robotic Assistant for MRI-Guided Prostate Biopsy and Brachytherapy.

    PubMed

    Li, Gang; Su, Hao; Shang, Weijian; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M; Fischer, Gregory S

    2013-03-12

    Intra-operative medical imaging enables incorporation of human experience and intelligence in a controlled, closed-loop fashion. Magnetic resonance imaging (MRI) is an ideal modality for surgical guidance of diagnostic and therapeutic procedures, with its ability to perform high resolution, real-time, high soft tissue contrast imaging without ionizing radiation. However, for most current image-guided approaches only static pre-operative images are accessible for guidance, which are unable to provide updated information during a surgical procedure. The high magnetic field, electrical interference, and limited access of closed-bore MRI render great challenges to developing robotic systems that can perform inside a diagnostic high-field MRI while obtaining interactively updated MR images. To overcome these limitations, we are developing a piezoelectrically actuated robotic assistant for actuated percutaneous prostate interventions under real-time MRI guidance. Utilizing a modular design, the system enables coherent and straight forward workflow for various percutaneous interventions, including prostate biopsy sampling and brachytherapy seed placement, using various needle driver configurations. The unified workflow compromises: 1) system hardware and software initialization, 2) fiducial frame registration, 3) target selection and motion planning, 4) moving to the target and performing the intervention (e.g. taking a biopsy sample) under live imaging, and 5) visualization and verification. Phantom experiments of prostate biopsy and brachytherapy were executed under MRI-guidance to evaluate the feasibility of the workflow. The robot successfully performed fully actuated biopsy sampling and delivery of simulated brachytherapy seeds under live MR imaging, as well as precise delivery of a prostate brachytherapy seed distribution with an RMS accuracy of 0.98mm.

  11. Kinematics and control of redundant robotic arm based on dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Branz, Francesco; Antonello, Andrea; Carron, Andrea; Carli, Ruggero; Francesconi, Alessandro

    2015-04-01

    Soft robotics is a promising field and its application to space mechanisms could represent a breakthrough in space technologies by enabling new operative scenarios (e.g. soft manipulators, capture systems). Dielectric Elastomers Actuators have been under deep study for a number of years and have shown several advantages that could be of key importance for space applications. Among such advantages the most notable are high conversion efficiency, distributed actuation, self-sensing capability, multi-degree-of-freedom design, light weight and low cost. The big potentialities of double cone actuators have been proven in terms of good performances (i.e. stroke and force/torque), ease of manufacturing and durability. In this work the kinematic, dynamic and control design of a two-joint redundant robotic arm is presented. Two double cone actuators are assembled in series to form a two-link design. Each joint has two degrees of freedom (one rotational and one translational) for a total of four. The arm is designed to move in a 2-D environment (i.e. the horizontal plane) with 4 DoF, consequently having two degrees of redundancy. The redundancy is exploited in order to minimize the joint loads. The kinematic design with redundant Jacobian inversion is presented. The selected control algorithm is described along with the results of a number of dynamic simulations that have been executed for performance verification. Finally, an experimental setup is presented based on a flexible structure that counteracts gravity during testing in order to better emulate future zero-gravity applications.

  12. Construction of a Fish-like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials.

    PubMed

    Xiao, Peishuang; Yi, Ningbo; Zhang, Tengfei; Huang, Yi; Chang, Huicong; Yang, Yang; Zhou, Ying; Chen, Yongsheng

    2016-06-01

    Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish-like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene-PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene-based materials at a macro scale.

  13. Distributed power and control actuation in the thoracic mechanics of a robotic insect.

    PubMed

    Finio, Benjamin M; Wood, Robert J

    2010-12-01

    Recent advances in the understanding of biological flight have inspired roboticists to create flapping-wing vehicles on the scale of insects and small birds. While our understanding of the wing kinematics, flight musculature and neuromotor control systems of insects has expanded, in practice it has proven quite difficult to construct an at-scale mechanical device capable of similar flight performance. One of the key challenges is the development of an effective and efficient transmission mechanism to control wing motions. Here we present multiple insect-scale robotic thorax designs capable of producing asymmetric wing kinematics similar to those observed in nature and utilized by dipteran insects to maneuver. Inspired by the thoracic mechanics of dipteran insects, which entail a morphological separation of power and control muscles, these designs show that such distributed actuation can also modulate wing motion in a robotic design.

  14. Adaptive control of rigid-link electrically-driven robots actuated with brushless DC motors

    SciTech Connect

    Bridges, M.M.; Dawson, D.M.

    1994-12-31

    In this paper, we extend the work of [1] and [2] to design an adaptive controller for rigid-link electrically-driven (RLED) robot manipulators specifically actuated with Brushless Direct Current (BLDC) motors. In particular the adaptive controller presented is tailored to handle the multi-link dynamics of a rigid-link robot as opposed to a simple inertial load. Furthermore, the linear electrical dynamics of brushed DC motors used in the development of [1], are replaced with the multiple input nonlinear dynamics of BLDC motors. The result is an adaptive controller that guarantees globally asymptotic convergence of the link position tracking error in spite of parametric uncertainty throughout the entire electro-mechanical model.

  15. Toward robotic needle steering in lung biopsy: a tendon-actuated approach

    NASA Astrophysics Data System (ADS)

    Kratchman, Louis B.; Rahman, Mohammed M.; Saunders, Justin R.; Swaney, Philip J.; Webster, Robert J., III

    2011-03-01

    Needle tip dexterity is advantageous for transthoracic lung biopsies, which are typically performed with rigid, straight biopsy needles. By providing intraoperative compensation for trajectory error and lesion motion, tendon-driven biopsy needles may reach smaller or deeper nodules in fewer attempts, thereby reducing trauma. An image-guided robotic system that uses these needles also has the potential to reduce radiation exposure to the patient and physician. In this paper, we discuss the design, workflow, kinematic modeling, and control of both the needle and a compact and inexpensive robotic prototype that can actuate the tendon-driven needle for transthoracic lung biopsy. The system is designed to insert and steer the needle under Computed Tomography (CT) guidance. In a free-space targeting experiment using a discrete proportional control law with digital camera feedback, we show a position error of less than 1 mm achieved using an average of 8.3 images (n=3).

  16. Helicopter force-feel and stability augmentation system with parallel servo-actuator

    NASA Technical Reports Server (NTRS)

    Hoh, Roger H. (Inventor)

    2006-01-01

    A force-feel system is implemented by mechanically coupling a servo-actuator to and in parallel with a flight control system. The servo-actuator consists of an electric motor, a gearing device, and a clutch. A commanded cockpit-flight-controller position is achieved by pilot actuation of a trim-switch. The position of the cockpit-flight-controller is compared with the commanded position to form a first error which is processed by a shaping function to correlate the first error with a commanded force at the cockpit-flight-controller. The commanded force on the cockpit-flight-controller provides centering forces and improved control feel for the pilot. In an embodiment, the force-feel system is used as the basic element of stability augmentation system (SAS). The SAS provides a stabilization signal that is compared with the commanded position to form a second error signal. The first error is summed with the second error for processing by the shaping function.

  17. An Analytic Model for the Success Rate of a Robotic Actuator System in Hitting Random Targets

    PubMed Central

    Bradley, Stuart

    2015-01-01

    Autonomous robotic systems are increasingly being used in a wide range of applications such as precision agriculture, medicine, and the military. These systems have common features which often includes an action by an “actuator” interacting with a target. While simulations and measurements exist for the success rate of hitting targets by some systems, there is a dearth of analytic models which can give insight into, and guidance on optimization, of new robotic systems. The present paper develops a simple model for estimation of the success rate for hitting random targets from a moving platform. The model has two main dimensionless parameters: the ratio of actuator spacing to target diameter; and the ratio of platform distance moved (between actuator “firings”) to the target diameter. It is found that regions of parameter space having specified high success are described by simple equations, providing guidance on design. The role of a “cost function” is introduced which, when minimized, provides optimization of design, operating, and risk mitigation costs. PMID:26610500

  18. Design and Control of a 1-DOF MRI Compatible Pneumatically Actuated Robot with Long Transmission Lines

    PubMed Central

    Yang, Bo; Tan, U-Xuan; McMillan, Alan; Gullapalli, Rao; Desai, Jaydev P.

    2011-01-01

    This paper presents the design and control of an MRI-compatible 1-DOF needle driver robot and its precise position control using pneumatic actuation with long transmission lines. MRI provides superior image quality compared to other imaging modalities such as CT or ultrasound, but imposes severe limitations on the material and actuator choice (to prevent image distortion) due to its strong magnetic field. We are primarily interested in developing a pneumatically actuated breast biopsy robot with a large force bandwidth and precise targeting capability during radio-frequency ablation (RFA) of breast tumor, and exploring the possibility of using long pneumatic transmission lines from outside the MRI room to the device in the magnet to prevent any image distortion whatsoever. This paper presents a model of the entire pneumatic system. The pneumatic lines are approximated by a first order system with time delay, because its dynamics are governed by the telegraph equation with varying coefficients and boundary conditions, which cannot be solved precisely. The slow response of long pneumatic lines and valve subsystems make position control challenging. This is further compounded by the presence of non-uniform friction in the device. Sliding mode control (SMC) was adopted, where friction was treated as an uncertainty term to drive the system onto the sliding surface. Three different controllers were designed, developed, and evaluated to achieve precise position control of the RFA probe. Experimental results revealed that all SMCs gave satisfactory performance with long transmission lines. We also performed several experiments with a 3-DOF fiber-optic force sensor attached to the needle driver to evaluate the performance of the device in the MRI under continuous imaging. PMID:22058649

  19. Gait analysis of a radial symmetrical hexapod robot based on parallel mechanisms

    NASA Astrophysics Data System (ADS)

    Xu, Kun; Ding, Xilun

    2014-09-01

    Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height. This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism. Assuming the constraints between the supporting feet and the ground with hinges, the supporting legs and the hexapod body are taken as a parallel mechanism, and each swing leg is regarded as a serial manipulator. The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground. Locomotion performance can be got by analyzing these equivalent mechanisms. The kinematics of the whole robotic system is established, and the influence of foothold position on the workspace of robot body is analyzed. A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle. Referring to service region and service sphere, weight service sphere and weight service region are put forward to evaluate the dexterity of robot body. The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated. Simulation shows when the foothold offset goes up to 174 mm, the dexterity of robot body achieves its maximum value 0.1644 in mixed gait. The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot, and provide new approach to determine the stride length, body height, footholds in gait planning of multi-legged robot.

  20. Actuation of a robotic fish caudal fin for low reaction torque.

    PubMed

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

    2011-07-01

    In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

  1. Actuation of a robotic fish caudal fin for low reaction torque

    NASA Astrophysics Data System (ADS)

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

    2011-07-01

    In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

  2. Biped walking robot based on a 2-UPU+2-UU parallel mechanism

    NASA Astrophysics Data System (ADS)

    Miao, Zhihuai; Yao, Yan'an; Kong, Xianwen

    2014-03-01

    Existing biped robots mainly fall into two categories: robots with left and right feet and robots with upper and lower feet. The load carrying capability of a biped robot is quite limited since the two feet of a walking robot supports the robot alternatively during walking. To improve the load carrying capability, a novel biped walking robot is proposed based on a 2-UPU+2-UU parallel mechanism. The biped walking robot is composed of two identical platforms(feet) and four limbs, including two UPU(universal-prismatic-universal serial chain) limbs and two UU limbs. To enhance its terrain adaptability like articulated vehicles, the two feet of the biped walking robot are designed as two vehicles in detail. The conditions that the geometric parameters of the feet must satisfy are discussed. The degrees-of-freedom of the mechanism is analyzed by using screw theory. Gait analysis, kinematic analysis and stability analysis of the mechanism are carried out to verify the structural design parameters. The simulation results validate the feasibility of walking on rugged terrain. Experiments with a physical prototype show that the novel biped walking robot can walk stably on smooth terrain. Due to its unique feet design and high stiffness, the biped walking robot may adapt to rugged terrain and is suitable for load-carrying.

  3. Development and Evaluation of an Actuated MRI-Compatible Robotic System for MRI-Guided Prostate Intervention

    PubMed Central

    Krieger, Axel; Song, Sang-Eun; Cho, Nathan B.; Iordachita, Iulian; Guion, Peter; Fichtinger, Gabor; Whitcomb, Louis L.

    2012-01-01

    This paper reports the design, development, and magnetic resonance imaging (MRI) compatibility evaluation of an actuated transrectal prostate robot for MRI-guided needle intervention in the prostate. The robot performs actuated needle MRI-guidance with the goals of providing (i) MRI compatibility, (ii) MRI-guided needle placement with accuracy sufficient for targeting clinically significant prostate cancer foci, (iii) reducing interventional procedure times (thus increasing patient comfort and reducing opportunity for needle targeting error due to patient motion), (iv) enabling real-time MRI monitoring of interventional procedures, and (v) reducing the opportunities for error that arise in manually actuated needle placement. The design of the robot, employing piezo-ceramic-motor actuated needle guide positioning and manual needle insertion, is reported. Results of a MRI compatibility study show no reduction of MRI signal-to-noise-ratio (SNR) with the motors disabled. Enabling the motors reduces the SNR by 80% without RF shielding, but SNR is only reduced by 40% to 60% with RF shielding. The addition of radio-frequency shielding is shown to significantly reduce image SNR degradation caused by the presence of the robotic device. An accuracy study of MRI-guided biopsy needle placements in a prostate phantom is reported. The study shows an average in-plane targeting error of 2.4 mm with a maximum error of 3.7 mm. These data indicate the system’s needle targeting accuracy is similar to that obtained with a previously reported manually actuated system, and is sufficient to reliably sample clinically significant prostate cancer foci under MRI-guidance. PMID:23326181

  4. A New Approach for Human Forearm Motion Assist by Actuated Artificial Joint-An Inner Skeleton Robot

    NASA Astrophysics Data System (ADS)

    Kundu, Subrata Kumar; Kiguchi, Kazuo; Teramoto, Kenbu

    In order to help the physical activities of the elderly or physically disabled persons, we propose a new concept of a power-assist inner skeleton robot (i.e., actuated artificial joint) that is supposed to assist the human daily life motion from inside of the human body. This paper presents an implantable 2 degree of freedom (DOF) inner skeleton robot that is designed to assist human elbow flexion-extension motion and forearm supination-pronation motion for daily life activities. We have developed a prototype of the inner skeleton robot that is supposed to assist the motion from inside of the body and act as an actuated artificial joint. The proposed system is controlled based on the activation patterns of the electromyogram (EMG) signals of the user's muscles by applying fuzzy-neuro control method. A joint actuator with angular position sensor is designed for the inner skeleton robot and a T-Mechanism is proposed to keep the bone arrangement similar to the normal human articulation after the elbow arthroplasty. The effectiveness of the proposed system has been evaluated by experiment.

  5. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, Douglas B.; Shahinpoor, Mohsen; Segalman, Daniel J.; Witkowski, Walter R.

    1993-01-01

    Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

  6. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

    1993-10-05

    Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

  7. Influence of Segmentation of Ring-Shaped NdFeB Magnets with Parallel Magnetization on Cylindrical Actuators

    PubMed Central

    Eckert, Paulo Roberto; Goltz, Evandro Claiton; Filho, Aly Ferreira Flores

    2014-01-01

    This work analyses the effects of segmentation followed by parallel magnetization of ring-shaped NdFeB permanent magnets used in slotless cylindrical linear actuators. The main purpose of the work is to evaluate the effects of that segmentation on the performance of the actuator and to present a general overview of the influence of parallel magnetization by varying the number of segments and comparing the results with ideal radially magnetized rings. The analysis is first performed by modelling mathematically the radial and circumferential components of magnetization for both radial and parallel magnetizations, followed by an analysis carried out by means of the 3D finite element method. Results obtained from the models are validated by measuring radial and tangential components of magnetic flux distribution in the air gap on a prototype which employs magnet rings with eight segments each with parallel magnetization. The axial force produced by the actuator was also measured and compared with the results obtained from numerical models. Although this analysis focused on a specific topology of cylindrical actuator, the observed effects on the topology could be extended to others in which surface-mounted permanent magnets are employed, including rotating electrical machines. PMID:25051032

  8. Influence of segmentation of ring-shaped NdFeB magnets with parallel magnetization on cylindrical actuators.

    PubMed

    Eckert, Paulo Roberto; Goltz, Evandro Claiton; Flores Filho, Aly Ferreira

    2014-07-21

    This work analyses the effects of segmentation followed by parallel magnetization of ring-shaped NdFeB permanent magnets used in slotless cylindrical linear actuators. The main purpose of the work is to evaluate the effects of that segmentation on the performance of the actuator and to present a general overview of the influence of parallel magnetization by varying the number of segments and comparing the results with ideal radially magnetized rings. The analysis is first performed by modelling mathematically the radial and circumferential components of magnetization for both radial and parallel magnetizations, followed by an analysis carried out by means of the 3D finite element method. Results obtained from the models are validated by measuring radial and tangential components of magnetic flux distribution in the air gap on a prototype which employs magnet rings with eight segments each with parallel magnetization. The axial force produced by the actuator was also measured and compared with the results obtained from numerical models. Although this analysis focused on a specific topology of cylindrical actuator, the observed effects on the topology could be extended to others in which surface-mounted permanent magnets are employed, including rotating electrical machines.

  9. Kinematic, workspace and singularity analysis of a new parallel robot used in minimally invasive surgery

    NASA Astrophysics Data System (ADS)

    Stoica, Alin; Pisla, Doina; Andras, Szilaghyi; Gherman, Bogdan; Gyurka, Bela-Zoltan; Plitea, Nicolae

    2013-03-01

    In the last ten years, due to development in robotic assisted surgery, the minimally invasive surgery has greatly changed. Until now, the vast majority of robots used in surgery, have serial structures. Due to the orientation parallel module, the structure is able to reduce the pressure exerted on the entrance point in the patient's abdominal wall. The parallel robot can also handle both a laparoscope as well an active instrument for different surgical procedures. The advantage of this parallel structure is that the geometric model has been obtained through an analytical approach. The kinematic modelling of a new parallel architecture, the inverse and direct geometric model and the inverse and direct kinematic models for velocities and accelerations are being determined. The paper will demonstrate that with this parallel structure, one can obtain the necessary workspace required for a minimally invasive operation. The robot workspace was generated using the inverse geometric model. An indepth study of different types of singularity is performed, allowing the development of safe control algorithms of the experimental model. Some kinematic simulation results and the experimental model of the robot are presented in the paper.

  10. An Attempt to Make a Large-Scale Stacked-Type Electrostatic Actuator for Artificial Muscles of Robots

    NASA Astrophysics Data System (ADS)

    Ito, Makoto; Saneyoshi, Keiji

    This research introduces the structure and the prototypes of a large-scale stacked-type electrostatic actuator (LSEA) which developed as an artificial muscle of robots. LSEA is lightweight and can have large force and long stroke. In addition, the structure can prevent the gaps between the facing electrodes from overextending. We also measured the spring property and the generative force by measuring the force as a function of stretch length.

  11. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  12. Direct kinematics solution architectures for industrial robot manipulators: Bit-serial versus parallel

    NASA Technical Reports Server (NTRS)

    Lee, J.; Kim, K.

    1991-01-01

    A Very Large Scale Integration (VLSI) architecture for robot direct kinematic computation suitable for industrial robot manipulators was investigated. The Denavit-Hartenberg transformations are reviewed to exploit a proper processing element, namely an augmented CORDIC. Specifically, two distinct implementations are elaborated on, such as the bit-serial and parallel. Performance of each scheme is analyzed with respect to the time to compute one location of the end-effector of a 6-links manipulator, and the number of transistors required.

  13. Development of micropump-actuated negative pressure pinched injection for parallel electrophoresis on array microfluidic chip.

    PubMed

    Li, Bowei; Jiang, Lei; Xie, Hua; Gao, Yan; Qin, Jianhua; Lin, Bingcheng

    2009-09-01

    A micropump-actuated negative pressure pinched injection method is developed for parallel electrophoresis on a multi-channel LIF detection system. The system has a home-made device that could individually control 16-port solenoid valves and a high-voltage power supply. The laser beam is excitated and distributes to the array separation channels for detection. The hybrid Glass-PDMS microfluidic chip comprises two common reservoirs, four separation channels coupled to their respective pneumatic micropumps and two reference channels. Due to use of pressure as a driving force, the proposed method has no sample bias effect for separation. There is only one high-voltage supply needed for separation without relying on the number of channels, which is significant for high-throughput analysis, and the time for sample loading is shortened to 1 s. In addition, the integrated micropumps can provide the versatile interface for coupling with other function units to satisfy the complicated demands. The performance is verified by separation of DNA marker and Hepatitis B virus DNA samples. And this method is also expected to show the potential throughput for the DNA analysis in the field of disease diagnosis.

  14. Visual servoing of a planar overactuated parallel robot

    NASA Astrophysics Data System (ADS)

    Garrido, Rubén; Soria, Alberto; Loreto, Gerardo

    2007-10-01

    In this work a Proportional Derivative (PD) image-based visual servoing scheme applied to planar robot manipulators with revolute joints is proposed. Damping is added at the joint level using the robot active joints. The proposed control law may be though as a velocity inner loop at the joint level implementing the derivative action and a visual outer loop at the task level performing the proportional action. Since it is assumed that velocity measurements are not available, velocity estimates are obtained from active joint position measurements using a linear filter. Another feature of the proposed approach is the fact that calibration procedures for the vision system are avoided since an image-based approach is adopted. Closed loop stability is studied using Lyapunov Stability Theory. Experimental results on a laboratory prototype validates the proposed approach, moreover, it is also experimentally shown that by using a vision system for measurement of the robot end effector, kinematics errors may be tolerated in contrast with control strategies making use of the direct kinematics where performance depends on the precise knowledge of the robot kinematics.

  15. Soft and smart modular structures actuated by shape memory alloy (SMA) wires as tentacles of soft robots

    NASA Astrophysics Data System (ADS)

    Jin, Hu; Dong, Erbao; Xu, Min; Liu, Chunshan; Alici, Gursel; Jie, Yang

    2016-08-01

    This paper introduces the design and fabrication of a multi-layered smart modular structure (SMS) that has been inspired by the muscular organs and modularity in soft animals. The SMS is capable of planar reciprocal motion of bending in heating process and recovering in cooling process when SMA wires carry out phase transformation. An adaptive regulation heating strategy is applied to avoid overheating and achieve bending range control of the SMS based on the resistance feedback of the SMA wires which as actuator of the SMS. The SMS can modular assemble soft robots with multiple morphologies such as lateral robots, bilateral robots and actinomorphic robots. A five-armed actinomorphic soft robot is conducted to crawling in terrestrial ground (max speed: 140 mm s-1, 0.7 body s-1), swimming in underwater environment (max speed: 67 mm s-1, 2.5 height s-1) and griping fragile objects (max object weight: 0.91 kg, 15 times the weight of itself). Those demonstrate that the performance of the SMS is good enough to be modular units to establish soft robots which possess a high speed of response, good adaptability and a safe interaction with their environments.

  16. Robust gain-scheduling for smart-structures in parallel robots

    NASA Astrophysics Data System (ADS)

    Algermissen, Stephan; Rose, Michael; Keimer, Ralf; Sinapius, Michael

    2009-03-01

    In the past years parallel robots demonstrated their capability in applications with high-dynamic trajectories. Smart-structures offer the potential to further increase the productivity of parallel robots by reducing disturbing vibrations caused by high dynamic loads effectively. To investigate parallel robots and their applications, including suitable control concepts for smart-structures, the Collaborative Research Center 562 was founded by the German Research Council (DFG). The latest prototype within this research center is called Triglide. It is a four degree of freedom (DOF) robot with three translational and one rotational DOF. It realizes an acceleration of 10 g* at the effector. In the structure of the robot six active rods and a tri-axial accelerometer are integrated to control effector vibrations in three translational DOF. The main challenge of this control application is the position dependent vibration behavior. A single robust controller is not able to gain satisfying performance within the entire workspace. Therefore a strategy for describing the vibration behavior by linearization at several operating points is developed. Behavior in-between is approximated by a linear approach. On a trajectory robust controllers in all operating points are smoothly switched by robust gain-scheduling. The scheduling parameters are fast varying and though a suitable stability proof is defined, based on Small-Gain approach. Several transformations enhance the results from Small-Gain Theorem and reduce the usual conservatism. Experimental data is used to show the improvements made.

  17. On the dynamic model and motion planning for a spherical rolling robot actuated by orthogonal internal rotors

    NASA Astrophysics Data System (ADS)

    Svinin, Mikhail; Morinaga, Akihiro; Yamamoto, Motoji

    2013-01-01

    The paper deals with the dynamics of a spherical rolling robot actuated by internal rotors that are placed on orthogonal axes. The driving principle for such a robot exploits nonholonomic constraints to propel the rolling carrier. A full mathematical model as well as its reduced version are derived, and the inverse dynamics are addressed. It is shown that if the rotors are mounted on three orthogonal axes, any feasible kinematic trajectory of the rolling robot is dynamically realizable. For the case of only two rotors the conditions of controllability and dynamic realizability are established. It is shown that in moving the robot by tracing straight lines and circles in the contact plane the dynamically realizable trajectories are not represented by the circles on the sphere, which is a feature of the kinematic model of pure rolling. The implication of this fact to motion planning is explored under a case study. It is shown there that in maneuvering the robot by tracing circles on the sphere the dynamically realizable trajectories are essentially different from those resulted from kinematic models. The dynamic motion planning problem is then formulated in the optimal control settings, and properties of the optimal trajectories are illustrated under simulation.

  18. Inspiration, simulation and design for smart robot manipulators from the sucker actuation mechanism of cephalopods.

    PubMed

    Grasso, Frank W; Setlur, Pradeep

    2007-12-01

    Octopus arms house 200-300 independently controlled suckers that can alternately afford an octopus fine manipulation of small objects and produce high adhesion forces on virtually any non-porous surface. Octopuses use their suckers to grasp, rotate and reposition soft objects (e.g., octopus eggs) without damaging them and to provide strong, reversible adhesion forces to anchor the octopus to hard substrates (e.g., rock) during wave surge. The biological 'design' of the sucker system is understood to be divided anatomically into three functional groups: the infundibulum that produces a surface seal that conforms to arbitrary surface geometry; the acetabulum that generates negative pressures for adhesion; and the extrinsic muscles that allow adhered surfaces to be rotated relative to the arm. The effector underlying these abilities is the muscular hydrostat. Guided by sensory input, the thousands of muscle fibers within the muscular hydrostats of the sucker act in coordination to provide stiffness or force when and where needed. The mechanical malleability of octopus suckers, the interdigitated arrangement of their muscle fibers and the flexible interconnections of its parts make direct studies of their control challenging. We developed a dynamic simulator (ABSAMS) that models the general functioning of muscular hydrostat systems built from assemblies of biologically constrained muscular hydrostat models. We report here on simulation studies of octopus-inspired and artificial suckers implemented in this system. These simulations reproduce aspects of octopus sucker performance and squid tentacle extension. Simulations run with these models using parameters from man-made actuators and materials can serve as tools for designing soft robotic implementations of man-made artificial suckers and soft manipulators.

  19. Evaluation of parallel reduction strategies for fusion of sensory information from a robot team

    NASA Astrophysics Data System (ADS)

    Lyons, Damian M.; Leroy, Joseph

    2015-05-01

    The advantage of using a team of robots to search or to map an area is that by navigating the robots to different parts of the area, searching or mapping can be completed more quickly. A crucial aspect of the problem is the combination, or fusion, of data from team members to generate an integrated model of the search/mapping area. In prior work we looked at the issue of removing mutual robots views from an integrated point cloud model built from laser and stereo sensors, leading to a cleaner and more accurate model. This paper addresses a further challenge: Even with mutual views removed, the stereo data from a team of robots can quickly swamp a WiFi connection. This paper proposes and evaluates a communication and fusion approach based on the parallel reduction operation, where data is combined in a series of steps of increasing subsets of the team. Eight different strategies for selecting the subsets are evaluated for bandwidth requirements using three robot missions, each carried out with teams of four Pioneer 3-AT robots. Our results indicate that selecting groups to combine based on similar pose but distant location yields the best results.

  20. Special purpose parallel computer architecture for real-time control and simulation in robotic applications

    NASA Technical Reports Server (NTRS)

    Fijany, Amir (Inventor); Bejczy, Antal K. (Inventor)

    1993-01-01

    This is a real-time robotic controller and simulator which is a MIMD-SIMD parallel architecture for interfacing with an external host computer and providing a high degree of parallelism in computations for robotic control and simulation. It includes a host processor for receiving instructions from the external host computer and for transmitting answers to the external host computer. There are a plurality of SIMD microprocessors, each SIMD processor being a SIMD parallel processor capable of exploiting fine grain parallelism and further being able to operate asynchronously to form a MIMD architecture. Each SIMD processor comprises a SIMD architecture capable of performing two matrix-vector operations in parallel while fully exploiting parallelism in each operation. There is a system bus connecting the host processor to the plurality of SIMD microprocessors and a common clock providing a continuous sequence of clock pulses. There is also a ring structure interconnecting the plurality of SIMD microprocessors and connected to the clock for providing the clock pulses to the SIMD microprocessors and for providing a path for the flow of data and instructions between the SIMD microprocessors. The host processor includes logic for controlling the RRCS by interpreting instructions sent by the external host computer, decomposing the instructions into a series of computations to be performed by the SIMD microprocessors, using the system bus to distribute associated data among the SIMD microprocessors, and initiating activity of the SIMD microprocessors to perform the computations on the data by procedure call.

  1. A spherical parallel three degrees-of-freedom robot for ankle-foot neuro-rehabilitation.

    PubMed

    Malosio, Matteo; Negri, Simone Pio; Pedrocchi, Nicola; Vicentini, Federico; Caimmi, Marco; Molinari Tosatti, Lorenzo

    2012-01-01

    The ankle represents a fairly complex bone structure, resulting in kinematics that hinders a flawless robot-assisted recovery of foot motility in impaired subjects. The paper proposes a novel device for ankle-foot neuro-rehabilitation based on a mechatronic redesign of the remarkable Agile Eye spherical robot on the basis of clinical requisites. The kinematic design allows the positioning of the ankle articular center close to the machine rotation center with valuable benefits in term of therapy functions. The prototype, named PKAnkle, Parallel Kinematic machine for Ankle rehabilitation, provides a 6-axes load cell for the measure of subject interaction forces/torques, and it integrates a commercial EMG-acquisition system. Robot control provides active and passive therapeutic exercises.

  2. Development of a shape memory alloy actuator for a robotic eye prosthesis

    NASA Astrophysics Data System (ADS)

    Bunton, T. B. Wolfe; Faulkner, M. G.; Wolfaardt, J.

    2005-08-01

    The quality of life of patients who wear an orbital prosthesis would be vastly improved if their prostheses were also able to execute vertical and horizontal motion. This requires appropriate actuation and control systems to create an intelligent prosthesis. A method of actuation that meets the demanding design criteria is currently not available. The present work considers an activation system that follows a design philosophy of biomimicry, simplicity and space optimization. While several methods of actuation were considered, shape memory alloys were chosen for their high power density, high actuation forces and high displacements. The behaviour of specific shape memory alloys as an actuator was investigated to determine the force obtained, the transformation temperatures and details of the material processing. In addition, a large-scale prototype was constructed to validate the response of the proposed system.

  3. Six degree-of-freedom scanning supports and manipulators based on parallel robots

    NASA Astrophysics Data System (ADS)

    Comin, Fabio

    1995-02-01

    The exploitation of third generation SR sources heavily relies on accurate and stable positioning and scanning of samples and optical elements. In some cases, active feedback is also necessary. Normally, these tasks are carried out by serial addition of individual components, each of them providing a well-defined excursion path. On the contrary, the exploitation of the concept of parallel robots, structures in close cinematic chain, permits us to follow any given trajectory in the six-dimensional space with a large increase in accuracy and stiffness. At ESRF, the parallel robot architecture conceived some tens of years ago for flight simulators has been adapted to both actively align and operate optical elements of considerable weight and position small samples in ultrahigh vacuum. The performance of these devices gives results far superior to the initial specification and a variety of drive mechanisms are being developed to fit the different needs of the ESRF beamlines.

  4. Strength analysis of parallel robot components in PLM Siemens NX 8.5 program

    NASA Astrophysics Data System (ADS)

    Ociepka, P.; Herbus, K.

    2015-11-01

    This article presents a series of numerical analyses in order to identify the states of stress in elements, which arise during the operation of the mechanism. The object of the research was parallel robot, which is the basis for the prototype of a driving simulator. To conduct the dynamic analysis was used the Motion Simulation module and the RecurDyn solver. In this module were created the joints which occur in the mechanism of a parallel robot. Next dynamic analyzes were performed to determine the maximal forces that will applied to the analyzed elements. It was also analyzed the platform motion during the simulation a collision of a car with a wall. In the next step, basing on the results obtained in the dynamic analysis, were performed the strength analyzes in the Advanced Simulation module. For calculation the NX Nastran solver was used.

  5. Biodegradable and edible gelatine actuators for use as artificial muscles

    NASA Astrophysics Data System (ADS)

    Chambers, L. D.; Winfield, J.; Ieropoulos, I.; Rossiter, J.

    2014-03-01

    The expense and use of non-recyclable materials often requires the retrieval and recovery of exploratory robots. Therefore, conventional materials such as plastics and metals in robotics can be limiting. For applications such as environmental monitoring, a fully biodegradable or edible robot may provide the optimum solution. Materials that provide power and actuation as well as biodegradability provide a compelling dimension to future robotic systems. To highlight the potential of novel biodegradable and edible materials as artificial muscles, the actuation of a biodegradable hydrogel was investigated. The fabricated gelatine based polymer gel was inexpensive, easy to handle, biodegradable and edible. The electro-mechanical performance was assessed using two contactless, parallel stainless steel electrodes immersed in 0.1M NaOH solution and fixed 40 mm apart with the strip actuator pinned directly between the electrodes. The actuation displacement in response to a bias voltage was measured over hydration/de-hydration cycles. Long term (11 days) and short term (1 hour) investigations demonstrated the bending behaviour of the swollen material in response to an electric field. Actuation voltage was low (<10 V) resulting in a slow actuation response with large displacement angles (<55 degrees). The stability of the immersed material decreased within the first hour due to swelling, however, was recovered on de-hydrating between actuations. The controlled degradation of biodegradable and edible artificial muscles could help to drive the development of environmentally friendly robotics.

  6. Miniaturized Swimming Soft Robot with Complex Movement Actuated and Controlled by Remote Light Signals

    PubMed Central

    Huang, Chaolei; Lv, Jiu-an; Tian, Xiaojun; Wang, Yuechao; Yu, Yanlei; Liu, Jie

    2015-01-01

    Powering and communication with micro robots to enable complex functions is a long-standing challenge as the size of robots continues to shrink. Physical connection of wires or components needed for wireless communication are complex and limited by the size of electronic and energy storage devices, making miniaturization of robots difficult. To explore an alternative solution, we designed and fabricated a micro soft swimming robot with both powering and controlling functions provided by remote light, which does not carry any electronic devices and batteries. In this approach, a polymer film containing azobenzene chromophore which is sensitive to ultra-violet (UV) light works as “motor”, and the UV light and visible light work as “power and signal lines”. Periodically flashing UV light and white light drives the robot flagellum periodically to swing to eventually push forward the robot in the glass tube filled with liquid. The gripper on robot head can be opened or closed by lights to grab and carry the load. This kind of remotely light-driven approach realizes complex driving and controlling of micro robotic structures, making it possible to design and fabricate even smaller robots. It will have great potential among applications in the micro machine and robot fields. PMID:26633758

  7. Miniaturized Swimming Soft Robot with Complex Movement Actuated and Controlled by Remote Light Signals

    NASA Astrophysics Data System (ADS)

    Huang, Chaolei; Lv, Jiu-An; Tian, Xiaojun; Wang, Yuechao; Yu, Yanlei; Liu, Jie

    2015-12-01

    Powering and communication with micro robots to enable complex functions is a long-standing challenge as the size of robots continues to shrink. Physical connection of wires or components needed for wireless communication are complex and limited by the size of electronic and energy storage devices, making miniaturization of robots difficult. To explore an alternative solution, we designed and fabricated a micro soft swimming robot with both powering and controlling functions provided by remote light, which does not carry any electronic devices and batteries. In this approach, a polymer film containing azobenzene chromophore which is sensitive to ultra-violet (UV) light works as “motor”, and the UV light and visible light work as “power and signal lines”. Periodically flashing UV light and white light drives the robot flagellum periodically to swing to eventually push forward the robot in the glass tube filled with liquid. The gripper on robot head can be opened or closed by lights to grab and carry the load. This kind of remotely light-driven approach realizes complex driving and controlling of micro robotic structures, making it possible to design and fabricate even smaller robots. It will have great potential among applications in the micro machine and robot fields.

  8. New Factorization Techniques and Parallel (log N) Algorithms for Forward Dynamics Solution of Single Closed-Chain Robot Manipulators

    NASA Technical Reports Server (NTRS)

    Fijany, Amir

    1993-01-01

    In this paper parallel 0(log N) algorithms for dynamic simulation of single closed-chain rigid multibody system as specialized to the case of a robot manipulatoar in contact with the environment are developed.

  9. Modeling and control of a hydraulically actuated flexible-prismatic link robot

    SciTech Connect

    Love, L.; Kress, R.; Jansen, J.

    1996-12-01

    Most of the research related to flexible link manipulators to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long reach systems. This manuscript describes a new hydraulically actuated, long reach manipulator with a flexible prismatic link at Oak Ridge National Laboratory (ORNL). Focus is directed towards both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies.

  10. Microfabrication of stacked dielectric elastomer actuator fibers

    NASA Astrophysics Data System (ADS)

    Corbaci, Mert; Walter, Wayne; Lamkin-Kennard, Kathleen

    2016-04-01

    Dielectric elastomer actuators (DEA) are one of the best candidate materials for next generation of robotic actuators, soft sensors and artificial muscles due to their fast response, mechanical robustness and compliance. However, high voltage requirements of DEAs have impeded their potential to become widely used in such applications. In this study, we propose a method for fabrication of silicon based multilayer DEA fibers composed of microlevel dielectric layers to improve the actuation ratios of DEAs at lower voltages. A multi-walled carbon nanotube - polydimethylsiloxane (MWCNT/PDMS) composite was used to fabricate mechanically compliant, conductive parallel plates and electrode connections for the DEA actuators. Active surface area and layer thickness were varied to study the effects of these parameters on actuation ratio as a function of applied voltage. Different structures were fabricated to assess the flexibility of the fabrication method for specific user-end applications.

  11. Design of a variable-stiffness robotic hand using pneumatic soft rubber actuators

    NASA Astrophysics Data System (ADS)

    Nagase, Jun-ya; Wakimoto, Shuichi; Satoh, Toshiyuki; Saga, Norihiko; Suzumori, Koichi

    2011-10-01

    In recent years, Japanese society has been ageing, engendering a labor shortage of young workers. Robots are therefore expected to be useful in performing tasks such as day-to-day support for elderly people. In particular, robots that are intended for use in the field of medical care and welfare are expected to be safe when operating in a human environment because they often come into contact with people. Furthermore, robots must perform various tasks such as regrasping, grasping of soft objects, and tasks using frictional force. Given these demands and circumstances, a tendon-driven robot hand with a stiffness changing finger has been developed. The finger surface stiffness can be altered by adjusting the input pressure depending on the task. Additionally, the coefficient of static friction can be altered by changing the surface stiffness merely by adjusting the input air pressure. This report describes the basic structure, driving mechanism, and basic properties of the proposed robot hand.

  12. [Key technologies and implementation of the medical equipment road transportation simulation platform based on 6-DOF parallel robots].

    PubMed

    Pei, Yidong; Pei, Baoqing; Li, Hui; Fan, Yubo

    2013-01-01

    In view of the shortage of medical equipment road transportation simulation platform, we put forward a road transportation simulation method based on 6-DOF parallel robots. A 3D road spectrum model was built by the improvement of the harmonic superposition method. The simulation model was then compared with the standard model to verify its performance. Taking the road spectrum as the excitation, we could get the robot motion data to control the parallel robot through the S-shaped linear interpolation of the absolute position. It can simulate the movement of vehicles with different speed under various road conditions efficiently and accurately.

  13. Design, fabrication and characterization of a micro-fluxgate intended for parallel robot application

    NASA Astrophysics Data System (ADS)

    Kirchhoff, M. R.; Bogdanski, G.; Büttgenbach, S.

    2009-05-01

    This paper presents a micro-magnetometer based on the fluxgate principle. Fluxgates detect the magnitude and direction of DC and low-frequency AC magnetic fields. The detectable flux density typically ranges from several 10 nT to about 1 mT. The introduced fluxgate sensor is fabricated using MEMS-technologies, basically UV depth lithography and electroplating for manufacturing high aspect ratio structures. It consists of helical copper coils around a soft magnetic nickel-iron (NiFe) core. The core is designed in so-called racetrack geometry, whereby the directional sensitivity of the sensor is considerably higher compared to common ring-core fluxgates. The electrical operation is based on analyzing the 2nd harmonic of the AC output signal. Configuration, manufacturing and selected characteristics of the fluxgate magnetometer are discussed in this work. The fluxgate builds the basis of an innovative angular sensor system for a parallel robot with HEXA-structure. Integrated into the passive joints of the parallel robot, the fluxgates are combined with permanent magnets rotating on the joint shafts. The magnet transmits the angular information via its magnetic orientation. In this way, the angles between the kinematic elements are measured, which allows self-calibration of the robot and the fast analytical solution of direct kinematics for an advanced workspace monitoring.

  14. Conceptual design of a miniaturized hybrid local actuator for Minimally Invasive Robotic Surgery (MIRS) instruments.

    PubMed

    Saedi, Soheil; Mirbagheri, Alireza; Farahmand, Farzam

    2011-01-01

    The actuation mechanism of the tip of an endoscopic instrument is a major problem in designing miniature scale motorized instruments, especially when a high level of functionality and multi degrees of freedom (DOF) are concerned. We evaluated the different possible actuation methods for an endoscopic needle holder and proposed a new design of hybrid local-actuation, including a micro DC motor and a piezoelectric (PZT) actuator. The DC motor provided the long movement course required for opening-closing function of the gripper while the PZT guaranteed the high gripping force required for holding the needle. A compact serial configuration was considered for the actuators, producing an overall size of 10 mm in diameter and 39 mm in length, so that it could be implemented in the limited space available. The efficacy of the design was analyzed in a simulation study, using FEM and it was shown that the needle holder is capable to apply a sufficiently high gripping force of 22 N.

  15. Memory metal actuator

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F. (Inventor)

    1985-01-01

    A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

  16. Characterization of an acoustic actuation mechanism for robotic propulsion in low Reynolds number environments

    NASA Astrophysics Data System (ADS)

    House, Christopher; Armstrong, Jenelle; Burkhardt, John; Firebaugh, Samara

    2014-06-01

    With the end goal of medical applications such as non-invasive surgery and targeted drug delivery, an acoustically driven resonant structure is proposed for microrobotic propulsion. At the proposed scale, the low Reynolds number environment requires non-reciprocal motion from the robotic structure for propulsion; thus, a "flapper" with multiple, flexible joints, has been designed to produce excitation modes that involve the necessary flagella-like bending for non-reciprocal motion. The key design aspect of the flapper structure involves a very thin joint that allows bending in one (vertical) direction, but not the opposing direction. This allows for the second mass and joint to bend in a manner similar to a dolphin's "kick" at the bottom of their stroke, resulting in forward thrust. A 130 mm x 50 mm x 0.2 mm prototype of a swimming robot that utilizes the flapper was fabricated out of acrylic using a laser cutter. The robot was tested in water and in a water-glycerine solution designed to mimic microscale fluid conditions. The robot exhibited forward propulsion when excited by an underwater speaker at its resonance mode, with velocities up to 2.5 mm/s. The robot also displayed frequency selectivity, leading to the possibility of exploring a steering mechanism with alternatively tuned flappers. Additional tests were conducted with a robot at a reduced size scale.

  17. Parallel robot for micro assembly with integrated innovative optical 3D-sensor

    NASA Astrophysics Data System (ADS)

    Hesselbach, Juergen; Ispas, Diana; Pokar, Gero; Soetebier, Sven; Tutsch, Rainer

    2002-10-01

    Recent advances in the fields of MEMS and MOEMS often require precise assembly of very small parts with an accuracy of a few microns. In order to meet this demand, a new approach using a robot based on parallel mechanisms in combination with a novel 3D-vision system has been chosen. The planar parallel robot structure with 2 DOF provides a high resolution in the XY-plane. It carries two additional serial axes for linear and rotational movement in/about z direction. In order to achieve high precision as well as good dynamic capabilities, the drive concept for the parallel (main) axes incorporates air bearings in combination with a linear electric servo motors. High accuracy position feedback is provided by optical encoders with a resolution of 0.1 μm. To allow for visualization and visual control of assembly processes, a camera module fits into the hollow tool head. It consists of a miniature CCD camera and a light source. In addition a modular gripper support is integrated into the tool head. To increase the accuracy a control loop based on an optoelectronic sensor will be implemented. As a result of an in-depth analysis of different approaches a photogrammetric system using one single camera and special beam-splitting optics was chosen. A pattern of elliptical marks is applied to the surfaces of workpiece and gripper. Using a model-based recognition algorithm the image processing software identifies the gripper and the workpiece and determines their relative position. A deviation vector is calculated and fed into the robot control to guide the gripper.

  18. Thin Film PZT Piezo MEMS for Micro-Robotic Angular Rate Sensing and Rotary Actuation

    DTIC Science & Technology

    2012-07-31

    Luz Sanchez, Rob Proie, Vishnu Ganesan, Joe Conroy, and Ron Polcawich July 31, 2012 U.S. Army Research Laboratory THIN FILM PZT PIEZO MEMS FOR...Caltech Angular rate sensing on 1-30 mg platform • 2 orders smaller than packaged state of the art gyroscope. • Integrated biomimetic PZT actuator

  19. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators.

    PubMed

    Colorado, J; Barrientos, A; Rossi, C; Bahlman, J W; Breuer, K S

    2012-09-01

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance-motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s(-1).

  20. Vibration analysis of cable-driven parallel robots based on the dynamic stiffness matrix method

    NASA Astrophysics Data System (ADS)

    Yuan, Han; Courteille, Eric; Gouttefarde, Marc; Hervé, Pierre-Elie

    2017-04-01

    This paper focuses on the vibration analysis of Cable-Driven Parallel Robots (CDPRs). An oscillating model of CDPRs able to capture the dynamic behavior of the cables is derived using Lagrangian approach in conjunction with the Dynamic Stiffness Matrix method. Then, an original approach to analyze the modal interaction between the local cable modes and the global CDPR modes is presented. To illustrate this approach, numerical investigations and experimental analyses are carried out on a large-dimension 6-DOF suspended CDPR driven by 8 cables.

  1. Adaptive fuzzy neural network control design via a T-S fuzzy model for a robot manipulator including actuator dynamics.

    PubMed

    Wai, Rong-Jong; Yang, Zhi-Wei

    2008-10-01

    This paper focuses on the development of adaptive fuzzy neural network control (AFNNC), including indirect and direct frameworks for an n-link robot manipulator, to achieve high-precision position tracking. In general, it is difficult to adopt a model-based design to achieve this control objective due to the uncertainties in practical applications, such as friction forces, external disturbances, and parameter variations. In order to cope with this problem, an indirect AFNNC (IAFNNC) scheme and a direct AFNNC (DAFNNC) strategy are investigated without the requirement of prior system information. In these model-free control topologies, a continuous-time Takagi-Sugeno (T-S) dynamic fuzzy model with online learning ability is constructed to represent the system dynamics of an n-link robot manipulator. In the IAFNNC, an FNN estimator is designed to tune the nonlinear dynamic function vector in fuzzy local models, and then, the estimative vector is used to indirectly develop a stable IAFNNC law. In the DAFNNC, an FNN controller is directly designed to imitate a predetermined model-based stabilizing control law, and then, the stable control performance can be achieved by only using joint position information. All the IAFNNC and DAFNNC laws and the corresponding adaptive tuning algorithms for FNN weights are established in the sense of Lyapunov stability analyses to ensure the stable control performance. Numerical simulations and experimental results of a two-link robot manipulator actuated by dc servomotors are given to verify the effectiveness and robustness of the proposed methodologies. In addition, the superiority of the proposed control schemes is indicated in comparison with proportional-differential control, fuzzy-model-based control, T-S-type FNN control, and robust neural fuzzy network control systems.

  2. Energy-efficient control of a screw-drive pipe robot with consideration of actuator's characteristics.

    PubMed

    Li, Peng; Ma, Shugen; Lyu, Congyi; Jiang, Xin; Liu, Yunhui

    Pipe robots can perform inspection tasks to alleviate the damage caused by the pipe problems. Usually, the pipe robots carry batteries or use a power cable draining power from a vehicle that has many equipments for exploration. Nevertheless, the energy is limited for the whole inspection task and cannot keep the inspection time too long. In this paper, we use the total input energy as the cost function and a more accurate DC motor model to generate an optimal energy-efficient velocity control for a screw-drive pipe robot to make use of the limited energy in field environment. We also propose a velocity selection strategy that includes the actual velocity capacity of the motor, according to the velocity ratio [Formula: see text], to keep the robot working in safe region and decrease the energy dissipation. This selection strategy considers three situations of the velocity ratio [Formula: see text] and has a wide range of application. Simulations are conducted to compare the proposed method with the sinusoidal control and loss minimization control (minimization of copper losses of the motor), and results are discussed in this paper.

  3. A Computer Simulation of Vehicle and Actuator Dynamics for a Hexapod Walking Robot

    DTIC Science & Technology

    1994-03-01

    NAVAL POSTGRADUATE SCHOOL Monterey, California f,.i DTIC I sa , DO ELECTEo JUN 3 01994 THESIS A Computer Simulation of Vehicle and Actuator Dynamics...o olldto d 0401rdlir So n regedi tha bsdai atiti er a•ry othw aspea of this oolietr @4 mao•r oari. lndudrig suggeseom for retducig this bufdon to...Offiof Matagensied aid Budget. Pspew.,,A pReujamn Prmg (07044I0 ). WashitOn. DC 20503 1. AGENCY USE ONLY (Leave Ban PONT DATE 3 . REPORTT AND DATE5

  4. Robust Agent Control of an Autonomous Robot with Many Sensors and Actuators

    DTIC Science & Technology

    1993-05-01

    The neural con- troller was developed by Beer and was inspired by Pearson’s flexor burst- generator model of cockroach locomotion. The goal was to...Workshop on Intelligent Robots and Systems’, Ibaraki, Japan, pp. 383-388. Beer , R. & Chiel, H. (1993), Simulations of Cockroach Locomotion and Es...Previous work exploring fully distributed, insect-like locomotion controllers has only been addressed for flat terrain ( Beer , Chiel, Quinn & Espenschied

  5. An Inexpensive Method for Kinematic Calibration of a Parallel Robot by Using One Hand-Held Camera as Main Sensor

    PubMed Central

    Traslosheros, Alberto; Sebastián, José María; Torrijos, Jesús; Carelli, Ricardo; Castillo, Eduardo

    2013-01-01

    This paper presents a novel method for the calibration of a parallel robot, which allows a more accurate configuration instead of a configuration based on nominal parameters. It is used, as the main sensor with one camera installed in the robot hand that determines the relative position of the robot with respect to a spherical object fixed in the working area of the robot. The positions of the end effector are related to the incremental positions of resolvers of the robot motors. A kinematic model of the robot is used to find a new group of parameters, which minimizes errors in the kinematic equations. Additionally, properties of the spherical object and intrinsic camera parameters are utilized to model the projection of the object in the image and thereby improve spatial measurements. Finally, several working tests, static and tracking tests are executed in order to verify how the robotic system behaviour improves by using calibrated parameters against nominal parameters. In order to emphasize that, this proposed new method uses neither external nor expensive sensor. That is why new robots are useful in teaching and research activities. PMID:23921827

  6. Soft Pneumatic Actuator Fascicles for High Force and Reliability.

    PubMed

    Robertson, Matthew A; Sadeghi, Hamed; Florez, Juan Manuel; Paik, Jamie

    2017-03-01

    Soft pneumatic actuators (SPAs) are found in mobile robots, assistive wearable devices, and rehabilitative technologies. While soft actuators have been one of the most crucial elements of technology leading the development of the soft robotics field, they fall short of force output and bandwidth requirements for many tasks. In addition, other general problems remain open, including robustness, controllability, and repeatability. The SPA-pack architecture presented here aims to satisfy these standards of reliability crucial to the field of soft robotics, while also improving the basic performance capabilities of SPAs by borrowing advantages leveraged ubiquitously in biology; namely, the structured parallel arrangement of lower power actuators to form the basis of a larger and more powerful actuator module. An SPA-pack module consisting of a number of smaller SPAs will be studied using an analytical model and physical prototype. Experimental measurements show an SPA pack to generate over 112 N linear force, while the model indicates the benefit of parallel actuator grouping over a geometrically equivalent single SPA scale as an increasing function of the number of individual actuators in the group. For a module of four actuators, a 23% increase in force production over a volumetrically equivalent single SPA is predicted and validated, while further gains appear possible up to 50%. These findings affirm the advantage of utilizing a fascicle structure for high-performance soft robotic applications over existing monolithic SPA designs. An example of high-performance soft robotic platform will be presented to demonstrate the capability of SPA-pack modules in a complete and functional system.

  7. Soft Pneumatic Actuator Fascicles for High Force and Reliability

    PubMed Central

    Robertson, Matthew A.; Sadeghi, Hamed; Florez, Juan Manuel

    2017-01-01

    Abstract Soft pneumatic actuators (SPAs) are found in mobile robots, assistive wearable devices, and rehabilitative technologies. While soft actuators have been one of the most crucial elements of technology leading the development of the soft robotics field, they fall short of force output and bandwidth requirements for many tasks. In addition, other general problems remain open, including robustness, controllability, and repeatability. The SPA-pack architecture presented here aims to satisfy these standards of reliability crucial to the field of soft robotics, while also improving the basic performance capabilities of SPAs by borrowing advantages leveraged ubiquitously in biology; namely, the structured parallel arrangement of lower power actuators to form the basis of a larger and more powerful actuator module. An SPA-pack module consisting of a number of smaller SPAs will be studied using an analytical model and physical prototype. Experimental measurements show an SPA pack to generate over 112 N linear force, while the model indicates the benefit of parallel actuator grouping over a geometrically equivalent single SPA scale as an increasing function of the number of individual actuators in the group. For a module of four actuators, a 23% increase in force production over a volumetrically equivalent single SPA is predicted and validated, while further gains appear possible up to 50%. These findings affirm the advantage of utilizing a fascicle structure for high-performance soft robotic applications over existing monolithic SPA designs. An example of high-performance soft robotic platform will be presented to demonstrate the capability of SPA-pack modules in a complete and functional system. PMID:28289573

  8. Development of nonresonant elliptical vibration cutting device based on parallel piezoelectric actuator

    NASA Astrophysics Data System (ADS)

    Jieqiong, Lin; Jinguo, Han; Mingming, Lu; Yan, Gu; Wenhui, Zhu

    2017-03-01

    Because of its unique intermittent cutting and friction reversal characteristics, elliptical vibration cutting (EVC) has become the most promising method for machining of otherwise difficult-to-machine materials in recent years. However, some problems remain in the research towards development of EVC devices. In this paper, with the intention of solving the existing problems of EVC devices, a nonresonant-type EVC device that is driven by two parallel piezoelectric stacks is developed. After the principle of the device is introduced, the stiffness of the EVC device is calculated, and device simulations and experimental evaluations are performed. In addition, the performance of the EVC device is also tested. The experimental results show that the maximum strokes of the two directional mechanisms operating along the X- and Z-axes can reach 16.78 μm and 15.35 μm, respectively, and the motion resolutions in the X-axis and Z-axis directions both reach approximately 50 nm. Finally, a curved surface cutting experiment is carried out to verify the performance of the developed device.

  9. Hopping robot

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Marron, Lisa C.; Martinez, Michael A.; Kuehl, Michael A.; Feddema, John T.

    2001-01-01

    The present invention provides a hopping robot that includes a misfire tolerant linear actuator suitable for long trips, low energy steering and control, reliable low energy righting, miniature low energy fuel control. The present invention provides a robot with hopping mobility, capable of traversing obstacles significant in size relative to the robot and capable of operation on unpredictable terrain over long range. The present invention further provides a hopping robot with misfire-tolerant combustion actuation, and with combustion actuation suitable for use in oxygen-poor environments.

  10. Controlling under-actuated robot arms using a high speed dynamics process

    NASA Technical Reports Server (NTRS)

    Jain, Abhinandan (Inventor); Rodriguez, Guillermo (Inventor)

    1994-01-01

    The invention controls an under-actuated manipulator by first obtaining predetermined active joint accelerations of the active joints and the passive joint friction forces of the passive joints, then computing articulated body qualities for each of the joints from the current positions of the links, and finally computing from the articulated body qualities and from the active joint accelerations and the passive joint forces, active joint forces of the active joints. Ultimately, the invention transmits servo commands to the active joint forces thus computed to the respective ones of the joint servos. The computation of the active joint forces is accomplished using a recursive dynamics algorithm. In this computation, an inward recursion is first carried out for each link, beginning with the outermost link in order to compute the residual link force of each link from the active joint acceleration if the corresponding joint is active, or from the known passive joint force if the corresponding joint is passive. Then, an outward recursion is carried out for each link in which the active joint force is computed from the residual link force if the corresponding joint is active or the passive joint acceleration is computed from the residual link force if the corresponding joint is passive.

  11. Magnetic actuated pH-responsive hydrogel-based soft micro-robot for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Li, Hao; Go, Gwangjun; Ko, Seong Yong; Park, Jong-Oh; Park, Sukho

    2016-02-01

    For drug delivery in cancer therapy, various stimuli-responsive hydrogel-based micro-devices have been studied with great interest. Here, we present a new concept for a hybrid actuated soft microrobot targeted drug delivery. The proposed soft microrobot consists of a hydrogel bilayer structure of 2-hydroxyethyl methacrylate (PHEMA) and poly (ethylene glycol) acrylate (PEGDA) with iron (II, III) oxide particles (Fe3O4). The PHEMA layer as a pH-responsive gel is used for a trapping and unfolding motion of the soft microrobot in pH-varying solution, and the PEGDA-with-Fe3O4 layer is employed for the locomotion of the soft microrobot in the magnetic field. The bilayer soft microrobot was fabricated by a conventional photolithography procedure and its characteristics were analyzed and presented. To evaluate the trapping performance and the motility of the soft microrobot, test solutions with different pH values and an electromagnetic actuation (EMA) system were used. First, the soft microrobot showed its full trapping motion at about pH 9.58 and its unfolding motion at about pH 2.6. Second, the soft microrobot showed a moving velocity of about 600 μm s-1 through the generated magnetic field of the EMA system. Finally, we fabricated the real anti-cancer drug microbeads (PCL-DTX) and executed the cytotoxicity test using the mammary carcinoma cells (4T1). The viability of the 4T1 cells treated with the proposed microrobot and the PCL-DTX microbeads decreased to 70.25 ± 1.52%. The result demonstrated that the soft microrobot can be moved to a target position by the EMA system and can release a small amount of beads by the pH variation and the robot exhibited no toxicity to the cells. In the future, we expect that the proposed soft microrobot can be applied to a new tumor-therapeutic tool that can move to a target tumor and release anti-tumor drugs.

  12. Combustion powered linear actuator

    DOEpatents

    Fischer, Gary J.

    2007-09-04

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  13. Robotics.

    ERIC Educational Resources Information Center

    Waddell, Steve; Doty, Keith L.

    1999-01-01

    "Why Teach Robotics?" (Waddell) suggests that the United States lags behind Europe and Japan in use of robotics in industry and teaching. "Creating a Course in Mobile Robotics" (Doty) outlines course elements of the Intelligent Machines Design Lab. (SK)

  14. Parallel algorithm for dominant points correspondences in robot binocular stereo vision

    NASA Technical Reports Server (NTRS)

    Al-Tammami, A.; Singh, B.

    1993-01-01

    This paper presents an algorithm to find the correspondences of points representing dominant feature in robot stereo vision. The algorithm consists of two main steps: dominant point extraction and dominant point matching. In the feature extraction phase, the algorithm utilizes the widely used Moravec Interest Operator and two other operators: the Prewitt Operator and a new operator called Gradient Angle Variance Operator. The Interest Operator in the Moravec algorithm was used to exclude featureless areas and simple edges which are oriented in the vertical, horizontal, and two diagonals. It was incorrectly detecting points on edges which are not on the four main directions (vertical, horizontal, and two diagonals). The new algorithm uses the Prewitt operator to exclude featureless areas, so that the Interest Operator is applied only on the edges to exclude simple edges and to leave interesting points. This modification speeds-up the extraction process by approximately 5 times. The Gradient Angle Variance (GAV), an operator which calculates the variance of the gradient angle in a window around the point under concern, is then applied on the interesting points to exclude the redundant ones and leave the actual dominant ones. The matching phase is performed after the extraction of the dominant points in both stereo images. The matching starts with dominant points in the left image and does a local search, looking for corresponding dominant points in the right image. The search is geometrically constrained the epipolar line of the parallel-axes stereo geometry and the maximum disparity of the application environment. If one dominant point in the right image lies in the search areas, then it is the corresponding point of the reference dominant point in the left image. A parameter provided by the GAV is thresholded and used as a rough similarity measure to select the corresponding dominant point if there is more than one point the search area. The correlation is used as

  15. Development of a Stereo Vision Measurement System for a 3D Three-Axial Pneumatic Parallel Mechanism Robot Arm

    PubMed Central

    Chiang, Mao-Hsiung; Lin, Hao-Ting; Hou, Chien-Lun

    2011-01-01

    In this paper, a stereo vision 3D position measurement system for a three-axial pneumatic parallel mechanism robot arm is presented. The stereo vision 3D position measurement system aims to measure the 3D trajectories of the end-effector of the robot arm. To track the end-effector of the robot arm, the circle detection algorithm is used to detect the desired target and the SAD algorithm is used to track the moving target and to search the corresponding target location along the conjugate epipolar line in the stereo pair. After camera calibration, both intrinsic and extrinsic parameters of the stereo rig can be obtained, so images can be rectified according to the camera parameters. Thus, through the epipolar rectification, the stereo matching process is reduced to a horizontal search along the conjugate epipolar line. Finally, 3D trajectories of the end-effector are computed by stereo triangulation. The experimental results show that the stereo vision 3D position measurement system proposed in this paper can successfully track and measure the fifth-order polynomial trajectory and sinusoidal trajectory of the end-effector of the three- axial pneumatic parallel mechanism robot arm. PMID:22319408

  16. Development of a stereo vision measurement system for a 3D three-axial pneumatic parallel mechanism robot arm.

    PubMed

    Chiang, Mao-Hsiung; Lin, Hao-Ting; Hou, Chien-Lun

    2011-01-01

    In this paper, a stereo vision 3D position measurement system for a three-axial pneumatic parallel mechanism robot arm is presented. The stereo vision 3D position measurement system aims to measure the 3D trajectories of the end-effector of the robot arm. To track the end-effector of the robot arm, the circle detection algorithm is used to detect the desired target and the SAD algorithm is used to track the moving target and to search the corresponding target location along the conjugate epipolar line in the stereo pair. After camera calibration, both intrinsic and extrinsic parameters of the stereo rig can be obtained, so images can be rectified according to the camera parameters. Thus, through the epipolar rectification, the stereo matching process is reduced to a horizontal search along the conjugate epipolar line. Finally, 3D trajectories of the end-effector are computed by stereo triangulation. The experimental results show that the stereo vision 3D position measurement system proposed in this paper can successfully track and measure the fifth-order polynomial trajectory and sinusoidal trajectory of the end-effector of the three- axial pneumatic parallel mechanism robot arm.

  17. Online optimal experimental re-design in robotic parallel fed-batch cultivation facilities.

    PubMed

    Cruz Bournazou, M N; Barz, T; Nickel, D B; Lopez Cárdenas, D C; Glauche, F; Knepper, A; Neubauer, P

    2017-03-01

    We present an integrated framework for the online optimal experimental re-design applied to parallel nonlinear dynamic processes that aims to precisely estimate the parameter set of macro kinetic growth models with minimal experimental effort. This provides a systematic solution for rapid validation of a specific model to new strains, mutants, or products. In biosciences, this is especially important as model identification is a long and laborious process which is continuing to limit the use of mathematical modeling in this field. The strength of this approach is demonstrated by fitting a macro-kinetic differential equation model for Escherichia coli fed-batch processes after 6 h of cultivation. The system includes two fully-automated liquid handling robots; one containing eight mini-bioreactors and another used for automated at-line analyses, which allows for the immediate use of the available data in the modeling environment. As a result, the experiment can be continually re-designed while the cultivations are running using the information generated by periodical parameter estimations. The advantages of an online re-computation of the optimal experiment are proven by a 50-fold lower average coefficient of variation on the parameter estimates compared to the sequential method (4.83% instead of 235.86%). The success obtained in such a complex system is a further step towards a more efficient computer aided bioprocess development. Biotechnol. Bioeng. 2017;114: 610-619. © 2016 Wiley Periodicals, Inc.

  18. A Framework for Information Distribution, Task Execution and Decision Making in Multi-Robot Systems

    NASA Astrophysics Data System (ADS)

    Rambow, Matthias; Rohrmüller, Florian; Kourakos, Omiros; Bršcic, Drazen; Wollherr, Dirk; Hirche, Sandra; Buss, Martin

    Robotic systems operating in the real-world have to cope with unforeseen events by determining appropriate decisions based on noisy or partial knowledge. In this respect high functional robots are equipped with many sensors and actuators and run multiple processing modules in parallel. The resulting complexity is even further increased in case of cooperative multi-robot systems, since mechanisms for joint operation are needed. In this paper a complete and modular framework that handles this complexity in multi-robot systems is presented. It provides efficient exchange of generated data as well as a generic scheme for task execution and robot coordination.

  19. Micromachined electrostatic vertical actuator

    DOEpatents

    Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.; Krulevitch, Peter A.

    1999-10-19

    A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

  20. Robotics

    SciTech Connect

    Scheide, A.W.

    1983-11-01

    This article reviews some of the technical areas and history associated with robotics, provides information relative to the formation of a Robotics Industry Committee within the Industry Applications Society (IAS), and describes how all activities relating to robotics will be coordinated within the IEEE. Industrial robots are being used for material handling, processes such as coating and arc welding, and some mechanical and electronics assembly. An industrial robot is defined as a programmable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for a variety of tasks. The initial focus of the Robotics Industry Committee will be on the application of robotics systems to the various industries that are represented within the IAS.

  1. Series elastic actuators

    NASA Astrophysics Data System (ADS)

    Williamson, Matthew M.

    1995-01-01

    This thesis presents the design, construction, control and evaluation of a novel for controlled actuator. Traditional force controlled actuators are designed from the premise that 'Stiffer is better'. This approach gives a high bandwidth system, prone to problems of contact instability, noise, and low power density. The actuator presented in this thesis is designed from the premise that 'Stiffness isn't everything'. The actuator, which incorporates a series elastic element, trades off achievable bandwidth for gains in stable, low noise force control, and protection against shock loads. This thesis reviews related work in robot force control, presents theoretical descriptions of the control and expected performance from a series elastic actuator, and describes the design of a test actuator constructed to gather performance data. Finally the performance of the system is evaluated by comparing the performance data to theoretical predictions.

  2. Preliminary study of a serial-parallel redundant manipulator

    NASA Technical Reports Server (NTRS)

    Hayward, Vincent; Kurtz, Ronald

    1989-01-01

    The manipulator design discussed here results from the examination of some of the reasons why redundancy is necessary in general purpose manipulation systems. A spherical joint design actuated in-parallel, having the many advantages of parallel actuation, is described. In addition, the benefits of using redundant actuators are discussed and illustrated in the design by the elimination of loci of singularities from the usable workspace with the addition of only one actuator. Finally, what is known by the authors about space robotics requirements is summarized and the relevance of the proposed design matched against these requirements. The design problems outlined here are viewed as much from the mechanical engineering aspect as from concerns arising from the control and the programming of manipulators.

  3. Error Analysis and Experimental Study of a Bi-Planar Parallel Mechanism in a Pedicle Screw Robot System.

    PubMed

    Duan, Qingjuan; Du, Zhijiang; Yu, Hongjian; Wang, Yongfeng; Dong, Wei

    2016-11-30

    Due to the urgent need for high precision surgical equipment for minimally invasive spinal surgery, a novel robot-assistant system was developed for the accurate placement of pedicle screws in lumbar spinal surgeries. The structure of the robot was based on a macro-micro mechanism, which includes a serial mechanism (macro part) and a bi-planar 5R parallel mechanism (micro part). The macro part was used to achieve a large workspace, while the micro part was used to obtain high stiffness and accuracy. Based on the transfer function of dimension errors, the factors affecting the accuracy of the end effectors were analyzed. Then the manufacturing errors and joint angle error on the position-stance of the end effectors were investigated. Eventually, the mechanism of the strain energy produced by the deformation of linkage via forced assembly and displacements of the output point were calculated. The amount of the transfer errors was quantitatively analyzed by the simulation. Experimental tests show that the error of the bi-planar 5R mechanism can be controlled no more than 1 mm for translation and 1° for rotation, which satisfies the required absolute position accuracy of the robot.

  4. Error Analysis and Experimental Study of a Bi-Planar Parallel Mechanism in a Pedicle Screw Robot System

    PubMed Central

    Duan, Qingjuan; Du, Zhijiang; Yu, Hongjian; Wang, Yongfeng; Dong, Wei

    2016-01-01

    Due to the urgent need for high precision surgical equipment for minimally invasive spinal surgery, a novel robot-assistant system was developed for the accurate placement of pedicle screws in lumbar spinal surgeries. The structure of the robot was based on a macro-micro mechanism, which includes a serial mechanism (macro part) and a bi-planar 5R parallel mechanism (micro part). The macro part was used to achieve a large workspace, while the micro part was used to obtain high stiffness and accuracy. Based on the transfer function of dimension errors, the factors affecting the accuracy of the end effectors were analyzed. Then the manufacturing errors and joint angle error on the position-stance of the end effectors were investigated. Eventually, the mechanism of the strain energy produced by the deformation of linkage via forced assembly and displacements of the output point were calculated. The amount of the transfer errors was quantitatively analyzed by the simulation. Experimental tests show that the error of the bi-planar 5R mechanism can be controlled no more than 1 mm for translation and 1° for rotation, which satisfies the required absolute position accuracy of the robot. PMID:27916869

  5. Rotary Series Elastic Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2013-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  6. Rotary series elastic actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2012-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  7. Robotics

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of research being done into the use of robotic devices in space by MSFC is discussed. The video includes footage and explanations of robots being used to blast layers of thermal coating from the Space Shuttle's external tanks, the Shuttle's Remote Manipulator Arm, and animations of an Orbiting Maneuvering Vehicle to retrieve and repair satellites.

  8. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  9. Analysis of the kinematic characteristics of a high-speed parallel robot with Schönflies motion: Mobility, kinematics, and singularity

    NASA Astrophysics Data System (ADS)

    Xie, Fugui; Liu, Xin-Jun

    2016-06-01

    This study introduces a high-speed parallel robot with Schönflies motion. This robot exhibits a promising prospect in realizing high-speed pick-andplace manipulation for packaging production lines. The robot has four identical limbs and a single platform. Its compact structure and single-platform concept provides this robot with good dynamic response potential. A line graph method based on Grassmann line geometry is used to investigate the mobility characteristics of the proposed robot. A generalized Blanding rule is also introduced into this procedure to realize mutual conversion between the line graphs for motions and constraints. Subsequently, the inverse kinematics is derived, and the singularity issue of the robot is investigated using both qualitative and quantitative approaches. Input and output transmission singularity indices are defined based on the reciprocal product in screw theory and the virtual coefficient by considering motion/force transmission performance. Thereafter, the singular loci of the proposed robot with specific geometric parameters are derived. The mobility analysis, inverse kinematics modeling, and singularity analysis conducted in this study are helpful in developing the robot.

  10. Anthropomorphic finger antagonistically actuated by SMA plates.

    PubMed

    Engeberg, Erik D; Dilibal, Savas; Vatani, Morteza; Choi, Jae-Won; Lavery, John

    2015-08-20

    Most robotic applications that contain shape memory alloy (SMA) actuators use the SMA in a linear or spring shape. In contrast, a novel robotic finger was designed in this paper using SMA plates that were thermomechanically trained to take the shape of a flexed human finger when Joule heated. This flexor actuator was placed in parallel with an extensor actuator that was designed to straighten when Joule heated. Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend. Three different NiTi based SMA plates were evaluated for their ability to apply forces to a rigid and compliant object. The best of these three SMAs was able to apply a maximum fingertip force of 9.01N on average. A 3D CAD model of a human finger was used to create a solid model for the mold of the finger covering skin. Using a 3D printer, inner and outer molds were fabricated to house the actuators and a position sensor, which were assembled using a multi-stage casting process. Next, a nonlinear antagonistic controller was developed using an outer position control loop with two inner MOSFET current control loops. Sine and square wave tracking experiments demonstrated minimal errors within the operational bounds of the finger. The ability of the finger to recover from unexpected disturbances was also shown along with the frequency response up to 7 rad s(-1). The closed loop bandwidth of the system was 6.4 rad s(-1) when operated intermittently and 1.8 rad s(-1) when operated continuously.

  11. Probe Scanning Support System by a Parallel Mechanism for Robotic Echography

    NASA Astrophysics Data System (ADS)

    Aoki, Yusuke; Kaneko, Kenta; Oyamada, Masami; Takachi, Yuuki; Masuda, Kohji

    We propose a probe scanning support system based on force/visual servoing control for robotic echography. First, we have designed and formulated its inverse kinematics the construction of mechanism. Next, we have developed a scanning method of the ultrasound probe on body surface to construct visual servo system based on acquired echogram by the standalone medical robot to move the ultrasound probe on patient abdomen in three-dimension. The visual servo system detects local change of brightness in time series echogram, which is stabilized the position of the probe by conventional force servo system in the robot, to compensate not only periodical respiration motion but also body motion. Then we integrated control method of the visual servo with the force servo as a hybrid control in both of position and force. To confirm the ability to apply for actual abdomen, we experimented the total system to follow the gallbladder as a moving target to keep its position in the echogram by minimizing variation of reaction force on abdomen. As the result, the system has a potential to be applied to automatic detection of human internal organ.

  12. MEMS fluidic actuator

    DOEpatents

    Kholwadwala, Deepesh K.; Johnston, Gabriel A.; Rohrer, Brandon R.; Galambos, Paul C.; Okandan, Murat

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  13. Soft electrothermal actuators using silver nanowire heaters.

    PubMed

    Yao, Shanshan; Cui, Jianxun; Cui, Zheng; Zhu, Yong

    2017-03-17

    Low-voltage and extremely flexible electrothermal bimorph actuators were fabricated in a simple, efficient and scalable process. The bimorph actuators were made of flexible silver nanowire (AgNW) based heaters, which exhibited a fast heating rate of 18 °C s(-1) and stable heating performance with large bending. The actuators offered the largest bending angle (720°) or curvature (2.6 cm(-1)) at a very low actuation voltage (0.2 V sq(-1) or 4.5 V) among all types of bimorph actuators that have been reported to date. The actuators can be designed and fabricated in different configurations that can achieve complex patterns and shapes upon actuation. Two applications of this type of soft actuators were demonstrated towards biomimetic robotics - a crawling robot that can walk spontaneously on ratchet surfaces and a soft gripper that is capable of manipulating lightweight and delicate objects.

  14. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  15. Robotics of human movements.

    PubMed

    van der Smagt, Patrick; Grebenstein, Markus; Urbanek, Holger; Fligge, Nadine; Strohmayr, Michael; Stillfried, Georg; Parrish, Jonathon; Gustus, Agneta

    2009-01-01

    The construction of robotic systems that can move the way humans do, with respect to agility, stability and precision, is a necessary prerequisite for the successful integration of robotic systems in human environments. We explain human-centered views on robotics, based on the three basic ingredients (1) actuation; (2) sensing; and (3) control, and formulate detailed examples thereof.

  16. Extended Task Space Control for Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Backes, Paul G. (Inventor); Long, Mark K. (Inventor)

    1996-01-01

    The invention is a method of operating a robot in successive sampling intervals to perform a task, the robot having joints and joint actuators with actuator control loops, by decomposing the task into behavior forces, accelerations, velocities and positions of plural behaviors to be exhibited by the robot simultaneously, computing actuator accelerations of the joint actuators for the current sampling interval from both behavior forces, accelerations velocities and positions of the current sampling interval and actuator velocities and positions of the previous sampling interval, computing actuator velocities and positions of the joint actuators for the current sampling interval from the actuator velocities and positions of the previous sampling interval, and, finally, controlling the actuators in accordance with the actuator accelerations, velocities and positions of the current sampling interval. The actuator accelerations, velocities and positions of the current sampling interval are stored for use during the next sampling interval.

  17. Electro-Active Polymer (EAP) Actuators for Planetary Applications

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.; Leary, S.; Shahinpoor, M.; Harrison, J. O.; Smith, J.

    1999-01-01

    NASA is seeking to reduce the mass, size, consumed power, and cost of the instrumentation used in its future missions. An important element of many instruments and devices is the actuation mechanism and electroactive polymers (EAP) are offering an effective alternative to current actuators. In this study, two families of EAP materials were investigated, including bending ionomers and longitudinal electrostatically driven elastomers. These materials were demonstrated to effectively actuate manipulation devices and their performance is being enhanced in this on-going study. The recent observations are reported in this paper, include the operation of the bending-EAP at conditions that exceed the harsh environment on Mars, and identify the obstacles that its properties and characteristics are posing to using them as actuators. Analysis of the electrical characteristics of the ionomer EAP showed that it is a current driven material rather than voltage driven and the conductivity distribution on the surface of the material greatly influences the bending performance. An accurate equivalent circuit modeling of the ionomer EAP performance is essential for the design of effective drive electronics. The ionomer main limitations are the fact that it needs to be moist continuously and the process of electrolysis that takes place during activation. An effective coating technique using a sprayed polymer was developed extending its operation in air from a few minutes to about four months. The coating technique effectively forms the equivalent of a skin to protect the moisture content of the ionomer. In parallel to the development of the bending EAP, the development of computer control of actuated longitudinal EAP has been pursued. An EAP driven miniature robotic arm was constructed and it is controlled by a MATLAB code to drop and lift the arm and close and open EAP fingers of a 4-finger gripper. Keywords: Miniature Robotics, Electroactive Polymers, Electroactive Actuators, EAP

  18. Dielectric elastomer actuators for facial expression

    NASA Astrophysics Data System (ADS)

    Wang, Yuzhe; Zhu, Jian

    2016-04-01

    Dielectric elastomer actuators have the advantage of mimicking the salient feature of life: movements in response to stimuli. In this paper we explore application of dielectric elastomer actuators to artificial muscles. These artificial muscles can mimic natural masseter to control jaw movements, which are key components in facial expressions especially during talking and singing activities. This paper investigates optimal design of the dielectric elastomer actuator. It is found that the actuator with embedded plastic fibers can avert electromechanical instability and can greatly improve its actuation. Two actuators are then installed in a robotic skull to drive jaw movements, mimicking the masseters in a human jaw. Experiments show that the maximum vertical displacement of the robotic jaw, driven by artificial muscles, is comparable to that of the natural human jaw during speech activities. Theoretical simulations are conducted to analyze the performance of the actuator, which is quantitatively consistent with the experimental observations.

  19. Robotic platform for parallelized cultivation and monitoring of microbial growth parameters in microwell plates.

    PubMed

    Knepper, Andreas; Heiser, Michael; Glauche, Florian; Neubauer, Peter

    2014-12-01

    The enormous variation possibilities of bioprocesses challenge process development to fix a commercial process with respect to costs and time. Although some cultivation systems and some devices for unit operations combine the latest technology on miniaturization, parallelization, and sensing, the degree of automation in upstream and downstream bioprocess development is still limited to single steps. We aim to face this challenge by an interdisciplinary approach to significantly shorten development times and costs. As a first step, we scaled down analytical assays to the microliter scale and created automated procedures for starting the cultivation and monitoring the optical density (OD), pH, concentrations of glucose and acetate in the culture medium, and product formation in fed-batch cultures in the 96-well format. Then, the separate measurements of pH, OD, and concentrations of acetate and glucose were combined to one method. This method enables automated process monitoring at dedicated intervals (e.g., also during the night). By this approach, we managed to increase the information content of cultivations in 96-microwell plates, thus turning them into a suitable tool for high-throughput bioprocess development. Here, we present the flowcharts as well as cultivation data of our automation approach.

  20. Serpentine Robot Model and Gait Design Using Autodesk Inventor and Simulink SimMechanics

    NASA Astrophysics Data System (ADS)

    Daniel; Iman Alamsyah, Mohammad; Erwin; Tan, Sofyan

    2014-03-01

    The authors introduce gaits of a serpentine robot with linear expansion mechanism where the robot varies its length using joints with three degrees of freedom. The 3D model of the serpentine robot is drawed in Autocad Inventor® and exported to SimMechanics® for straighforward modeling of the kinematics. The gaits are important for robots designed to explore ruins of disasters where the working spaces are very tight. For maximum flexibility of the serpentine robot, we adopted a joint design with three parallel actuators, where the joint is capable of linear movement in the forward axis, and rotational movements around two other axes. The designed linear expansion gaits is calculated for forward movement when the robot is posing straight or turning laterally.

  1. Tool Changer For Robot

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    1992-01-01

    Mechanism enables robot to change tools on end of arm. Actuated by motion of robot: requires no additional electrical or pneumatic energy to make or break connection between tool and wrist at end of arm. Includes three basic subassemblies: wrist interface plate attached to robot arm at wrist, tool interface plate attached to tool, and holster. Separate tool interface plate and holster provided for each tool robot uses.

  2. Climbing robot

    NASA Astrophysics Data System (ADS)

    Kerley, James J.; May, Edward L.; Ecklund, Wayne D.

    1993-11-01

    A mobile robot for traversing any surface consisting of a number of interconnected segments, each interconnected segment having an upper 'U' frame member, a lower 'U' frame member, a compliant joint between the upper 'U' frame member and the lower 'U' frame member, a number of linear actuators between the two frame members acting to provide relative displacement between the frame members, a foot attached to the lower 'U' frame member for adherence of the segment to the surface, an inter-segment attachment attached to the upper 'U' frame member for interconnecting the segments, a power source connected to the linear actuator, and a computer/controller for independently controlling each linear actuator in each interconnected segment such that the mobile robot moves in a caterpillar like fashion.

  3. Hydraulically actuated artificial muscles

    NASA Astrophysics Data System (ADS)

    Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

    2012-04-01

    Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

  4. A bidirectional shape memory alloy folding actuator

    NASA Astrophysics Data System (ADS)

    Paik, Jamie K.; Wood, Robert J.

    2012-06-01

    This paper presents a low-profile bidirectional folding actuator based on annealed shape memory alloy sheets applicable for meso- and microscale systems. Despite the advantages of shape memory alloys—high strain, silent operation, and mechanical simplicity—their application is often limited to unidirectional operation. We present a bidirectional folding actuator that produces two opposing 180° motions. A laser-patterned nickel alloy (Inconel 600) heater localizes actuation to the folding sections. The actuator has a thin ( < 1 mm) profile, making it appropriate for use in robotic origami. Various design parameters and fabrication variants are described and experimentally explored in the actuator prototype.

  5. Robotics

    NASA Technical Reports Server (NTRS)

    Ambrose, Robert O.

    2007-01-01

    Lunar robotic functions include: 1. Transport of crew and payloads on the surface of the moon; 2. Offloading payloads from a lunar lander; 3. Handling the deployment of surface systems; with 4. Human commanding of these functions from inside a lunar vehicle, habitat, or extravehicular (space walk), with Earth-based supervision. The systems that will perform these functions may not look like robots from science fiction. In fact, robotic functions may be automated trucks, cranes and winches. Use of this equipment prior to the crew s arrival or in the potentially long periods without crews on the surface, will require that these systems be computer controlled machines. The public release of NASA's Exploration plans at the 2nd Space Exploration Conference (Houston, December 2006) included a lunar outpost with as many as four unique mobility chassis designs. The sequence of lander offloading tasks involved as many as ten payloads, each with a unique set of geometry, mass and interface requirements. This plan was refined during a second phase study concluded in August 2007. Among the many improvements to the exploration plan were a reduction in the number of unique mobility chassis designs and a reduction in unique payload specifications. As the lunar surface system payloads have matured, so have the mobility and offloading functional requirements. While the architecture work continues, the community can expect to see functional requirements in the areas of surface mobility, surface handling, and human-systems interaction as follows: Surface Mobility 1. Transport crew on the lunar surface, accelerating construction tasks, expanding the crew s sphere of influence for scientific exploration, and providing a rapid return to an ascent module in an emergency. The crew transport can be with an un-pressurized rover, a small pressurized rover, or a larger mobile habitat. 2. Transport Extra-Vehicular Activity (EVA) equipment and construction payloads. 3. Transport habitats and

  6. A curved ultrasonic actuator optimized for spherical motors: design and experiments.

    PubMed

    Leroy, Edouard; Lozada, José; Hafez, Moustapha

    2014-08-01

    Multi-degree-of-freedom angular actuators are commonly used in numerous mechatronic areas such as omnidirectional robots, robot articulations or inertially stabilized platforms. The conventional method to design these devices consists in placing multiple actuators in parallel or series using gimbals which are bulky and difficult to miniaturize. Motors using a spherical rotor are interesting for miniature multidegree-of-freedom actuators. In this paper, a new actuator is proposed. It is based on a curved piezoelectric element which has its inner contact surface adapted to the diameter of the rotor. This adaptation allows to build spherical motors with a fully constrained rotor and without a need for additional guiding system. The work presents a design methodology based on modal finite element analysis. A methodology for mode selection is proposed and a sensitivity analysis of the final geometry to uncertainties and added masses is discussed. Finally, experimental results that validate the actuator concept on a single degree-of-freedom ultrasonic motor set-up are presented.

  7. Robotics

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2012-01-01

    Earth's upper atmosphere is an extreme environment: dry, cold, and irradiated. It is unknown whether our aerobiosphere is limited to the transport of life, or there exist organisms that grow and reproduce while airborne (aerophiles); the microenvironments of suspended particles may harbor life at otherwise uninhabited altitudes[2]. The existence of aerophiles would significantly expand the range of planets considered candidates for life by, for example, including the cooler clouds of a hot Venus-like planet. The X project is an effort to engineer a robotic exploration and biosampling payload for a comprehensive survey of Earth's aerobiology. While many one-shot samples have been retrieved from above 15 km, their results are primarily qualitative; variations in method confound comparisons, leaving such major gaps in our knowledge of aerobiology as quantification of populations at different strata and relative species counts[1]. These challenges and X's preliminary solutions are explicated below. X's primary balloon payload is undergoing a series of calibrations before beginning flights in Spring 2012. A suborbital launch is currently planned for Summer 2012. A series of ground samples taken in Winter 2011 is being used to establish baseline counts and identify likely background contaminants.

  8. Wheeled hopping robot

    DOEpatents

    Fischer, Gary J.

    2010-08-17

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  9. Hybrid electromechanical actuator and actuation system

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Xu, Tian-Bing (Inventor)

    2008-01-01

    A hybrid electromechanical actuator has two different types of electromechanical elements, one that expands in a transverse direction when electric power is applied thereto and one that contracts in a transverse direction when electric power is applied thereto. The two electromechanical elements are (i) disposed in relation to one another such that the transverse directions thereof are parallel to one another, and (ii) mechanically coupled to one another at least at two opposing edges thereof. Electric power is applied simultaneously to the elements.

  10. Simulation and experimental control of a 3-RPR parallel robot using optimal fuzzy controller and fast on/off solenoid valves based on the PWM wave.

    PubMed

    Moezi, Seyed Alireza; Rafeeyan, Mansour; Zakeri, Ehsan; Zare, Amin

    2016-03-01

    In this paper, a robust optimal fuzzy controller based on the Pulse Width Modulation (PWM) technique is proposed to control a laboratory parallel robot using inexpensive on/off solenoid valves. The controller coefficients are determined using Modified Cuckoo Optimization Algorithm. The objective function of this method is considered such that the results show the position tracking by the robot with less force and more efficiency. Regarding the results of experimental tests, the control strategy with on/off valves indicates good performance such that the maximum value of RMS of error for a circular path with increasing force on the system is 3.1mm. Furthermore, the results show the superiority of the optimal fuzzy controller compared with optimal PID controller in tracking paths with different conditions and uncertainties.

  11. Analysis of a closed-kinematic chain robot manipulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Pooran, Farhad J.

    1988-01-01

    Presented are the research results from the research grant entitled: Active Control of Robot Manipulators, sponsored by the Goddard Space Flight Center (NASA) under grant number NAG-780. This report considers a class of robot manipulators based on the closed-kinematic chain mechanism (CKCM). This type of robot manipulators mainly consists of two platforms, one is stationary and the other moving, and they are coupled together through a number of in-parallel actuators. Using spatial geometry and homogeneous transformation, a closed-form solution is derived for the inverse kinematic problem of the six-degree-of-freedom manipulator, built to study robotic assembly in space. Iterative Newton Raphson method is employed to solve the forward kinematic problem. Finally, the equations of motion of the above manipulators are obtained by employing the Lagrangian method. Study of the manipulator dynamics is performed using computer simulation whose results show that the robot actuating forces are strongly dependent on the mass and centroid locations of the robot links.

  12. Rotary ultrasonic motors actuated by traveling flexural waves

    NASA Astrophysics Data System (ADS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Grandia, Willem

    1998-07-01

    Efficient miniature actuators that are compact and consume low power are needed to drive telerobotic devices and space mechanisms in future NASA missions. Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. The technology that has emerged in commercial products requires rigorous analytical tools for effective design of such motors. A finite element analytical model was developed to examine the excitation of flexural plate wave traveling in a rotary piezoelectrically actuated motor. The model uses annular finite elements that are applied to predict the excitation frequency and modal response of an annular stator. This model is being developed to enable the design of efficient ultrasonic motors (USMs) and it incorporates the details of the stator which include the teeth, piezoelectric crystals, stator geometry, etc. The theoretical predictions were corroborated experimentally for the stator. Parallel to this effect, USMs are made and incorporated into a robotic arm and their capability to operate at the environment of Mars is being studied. Motors with two different actuators layout were tested at cryovac conditions and were shown to operate down to -150 degree(s)C and 16-mTorr when the activation starts at ambient conditions.

  13. Engineered muscle systems having individually addressable distributed muscle actuators controlled by optical stimuli.

    PubMed

    Neal, Devin; Asada, H Harry

    2013-01-01

    A multi degree-of-freedom system using live skeletal muscles as actuators is presented. Millimeter-scale, optically excitable 3D skeletal muscle strips are created by culturing genetically coded precursory muscle cells that are activated with light: optogenetics. These muscle bio-actuators are networked together to create a distributed actuator system. Unlike traditional mechanical systems where fixed axis joints are rotated with electric motors, the new networked muscle bio-actuators can activate loads having no fixed joint. These types of loads include shoulders, the mouth, and the jaw. The optogenetic approach offers high spatiotemporal resolution for precise control of muscle activation, and opens up the possibility to activate hundreds of interconnected muscles in a spatiotemporally coordinated manner. In this work, we explore the design of robotic systems composed of multiple light-activated live muscular actuator units. We describe and compare massively parallel and highly serial/networked distributions of these building-block actuator units. We have built functional fundamental prototypes and present experimental results to demonstrate the feasibility of the construction of larger scale muscle systems.

  14. Development of a Pneumatic Robot for MRI-guided Transperineal Prostate Biopsy and Brachytherapy: New Approaches.

    PubMed

    Song, Sang-Eun; Cho, Nathan B; Fischer, Gregory; Hata, Nobuhito; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

    2010-07-15

    Magnetic Resonance Imaging (MRI) guided prostate biopsy and brachytherapy has been introduced in order to enhance the cancer detection and treatment. For the accurate needle positioning, a number of robotic assistants have been developed. However, problems exist due to the strong magnetic field and limited workspace. Pneumatically actuated robots have shown the minimum distraction in the environment but the confined workspace limits optimal robot design and thus controllability is often poor. To overcome the problem, a simple external damping mechanism using timing belts was sought and a 1-DOF mechanism test result indicated sufficient positioning accuracy. Based on the damping mechanism and modular system design approach, a new workspace-optimized 4-DOF parallel robot was developed for the MRI-guided prostate biopsy and brachytherapy. A preliminary evaluation of the robot was conducted using previously developed pneumatic controller and satisfying results were obtained.

  15. Development of a Pneumatic Robot for MRI-guided Transperineal Prostate Biopsy and Brachytherapy: New Approaches

    PubMed Central

    Song, Sang-Eun; Cho, Nathan B.; Fischer, Gregory; Hata, Nobuhito; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

    2011-01-01

    Magnetic Resonance Imaging (MRI) guided prostate biopsy and brachytherapy has been introduced in order to enhance the cancer detection and treatment. For the accurate needle positioning, a number of robotic assistants have been developed. However, problems exist due to the strong magnetic field and limited workspace. Pneumatically actuated robots have shown the minimum distraction in the environment but the confined workspace limits optimal robot design and thus controllability is often poor. To overcome the problem, a simple external damping mechanism using timing belts was sought and a 1-DOF mechanism test result indicated sufficient positioning accuracy. Based on the damping mechanism and modular system design approach, a new workspace-optimized 4-DOF parallel robot was developed for the MRI-guided prostate biopsy and brachytherapy. A preliminary evaluation of the robot was conducted using previously developed pneumatic controller and satisfying results were obtained. PMID:21399734

  16. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    NASA Astrophysics Data System (ADS)

    Wang, Zhenlong; Hang, Guanrong; Wang, Yangwei; Li, Jian; Du, Wei

    2008-04-01

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s-1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s-1 and 22° s-1, respectively.

  17. Compliant Robotic Structures

    DTIC Science & Technology

    1985-08-01

    robotic structure is one or more continuously flexible arms -hat can be controlled to manipulate objects. A typical arm is comprised of ... of ideas for the design of versatile, strong robotic manipulators. In this paper a mathematical model of an elephant trunk lifting a weight is...Results may be used for the design of robotic actuators driven by internal pressure. I,g or 67 I* .,.. INTRODUCTION Improvement in the

  18. Method and apparatus for actuating vehicle transmission

    SciTech Connect

    Ishida, H.; Ishihara, M.; Uriuhara, M.

    1988-11-15

    This patent describes a method of actuating a vehicle parallel-gear transmission having gears and an internal lever for moving shift blocks connected with shift rods and shift forks for changing gear ratios of the transmission, a hydraulically controlled select actuator operatively connected to the internal lever for moving the internal lever in a select direction, a hydraulically controlled shift actuator operatively connected to the internal lever for moving the internal lever in a shift direction substantially normal to the select direction, a hydraulically controlled clutch actuator for connecting and disconnecting a clutch of the transmission, and a common fluid discharge passage connected to fluid discharge ports of the select and shift actuators and a fluid discharge port of the clutch actuator, the select and shift actuators being alternately actuatable to effect a gear changing operation.

  19. A power-autonomous self-rolling wheel using ionic and capacitive actuators

    NASA Astrophysics Data System (ADS)

    Must, Indrek; Kaasik, Toomas; Baranova, Inna; Johanson, Urmas; Punning, Andres; Aabloo, Alvo

    2015-04-01

    Ionic electroactive polymer (IEAP) laminates are often considered as perspective actuator technology for mobile robotic appliances; however, only a few real proof-of-concept-stage robots have been built previously, a majority of which are dependent on an off-board power supply. In this work, a power-autonomous robot, propelled by four IEAP actuators having carbonaceous electrodes, is constructed. The robot consists of a light outer section in the form of a hollow cylinder, and a heavy inner section, referred to as the rim and the hub, respectively. The hub is connected to the rim using IEAP actuators, which form `spokes' of variable length. The effective length of the spokes is changed via charging and discharging of the capacitive IEAP actuators and a change in the effective lengths of the spokes eventuate in a rolling motion of the robot. The constructed IEAP robot takes advantage of the distinctive properties of the IEAP actuators. The IEAP actuators transform the geometry of the whole robot, while being soft and compliant. The low-voltage IEAP actuators in the robot are powered directly from an embedded single-cell lithium-ion battery, with no voltage regulation required; instead, only the input current is regulated. The charging of the actuators is commuted correspondingly to the robot's transitory position using an on-board control electronics. The constructed robot is able to roll for an extended period on a smooth surface. The locomotion of the IEAP robot is analyzed using video recognition.

  20. Efficient active actuation to imitate locomotion of gecko's toes using an ionic polymer-metal composite actuator enhanced by carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Min; He, Qingsong; Yu, Dingshan; Zhang, Xiaoqing; Ji, Aihong; Zhang, Hao; Guo, Ce; Dai, Zhendong

    2012-10-01

    Active actuation of the adhesive pads is important for a gecko-robot climbing on walls. We demonstrate the fabrication of an ionic polymer-metal composite (IPMC) actuator enhanced with carbon nanotubes (CNTs) and its use for actively actuating an adhesive array to imitate the locomotion of gecko's toes. The as-fabricated IPMC actuator doped with CNTs exhibits a maximum blocking force of 3.59 gf driven at a low voltage of 3 V. It can be easily controlled by voltage signals to actuate an artificial gecko's toe to attach and detach from a surface. This will allow active, distributed actuation in a gecko robot.

  1. Folded dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Carpi, Federico; Salaris, Claudio; DeRossi, Danilo

    2007-04-01

    Polymer-based linear actuators with contractile ability are currently demanded for several types of applications. Within the class of dielectric elastomer actuators, two basic configurations are available today for such a purpose: the multi-layer stack and the helical structure. The first consists of several layers of elementary planar actuators stacked in series mechanically and parallel electrically. The second configuration relies on a couple of helical compliant electrodes alternated with a couple of helical dielectrics. The fabrication of both these configurations presents some specific drawbacks today, arising from the peculiarity of each structure. Accordingly, the availability of simpler solutions may boost the short-term use of contractile actuators in practical applications. For this purpose, a new configuration is here described. It consists of a monolithic structure made of an electroded sheet, which is folded up and compacted. The resulting device is functionally equivalent to a multi-layer stack with interdigitated electrodes. However, with respect to a stack the new configuration is advantageously not discontinuous and can be manufactured in one single phase, avoiding layer-by-layer multi-step procedures. The development and preliminary testing of prototype samples of this new actuator made of a silicone elastomer are presented here.

  2. Multi-fingered robotic hand

    NASA Technical Reports Server (NTRS)

    Ruoff, Carl F. (Inventor); Salisbury, Kenneth, Jr. (Inventor)

    1990-01-01

    A robotic hand is presented having a plurality of fingers, each having a plurality of joints pivotally connected one to the other. Actuators are connected at one end to an actuating and control mechanism mounted remotely from the hand and at the other end to the joints of the fingers for manipulating the fingers and passing externally of the robot manipulating arm in between the hand and the actuating and control mechanism. The fingers include pulleys to route the actuators within the fingers. Cable tension sensing structure mounted on a portion of the hand are disclosed, as is covering of the tip of each finger with a resilient and pliable friction enhancing surface.

  3. On stability and passivity of haptic devices characterized by a series elastic actuation and considerable end-point mass.

    PubMed

    Oblak, Jakob; Matjačić, Zlatko

    2011-01-01

    Series elastic actuators have considerable potential in rehabilitation robotics. However, the reflected mass of the motor and considerable robot's end-point mass, both linked by an elastic element, result in a potentially unstable coupled mechanical oscillator. Since rehabilitation devices are in constant contact with patients, safety concerns and consequently the devices' stability are very important. In this study, the conservative conditions that guarantee the stability of the haptic device (with a considerable end-point mass and driven by a series elastic actuator) were established. We have shown that sufficient damping should be presented in parallel to the spring in order to achieve the passivity of the haptic device. Theoretical results were confirmed in an experimental evaluation on previously developed rehabilitation device.

  4. IEEE Micro Robots and Teleoperators Workshop: An investigation of micromechanical structures, actuators and sensors, Hyannis, MA, Nov. 9-11, 1987, Proceedings

    NASA Astrophysics Data System (ADS)

    Various papers on microrobots and teleoperators are presented. The general topics addressed include: microstructural fabrication technology; design, performance, and fabrication of microelectromechanical systems; and applications of micromechanical systems. Some of the individual subjects considered are: electromechanical characteristics of electric micromotors; manipulation and control of microscopic objects immersed in a fluid medium; gnat robots and how they will change robotics; atomically precise gears and bearings; and autonomous microbots.

  5. The NIST SPIDER, A Robot Crane

    PubMed Central

    Albus, James; Bostelman, Roger; Dagalakis, Nicholas

    1992-01-01

    The Robot Systems Division of the National Institute of Standards and Technology has been experimenting for several years with new concepts for robot cranes. These concepts utilize the basic idea of the Stewart Platform parallel link manipulator. The unique feature of the NIST approach is to use cables as the parallel links and to use winches as the actuators. So long as the cables are all in tension, the load is kinematically constrained, and the cables resist perturbing forces and moments with equal stiffness to both positive and negative loads. The result is that the suspended load is constrained with a mechanical stiffness determined by the elasticity of the cables, the suspended weight, and the geometry of the mechanism. Based on these concepts, a revolutionary new type of robot crane, the NIST SPIDER (Stewart Platform Instrumented Drive Environmental Robot) has been developed that can control the position, velocity, and force of tools and heavy machinery in all six degrees of freedom (x, y, z, roll, pitch, and yaw). Depending on what is suspended from its work platform, the SPIDER can perform a variety of tasks. Examples are: cutting, excavating and grading, shaping and finishing, lifting and positioning. A 6 m version of the SPIDER has been built and critical performance characteristics analyzed. PMID:28053439

  6. Modeling and control of a dielectric elastomer actuator

    NASA Astrophysics Data System (ADS)

    Gupta, Ujjaval; Gu, Guo-Ying; Zhu, Jian

    2016-04-01

    The emerging field of soft robotics offers the prospect of applying soft actuators as artificial muscles in the robots, replacing traditional actuators based on hard materials, such as electric motors, piezoceramic actuators, etc. Dielectric elastomers are one class of soft actuators, which can deform in response to voltage and can resemble biological muscles in the aspects of large deformation, high energy density and fast response. Recent research into dielectric elastomers has mainly focused on issues regarding mechanics, physics, material designs and mechanical designs, whereas less importance is given to the control of these soft actuators. Strong nonlinearities due to large deformation and electromechanical coupling make control of the dielectric elastomer actuators challenging. This paper investigates feed-forward control of a dielectric elastomer actuator by using a nonlinear dynamic model. The material and physical parameters in the model are identified by quasi-static and dynamic experiments. A feed-forward controller is developed based on this nonlinear dynamic model. Experimental evidence shows that this controller can control the soft actuator to track the desired trajectories effectively. The present study confirms that dielectric elastomer actuators are capable of being precisely controlled with the nonlinear dynamic model despite the presence of material nonlinearity and electromechanical coupling. It is expected that the reported results can promote the applications of dielectric elastomer actuators to soft robots or biomimetic robots.

  7. Pneumatic Variable Series Elastic Actuator.

    PubMed

    Zheng, Hao; Wu, Molei; Shen, Xiangrong

    2016-08-01

    Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on-off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator.

  8. High-Performance Multiresponsive Paper Actuators.

    PubMed

    Amjadi, Morteza; Sitti, Metin

    2016-11-22

    There is an increasing demand for soft actuators because of their importance in soft robotics, artificial muscles, biomimetic devices, and beyond. However, the development of soft actuators capable of low-voltage operation, powerful actuation, and programmable shape-changing is still challenging. In this work, we propose programmable bilayer actuators that operate based on the large hygroscopic contraction of the copy paper and simultaneously large thermal expansion of the polypropylene film upon increasing the temperature. The electrothermally activated bending actuators can function with low voltages (≤ 8 V), low input electric power per area (P ≤ 0.14 W cm(-2)), and low temperature changes (≤ 35 °C). They exhibit reversible shape-changing behavior with curvature radii up to 1.07 cm(-1) and bending angle of 360°, accompanied by powerful actuation. Besides the electrical activation, they can be powered by humidity or light irradiation. We finally demonstrate the use of our paper actuators as a soft gripper robot and a lightweight paper wing for aerial robotics.

  9. Electromechanical actuators

    NASA Technical Reports Server (NTRS)

    Bigham, J.

    1982-01-01

    Materials illustrating a presentation on the development of electromechanical actuators (EMA) for electric flight systems are presented. Technology issues are identified, and major steps relative to EMA development, NASA's role, and a technology procurement plan are outlined.

  10. Kinematics and dynamics of a six-degree-of-freedom robot manipulator with closed kinematic chain mechanism

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Pooran, Farhad J.

    1989-01-01

    This paper deals with a class of robot manipulators built based on the kinematic chain mechanism (CKCM). This class of CKCM manipulators consists of a fixed and a moving platform coupled together via a number of in-parallel actuators. A closed-form solution is derived for the inverse kinematic problem of a six-degre-of-freedom CKCM manipulator designed to study robotic applications in space. Iterative Newton-Raphson method is employed to solve the forward kinematic problem. Dynamics of the above manipulator is derived using the Lagrangian approach. Computer simulation of the dynamical equations shows that the actuating forces are strongly dependent on the mass and centroid of the robot links.

  11. Optimized actuators for ultrathin deformable primary mirrors.

    PubMed

    Laslandes, Marie; Patterson, Keith; Pellegrino, Sergio

    2015-05-20

    A novel design and selection scheme for surface-parallel actuators for ultrathin, lightweight mirrors is presented. The actuation system consists of electrodes printed on a continuous layer of piezoelectric material bonded to an optical-quality substrate. The electrodes provide almost full coverage of the piezoelectric layer, in order to maximize the amount of active material that is available for actuation, and their shape is optimized to maximize the correctability and stroke of the mirror for a chosen number of independent actuators and for a dominant imperfection mode. The starting point for the design of the electrodes is the observation that the correction of a figure error that has at least two planes of mirror symmetry is optimally done with twin actuators that have the same optimized shape but are rotated through a suitable angle. Additional sets of optimized twin actuators are defined by considering the intersection between the twin actuators, and hence an arbitrarily fine actuation pattern can be generated. It is shown that this approach leads to actuator systems with better performance than simple, geometrically based actuators. Several actuator patterns to correct third-order astigmatism aberrations are presented, and an experimental demonstration of a 41-actuator mirror is also presented.

  12. Bio-hybrid cell-based actuators for microsystems.

    PubMed

    Carlsen, Rika Wright; Sitti, Metin

    2014-10-15

    As we move towards the miniaturization of devices to perform tasks at the nano and microscale, it has become increasingly important to develop new methods for actuation, sensing, and control. Over the past decade, bio-hybrid methods have been investigated as a promising new approach to overcome the challenges of scaling down robotic and other functional devices. These methods integrate biological cells with artificial components and therefore, can take advantage of the intrinsic actuation and sensing functionalities of biological cells. Here, the recent advancements in bio-hybrid actuation are reviewed, and the challenges associated with the design, fabrication, and control of bio-hybrid microsystems are discussed. As a case study, focus is put on the development of bacteria-driven microswimmers, which has been investigated as a targeted drug delivery carrier. Finally, a future outlook for the development of these systems is provided. The continued integration of biological and artificial components is envisioned to enable the performance of tasks at a smaller and smaller scale in the future, leading to the parallel and distributed operation of functional systems at the microscale.

  13. Rotary ultrasonic motors actuated by traveling flexural waves

    NASA Astrophysics Data System (ADS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Grandia, Willem

    1999-06-01

    Efficient miniature actuators that are compact and consume low power are needed to drive space and planetary mechanisms in future NASA missions. Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors have emerged in commercial products but they need to be adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and also require effective analytical tools for the design of efficient motors. A finite element analytical model was developed to examine the excitation of flexural plate wave traveling in a piezoelectrically actuated rotary motor. The model uses 3D finite element and equivalent circuit models that are applied to predict the excitation frequency and modal response of the stator. This model incorporates the details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. The theoretical predictions were corroborated experimentally for the stator. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. Experiments have shown that the motor can sustain at least 230 temperature cycles from 0 degree(s)C to -90 degree(s)C at 7 Torr pressure significant performance change. Also, in an earlier study the motor lasted over 334 hours at -150 degree(s)C and vacuum. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.

  14. Rotary Motors Actuated by Traveling Ultrasonic Flexural Waves

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Grandia, Willem

    1999-01-01

    Efficient miniature actuators that are compact and consume low power are needed to drive space and planetary mechanisms in future NASA missions. Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors have emerged in commercial products but they need to be adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and also require effective analytical tools for the design of efficient motors. A finite element analytical model was developed to examine the excitation of flexural plate wave traveling in a piezoelectrically actuated rotary motor. The model uses 3D finite element and equivalent circuit models that are applied to predict the excitation frequency and modal response of the stator. This model incorporates the details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. The theoretical predictions were corroborated experimentally for the stator. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. Experiments have shown that the motor can sustain at least 230 temperature cycles from 0 C to -90 C at 7 Torr pressure significant performance change. Also, in an earlier study the motor lasted over 334 hours at -150 C and vacuum. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.

  15. T-Slide Linear Actuators

    NASA Technical Reports Server (NTRS)

    Vranish, John

    2009-01-01

    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  16. Robotic Ankle for Omnidirectional Rock Anchors

    NASA Technical Reports Server (NTRS)

    Parness, Aaron; Frost, Matthew; Thatte, Nitish

    2013-01-01

    rotary DC motor that can drag the microspine arrays across the surface to engage them with asperities, as well as a linear actuator to disengage the hooks from the surface. Additionally, the ankle allows the gripper to rotate freely about all three axes so that when the robot takes a step, the gripper may optimally orient itself with respect to the wall or ground. Finally, the ankle contains some minimal elasticity, so that between steps, the gripper returns to a default position that is roughly parallel to the wall.

  17. Design and development of an affordable haptic robot with force-feedback and compliant actuation to improve therapy for patients with severe hemiparesis.

    PubMed

    Theriault, Andrew; Nagurka, Mark; Johnson, Michelle J

    2014-01-01

    The study describes the design and development of a single degree-of-freedom haptic robot, Haptic Theradrive, for post-stroke arm rehabilitation for in-home and clinical use. The robot overcomes many of the weaknesses of its predecessor, the TheraDrive system, that used a Logitech steering wheel as the haptic interface for rehabilitation. Although the original TheraDrive system showed success in a pilot study, its wheel was not able to withstand the rigors of use. A new haptic robot was developed that functions as a drop-in replacement for the Logitech wheel. The new robot can apply larger forces in interacting with the patient, thereby extending the functionality of the system to accommodate low-functioning patients. A new software suite offers appreciably more options for tailored and tuned rehabilitation therapies. In addition to describing the design of the hardware and software, the paper presents the results of simulation and experimental case studies examining the system's performance and usability.

  18. Robotics for Human Exploration

    NASA Technical Reports Server (NTRS)

    Fong, Terrence; Deans, Mathew; Bualat, Maria

    2013-01-01

    Robots can do a variety of work to increase the productivity of human explorers. Robots can perform tasks that are tedious, highly repetitive or long-duration. Robots can perform precursor tasks, such as reconnaissance, which help prepare for future human activity. Robots can work in support of astronauts, assisting or performing tasks in parallel. Robots can also perform "follow-up" work, completing tasks designated or started by humans. In this paper, we summarize the development and testing of robots designed to improve future human exploration of space.

  19. Soft Robotics: New Perspectives for Robot Bodyware and Control

    PubMed Central

    Laschi, Cecilia; Cianchetti, Matteo

    2014-01-01

    The remarkable advances of robotics in the last 50 years, which represent an incredible wealth of knowledge, are based on the fundamental assumption that robots are chains of rigid links. The use of soft materials in robotics, driven not only by new scientific paradigms (biomimetics, morphological computation, and others), but also by many applications (biomedical, service, rescue robots, and many more), is going to overcome these basic assumptions and makes the well-known theories and techniques poorly applicable, opening new perspectives for robot design and control. The current examples of soft robots represent a variety of solutions for actuation and control. Though very first steps, they have the potential for a radical technological change. Soft robotics is not just a new direction of technological development, but a novel approach to robotics, unhinging its fundamentals, with the potential to produce a new generation of robots, in the support of humans in our natural environments. PMID:25022259

  20. Spatial abstraction for autonomous robot navigation.

    PubMed

    Epstein, Susan L; Aroor, Anoop; Evanusa, Matthew; Sklar, Elizabeth I; Parsons, Simon

    2015-09-01

    Optimal navigation for a simulated robot relies on a detailed map and explicit path planning, an approach problematic for real-world robots that are subject to noise and error. This paper reports on autonomous robots that rely on local spatial perception, learning, and commonsense rationales instead. Despite realistic actuator error, learned spatial abstractions form a model that supports effective travel.

  1. Mesofluidic controlled robotic or prosthetic finger

    DOEpatents

    Lind, Randall F; Jansen, John F; Love, Lonnie J

    2013-11-19

    A mesofluidic powered robotic and/or prosthetic finger joint includes a first finger section having at least one mesofluidic actuator in fluid communication with a first actuator, a second mesofluidic actuator in fluid communication with a second actuator and a second prosthetic finger section pivotally connected to the first finger section by a joint pivot, wherein the first actuator pivotally cooperates with the second finger to provide a first mechanical advantage relative to the joint point and wherein the second actuator pivotally cooperates with the second finger section to provide a second mechanical advantage relative to the joint point.

  2. Performance characterization of flexible dipole rectennas for smart actuator use

    NASA Astrophysics Data System (ADS)

    Kim, Jaehwan; Yang, Sang Yeol; Song, Kyo D.; Jones, Sean; Choi, Sang H.

    2006-06-01

    The concept of power transmission by a microwave is envisioned as the best option for alleviating the complexity associated with hard-wired control circuitry in controlling smart actuators and robots such as micro-aerial vehicles, biomimetic robots and space vehicles to produce remotely maneuverable capability. A flexible dipole rectenna array is conformably adaptable on the complex structure of vehicles used for practical applications of wireless power. For these applications, various flexible dipole rectennas and arrays were designed, fabricated and characterized over a frequency range of 9-12 GHz with 20 W and 200 W amplifiers through laboratory testing. The irradiance of the microwave power was measured. Also the irradiated power, the output power and the efficiency of the rectenna arrays were evaluated along with the microwave power and frequency. The maximum voltage of 65 VDC was observed from a series connected dipole rectenna array and the maximum current of 2.50 mA was obtained from a parallel connected rectenna array. The efficiency of dipole rectenna arrays ranges from 20% to 50% depending on the input power and the pole configuration. It was also demonstrated that the voltage, current and power output from a dipole rectenna array can be tailored by configuring the dipole rectenna elements in serial and parallel mode connections.

  3. Actuator and electronics packaging for extrinsic humanoid hand

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Reich, David M. (Inventor); Askew, Scott R. (Inventor)

    2013-01-01

    The lower arm assembly for a humanoid robot includes an arm support having a first side and a second side, a plurality of wrist actuators mounted to the first side of the arm support, a plurality of finger actuators mounted to the second side of the arm support and a plurality of electronics also located on the first side of the arm support.

  4. Robotic Arms. A Contribution to the Curriculum. An Occasional Paper.

    ERIC Educational Resources Information Center

    Arnold, W. F.; Carpenter, C. J.

    This report examines ways of providing technician training in the operating principles of robotic devices. The terms "robotics" and "robotic arms" are first defined. Some background information on the principal features of robotic arms is given, including their geometric arrangement, type of actuator used, control method, and…

  5. Development of a Meso-Scale SMA-Based Torsion Actuator for Image-Guided Procedures.

    PubMed

    Sheng, Jun; Gandhi, Dheeraj; Gullapalli, Rao; Simard, J Marc; Desai, Jaydev P

    2017-02-01

    This paper presents the design, modeling, and control of a meso-scale torsion actuator based on shape memory alloy (SMA) for image-guided surgical procedures. Developing a miniature torsion actuator is challenging, but it opens the possibility of significantly enhancing the robot agility and maneuverability. The proposed torsion actuator is bi-directionally actuated by a pair of antagonistic SMA torsion springs through alternate Joule heating and natural cooling. The torsion actuator is integrated into a surgical robot prototype to demonstrate its working performance in the humid environment under C-Arm CT image guidance.

  6. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  7. Effective Motion Tracking Using Known and Learned Actuation Models

    DTIC Science & Technology

    2008-06-06

    Tactic-Based Motion Model (TBMM), Play-Based Motion Model (PBMM) and Communication-Based Motion Model ( CBMM ). TBMM is the basic object motion model when...plays. CBMM is an extension of PBMM when robots communicate their actions on the object. • We incorporate a single robot and a team actuation models

  8. Multiple forearm robotic elbow configuration

    DOEpatents

    Fisher, John J.

    1990-01-01

    A dual forearmed robotic elbow configuration comprises a main arm having a double elbow from which two coplanar forearms depend, two actuators carried in the double elbow for moving the forearms, and separate, independent end effectors, operated by a cable carried from the main arm through the elbow, is attached to the distal end of each forearm. Coiling the cables around the actuators prevents bending or kinking when the forearms are rotated 360 degrees. The end effectors can have similar or different capabilities. Actuator cannisters within the dual elbow are modular for rapid replacement or maintenance. Coarse and fine resolver transducers within the actuators provide accurate position referencing information.

  9. Reversibly Actuating Solid Janus Polymeric Fibers.

    PubMed

    Ionov, Leonid; Stoychev, Georgi; Jehnichen, Dieter; Sommer, Jens Uwe

    2017-02-08

    It is commonly assumed that the substantial element of reversibly actuating soft polymeric materials is chemical cross-linking, which is needed to provide elasticity required for the reversible actuation. On the example of melt spun and three-dimensional printed Janus fibers, we demonstrate here for the first time that cross-linking is not an obligatory prerequisite for reversible actuation of solid entangled polymers, since the entanglement network itself can build elasticity during crystallization. Indeed, we show that not-cross-linked polymers, which typically demonstrate plastic deformation in melt, possess enough elastic behavior to actuate reversibly. The Janus polymeric structure bends because of contraction of the polymer and due to entanglements and formation of nanocrystallites upon cooling. Actuation upon melting is simply due to relaxation of the stressed nonfusible component. This approach opens perspectives for design of solid active materials and actuator for robotics, biotechnology, and smart textile applications. The great advantage of our principle is that it allows design of non-cross-linked self-moving materials, which are able to actuate in both water and air, which are not cross-linked. We demonstrate application of actuating fibers for design of walkers, structures with switchable length, width, and thickness, which can be used for smart textile applications.

  10. Modular droplet actuator drive

    NASA Technical Reports Server (NTRS)

    Pollack, Michael G. (Inventor); Paik, Philip (Inventor)

    2011-01-01

    A droplet actuator drive including a detection apparatus for sensing a property of a droplet on a droplet actuator; circuitry for controlling the detection apparatus electronically coupled to the detection apparatus; a droplet actuator cartridge connector arranged so that when a droplet actuator cartridge electronically is coupled thereto: the droplet actuator cartridge is aligned with the detection apparatus; and the detection apparatus can sense the property of the droplet on a droplet actuator; circuitry for controlling a droplet actuator coupled to the droplet actuator connector; and the droplet actuator circuitry may be coupled to a processor.

  11. Robotics: An introduction

    SciTech Connect

    Mc Cloy, D.; Harris, D.

    1986-01-01

    This book is an account encompassing the entire range of disciplines involved in robotics: mechanical, electrical, electronic, and software design, as well as the related technologies of pick-and-place devices, walking machines, teleoperators, and prosthetics. The book explores the evolution of robotics and major trends in the field, and covers an array of robot configurations and mechanisms. It also looks at fundamentals such as actuation, control, measurement, computers, sensing and interaction with the environment, and pattern recognition. Important economic and financial aspects as well as safety and social implications are detailed.

  12. The climbing crawling robot (a unique cable robot for space and Earth)

    NASA Technical Reports Server (NTRS)

    Kerley, James J.; May, Edward; Eklund, Wayne

    1991-01-01

    Some of the greatest concerns in robotic designs have been the high center of gravity of the robot, the irregular or flat surface that the robot has to work on, the weight of the robot that has to handle heavy weights or use heavy forces, and the ability of the robot to climb straight up in the air. This climbing crawling robot handles these problems well with magnets, suction cups, or actuators. The cables give body to the robot and it performs very similar to a caterpillar. The computer program is simple and inexpensive as is the robot. One of the important features of this system is that the robot can work in pairs or triplets to handle jobs that would be extremely difficult for single robots. The light weight of the robot allows it to handle quite heavy weights. The number of feet give the robot many roots where a simple set of feet would give it trouble.

  13. Smart energy management and low-power design of sensor and actuator nodes on algorithmic level for self-powered sensorial materials and robotics

    NASA Astrophysics Data System (ADS)

    Bosse, Stefan; Behrmann, Thomas

    2011-06-01

    We propose and demonstrate a design methodology for embedded systems satisfying low power requirements suitable for self-powered sensor and actuator nodes. This design methodology focuses on 1. smart energy management at runtime and 2. application-specific System-On- Chip (SoC) design at design time, contributing to low-power systems on both algorithmic and technology level. Smart energy management is performed spatially at runtime by a behaviour-based or state-action-driven selection from a set of different (implemented) algorithms classified by their demand of computation power, and temporally by varying data processing rates. It can be shown that power/energy consumption of an application-specific SoC design depends strongly on computation complexity. Signal and control processing is modelled on abstract level using signal flow diagrams. These signal flow graphs are mapped to Petri Nets to enable direct high-level synthesis of digital SoC circuits using a multi-process architecture with the Communicating-Sequential-Process model on execution level. Power analysis using simulation techniques on gatelevel provides input for the algorithmic selection during runtime of the system, leading to a closed-loop design flow. Additionally, the signal-flow approach enables power management by varying the signal flow and data processing rates depending on actual energy consumption, estimated energy deposit, and required Quality-of-Service.

  14. Energy Efficient Legged Robotics at Sandia Labs

    SciTech Connect

    Buerger, Steve

    2014-12-16

    Sandia is developing energy efficient actuation and drive train technologies to dramatically improve the charge life of legged robots. The work is supported by DARPA, and Sandia will demonstrate an energy efficient bipedal robot at the technology exposition section of the DARPA Robotics Challenge Finals in June, 2015. This video, the first in a series, describes early development and initial integration of the Sandia Transmission Efficient Prototype Promoting Research (STEPPR) robot.

  15. Energy Efficient Legged Robotics at Sandia Labs

    ScienceCinema

    Buerger, Steve

    2016-07-12

    Sandia is developing energy efficient actuation and drive train technologies to dramatically improve the charge life of legged robots. The work is supported by DARPA, and Sandia will demonstrate an energy efficient bipedal robot at the technology exposition section of the DARPA Robotics Challenge Finals in June, 2015. This video, the first in a series, describes early development and initial integration of the Sandia Transmission Efficient Prototype Promoting Research (STEPPR) robot.

  16. Jamming as an enabling technology for soft robotics

    NASA Astrophysics Data System (ADS)

    Steltz, E.; Mozeika, A.; Rembisz, J.; Corson, N.; Jaeger, H. M.

    2010-04-01

    This paper presents a new architecture in soft robotics that utilizes particulate jamming technology. A novel concept of actuation is described that utilizes jamming technology to modulate the direction and magnitude of the work performed by a single central actuator. Jamming "activators" modulate work by jamming and unjamming (solidifying and liquifying) a granular medium coupled to a core actuator. These ideas are demonstrated in the Jamming Skin Enabled Locomotion (JSEL) prototype which can morph its shape and achieve locomotion. Next, a new actuator, denoted a Jamming Modulated Unimorph (JMU), is presented in addition to the JSEL topology. The JMU uses a single linear actuator and a discrete number of jamming cells to turn the 1 degree of freedom (DOF) linear actuator into a multi DOF bending actuator. Full characterization of the JMU actuator is presented, followed by a concluding argument for jamming as an enabling mechanism for soft robots in general, regardless of actuation technology.

  17. Climbing robot. [caterpillar design

    NASA Technical Reports Server (NTRS)

    Kerley, James J. (Inventor); May, Edward L. (Inventor); Ecklund, Wayne D. (Inventor)

    1993-01-01

    A mobile robot for traversing any surface consisting of a number of interconnected segments, each interconnected segment having an upper 'U' frame member, a lower 'U' frame member, a compliant joint between the upper 'U' frame member and the lower 'U' frame member, a number of linear actuators between the two frame members acting to provide relative displacement between the frame members, a foot attached to the lower 'U' frame member for adherence of the segment to the surface, an inter-segment attachment attached to the upper 'U' frame member for interconnecting the segments, a power source connected to the linear actuator, and a computer/controller for independently controlling each linear actuator in each interconnected segment such that the mobile robot moves in a caterpillar like fashion.

  18. Robotic Vehicle

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A commercially available ANDROS Mark V-A robot was used by Jet Propulsion Laboratory (JPL) as the departure point in the development of the HAZBOT III, a prototype teleoperated mobile robot designed for response to emergencies. Teleoperated robots contribute significantly to reducing human injury levels by performing tasks too hazardous for humans. ANDROS' manufacturer, REMOTEC, Inc., in turn, adopted some of the JPL concepts, particularly the control panel. HAZBOT III has exceptional mobility, employs solid state electronics and brushless DC motors for safer operation, and is designed so combustible gases cannot penetrate areas containing electronics and motors. Other features include the six-degree-of-freedom manipulator, the 30-pound squeeze force parallel jaw gripper and two video cameras, one for general viewing and navigation and the other for manipulation/grasping.

  19. Tension Stiffened and Tendon Actuated Manipulator

    NASA Technical Reports Server (NTRS)

    Doggett, William R. (Inventor); Dorsey, John T. (Inventor); Ganoe, George G. (Inventor); King, Bruce D. (Inventor); Jones, Thomas C. (Inventor); Mercer, Charles D. (Inventor); Corbin, Cole K. (Inventor)

    2015-01-01

    A tension stiffened and tendon actuated manipulator is provided performing robotic-like movements when acquiring a payload. The manipulator design can be adapted for use in-space, lunar or other planetary installations as it is readily configurable for acquiring and precisely manipulating a payload in both a zero-g environment and in an environment with a gravity field. The manipulator includes a plurality of link arms, a hinge connecting adjacent link arms together to allow the adjacent link arms to rotate relative to each other and a cable actuation and tensioning system provided between adjacent link arms. The cable actuation and tensioning system includes a spreader arm and a plurality of driven and non-driven elements attached to the link arms and the spreader arm. At least one cable is routed around the driven and non-driven elements for actuating the hinge.

  20. Hopping Robot with Wheels

    NASA Technical Reports Server (NTRS)

    Barlow, Edward; Marzwell, Nevellie; Fuller, Sawyer; Fionni, Paolo; Tretton, Andy; Burdick, Joel; Schell, Steve

    2003-01-01

    A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot described in "Minimally Actuated Hopping Robot" (NPO- 20911), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 50. There are many potential applications for robots with hopping and wheeled-locomotion (roving) capabilities in diverse fields of endeavor, including agriculture, search-and-rescue operations, general military operations, removal or safe detonation of land mines, inspection, law enforcement, and scientific exploration on Earth and remote planets. The combination of hopping and roving enables this robot to move rapidly over very rugged terrain, to overcome obstacles several times its height, and then to position itself precisely next to a desired target. Before a long hop, the robot aims itself in the desired hopping azimuth and at a desired takeoff angle above horizontal. The robot approaches the target through a series of hops and short driving operations utilizing the steering wheels for precise positioning.

  1. Wavefront correction performed by a deformable mirror of arbitrary actuator pattern within a multireflection waveguide.

    PubMed

    Ma, Xingkun; Huang, Lei; Bian, Qi; Gong, Mali

    2014-09-10

    The wavefront correction ability of a deformable mirror with a multireflection waveguide was investigated and compared via simulations. By dividing a conventional actuator array into a multireflection waveguide that consisted of single-actuator units, an arbitrary actuator pattern could be achieved. A stochastic parallel perturbation algorithm was proposed to find the optimal actuator pattern for a particular aberration. Compared with conventional an actuator array, the multireflection waveguide showed significant advantages in correction of higher order aberrations.

  2. Formation control for a network of small-scale robots.

    PubMed

    Kim, Yoonsoo

    2014-10-01

    In this paper, a network of small-scale robots (typically centimeter-scale robots) equipped with artificial actuators such as electric motors is considered. The purpose of this network is to have the robots keep a certain formation shape (or change to another formation shape) during maneuvers. The network has a fixed communication topology in the sense that robots have a fixed group of neighbors to communicate during maneuvers. Assuming that each robot and its actuator can be modeled as a linear system, a decentralized control law (such that each robot activates its actuator based on the information from its neighbors only) is introduced to achieve the purpose of formation keeping or change. A linear matrix inequality (LMI) for deriving the upper bound on the actuator's time constant is also presented. Simulation results are shown to demonstrate the merit of the introduced control law.

  3. Another Lesson from Plants: The Forward Osmosis-Based Actuator

    PubMed Central

    Sinibaldi, Edoardo; Argiolas, Alfredo; Puleo, Gian Luigi; Mazzolai, Barbara

    2014-01-01

    Osmotic actuation is a ubiquitous plant-inspired actuation strategy that has a very low power consumption but is capable of generating effective movements in a wide variety of environmental conditions. In light of these features, we aimed to develop a novel, low-power-consumption actuator that is capable of generating suitable forces during a characteristic actuation time on the order of a few minutes. Based on the analysis of plant movements and on osmotic actuation modeling, we designed and fabricated a forward osmosis-based actuator with a typical size of 10 mm and a characteristic time of 2–5 minutes. To the best of our knowledge, this is the fastest osmotic actuator developed so far. Moreover, the achieved timescale can be compared to that of a typical plant cell, thanks to the integrated strategy that we pursued by concurrently addressing and solving design and material issues, as paradigmatically explained by the bioinspired approach. Our osmotic actuator produces forces above 20 N, while containing the power consumption (on the order of 1 mW). Furthermore, based on the agreement between model predictions and experimental observations, we also discuss the actuator performance (including power consumption, maximum force, energy density and thermodynamic efficiency) in relation to existing actuation technologies. In light of the achievements of the present study, the proposed osmotic actuator holds potential for effective exploitation in bioinspired robotics systems. PMID:25020043

  4. Another lesson from plants: the forward osmosis-based actuator.

    PubMed

    Sinibaldi, Edoardo; Argiolas, Alfredo; Puleo, Gian Luigi; Mazzolai, Barbara

    2014-01-01

    Osmotic actuation is a ubiquitous plant-inspired actuation strategy that has a very low power consumption but is capable of generating effective movements in a wide variety of environmental conditions. In light of these features, we aimed to develop a novel, low-power-consumption actuator that is capable of generating suitable forces during a characteristic actuation time on the order of a few minutes. Based on the analysis of plant movements and on osmotic actuation modeling, we designed and fabricated a forward osmosis-based actuator with a typical size of 10 mm and a characteristic time of 2-5 minutes. To the best of our knowledge, this is the fastest osmotic actuator developed so far. Moreover, the achieved timescale can be compared to that of a typical plant cell, thanks to the integrated strategy that we pursued by concurrently addressing and solving design and material issues, as paradigmatically explained by the bioinspired approach. Our osmotic actuator produces forces above 20 N, while containing the power consumption (on the order of 1 mW). Furthermore, based on the agreement between model predictions and experimental observations, we also discuss the actuator performance (including power consumption, maximum force, energy density and thermodynamic efficiency) in relation to existing actuation technologies. In light of the achievements of the present study, the proposed osmotic actuator holds potential for effective exploitation in bioinspired robotics systems.

  5. Proprioceptive Actuation Design for Dynamic Legged locomotion

    NASA Astrophysics Data System (ADS)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  6. Exploratorium: Robots.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic robotics. It explains how to make a vibrating robotic bug and features articles on robots. Contents include: (1) "Where Robot Mice and Robot Men Run Round in Robot Towns" (Ray Bradbury); (2) "Robots at Work" (Jake Widman); (3) "Make a Vibrating Robotic Bug" (Modesto Tamez); (4) "The Robot…

  7. A power autonomous monopedal robot

    NASA Astrophysics Data System (ADS)

    Krupp, Benjamin T.; Pratt, Jerry E.

    2006-05-01

    We present the design and initial results of a power-autonomous planar monopedal robot. The robot is a gasoline powered, two degree of freedom robot that runs in a circle, constrained by a boom. The robot uses hydraulic Series Elastic Actuators, force-controllable actuators which provide high force fidelity, moderate bandwidth, and low impedance. The actuators are mounted in the body of the robot, with cable drives transmitting power to the hip and knee joints of the leg. A two-stroke, gasoline engine drives a constant displacement pump which pressurizes an accumulator. Absolute position and spring deflection of each of the Series Elastic Actuators are measured using linear encoders. The spring deflection is translated into force output and compared to desired force in a closed loop force-control algorithm implemented in software. The output signal of each force controller drives high performance servo valves which control flow to each of the pistons of the actuators. In designing the robot, we used a simulation-based iterative design approach. Preliminary estimates of the robot's physical parameters were based on past experience and used to create a physically realistic simulation model of the robot. Next, a control algorithm was implemented in simulation to produce planar hopping. Using the joint power requirements and range of motions from simulation, we worked backward specifying pulley diameter, piston diameter and stroke, hydraulic pressure and flow, servo valve flow and bandwidth, gear pump flow, and engine power requirements. Components that meet or exceed these specifications were chosen and integrated into the robot design. Using CAD software, we calculated the physical parameters of the robot design, replaced the original estimates with the CAD estimates, and produced new joint power requirements. We iterated on this process, resulting in a design which was prototyped and tested. The Monopod currently runs at approximately 1.2 m/s with the weight of all

  8. Artificial muscle actuators in biorobotic fish fins.

    PubMed

    Phelan, Christopher T; Macdonald, Robert J; Tangorra, James L

    2009-01-01

    Artificial muscle technologies offer the possibility of designing robotic systems that take full advantage of biological architectures. Of current artificial muscle technologies, nickel titanium (Ni-Ti) shape memory alloys are among a few that are readily usable by engineering labs without specialized skills in material science and/or chemistry. Ni-Ti actuators are now being used to replace servomotors in biorobotic fins. This has significantly reduced the volume that is required for actuators, and will enable several fins to be integrated into a multi finned, flexible bodied, biorobotic fish.

  9. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  10. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  11. Robotic surgery

    MedlinePlus

    Robot-assisted surgery; Robotic-assisted laparoscopic surgery; Laparoscopic surgery with robotic assistance ... computer station and directs the movements of a robot. Small surgical tools are attached to the robot's ...

  12. Biomimetic jellyfish-inspired underwater vehicle actuated by ionic polymer metal composite actuators

    NASA Astrophysics Data System (ADS)

    Najem, Joseph; Sarles, Stephen A.; Akle, Barbar; Leo, Donald J.

    2012-09-01

    This paper presents the design, fabrication, and characterization of a biomimetic jellyfish robot that uses ionic polymer metal composites (IPMCs) as flexible actuators for propulsion. The shape and swimming style of this underwater vehicle are based on the Aequorea victoria jellyfish, which has an average swimming speed of 20 mm s-1 and which is known for its high swimming efficiency. The Aequorea victoria is chosen as a model system because both its bell morphology and kinematic properties match the mechanical properties of IPMC actuators. This medusa is characterized by its low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The critical components of the robot include the flexible bell that provides the overall shape and dimensions of the jellyfish, a central hub and a stage used to provide electrical connections and mechanical support to the actuators, eight distinct spars meant to keep the upper part of the bell stationary, and flexible IPMC actuators that extend radially from the central stage. The bell is fabricated from a commercially available heat-shrinkable polymer film to provide increased shape-holding ability and reduced weight. The IPMC actuators constructed for this study demonstrated peak-to-peak strains of ˜0.7% in water across a frequency range of 0.1-1.0 Hz. By tailoring the applied voltage waveform and the flexibility of the bell, the completed robotic jellyfish with four actuators swam at an average speed 0.77 mm s-1 and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm s-1 with a power consumption of 1.14 W.

  13. Stable electroosmotically driven actuators

    NASA Astrophysics Data System (ADS)

    Sritharan, Deepa; Motsebo, Mylene; Tumbic, Julia; Smela, Elisabeth

    2013-04-01

    We have previously presented "nastic" actuators based on electroosmotic (EO) pumping of fluid in microchannels using high electric fields for potential application in soft robotics. In this work we address two challenges facing this technology: applying EO to meso-scale devices and the stability of the pumping fluid. The hydraulic pressure achieved by EO increases with as 1/d2, where d is the depth of the microchannel, but the flow rate (which determines the stroke and the speed) is proportional to nd, where n is the number of channels. Therefore to get high force and high stroke the device requires a large number of narrow channels, which is not readily achievable using standard microfabrication techniques. Furthermore, for soft robotics the structure must be soft. In this work we present a method of fabricating a three-dimensional porous elastomer to serve as the array of channels based on a sacrificial sugar scaffold. We demonstrate the concept by fabricating small pumps. The flexible devices were made from polydimethylsiloxane (PDMS) and comprise the 3D porous elastomer flanked on either side by reservoirs containing electrodes. The second issue addressed here involves the pumping fluid. Typically, water is used for EO, but water undergoes electrolysis even at low voltages. Since EO takes place at kV, these systems must be open to release the gases. We have recently reported that propylene carbonate (PC) is pumped at a comparable rate as water and is also stable for over 30 min at 8 kV. Here we show that PC is, however, degraded by moisture, so future EO systems must prevent water from reaching the PC.

  14. Emulating a robotic manipulator arm with an hybrid motion-control system

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; León-Galicia, A.; Noriega-Hernández, M.; Salazar-Hueta, A.

    2015-01-01

    A motion control system with four and 1/2 degrees of freedom, designed to move small objects within a 0.25 m3 space, parallel to a horizontal table, with high speed and performance similar to a robotic manipulator arm was built. The machine employs several actuators and control devices. Its main characteristic is to incorporate a servomotor, steeper motors, electromechanical and fluid power actuators and diverse control resources. A group of actuators arranged on a spherical coordinates system is attached to the servomotor platform. A linear pneumatic actuator with an angular grip provides the radial extension and load clamping capacity. Seven inductive proximity sensors and one encoder provide feedback, for operating the actuators under closed loop conditions. Communication between the sensors and control devices is organized by a PLC. A touch screen allows governing the system remotely, easily and interactively, without knowing the specific programming language of each control component. The graphic environment on the touch screen guides the user to design and store control programs, establishing coordinated automatic routines for moving objects in space, simulation and implementation of industrial positioning or machining processes.

  15. Applying High-Speed Vision Sensing to an Industrial Robot for High-Performance Position Regulation under Uncertainties.

    PubMed

    Huang, Shouren; Bergström, Niklas; Yamakawa, Yuji; Senoo, Taku; Ishikawa, Masatoshi

    2016-07-29

    It is traditionally difficult to implement fast and accurate position regulation on an industrial robot in the presence of uncertainties. The uncertain factors can be attributed either to the industrial robot itself (e.g., a mismatch of dynamics, mechanical defects such as backlash, etc.) or to the external environment (e.g., calibration errors, misalignment or perturbations of a workpiece, etc.). This paper proposes a systematic approach to implement high-performance position regulation under uncertainties on a general industrial robot (referred to as the main robot) with minimal or no manual teaching. The method is based on a coarse-to-fine strategy that involves configuring an add-on module for the main robot's end effector. The add-on module consists of a 1000 Hz vision sensor and a high-speed actuator to compensate for accumulated uncertainties. The main robot only focuses on fast and coarse motion, with its trajectories automatically planned by image information from a static low-cost camera. Fast and accurate peg-and-hole alignment in one dimension was implemented as an application scenario by using a commercial parallel-link robot and an add-on compensation module with one degree of freedom (DoF). Experimental results yielded an almost 100% success rate for fast peg-in-hole manipulation (with regulation accuracy at about 0.1 mm) when the workpiece was randomly placed.

  16. 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.

  17. Final report : compliant thermo-mechanical MEMS actuators, LDRD #52553.

    SciTech Connect

    Walraven, Jeremy Allen; Baker, Michael Sean; Headley, Thomas Jeffrey; Plass, Richard Anton

    2004-12-01

    Thermal actuators have proven to be a robust actuation method in surface-micromachined MEMS processes. Their higher output force and lower input voltage make them an attractive alternative to more traditional electrostatic actuation methods. A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. This tool has also been used to better understand thermal actuator reliability by comparing the maximum actuator temperature to the measured lifetime. Modeling thermal actuator behavior requires the use of two sequentially coupled models, the first to predict the temperature increase of the actuator due to the applied current and the second to model the mechanical response of the structure due to the increase in temperature. These two models have been developed using Matlab for the thermal response and ANSYS for the structural response. Both models have been shown to agree well with experimental data. In a parallel effort, the reliability and failure mechanisms of thermal actuators have been studied. Their response to electrical overstress and electrostatic discharge has been measured and a study has been performed to determine actuator lifetime at various temperatures and operating conditions. The results from this study have been used to determine a maximum reliable operating temperature that, when used in conjunction with the predictive model, enables us to design in reliability and customize the performance of an actuator at the design stage.

  18. Molecular robots with sensors and intelligence.

    PubMed

    Hagiya, Masami; Konagaya, Akihiko; Kobayashi, Satoshi; Saito, Hirohide; Murata, Satoshi

    2014-06-17

    CONSPECTUS: What we can call a molecular robot is a set of molecular devices such as sensors, logic gates, and actuators integrated into a consistent system. The molecular robot is supposed to react autonomously to its environment by receiving molecular signals and making decisions by molecular computation. Building such a system has long been a dream of scientists; however, despite extensive efforts, systems having all three functions (sensing, computation, and actuation) have not been realized yet. This Account introduces an ongoing research project that focuses on the development of molecular robotics funded by MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan). This 5 year project started in July 2012 and is titled "Development of Molecular Robots Equipped with Sensors and Intelligence". The major issues in the field of molecular robotics all correspond to a feedback (i.e., plan-do-see) cycle of a robotic system. More specifically, these issues are (1) developing molecular sensors capable of handling a wide array of signals, (2) developing amplification methods of signals to drive molecular computing devices, (3) accelerating molecular computing, (4) developing actuators that are controllable by molecular computers, and (5) providing bodies of molecular robots encapsulating the above molecular devices, which implement the conformational changes and locomotion of the robots. In this Account, the latest contributions to the project are reported. There are four research teams in the project that specialize on sensing, intelligence, amoeba-like actuation, and slime-like actuation, respectively. The molecular sensor team is focusing on the development of molecular sensors that can handle a variety of signals. This team is also investigating methods to amplify signals from the molecular sensors. The molecular intelligence team is developing molecular computers and is currently focusing on a new photochemical technology for accelerating DNA

  19. Research in lightweight elastic robotic arms

    NASA Astrophysics Data System (ADS)

    Nartker, T. A.

    1993-06-01

    The program involved a series of individual projects coordinated to develop controls for a flexible light weight robot arm. A hydraulically actuated 3-link robot arm was installed on a PRAB hydraulic base, and was designed of tubular steel. A PERT program chart was prepared (appendix B) on which various interrelated project milestones were projected.

  20. Alocomotino Control Algorithm for Robotic Linkage Systems

    SciTech Connect

    Dohner, Jeffrey L.

    2016-10-01

    This dissertation describes the development of a control algorithm that transitions a robotic linkage system between stabilized states producing responsive locomotion. The developed algorithm is demonstrated using a simple robotic construction consisting of a few links with actuation and sensing at each joint. Numerical and experimental validation is presented.

  1. Soft linear electroactive polymer actuators based on polypyrrole

    NASA Astrophysics Data System (ADS)

    Maziz, Ali; Khaldi, Alexandre; Persson, Nils-Krister; Jager, Edwin W. H.

    2015-04-01

    There is a growing demand for human-friendly robots that can interact and work closely with humans. Such robots need to be compliant, lightweight and equipped with silent and soft actuators. Electroactive polymers such as conducting polymers (CPs) are "smart" materials that deform in response to electrical simulation and are often addressed as artificial muscles due to their functional similarity with natural muscles. They offer unique possibilities and are perfect candidates for such actuators since they are lightweight, silent, and driven at low voltages. Most CP actuators are fabricated using electrochemical oxidative synthesis. We have developed new CP based fibres employing both vapour phase and liquid phase electrochemical synthesis. We will present the fabrication and characterisation of these fibres as well as their performance as linear actuators.

  2. Actuators for a space manipulator

    NASA Technical Reports Server (NTRS)

    Chun, W.; Brunson, P.

    1987-01-01

    The robotic manipulator can be decomposed into distinct subsytems. One particular area of interest of mechanical subsystems is electromechanical actuators (or drives). A drive is defined as a motor with an appropriate transmission. An overview is given of existing, as well as state-of-the-art drive systems. The scope is limited to space applications. A design philosophy and adequate requirements are the initial steps in designing a space-qualified actuator. The focus is on the d-c motor in conjunction with several types of transmissions (harmonic, tendon, traction, and gear systems). The various transmissions will be evaluated and key performance parameters will be addressed in detail. Included in the assessment is a shuttle RMS joint and a MSFC drive of the Prototype Manipulator Arm. Compound joints are also investigated. Space imposes a set of requirements for designing a high-performance drive assembly. Its inaccessibility and cryogenic conditions warrant special considerations. Some guidelines concerning these conditions are present. The goal is to gain a better understanding in designing a space actuator.

  3. Superconducting linear actuator

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce; Hockney, Richard

    1993-01-01

    Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

  4. Multiple-Segment Climbing Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James; May, Edward; Eklund, Wayne

    1994-01-01

    Multiple-segment climbing robots developed to perform such tasks as inspection, sandblasting, welding, and painting on towers and other structures. Look and move like caterpillars. Video camera mounted on one of segments rotated to desired viewing angle. Used in remote inspection of structure, to view motion of robot and/or provides video feedback for control of motion, and/or to guide operation of head mounted on foremost segment with motorized actuators.

  5. Tracking Control of a 2-DOF Arm Actuated by Pneumatic Muscle Actuators Using Adaptive Fuzzy Sliding Mode Control

    NASA Astrophysics Data System (ADS)

    Chang, Ming-Kun; Wu, Jui-Chi

    Pneumatic muscle actuators (PMAs) have the highest power/weight ratio and power/volume ratio of any actuator. Therefore, they can be used not only in the rehabilitation engineering, but also as an actuator in robots, including industrial robots and therapy robots. It is difficult to achieve excellent tracking performance using classical control methods because the compressibility of gas and the nonlinear elasticity of bladder container causes parameter variations. An adaptive fuzzy sliding mode control is developed in this study. The fuzzy sliding surface can be used to reduce fuzzy rule numbers, and the adaptive control law is used to modify fuzzy rules on-line. A model matching technique is then adopted to adjust scaling factors. The experimental results show that this control strategy can attain excellent tracking performance.

  6. Modular robot

    DOEpatents

    Ferrante, T.A.

    1997-11-11

    A modular robot may comprise a main body having a structure defined by a plurality of stackable modules. The stackable modules may comprise a manifold, a valve module, and a control module. The manifold may comprise a top surface and a bottom surface having a plurality of fluid passages contained therein, at least one of the plurality of fluid passages terminating in a valve port located on the bottom surface of the manifold. The valve module is removably connected to the manifold and selectively fluidically connects the plurality of fluid passages contained in the manifold to a supply of pressurized fluid and to a vent. The control module is removably connected to the valve module and actuates the valve module to selectively control a flow of pressurized fluid through different ones of the plurality of fluid passages in the manifold. The manifold, valve module, and control module are mounted together in a sandwich-like manner and comprise a main body. A plurality of leg assemblies are removably connected to the main body and are removably fluidically connected to the fluid passages in the manifold so that each of the leg assemblies can be selectively actuated by the flow of pressurized fluid in different ones of the plurality of fluid passages in the manifold. 12 figs.

  7. Modular robot

    DOEpatents

    Ferrante, Todd A.

    1997-01-01

    A modular robot may comprise a main body having a structure defined by a plurality of stackable modules. The stackable modules may comprise a manifold, a valve module, and a control module. The manifold may comprise a top surface and a bottom surface having a plurality of fluid passages contained therein, at least one of the plurality of fluid passages terminating in a valve port located on the bottom surface of the manifold. The valve module is removably connected to the manifold and selectively fluidically connects the plurality of fluid passages contained in the manifold to a supply of pressurized fluid and to a vent. The control module is removably connected to the valve module and actuates the valve module to selectively control a flow of pressurized fluid through different ones of the plurality of fluid passages in the manifold. The manifold, valve module, and control module are mounted together in a sandwich-like manner and comprise a main body. A plurality of leg assemblies are removably connected to the main body and are removably fluidically connected to the fluid passages in the manifold so that each of the leg assemblies can be selectively actuated by the flow of pressurized fluid in different ones of the plurality of fluid passages in the manifold.

  8. Systems and Algorithms for Automated Collaborative Observation Using Networked Robotic Cameras

    ERIC Educational Resources Information Center

    Xu, Yiliang

    2011-01-01

    The development of telerobotic systems has evolved from Single Operator Single Robot (SOSR) systems to Multiple Operator Multiple Robot (MOMR) systems. The relationship between human operators and robots follows the master-slave control architecture and the requests for controlling robot actuation are completely generated by human operators. …

  9. Tactile sensor integrated dielectric elastomer actuator for simultaneous actuation and sensing

    NASA Astrophysics Data System (ADS)

    Kadooka, Kevin; Imamura, Hiroya; Taya, Minoru

    2016-04-01

    Dielectric elastomers (DE) are a subgroup of electroactive polymers which may be used as soft transducers. Such soft transducers exhibit high energy density and silent operation, which makes them desirable for life-like robotic systems such as a robotic hand. A robotic hand must be able to sense the object being manipulated, in terms of normal and shear force being applied, and note when contact has been achieved or lost. To this end, a dielectric elastomer actuator (DEA) with integrated tactile sensing has been developed to provide simultaneous actuation and sensing. The tactile sensing dielectric elastomer actuator consists of a unimorph-type structure, where the active portion is a laminate of alternating DE and electrode material which expands under applied voltage, and the sensing portion is a stiffer sensing dielectric elastomer which has no electrical connection to the active portion. Under applied voltage, the deformation of the active portion expands but is constrained on one side by the sensing portion, resulting in bending actuation. The sensing portion is a DE with electrodes patterned to form 2x2 capacitive sensing arrays. Dome-shaped bumps positioned over the sensing arrays redistribute tactile forces onto the sensor segments, so that measurement of the capacitance change across the array allows for reconstruction of magnitude and direction of the incoming force.

  10. Tool-Changing Mechanism For Robot

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1994-01-01

    Tool-changing mechanism for robotic applications effects secure handoff of tool between end effector of robot and yoke in which tool stowed when not in use. Operated in any orientation in normal or low gravitation. Imposes lesser constraints on design of robot and of tool because it is relatively compact and does not require large insertion forces and large actuators needed to produce them. Stored in zero g and survives launch loads.

  11. Simulation of robot manipulators

    SciTech Connect

    Kress, R.L.; Babcock, S.M.; Bills, K.C.; Kwon, D.S.; Schoenwald, D.A.

    1995-03-01

    This paper describes Oak Ridge National Laboratory`s development of an environment for the simulation of robotic manipulators. Simulation includes the modeling of kinematics, dynamics, sensors, actuators, control systems, operators, and environments. Models will be used for manipulator design, proposal evaluation, control system design and analysis, graphical preview of proposed motions, safety system development, and training. Of particular interest is the development of models for robotic manipulators having at least one flexible link. As a first application, models have been developed for the Pacific Northwest Laboratories` Flexible Beam Testbed which is a one-Degree-Of-Freedom, flexible arm with a hydraulic base actuator. Initial results show good agreement between model and experiment.

  12. Elastomeric actuator devices for magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Dubowsky, Steven (Inventor); Hafez, Moustapha (Inventor); Jolesz, Ferenc A. (Inventor); Kacher, Daniel F. (Inventor); Lichter, Matthew (Inventor); Weiss, Peter (Inventor); Wingert, Andreas (Inventor)

    2008-01-01

    The present invention is directed to devices and systems used in magnetic imaging environments that include an actuator device having an elastomeric dielectric film with at least two electrodes, and a frame attached to the actuator device. The frame can have a plurality of configurations including, such as, for example, at least two members that can be, but not limited to, curved beams, rods, plates, or parallel beams. These rigid members can be coupled to flexible members such as, for example, links wherein the frame provides an elastic restoring force. The frame preferably provides a linear actuation force characteristic over a displacement range. The linear actuation force characteristic is defined as .+-.20% and preferably 10% over a displacement range. The actuator further includes a passive element disposed between the flexible members to tune a stiffness characteristic of the actuator. The passive element can be a bi-stable element. The preferred embodiment actuator includes one or more layers of the elastomeric film integrated into the frame. The elastomeric film can be made of many elastomeric materials such as, for example, but not limited to, acrylic, silicone and latex.

  13. Hybrid transition control approach for plasma actuators

    NASA Astrophysics Data System (ADS)

    Kurz, A.; Goldin, N.; King, R.; Tropea, C.; Grundmann, S.

    2013-11-01

    This work reports on the development of a novel hybrid transition control method for single DBD plasma actuators. The experiments have been carried out on a natural laminar flow airfoil in a wind tunnel and combine two methods previously used for transition control purposes with DBD plasma actuators: boundary-layer stabilization by quasi-steady wall-parallel momentum addition, and active wave cancelation by linear superposition utilizing modulated momentum injection. For this purpose, the modulated body force is controlled using an improved extremum seeking controller based on an extended Kalman filter. Combining the two methods in a single actuator has advantages. Applied to 2-D Tollmien-Schlichting waves, the achievable transition delay in hybrid mode is significantly larger than the isolated effects, while the energy consumption remains almost unchanged compared to the case of continuous actuation. For a Reynolds number of , a transition delay of could be observed.

  14. Micro autonomous robotic system

    NASA Astrophysics Data System (ADS)

    Ishihara, Hidenori; Fukuda, Toshio

    1995-12-01

    This paper deals with the structural proposal of the micro autonomous robotic system, and shows the design of the prototype. We aim at developing the micro robot, which autonomously acts based on its detection, in order to propose a solution to constitute the micro autonomous robotic system. However, as miniaturizing the size, the number of the sensors gets restricted and the information from them becomes lack. Lack of the information makes it difficult to realize an intelligence of quality. Because of that, the micro robotic system needs to develop the simple algorithm. In this paper, we propose the simply logical algorithms to control the actuator, and show the performance of the micro robot controlled by them, and design the Micro Line Trace Robot, which dimension is about 1 cm cube and which moves along the black line on the white-colored ground, and the programmable micro autonomous robot, which dimension is about 2 cm cube and which performs according to the program optionally.

  15. BioComponent Robots

    DTIC Science & Technology

    2014-02-13

    sterile water. Culture medium was prepared with 70% Leibovitz’s L15 medium, 18% Grace’s Insect Medium, 12% fetal bovine serum (FBS), 3.4 mg/mL yeast...SECURITY CLASSIFICATION OF: The project goal was to exploit insect cell culture and tissue engineering approaches to generate biological actuators...utilizing the unique hardiness and longevity of insect cell sources for device applications for robotics. In contrast to mammalian cells and tissues

  16. Review on design and control aspects of ankle rehabilitation robots.

    PubMed

    Jamwal, Prashant K; Hussain, Shahid; Xie, Sheng Q

    2015-03-01

    Ankle rehabilitation robots can play an important role in improving outcomes of the rehabilitation treatment by assisting therapists and patients in number of ways. Consequently, few robot designs have been proposed by researchers which fall under either of the two categories, namely, wearable robots or platform-based robots. This paper presents a review of both kinds of ankle robots along with a brief analysis of their design, actuation and control approaches. While reviewing these designs it was observed that most of them are undesirably inspired by industrial robot designs. Taking note of the design concerns of current ankle robots, few improvements in the ankle robot designs have also been suggested. Conventional position control or force control approaches, being used in the existing ankle robots, have been reviewed. Apparently, opportunities of improvement also exist in the actuation as well as control of ankle robots. Subsequently, a discussion on most recent research in the development of novel actuators and advanced controllers based on appropriate physical and cognitive human-robot interaction has also been included in this review. Implications for Rehabilitation Ankle joint functions are restricted/impaired as a consequence of stroke or injury during sports or otherwise. Robots can help in reinstating functions faster and can also work as tool for recording rehabilitation data useful for further analysis. Evolution of ankle robots with respect to their design and control aspects has been discussed in the present paper and a novel design with futuristic control approach has been proposed.

  17. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  18. A neuro-inspired spike-based PID motor controller for multi-motor robots with low cost FPGAs.

    PubMed

    Jimenez-Fernandez, Angel; Jimenez-Moreno, Gabriel; Linares-Barranco, Alejandro; Dominguez-Morales, Manuel J; Paz-Vicente, Rafael; Civit-Balcells, Anton

    2012-01-01

    In this paper we present a neuro-inspired spike-based close-loop controller written in VHDL and implemented for FPGAs. This controller has been focused on controlling a DC motor speed, but only using spikes for information representation, processing and DC motor driving. It could be applied to other motors with proper driver adaptation. This controller architecture represents one of the latest layers in a Spiking Neural Network (SNN), which implements a bridge between robotics actuators and spike-based processing layers and sensors. The presented control system fuses actuation and sensors information as spikes streams, processing these spikes in hard real-time, implementing a massively parallel information processing system, through specialized spike-based circuits. This spike-based close-loop controller has been implemented into an AER platform, designed in our labs, that allows direct control of DC motors: the AER-Robot. Experimental results evidence the viability of the implementation of spike-based controllers, and hardware synthesis denotes low hardware requirements that allow replicating this controller in a high number of parallel controllers working together to allow a real-time robot control.

  19. A Neuro-Inspired Spike-Based PID Motor Controller for Multi-Motor Robots with Low Cost FPGAs

    PubMed Central

    Jimenez-Fernandez, Angel; Jimenez-Moreno, Gabriel; Linares-Barranco, Alejandro; Dominguez-Morales, Manuel J.; Paz-Vicente, Rafael; Civit-Balcells, Anton

    2012-01-01

    In this paper we present a neuro-inspired spike-based close-loop controller written in VHDL and implemented for FPGAs. This controller has been focused on controlling a DC motor speed, but only using spikes for information representation, processing and DC motor driving. It could be applied to other motors with proper driver adaptation. This controller architecture represents one of the latest layers in a Spiking Neural Network (SNN), which implements a bridge between robotics actuators and spike-based processing layers and sensors. The presented control system fuses actuation and sensors information as spikes streams, processing these spikes in hard real-time, implementing a massively parallel information processing system, through specialized spike-based circuits. This spike-based close-loop controller has been implemented into an AER platform, designed in our labs, that allows direct control of DC motors: the AER-Robot. Experimental results evidence the viability of the implementation of spike-based controllers, and hardware synthesis denotes low hardware requirements that allow replicating this controller in a high number of parallel controllers working together to allow a real-time robot control. PMID:22666004

  20. A focused bibliography on robotics

    NASA Astrophysics Data System (ADS)

    Mergler, H. W.

    1983-08-01

    The present bibliography focuses on eight robotics-related topics believed by the author to be of special interest to researchers in the field of industrial electronics: robots, sensors, kinematics, dynamics, control systems, actuators, vision, economics, and robot applications. This literature search was conducted through the 1970-present COMPENDEX data base, which provides world-wide coverage of nearly 3500 journals, conference proceedings and reports, and the 1969-1981 INSPEC data base, which is the largest for the English language in the fields of physics, electrotechnology, computers, and control.

  1. Resonant hopping of a robot controlled by an artificial neural oscillator.

    PubMed

    Pelc, Evan H; Daley, Monica A; Ferris, Daniel P

    2008-06-01

    The bouncing gaits of terrestrial animals (hopping, running, trotting) can be modeled as a hybrid dynamic system, with spring-mass dynamics during stance and ballistic motion during the aerial phase. We used a simple hopping robot controlled by an artificial neural oscillator to test the ability of the neural oscillator to adaptively drive this hybrid dynamic system. The robot had a single joint, actuated by an artificial pneumatic muscle in series with a tendon spring. We examined how the oscillator-robot system responded to variation in two neural control parameters: descending neural drive and neuromuscular gain. We also tested the ability of the oscillator-robot system to adapt to variations in mechanical properties by changing the series and parallel spring stiffnesses. Across a 100-fold variation in both supraspinal gain and muscle gain, hopping frequency changed by less than 10%. The neural oscillator consistently drove the system at the resonant half-period for the stance phase, and adapted to a new resonant half-period when the muscle series and parallel stiffnesses were altered. Passive cycling of elastic energy in the tendon accounted for 70-79% of the mechanical work done during each hop cycle. Our results demonstrate that hopping dynamics were largely determined by the intrinsic properties of the mechanical system, not the specific choice of neural oscillator parameters. The findings provide the first evidence that an artificial neural oscillator will drive a hybrid dynamic system at partial resonance.

  2. Energy Efficient Legged Robotics at Sandia Labs, Part 2

    SciTech Connect

    Buerger, Steve; Mazumdar, Ani; Spencer, Steve

    2015-06-02

    Sandia is developing energy efficient actuation and drive train technologies to dramatically improve the charge life of legged robots. The work is supported by DARPA, and Sandia will demonstrate an energy efficient bipedal robot at the technology exposition section of the DARPA Robotics Challenge Finals in June, 2015. This video, the second in a series, describes the continued development and integration of the Sandia Transmission Efficient Prototype Promoting Research (STEPPR) robot.

  3. Energy Efficient Legged Robotics at Sandia Labs, Part 2

    ScienceCinema

    Buerger, Steve; Mazumdar, Ani; Spencer, Steve

    2016-07-12

    Sandia is developing energy efficient actuation and drive train technologies to dramatically improve the charge life of legged robots. The work is supported by DARPA, and Sandia will demonstrate an energy efficient bipedal robot at the technology exposition section of the DARPA Robotics Challenge Finals in June, 2015. This video, the second in a series, describes the continued development and integration of the Sandia Transmission Efficient Prototype Promoting Research (STEPPR) robot.

  4. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  5. Continuously-variable series-elastic actuator.

    PubMed

    Mooney, Luke; Herr, Hugh

    2013-06-01

    Actuator efficiency is an important factor in the design of powered leg prostheses, orthoses, exoskeletons, and legged robots. A continuously-variable series-elastic actuator (CV-SEA) is presented as an efficient actuator for legged locomotion. The CV-SEA implements a continuously-variable transmission (CVT) between a motor and series elastic element. The CVT reduces the torque seen at the motor and allows the motor to operate in speed regimes of higher efficiency, while the series-elastic element efficiently stores and releases mechanical energy, reducing motor work requirements for actuator applications where an elastic response is sought. An energy efficient control strategy for the CV-SEA was developed using a Monte-Carlo minimization method that randomly generates transmission profiles and converges on those that minimize the electrical energy consumption of the motor. The CV-SEA is compared to a standard SEA and an infinitely variable series elastic actuator (IV-SEA). Simulations suggest that a CV-SEA will require less energy that an SEA or IV-SEA when used in a knee prosthesis during level-ground walking.

  6. Applying High-Speed Vision Sensing to an Industrial Robot for High-Performance Position Regulation under Uncertainties

    PubMed Central

    Huang, Shouren; Bergström, Niklas; Yamakawa, Yuji; Senoo, Taku; Ishikawa, Masatoshi

    2016-01-01

    It is traditionally difficult to implement fast and accurate position regulation on an industrial robot in the presence of uncertainties. The uncertain factors can be attributed either to the industrial robot itself (e.g., a mismatch of dynamics, mechanical defects such as backlash, etc.) or to the external environment (e.g., calibration errors, misalignment or perturbations of a workpiece, etc.). This paper proposes a systematic approach to implement high-performance position regulation under uncertainties on a general industrial robot (referred to as the main robot) with minimal or no manual teaching. The method is based on a coarse-to-fine strategy that involves configuring an add-on module for the main robot’s end effector. The add-on module consists of a 1000 Hz vision sensor and a high-speed actuator to compensate for accumulated uncertainties. The main robot only focuses on fast and coarse motion, with its trajectories automatically planned by image information from a static low-cost camera. Fast and accurate peg-and-hole alignment in one dimension was implemented as an application scenario by using a commercial parallel-link robot and an add-on compensation module with one degree of freedom (DoF). Experimental results yielded an almost 100% success rate for fast peg-in-hole manipulation (with regulation accuracy at about 0.1 mm) when the workpiece was randomly placed. PMID:27483274

  7. A robot-assisted orthopedic telesurgery system.

    PubMed

    Kong, M; Du, Z; Sun, L; Fu, L; Jia, Z; Wu, D

    2005-01-01

    A robot-assisted orthopedic telesurgery system, named HIT-RAOTS, has been developed according to Chinese conventional operation method. Its main function includes obtaining images with information of position and orientation of fracture, providing fracture information for doctors, assisting the doctors to complete the reposition of fracture and locking operation of intramedullary nail. In this system, a 6-dof force-reflecting master device, with a pantographic parallelogram mechanisms driven by harmonic DC servomotors, is used to control the slave manipulator movement and to translate the force from the operating room to the surgeon console; A slave robot system integrated a 6-dof force sensor, with a parallel manipulator actuated by six AC servomotors, is applied for the accurate repositioning; A virtual simulation system and human-machine interface are also developed. PI controller based on local network is used to realize the teleoperation. Only little irradiation is issued during the reposition. It can assist surgeons to perform bone-setting more safely by reducing irradiation damage to both surgeries and patients, more easily by releasing the surgeons from the heavy operation and more perfect by improving accuracy of reposition.

  8. Prototyping a robotic dental testing simulator.

    PubMed

    Alemzadeh, K; Hyde, R A; Gao, J

    2007-05-01

    A parallel robot based on the Stewart platform is being developed to simulate jaw motion and investigate its effect on jaw function to test the wearing away of dental components such as individual teeth, crowns, bridges, full set of dentures, and implant-supported overdentures by controlling chewing motion. The current paper only describes the comparison between an alternative configuration proposed by Xu and the Stewart platform configuration. The Stewart platform was chosen as an ideal structure for simulating human mastication as it is easily assembled, has high rigidity, high load-carrying capacity, and accurate positioning capability. The kinematics and singularities of the Stewart platform have been analysed and software developed to (a) test the control algorithms/strategy of muscle movement for the six degree of freedom of mastication cycle and (b) simulate and observe various design options to be able to make the best judgement in product development. The human replica skull has been analysed and reverse engineered with further simplification before integration with the Stewart platform computer-aided design (CAD) to develop the robotic dental testing simulator. Assembly modelling of the reproduced skull was critically analysed for good occlusion in CAD environment. A pulse-width modulation (PWM) circuit plus interface was built to control position and speed of the chosen actuators. A computer numerical control (CNC) machine and wire-electro-discharge machining (wire EDM) were used to manufacture the critical parts such as lower mandible, upper maxilla, and universal joints.

  9. Control of a small working robot on a large flexible manipulator for suppressing vibrations

    NASA Technical Reports Server (NTRS)

    Lee, Soo Han

    1991-01-01

    The short term objective of this research is the completion of experimental configuration of the Small Articulated Robot (SAM) and the derivations of the actuator dynamics of the Robotic Arm, Large and Flexible (RALF). In order to control vibrations SAM should have larger bandwidth than that of the vibrations. The bandwidth of SAM consist of 3 parts; structural rigidity, processing speed of controller, and motor speed. The structural rigidity was increased to a reasonably high value by attaching aluminum angles at weak points and replacing thin side plates by thicker ones. The high processing speed of the controller was achieved by using parallel processors (three 68000 process, three interface board, and one main processor (IBM-XT)). Maximum joint speed and acceleration of SAM is known as about 4 rad/s and 15 rad/sq s. Hence SAM can move only .04 rad at 3 Hz which is the natural frequency of RALF. This will be checked by experiment.

  10. Robotic control and inspection verification

    NASA Technical Reports Server (NTRS)

    Davis, Virgil Leon

    1991-01-01

    Three areas of possible commercialization involving robots at the Kennedy Space Center (KSC) are discussed: a six degree-of-freedom target tracking system for remote umbilical operations; an intelligent torque sensing end effector for operating hand valves in hazardous locations; and an automatic radiator inspection device, a 13 by 65 foot robotic mechanism involving completely redundant motors, drives, and controls. Aspects concerning the first two innovations can be integrated to enable robots or teleoperators to perform tasks involving orientation and panal actuation operations that can be done with existing technology rather than waiting for telerobots to incorporate artificial intelligence (AI) to perform 'smart' autonomous operations. The third robot involves the application of complete control hardware redundancy to enable performance of work over and near expensive Space Shuttle hardware. The consumer marketplace may wish to explore commercialization of similiar component redundancy techniques for applications when a robot would not normally be used because of reliability concerns.

  11. Robot control with biological cells.

    PubMed

    Tsuda, Soichiro; Zauner, Klaus-Peter; Gunji, Yukio-Pegio

    2007-02-01

    At present there exists a large gap in size, performance, adaptability and robustness between natural and artificial information processors for performing coherent perception-action tasks under real-time constraints. Even the simplest organisms have an enviable capability of coping with an unknown dynamic environment. Robots, in contrast, are still clumsy if confronted with such complexity. This paper presents a bio-hybrid architecture developed for exploring an alternate approach to the control of autonomous robots. Circuits prepared from amoeboid plasmodia of the slime mold Physarum polycephalum are interfaced with an omnidirectional hexapod robot. Sensory signals from the macro-physical environment of the robot are transduced to cellular scale and processed using the unique micro-physical features of intracellular information processing. Conversely, the response form the cellular computation is amplified to yield a macroscopic output action in the environment mediated through the robot's actuators.

  12. MODULAR MANIPULATOR FOR ROBOTICS APPLICATIONS

    SciTech Connect

    Joseph W. Geisinger, Ph.D.

    2001-07-31

    ARM Automation, Inc. is developing a framework of modular actuators that can address the DOE's wide range of robotics needs. The objective of this effort is to demonstrate the effectiveness of this technology by constructing a manipulator from these actuators within a glovebox for Automated Plutonium Processing (APP). At the end of the project, the system of actuators was used to construct several different manipulator configurations, which accommodate common glovebox tasks such as repackaging. The modular nature and quickconnects of this system simplify installation into ''hot'' boxes and any potential modifications or repair therein. This work focused on the development of self-contained robotic actuator modules including the embedded electronic controls for the purpose of building a manipulator system. Both of the actuators developed under this project contain the control electronics, sensors, motor, gear train, wiring, system communications and mechanical interfaces of a complete robotics servo device. Test actuators and accompanying DISC{trademark}s underwent validation testing at The University of Texas at Austin and ARM Automation, Inc. following final design and fabrication. The system also included custom links, an umbilical cord, an open architecture PC-based system controller, and operational software that permitted integration into a completely functional robotic manipulator system. The open architecture on which this system is based avoids proprietary interfaces and communication protocols which only serve to limit the capabilities and flexibility of automation equipment. The system was integrated and tested in the contractor's facility for intended performance and operations. The manipulator was tested using the full-scale equipment and process mock-ups. The project produced a practical and operational system including a quantitative evaluation of its performance and cost.

  13. A study on the effect of surface topography on the actuation performance of stacked-rolled dielectric electro active polymer actuator

    NASA Astrophysics Data System (ADS)

    Sait, Usha; Muthuswamy, Sreekumar

    2016-05-01

    Dielectric electro active polymer (DEAP) is a suitable actuator material that finds wide applications in the field of robotics and medical areas. This material is highly controllable, flexible, and capable of developing large strain. The influence of geometrical behavior becomes critical when the material is used as miniaturized actuation devices in robotic applications. The present work focuses on the effect of surface topography on the performance of flat (single sheet) and stacked-rolled DEAP actuators. The non-active areas in the form of elliptical spots that affect the performance of the actuator are identified using scanning electron microscope (SEM) and energy dissipated X-ray (EDX) experiments. Performance of DEAP actuation is critically evaluated, compared, and presented with analytical and experimental results.

  14. Pneumatic robotic systems for upper limb rehabilitation.

    PubMed

    Morales, Ricardo; Badesa, Francisco Javier; García-Aracil, Nicolás; Sabater, José María; Pérez-Vidal, Carlos

    2011-10-01

    The aim of rehabilitation robotic area is to research on the application of robotic devices to therapeutic procedures. The goal is to achieve the best possible motor, cognitive and functional recovery for people with impairments following various diseases. Pneumatic actuators are attractive for robotic rehabilitation applications because they are lightweight, powerful, and compliant, but their control has historically been difficult, limiting their use. This article first reviews the current state-of-art in rehabilitation robotic devices with pneumatic actuation systems reporting main features and control issues of each therapeutic device. Then, a new pneumatic rehabilitation robot for proprioceptive neuromuscular facilitation therapies and for relearning daily living skills: like taking a glass, drinking, and placing object on shelves is described as a case study and compared with the current pneumatic rehabilitation devices.

  15. Electrostatic repulsive out-of-plane actuator using conductive substrate

    PubMed Central

    Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

    2016-01-01

    A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0–4.5 μm for a dc driving voltage of 0–100 V, when compared with that in two-layer mode. PMID:27713542

  16. Electrostatic repulsive out-of-plane actuator using conductive substrate

    NASA Astrophysics Data System (ADS)

    Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

    2016-10-01

    A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0–4.5 μm for a dc driving voltage of 0–100 V, when compared with that in two-layer mode.

  17. Electrostatic repulsive out-of-plane actuator using conductive substrate.

    PubMed

    Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

    2016-10-07

    A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0-4.5 μm for a dc driving voltage of 0-100 V, when compared with that in two-layer mode.

  18. Dielectric Elastomer Actuated Systems and Methods

    NASA Technical Reports Server (NTRS)

    Dubowsky, Steven (Inventor); Hafez, Moustapha (Inventor); Lichter, Matthew (Inventor); Weiss, Peter (Inventor); Wingert, Andreas (Inventor)

    2008-01-01

    The system of the present invention includes an actuator having at least two electrodes, an elastomeric dielectric film disposed between the two electrodes, and a frame attached to the elastomeric dielectric film. The frame provides a linear actuation force characteristic over a displacement range. The displacement range is preferably the stroke of the actuator. The displacement range can be about 5 mm and greater. Further, the frame can include a plurality of configurations, for example, at least a rigid members coupled to a flexible member wherein the frame provides an elastic restoring force. In preferred embodiments, the rigid member can be, but is not limited to, curved beams, parallel beams, rods and plates. In a preferred embodiment the actuator can further include a passive element disposed between two flexible members such as, for example, links to tune a stiffness characteristic of the actuator. The passive element can be a bi-stable element. Further, the actuator can include a plurality of layers of the elastomeric dielectric film integrated into the frame. The elastomeric film can be made of different materials such as, for example, acrylic, silicone and latex.

  19. Multi-layer robot skin with embedded sensors and muscles

    NASA Astrophysics Data System (ADS)

    Tomar, Ankit; Tadesse, Yonas

    2016-04-01

    Soft artificial skin with embedded sensors and actuators is proposed for a crosscutting study of cognitive science on a facial expressive humanoid platform. This paper focuses on artificial muscles suitable for humanoid robots and prosthetic devices for safe human-robot interactions. Novel composite artificial skin consisting of sensors and twisted polymer actuators is proposed. The artificial skin is conformable to intricate geometries and includes protective layers, sensor layers, and actuation layers. Fluidic channels are included in the elastomeric skin to inject fluids in order to control actuator response time. The skin can be used to develop facially expressive humanoid robots or other soft robots. The humanoid robot can be used by computer scientists and other behavioral science personnel to test various algorithms, and to understand and develop more perfect humanoid robots with facial expression capability. The small-scale humanoid robots can also assist ongoing therapeutic treatment research with autistic children. The multilayer skin can be used for many soft robots enabling them to detect both temperature and pressure, while actuating the entire structure.

  20. A novel stiffness control method for series elastic actuator

    NASA Astrophysics Data System (ADS)

    Lin, Guangmo; Zhao, Xingang; Han, Jianda

    2017-01-01

    Compliance plays an important role in human-robot cooperation. However, fixed compliance, or fixed stiffness, is difficult to meet the growing needs of human machine collaboration. As a result, the robot actuator is demanded to be able to adjust its stiffness. This paper presents a stiffness control scheme for a single DOF series elastic actuator (SEA) with a linear spring mounted in series in the mechanism. In this proposed method, the output angle of the spring is measured and used to calculate the input angle of the spring, thus the equivalent stiffness of the robot actuator revealed to the human operator can be rendered in accordance to the desired stiffness. Since the techniques used in this method only involve the position information of the system, there is no need to install an expensive force/torque sensor on the actuator. Further, the force/torque produced by the actuator can be estimated by simply multiplying the deformation angle of the spring and its constant stiffness coefficient. The analysis of the stiffness controller is provided. Then a simulation that emulates a human operates the SEA while the stiffness controller is running is carried out and the results also validate the proposed method.

  1. MEMS-based fabrication of multiple-degree-of-freedom ionic polymer-metal composite actuators

    NASA Astrophysics Data System (ADS)

    Chen, Zheng; Tan, Xiaobo

    2010-04-01

    Ionic polymer-metal composites (IPMC) are soft actuation materials with promising applications in robotics and biomedical devices. In this paper, a MEMS-based approach is presented for monolithic, batch fabrication of IPMC pectoral fin actuators that are capable of complex deformation. Such an actuator consists of multiple, individually controlled IPMC regions that are mechanically coupled through compliant, passive regions. Prototypes of artificial pectoral fins have been fabricated with the proposed method, and sophisticated deformation modes, including bending, twisting, and cupping, have been demonstrated, which shows the promise of the pectoral fin in robotic fish applications.

  2. Miga Aero Actuator and 2D Machined Mechanical Binary Latch

    NASA Technical Reports Server (NTRS)

    Gummin, Mark A.

    2013-01-01

    Shape memory alloy (SMA) actuators provide the highest force-to-weight ratio of any known actuator. They can be designed for a wide variety of form factors from flat, thin packages, to form-matching packages for existing actuators. SMA actuators can be operated many thousands of times, so that ground testing is possible. Actuation speed can be accurately controlled from milliseconds to position and hold, and even electronic velocity-profile control is possible. SMA actuators provide a high degree of operational flexibility, and are truly smart actuators capable of being accurately controlled by onboard microprocessors across a wide range of voltages. The Miga Aero actuator is a SMA actuator designed specifically for spaceflight applications. Providing 13 mm of stroke with either 20- or 40-N output force in two different models, the Aero actuator is made from low-outgassing PEEK (polyether ether ketone) plastic, stainless steel, and nickel-titanium SMA wires. The modular actuator weighs less than 28 grams. The dorsal output attachment allows the Aero to be used in either PUSH or PULL modes by inverting the mounting orientation. The SPA1 actuator utilizes commercially available SMA actuator wire to provide 3/8-in. (approx. =.1 cm) of stroke at a force of over 28 lb (approx. = .125 N). The force is provided by a unique packaging of the single SMA wire that provides the output force of four SMA wires mechanically in parallel. The output load is shared by allowing the SMA wire to slip around the output attachment end to adjust or balance the load, preventing any individual wire segment from experiencing high loads during actuation. A built-in end limit switch prevents overheating of the SMA element following actuation when used in conjunction with the Miga Analog Driver [a simple MOSFET (metal oxide semiconductor field-effect transistor) switching circuit]. A simple 2D machined mechanical binary latch has been developed to complement the capabilities of SMA wire

  3. A smart soft actuator using a single shape memory alloy for twisting actuation

    NASA Astrophysics Data System (ADS)

    Shim, Jae-Eul; Quan, Ying-Jun; Wang, Wei; Rodrigue, Hugo; Song, Sung-Hyuk; Ahn, Sung-Hoon

    2015-12-01

    Recently, robots have become a topic of interest with regard to their functionality as they need to complete a large number of diverse tasks in a variety of environments. When using traditional mechanical components, many parts are needed to realize complex deformations, such as motors, hinges, and cranks. To produce complex deformations, this work introduces a smart soft composite torsional actuator using a single shape memory alloy (SMA) wire without any additional elements. The proposed twisting actuator is composed of a torsionally prestrained SMA wire embedded at the center of a polydimethylsiloxane matrix that twists by applying an electric current upon joule heating of the SMA wire. This report shows the actuator design, fabrication method, and results for the twisting angle and actuation moment. Results show that a higher electric current helps reach the maximum twisting angle faster, but that if the current is too low or too high, it will not be able to reach its maximum deformation. Also, both the twisting angle and the twisting moment increase with a large applied twisting prestrain, but this increase has an asymptotic behavior. However, results for both the width and the thickness of the actuator show that a larger width and thickness reduce the maximum actuation angle of the actuator. This paper also presents a new mechanism for an SMA-actuated active catheter using only two SMA wires with a total length of 170 mm to bend the tip of the catheter in multiple directions. The fabricated active catheter’s maximum twisting angle is 270°, and the maximum bending curvature is 0.02 mm-1.

  4. Robot and robot system

    NASA Technical Reports Server (NTRS)

    Behar, Alberto E. (Inventor); Marzwell, Neville I. (Inventor); Wall, Jonathan N. (Inventor); Poole, Michael D. (Inventor)

    2011-01-01

    A robot and robot system that are capable of functioning in a zero-gravity environment are provided. The robot can include a body having a longitudinal axis and having a control unit and a power source. The robot can include a first leg pair including a first leg and a second leg. Each leg of the first leg pair can be pivotally attached to the body and constrained to pivot in a first leg pair plane that is substantially perpendicular to the longitudinal axis of the body.

  5. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices

    NASA Astrophysics Data System (ADS)

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie

    2016-09-01

    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes’ (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.

  6. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices.

    PubMed

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie

    2016-09-27

    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes' (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.

  7. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices

    PubMed Central

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie

    2016-01-01

    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes’ (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body. PMID:27670953

  8. Autonomous mobile robots: Vehicles with cognitive control

    SciTech Connect

    Meystel, A.

    1987-01-01

    This book explores a new rapidly developing area of robotics. It describes the state-of-the-art intelligence control, applied machine intelligence, and research and initial stages of manufacturing of autonomous mobile robots. A complete account of the theoretical and experimental results obtained during the last two decades together with some generalizations on Autonomous Mobile Systems are included in this book. Contents: Introduction; Requirements and Specifications; State-of-the-art in Autonomous Mobile Robots Area; Structure of Intelligent Mobile Autonomous System; Planner, Navigator; Pilot; Cartographer; Actuation Control; Computer Simulation of Autonomous Operation; Testing the Autonomous Mobile Robot; Conclusions; Bibliography.

  9. Mobile robots: motor challenges and materials solutions.

    PubMed

    Madden, John D

    2007-11-16

    Bolted-down robots labor in our factories, performing the same task over and over again. Where are the robots that run and jump? Equaling human performance is very difficult for many reasons, including the basic challenge of demonstrating motors and transmissions that efficiently match the power per unit mass of muscle. In order to exceed animal agility, new actuators are needed. Materials that change dimension in response to applied voltage, so-called artificial muscle technologies, outperform muscle in most respects and so provide a promising means of improving robots. In the longer term, robots powered by atomically perfect fibers will outrun us all.

  10. Research Trends of Soft Actuators based on Electroactive Polymers and Conducting Polymers

    NASA Astrophysics Data System (ADS)

    Kaneto, K.

    2016-04-01

    Artificial muscles (or soft actuators) based on electroactive polymers (EAPs) are attractive power sources to drive human-like robots in place of electrical motor, because they are quiet, powerful, light weight and compact. Among EAPs for soft actuators, conducting polymers are superior in strain, stress, deformation form and driving voltage compared with the other EAPs. In this paper, the research trends of EAPs and conducting polymers are reviewed by retrieval of the papers and patents. The research activity of EAP actuators showed the maximum around 2010 and somehow declining now days. The reasons for the reducing activity are found to be partly due to problems of conducting polymer actuators for the practical application. The unique characteristics of conducting polymer actuators are mentioned in terms of the basic mechanisms of actuation, creeping, training effect and shape retention under high tensile loads. The issues and limitation of conducting polymer soft actuators are discussed.

  11. Effective Actuation: High Bandwidth Actuators and Actuator Scaling Laws

    DTIC Science & Technology

    2007-11-02

    5c. PROGRAM ELEMENT NUMBER I-ioh Bandwidth Actiintorv and Actuator 9clinp Iaw-, 65502F 6. AUTHOR(S) 5d. PROJECT NUMBER A. B. Cain, G. R. Raman , and E...of possible applications include the high frequency excitation for supprc~sion of flow induced resonance in weapons bay cavities (see Raman et al...systems. Adaptive high bandwidth actuators are required to adapt to changes in flow speed and conditions during flight. Raman et al. (2000) and Stanek et

  12. Concurrent programming and robotics

    SciTech Connect

    Cox, I.J.; Gehani, N.H.

    1989-04-01

    Many current robot systems exhibit a significant degree of concurrency, doing many activities in parallel. Future sensor-based robots are expected to exhibit even more concurrency. Programs to control such robots are characterized by the need to wait for external events and/or handle interrupts, deal with concurrent activities, synchronize actions with external events, and communicate with other robots and processes. In this paper, the authors focus on the advantages of concurrent programming for robotics and suggest that a general-purpose language with the right facilities is a good vehicle for robot programming. In this context they discuss Concurrent C, an upward-compatible extension of the C language that provides high-level concurrent programming facilities. They give an historical perspective of concurrent programming followed by a brief description of Concurrent C and how Concurrent C programs communicate with robots and devices. They show by examples how Concurrent C simplifies writing robot programs. Of specific interest are the process interaction and related interrupt handling facilities.

  13. Hydraulic Actuator Project

    DTIC Science & Technology

    2003-11-01

    Hydraulic Actuator Project Stakeholder meeting held 7- 8 October in Los Angeles; 58 attendees representing aircraft and actuator OEMs, seal...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Research Laboratory,4555 Overlook Ave., SW ,Washington,DC,20375 8 . PERFORMING ORGANIZATION REPORT...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8 -98) Prescribed by ANSI Std Z39-18 Actuator JTP: Coupon Testing Substrate

  14. Remote switch actuator

    DOEpatents

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

    2013-01-29

    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  15. State Estimation for Tensegrity Robots

    NASA Technical Reports Server (NTRS)

    Caluwaerts, Ken; Bruce, Jonathan; Friesen, Jeffrey M.; Sunspiral, Vytas

    2016-01-01

    Tensegrity robots are a class of compliant robots that have many desirable traits when designing mass efficient systems that must interact with uncertain environments. Various promising control approaches have been proposed for tensegrity systems in simulation. Unfortunately, state estimation methods for tensegrity robots have not yet been thoroughly studied. In this paper, we present the design and evaluation of a state estimator for tensegrity robots. This state estimator will enable existing and future control algorithms to transfer from simulation to hardware. Our approach is based on the unscented Kalman filter (UKF) and combines inertial measurements, ultra wideband time-of-flight ranging measurements, and actuator state information. We evaluate the effectiveness of our method on the SUPERball, a tensegrity based planetary exploration robotic prototype. In particular, we conduct tests for evaluating both the robot's success in estimating global position in relation to fixed ranging base stations during rolling maneuvers as well as local behavior due to small-amplitude deformations induced by cable actuation.

  16. Electrostatically Driven Nanoballoon Actuator.

    PubMed

    Barzegar, Hamid Reza; Yan, Aiming; Coh, Sinisa; Gracia-Espino, Eduardo; Dunn, Gabriel; Wågberg, Thomas; Louie, Steven G; Cohen, Marvin L; Zettl, Alex

    2016-11-09

    We demonstrate an inflatable nanoballoon actuator based on geometrical transitions between the inflated (cylindrical) and collapsed (flattened) forms of a carbon nanotube. In situ transmission electron microscopy experiments employing a nanoelectromechanical manipulator show that a collapsed carbon nanotube can be reinflated by electrically charging the nanotube, thus realizing an electrostatically driven nanoballoon actuator. We find that the tube actuator can be reliably cycled with only modest control voltages (few volts) with no apparent wear or fatigue. A complementary theoretical analysis identifies critical parameters for nanotube nanoballoon actuation.

  17. Improved Electrohydraulic Linear Actuators

    NASA Technical Reports Server (NTRS)

    Hamtil, James

    2004-01-01

    A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also adaptable to many industrial uses, such as steam turbines, process control valves, dampers, motion control, etc. The advantageous features of the improved electrohydraulic linear actuators are best described with respect to shortcomings of prior electrohydraulic linear actuators that the improved ones are intended to supplant. The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal (a current having a value between 4 and 20 mA) from a supervisory control system of the facility. As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position.

  18. Conformal grasping using feedback controlled bubble actuator array

    NASA Astrophysics Data System (ADS)

    Carrigan, Wei; Stein, Richard; Mittal, Manoj; Wijesundara, Muthu B. J.

    2014-06-01

    This paper presents an implementation of a bubble actuator array (BAA) based active robotic skin, a modular system, onto existing low cost robotic end-effectors or prosthetic hands for conformal grasping of objects. The active skin is comprised of pneumatically controlled polyurethane rubber bubbles with overlaid sensors for feedback control. Sensor feedback allows the BAA based robotic skin to conformally grasp an object with an explicit uniform force distribution. The bubble actuator array reported here is capable of applying up to 4N of force at each point of contact and tested for conformally grasping objects with a radius of curvature up to 57.15mm. Once integrated onto a two-finger gripper with one degree of freedom (DOF), the active skin was shown to reduce point of contact forces of up to 50% for grasped objects.

  19. Soft Active Materials for Actuation, Sensing, and Electronics

    NASA Astrophysics Data System (ADS)

    Kramer, Rebecca Krone

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components increases, the challenges for functionality revert to basic questions of fabrication, materials, and design - whereas such aspects are far more developed for traditional rigid-bodied systems. This thesis will highlight preliminary materials and designs that address the need for soft actuators and sensors, as well as emerging fabrication techniques for manufacturing stretchable circuits and devices based on liquid-embedded elastomers.

  20. Contribution to the design of robotized tele-echography system

    NASA Astrophysics Data System (ADS)

    Essomba, T.; Laribi, M. A.; Gazeau, J. P.; Zeghloul, S.; Poisson, G.

    2012-06-01

    This paper introduces the design of a master-slave robotized system for tele-ultrasound application. The objective of these researches is to design the slave manipulator of this system and its control device (master part). The specification process of the architecture kinematic is based on the analysis of expert's gesture during ultrasound examinations. These studies have been carried out using a motion capture system. The medical gestures were analyzed in terms of ultrasound probe attitude and used in the definition of the kinematics specifications of the proposed manipulator. The Spherical Parallel Mechanism is selected because its characteristics meet the constraint requirements. The optimal synthesis of spherical parallel manipulators is performed using a realcoded Genetic Algorithm based method. Simulations on the actuator responses of the structure allowed us the validate it. In order to control this robot, we have also designed a haptic device that provides easiness to use as well as force feedback. Its orientation control strategy is based on a use of an adaptative kalman filter which efficiency was demonstrated during experimentations.

  1. Dynamic analysis of the Schilling Titan 7F robotic arm

    SciTech Connect

    Baker, C.P.

    1991-10-01

    A seven degree of freedom hydraulically actuated robotic arm is modeled using DADS. The low level control system for the arm is included in the model, as is the hydraulic system, and model results are compared with experimental results for the arm. Vane type rotary actuators are used in this arm, and a method for modeling them with DADS elements is presented. 10 figs.

  2. Novel Robotic Tools for Piping Inspection and Repair

    DTIC Science & Technology

    2015-01-14

    maintenance , flexible actuator, pneumatic actuator U U U Unlimited 58 Karl Edminster 508-967-0424 Novel Robotic Tools for Piping Inspection and...to be deployed for in situ remediation. Implementation of this system will allow for fleet preventative maintenance (PM), ensuring that possible

  3. Synthetic Bursae for Robots

    NASA Technical Reports Server (NTRS)

    Lovchik, Christopher S.

    2005-01-01

    Synthetic bursae are under development for incorporation into robot joints that are actuated by motor-driven cables in a manner similar to that of arthropod joints actuated by muscle-driven tendons. Like natural bursae, the synthetic bursae would serve as cushions and friction reducers. A natural bursa is a thin bladder filled with synovial fluid, which serves to reduce friction and provide a cushion between a bone and a muscle or a tendon. A synthetic bursa would be similar in form and function: It would be, essentially, a compact, soft roller consisting of a bladder filled with a non-Newtonian fluid. The bladder would be constrained to approximately constant volume. The synthetic bursa would cushion an actuator cable against one of the members of a robot joint and would reduce the friction between the cable and the member. Under load, the pressure in the bladder would hold the opposite walls of the bladder apart, making it possible for them to move freely past each other without rubbing.

  4. Amplifying the response of soft actuators by harnessing snap-through instabilities

    PubMed Central

    Overvelde, Johannes T. B.; Kloek, Tamara; D’haen, Jonas J. A.; Bertoldi, Katia

    2015-01-01

    Soft, inflatable segments are the active elements responsible for the actuation of soft machines and robots. Although current designs of fluidic actuators achieve motion with large amplitudes, they require large amounts of supplied volume, limiting their speed and compactness. To circumvent these limitations, here we embrace instabilities and show that they can be exploited to amplify the response of the system. By combining experimental and numerical tools we design and construct fluidic actuators in which snap-through instabilities are harnessed to generate large motion, high forces, and fast actuation at constant volume. Our study opens avenues for the design of the next generation of soft actuators and robots in which small amounts of volume are sufficient to achieve significant ranges of motion. PMID:26283372

  5. Self-actuated device

    DOEpatents

    Hecht, Samuel L.

    1984-01-01

    A self-actuated device, of particular use as a valve or an orifice for nuclear reactor fuel and blanket assemblies, in which a gas produced by a neutron induced nuclear reaction gradually accumulates as a function of neutron fluence. The gas pressure increase occasioned by such accumulation of gas is used to actuate the device.

  6. Remotely controllable actuating device

    NASA Technical Reports Server (NTRS)

    McKillip, Jr., Robert M. (Inventor)

    1998-01-01

    An actuating device can change a position of an active member that remains in substantially the same position in the absence of a force of a predetermined magnitude on the active member. The actuating device comprises a shape-memory alloy actuating member for exerting a force when actuated by changing the temperature thereof, which shape-memory alloy actuating member has a portion for connection to the active member for exerting thereon a force having a magnitude at least as large as the predetermined magnitude for moving the active member to a desired position. Actuation circuitry is provided for actuating the shape-memory alloy actuating member by changing the temperature thereof only for the time necessary to move the active member to the desired position. The invention is particularly useful for changing the position of a camber-adjusting tab on a helicopter rotor blade by using two shape-memory alloy members that can act against each other to adjust dynamic properties of the rotor blade as it is rotating.

  7. Massively Redundant Electromechanical Actuators

    DTIC Science & Technology

    2014-08-30

    date of determination). DoD Controlling Office is (insert controlling DoD office). "Massively Redundant Electromechanical Actuators" August... electromechanical systems) processes are used to manufacture reliable and reproducible stators and sliders for the actuators. These processes include

  8. Smart structures technologies for parallel kinematics in handling and assembly

    NASA Astrophysics Data System (ADS)

    Keimer, Ralf; Algermissen, Stephan; Pavlovic, Nenad; Budde, Christoph

    2007-04-01

    conditions otherwise. The additional feature to alter the DOF is realized by increasing friction to the point where clamping happens. This can be used to support the change in the machines configuration of parallel kinematics. Two kinds of adaptive joints are presented, both utilizing piezoceramic actuators. The first kind features an adjustable clearance of the slide bearing that provides low friction for high clearance conditions and great friction for reduced clearance. The second kind offers the possibility to reduce the friction by moving the rubbing surfaces dynamically. For both joints experimental results are shown. The paper closes with an outlook on ongoing research in the field of parallel robots for handling and assembly with an emphasis on smart structures technologies.

  9. A novel magnetorheological damper based parallel planar manipulator design

    NASA Astrophysics Data System (ADS)

    Hoyle, A.; Arzanpour, S.; Shen, Y.

    2010-05-01

    This paper presents a novel parallel planar robot design which is low cost and simple in structure. The design addresses some of the problems, such as concentration of excessive load on the links and joints, due to wrong commanding signals being given by the controller. In this application two of the conventional actuators are replaced by magnetorheological (MR) dampers, and only one actuator is used to generate motion. The design paradigm is based on the concept that a moving object 'intuitively' follows the path with minimum resistance to its motion. This implies that virtual adoptable constraints can be used effectively to define motion trajectories. In fact, motion generation and adaptive constraints are two elements essential to implementing this strategy. In this paper, MR dampers are used to provide adjustable constraints and to guide the platform that is moved by the linear motor. The model of the MR dampers is derived using the Bouc-Wen model. This model is then used for manipulator simulation and controller design. Two controllers are developed for this manipulator: (1) a closed loop on/off one and (2) a proportional-derivative controller. Also, three different trajectories are defined and used for both the simulations and experiments. The results indicate a good agreement between the simulations and experiments. The experimental results also demonstrate the capability of the manipulator for following sophisticated trajectories.

  10. Kirigami design and fabrication for biomimetic robotics

    NASA Astrophysics Data System (ADS)

    Rossiter, Jonathan; Sareh, Sina

    2014-03-01

    Biomimetics faces a continual challenge of how to bridge the gap between what Nature has so effectively evolved and the current tools and materials that engineers and scientists can exploit. Kirigami, from the Japanese `cut' and `paper', is a method of design where laminar materials are cut and then forced out-of-plane to yield 3D structures. Kirimimetic design provides a convenient and relatively closed design space within which to replicate some of the most interesting niche biological mechanisms. These include complex flexing organelles such as cilia in algae, energy storage and buckled structures in plants, and organic appendages that actuate out-of-plane such as the myoneme of the Vorticella protozoa. Where traditional kirigami employs passive materials which must be forced to transition to higher dimensions, we can exploit planar smart actuators and artificial muscles to create self-actuating kirigami structures. Here we review biomimetics with respect to the kirigami design and fabrication methods and examine how smart materials, including electroactive polymers and shape memory polymers, can be used to realise effective biomimetic components for robotic, deployable structures and engineering systems. One-way actuation, for example using shape memory polymers, can yield complete self-deploying structures. Bi-directional actuation, in contrast, can be exploited to mimic fundamental biological mechanisms such as thrust generation and fluid control. We present recent examples of kirigami robotic mechanisms and actuators and discuss planar fabrication methods, including rapid prototyping and 3D printing, and how current technologies, and their limitations, affect Kirigami robotics.

  11. Fast electrochemical actuator

    NASA Astrophysics Data System (ADS)

    Uvarov, I. V.; Postnikov, A. V.; Svetovoy, V. B.

    2016-03-01

    Lack of fast and strong microactuators is a well-recognized problem in MEMS community. Electrochemical actuators can develop high pressure but they are notoriously slow. Water electrolysis produced by short voltage pulses of alternating polarity can overcome the problem of slow gas termination. Here we demonstrate an actuation regime, for which the gas pressure is relaxed just for 10 μs or so. The actuator consists of a microchamber filled with the electrolyte and covered with a flexible membrane. The membrane bends outward when the pressure in the chamber increases. Fast termination of gas and high pressure developed in the chamber are related to a high density of nanobubbles in the chamber. The physical processes happening in the chamber are discussed so as problems that have to be resolved for practical applications of this actuation regime. The actuator can be used as a driving engine for microfluidics.

  12. Translatory and wobbling micro magnetostrictive actuator

    NASA Astrophysics Data System (ADS)

    Ueno, Toshiyuki; Saito, Chihiro; Imaizumi, Nobuo; Higuchi, Toshiro

    2008-03-01

    We propose a three-DOF magnetostrictive micro actuator using Iron-Gallium alloy (Galfenol). The actuator consists of two parallel beam structure having a Galfenol core, located at either end of a Galfenol rod of 1 mm square cross-section and length 11 mm, with two orthogonal ditches cut down it of width 0.3 mm. Around the resulting prongs are wound, and the prongs are bonded to an iron end cap to close the magnetic circuit. When current is passed through a coil wound round one of the orthogonal parallel beams, the resulting magnetostriction enables the actuator to bend in two directions. In addition, longitudinal displacement with high frequency bandwidth can be generated by excitation of two or of all four coils. Maximum displacements were observed of 8 to 10 μm in bending and 2.2 μm in the longitudinal direction. This actuator is potentially applicable in machining (drilling), positioning, and in a micro-motor using wobbling or translational motion when powered by a small power supply.

  13. MACCEPA, The mechanically adjustable compliance and controllable equilibrium position actuator: A 3DOF joint with two independent compliances

    NASA Astrophysics Data System (ADS)

    Van Ham, R.; Van Damme, M.; Verrelst, B.; Vanderborght, B.; Lefeber, D.

    2007-04-01

    The MACCEPA is a straightforward and easy to construct rotational actuator in which the compliance can be controlled separately from the equilibrium position. A 3DOF joint with adaptable compliance is presented. The generated torque is a linear function of the compliance and of the angle between the equilibrium position and actual position. This makes this actuator perfectly suitable for dynamic walking, human-robotic interfaces, and robotic rehabilitation devices

  14. Curved Piezoelectric Actuators for Stretching Optical Fibers

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  15. On controlling robots with redundancy

    NASA Technical Reports Server (NTRS)

    Colbaugh, R.; Glass, K.

    1991-01-01

    An adaptive position control scheme for manipulators possessing either kinematic or actuator redundancy is presented. The controller is developed by considering the end-effector position control problem and redundancy resolution problem separately. The end-effector position control problem is solved by using an adaptive scheme to generate the Cartesian-space control input required to track the desired end-effector position trajectory; this control problem is nonredundant even for redundant robots. The Cartesian-space position controller is derived using a model reference adaptive control (MRAC) approach, and does not require knowledge of the complex robot dynamic model or parameter values for the robot or the payload. As a result, the scheme is applicable to both open-chain and closed-chain robots, and is computationally efficient for on-line implementations.

  16. Carbon nanotube and graphene-based bioinspired electrochemical actuators.

    PubMed

    Kong, Lirong; Chen, Wei

    2014-02-01

    Bio-inspired actuation materials, also called artificial muscles, have attracted great attention in recent decades for their potential application in intelligent robots, biomedical devices, and micro-electro-mechanical systems. Among them, ionic polymer metal composite (IPMC) actuator has been intensively studied for their impressive high-strain under low voltage stimulation and air-working capability. A typical IPMC actuator is composed of one ion-conductive electrolyte membrane laminated by two electron-conductive metal electrode membranes, which can bend back and forth due to the electrode expansion and contraction induced by ion motion under alternating applied voltage. As its actuation performance is mainly dominated by electrochemical and electromechanical process of the electrode layer, the electrode material and structure become to be more crucial to higher performance. The recent discovery of one dimensional carbon nanotube and two dimensional graphene has created a revolution in functional nanomaterials. Their unique structures render them intriguing electrical and mechanical properties, which makes them ideal flexible electrode materials for IPMC actuators in stead of conventional metal electrodes. Currently although the detailed effect caused by those carbon nanomaterial electrodes is not very clear, the presented outstanding actuation performance gives us tremendous motivation to meet the challenge in understanding the mechanism and thus developing more advanced actuator materials. Therefore, in this review IPMC actuators prepared with different kinds of carbon nanomaterials based electrodes or electrolytes are addressed. Key parameters which may generate important influence on actuation process are discussed in order to shed light on possible future research and application of the novel carbon nanomateials based bio-inspired electrochemical actuators.

  17. Dynamics of Elastic Beams with Embedded Fluid-Filled Parallel-Channel Networks

    PubMed Central

    Gat, Amir D.

    2015-01-01

    Abstract A pressurized fluid-filled parallel-channel network embedded in an elastic beam, asymmetrically to the neutral plane, will create a deformation field within the beam. Deformation due to embedded fluidic networks is currently studied in the context of soft actuators and soft-robotic applications. Expanding on this concept, configurations can be designed so that the pressure in the channel network is created directly from external forces acting on the beam, and thus can be viewed as passive solid–fluid composite structures. We approximate the deformation of such structures and relate the fluid pressure and geometry of the network to a continuous deformation-field function. This enables the design of networks creating steady arbitrary deformation fields as well as to eliminate deformation created by external time-varying forces, thus increasing the effective rigidity of the beam. In addition, by including the effects of the deformation created by the channel network on the beam inertia, we can modify the response of the beam to external time-varying forces. We present a scheme to design channel networks that create predefined oscillating deformation patterns in response to external oscillating forces. The ability to include inertial effects is relevant to the design of dynamic soft robots and soft actuators. Our results are illustrated and validated by numerical computations. PMID:27625914

  18. A Recipe for Soft Fluidic Elastomer Robots

    PubMed Central

    Marchese, Andrew D.; Katzschmann, Robert K.

    2015-01-01

    Abstract This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes. PMID:27625913

  19. Ionic Polymer-Metal Composites (IPMCs) as dexterous manipulators and tactile sensors for minimally invasive robotic surgery

    NASA Astrophysics Data System (ADS)

    Bahramzadeh, Y.; Shahinpoor, M.

    2012-04-01

    Robot-assisted surgery provides the surgeons with new tools to perform sophisticated surgical operations in a minimally invasive manner. Small robotic end-effectors at the tip of the surgical forceps are the key advantage of robotic surgery over laparoscopic surgery and any improvement on the design of these small robots can significantly improve the overall functionality of the surgical robots. In this sense, novel bio-compatible electro-active polymeric actuators can improve the design and functionality of these robotic end-effectors particularly by introducing smaller and more flexible robotic tools. Here, we introduce the applications of IPMCs as flexible actuators with embedded tactile and force feedback sensors in minimally-invasive robotic surgery. A new design for the robotic manipulation of the organs is presented in which a two dimensional IPMC actuator is replaced with the rigid robotic distal tip. It is shown that with a customized design, IPMC actuators maintain the required dexterity for two-dimensional bending of robotic distal tip. The overall design of the robot could be considered as a hybrid robot with the combination of rigid robotic links and flexible IPMC actuator with two degrees of freedom. On the other hand with the current robotic distal tips, no tactile force feedback is available during surgery and the surgeons rely solely on vision feedback. With the proposed design of actuator, the IPMC based distal tip could be used to deliver force feedback data by using an embedded IPMC tactile sensor. Design considerations, kinematics and chemo-electro-mechanical model of the proposed actuator is presented.

  20. Design and investigation of a linear smart actuator

    NASA Astrophysics Data System (ADS)

    Krishna Chaitanya, S.; Dhanalakshmi, K.

    2015-04-01

    Motors are nearly the sole constituents for actuation and driving applications, but there exist cases where their use proves to be impractical. Shape memory alloy (SMA), then revolutionized the actuator technology, thereby opening the door for new ideas and designs and with it what seemed unfeasible in the past have now become challenging. Many conventional actuators and sensors could be substituted with SMA, obtaining advantages in terms of reduction of weight, dimensions and its cost. SMAs are a group of metallic materials that revert to a predefined shape via phase transformation induced by a thermal procedure. Unlike metals that exhibit thermal expansion, SMA exhibits contraction when heated, which is larger by a hundredfold and exerts tremendous force for its small size. The focus of this work is to realize SMA wire as actuator which finds suitable applications (space, aerospace, biomechanics, etc.) where minimizing space, weight and cost are prime objectives. The accomplishments reported in this paper represent a significant development in the design of SMA actuator configurations for linear actuation. Report on design, fabrication and characterisation of the proposed system is presented. The design took advantage of converting the small linear displacement of the SMA wire into a large linear elastic motion under the influence of biasing element. From the results with control it is aspired that with further improvements on the design, the actuator can be utilized in enabling practical SMA technologies for potential robotic and commercial applications.

  1. Three Degree of Freedom Parallel Mechanical Linkage

    NASA Technical Reports Server (NTRS)

    Adelstein, Bernard D. (Inventor)

    1998-01-01

    A three degree of freedom parallel mechanism or linkage that couples three degree of freedom translational displacements at an endpoint, such as a handle, a hand grip, or a robot tool, to link rotations about three axes that are fixed with respect to a common base or ground link. The mechanism includes a three degree of freedom spherical linkage formed of two closed loops, and a planar linkage connected to the endpoint. The closed loops are rotatably interconnected, and made of eight rigid links connected by a plurality of single degree of freedom revolute joints. Three of these revolute joints are base joints and are connected to a common ground. such that the axis lines passing through the revolute joints intersect at a common fixed center point K forming the center of a spherical work volume in which the endpoint is capable of moving. 'Me three degrees of freedom correspond to the spatial displacement of the endpoint, for instance. The mechanism provides a new overall spatial kinematic linkage composed of a minimal number of rigid links and rotary joints. The mechanism has improved mechanical stiffness, and conveys mechanical power bidirectionally between the human operator and the electromechanical actuators. It does not require gears, belts. cable, screw or other types of transmission elements, and is useful in applications requiring full backdrivability. Thus, this invention can serve as the mechanical linkage for actively powered devices such as compliant robotic manipulators and force-reflecting hand controllers, and passive devices such as manual input devices for computers and other systems.

  2. Towards a sustainable modular robot system for planetary exploration

    NASA Astrophysics Data System (ADS)

    Hossain, S. G. M.

    This thesis investigates multiple perspectives of developing an unmanned robotic system suited for planetary terrains. In this case, the unmanned system consists of unit-modular robots. This type of robot has potential to be developed and maintained as a sustainable multi-robot system while located far from direct human intervention. Some characteristics that make this possible are: the cooperation, communication and connectivity among the robot modules, flexibility of individual robot modules, capability of self-healing in the case of a failed module and the ability to generate multiple gaits by means of reconfiguration. To demonstrate the effects of high flexibility of an individual robot module, multiple modules of a four-degree-of-freedom unit-modular robot were developed. The robot was equipped with a novel connector mechanism that made self-healing possible. Also, design strategies included the use of series elastic actuators for better robot-terrain interaction. In addition, various locomotion gaits were generated and explored using the robot modules, which is essential for a modular robot system to achieve robustness and thus successfully navigate and function in a planetary environment. To investigate multi-robot task completion, a biomimetic cooperative load transportation algorithm was developed and simulated. Also, a liquid motion-inspired theory was developed consisting of a large number of robot modules. This can be used to traverse obstacles that inevitably occur in maneuvering over rough terrains such as in a planetary exploration. Keywords: Modular robot, cooperative robots, biomimetics, planetary exploration, sustainability.

  3. Robotic system for MRI-guided prostate biopsy: feasibility of teleoperated needle insertion and ex vivo phantom study

    PubMed Central

    Seifabadi, Reza; Song, Sang-Eun; Krieger, Axel; Cho, Nathan Bongjoon; Tokuda, Junichi; Fichtinger, Gabor; Iordachita, Iulian

    2012-01-01

    Purpose Magnetic Resonance Imaging (MRI) combined with robotic assistance has the potential to improve on clinical outcomes of biopsy and local treatment of prostate cancer. Methods We report the workspace optimization and phantom evaluation of a five Degree of Freedom (DOF) parallel pneumatically actuated modular robot for MRI-guided prostate biopsy. To shorten procedure time and consequently increase patient comfort and system accuracy, a prototype of a MRI-compatible master–slave needle driver module using piezo motors was also added to the base robot. Results Variable size workspace was achieved using appropriate link length, compared with the previous design. The 5-DOF targeting accuracy demonstrated an average error of 2.5mm (STD=1.37mm) in a realistic phantom inside a 3T magnet with a bevel-tip 18G needle. The average position tracking error of the master–slave needle driver was always below 0.1mm. Conclusion Phantom experiments showed sufficient accuracy for manual prostate biopsy. Also, the implementation of teleoperated needle insertion was feasible and accurate. These two together suggest the feasibility of accurate fully actuated needle placement into prostate while keeping the clinician supervision over the task. PMID:21698389

  4. Pneumatic Artificial Muscle Actuation and Modeling

    NASA Astrophysics Data System (ADS)

    Leephakpreeda, Thananchai; Wickramatunge, Kanchana C.

    2009-10-01

    A Pneumatic Artificial Muscle (PAM) yields a natural muscle-like actuator with a high force to weight ratio, a soft and flexible structure, and adaptable compliance for a humanoid robot, rehabilitation and prosthetic appliances to the disabled, etc. To obtain optimum design and usage, the mechanical behavior of the PAM need to be understood. In this study, observations of experimental results reveal an empirical model for relations of physical variables, contraction and air pressure within the PAM, as compared to mechanical characteristics, such as stiffness or/and pulling forces of the PAM available now in market.

  5. Robot Electronics Architecture

    NASA Technical Reports Server (NTRS)

    Garrett, Michael; Magnone, Lee; Aghazarian, Hrand; Baumgartner, Eric; Kennedy, Brett

    2008-01-01

    An electronics architecture has been developed to enable the rapid construction and testing of prototypes of robotic systems. This architecture is designed to be a research vehicle of great stability, reliability, and versatility. A system according to this architecture can easily be reconfigured (including expanded or contracted) to satisfy a variety of needs with respect to input, output, processing of data, sensing, actuation, and power. The architecture affords a variety of expandable input/output options that enable ready integration of instruments, actuators, sensors, and other devices as independent modular units. The separation of different electrical functions onto independent circuit boards facilitates the development of corresponding simple and modular software interfaces. As a result, both hardware and software can be made to expand or contract in modular fashion while expending a minimum of time and effort.

  6. Design and Optimization of a Hybrid-Driven Waist Rehabilitation Robot.

    PubMed

    Zi, Bin; Yin, Guangcai; Zhang, Dan

    2016-12-14

    In this paper a waist rehabilitation robot driven by cables and pneumatic artificial muscles (PAMs) has been conceptualized and designed. In the process of mechanism design, the human body structure, the waist movement characteristics, and the actuators' driving characteristics are the main considerable factors to make the hybrid-driven waist rehabilitation robot (HWRR) cost-effective, safe, flexible, and well-adapted. A variety of sensors are chosen to measure the position and orientation of the recovery patient to ensure patient safety at the same time as the structure design. According to the structure specialty and function, the HWRR is divided into two independent parallel robots: the waist twist device and the lower limb traction device. Then these two devices are analyzed and evaluated, respectively. Considering the characters of the human body in the HWRR, the inverse kinematics and statics are studied when the waist and the lower limb are considered as a spring and link, respectively. Based on the inverse kinematics and statics, the effect of the contraction parameter of the PAM is considered in the optimization of the waist twist device, and the lower limb traction device is optimized using particle swarm optimization (PSO) to minimize the global conditioning number over the feasible workspace. As a result of the optimization, an optimal rehabilitation robot design is obtained and the condition number of the Jacobian matrix over the feasible workspace is also calculated.

  7. Adaptive parallel logic networks

    NASA Technical Reports Server (NTRS)

    Martinez, Tony R.; Vidal, Jacques J.

    1988-01-01

    Adaptive, self-organizing concurrent systems (ASOCS) that combine self-organization with massive parallelism for such applications as adaptive logic devices, robotics, process control, and system malfunction management, are presently discussed. In ASOCS, an adaptive network composed of many simple computing elements operating in combinational and asynchronous fashion is used and problems are specified by presenting if-then rules to the system in the form of Boolean conjunctions. During data processing, which is a different operational phase from adaptation, the network acts as a parallel hardware circuit.

  8. Cryogenic Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  9. A surgical parallel continuum manipulator with a cable-driven grasper.

    PubMed

    Orekhov, Andrew L; Bryson, Caroline E; Till, John; Chung, Scotty; Rucker, D Caleb

    2015-01-01

    In this paper, we present the design, construction, and control of a six-degree-of-freedom (DOF), 12 mm diameter, parallel continuum manipulator with a 2-DOF, cable-driven grasper. This work is a proof-of-concept first step towards miniaturization of this type of manipulator design to provide increased dexterity and stability in confined-space surgical applications, particularly for endoscopic procedures. Our robotic system consists of six superelastic NiTi (Nitinol) tubes in a standard Stewart-Gough configuration and an end effector with 180 degree motion of its two jaws. Two Kevlar cables pass through the centers of the tube legs to actuate the end effector. A computationally efficient inverse kinematics model provides low-level control inputs to ten independent linear actuators, which drive the Stewart-Gough platform and end-effector actuation cables. We demonstrate the performance and feasibility of this design by conducting open-loop range-of-motion tests for our system.

  10. Modeling and analysis of bio-syncretic micro-swimmers for cardiomyocyte-based actuation.

    PubMed

    Zhang, Chuang; Wang, Jingyi; Wang, Wenxue; Xi, Ning; Wang, Yuechao; Liu, Lianqing

    2016-08-22

    Along with sensation and intelligence, actuation is one of the most important factors in the development of conventional robots. Many novel achievements have been made regarding bio-based actuators to solve the challenges of conventional actuation. However, few studies have focused on methods for controlling the movement performance of bio-syncretic robots by designing robotic structures and programming actuation bio-entities. In this paper, a theoretical model was derived considering kinematics and hydromechanics to describe the dynamics of a dolphin-shaped microstructure and to control the bio-syncretic swimmer movement by establishing the relationships between the swimming velocity of the bio-swimmer, the cell seeding concentration and the cell contractility. The proposed theoretical model was then verified with the fabricated biomimetic swimmer prototype actuated by equivalent external magnetism replacing the bio-entity force based on the study of living, beating cardiomyocyte contractility. This work can improve the development of bio-syncretic robots with an approach to preplanning the seeding concentration of cells for controlling the movement velocity of microstructures, and is also meaningful for biomimetic robots, medical treatments and interventional therapy applications.

  11. Tendon Based Full Size Biped Humanoid Robot Walking Platform Design

    NASA Astrophysics Data System (ADS)

    Kuo, Chung-Hsien; Chiou, Kuo-Wei

    Actuators and gear trains of most biped humanoid robots are divergently allocated on the links of two legs. Disadvantages of such a mechanical design are complicated wiring of power cord and sensing/ control signal bundles and imprecise kinetics models of mixed link-and-actuator structures. Based on these drawbacks, this paper proposes a tendon-driven mechanism to develop a lower body structure of a full-size biped humanoid robot. The actuators are compacted as an actuator module, and they are placed at a distal site. A 12 degree-of-freedom mechanical structure is proposed with 100 cm in height and 45 kg in weight. The gait planning module is simulated and evaluated using the Matlab software. At the same time, an ARM7 based controller is developed to automatically generate walking patterns as well as to control the motors. Finally, a tendon-driven biped humanoid robot prototype is realized for practical waling control in the future.

  12. Coalescence-induced droplet actuation

    NASA Astrophysics Data System (ADS)

    Sellier, Mathieu; Verdier, Claude; Nock, Volker

    2011-11-01

    This work investigates a little explored driving mechanism to actuate droplets: the surface tension gradient which arises during the coalescence of two droplets of liquid having different compositions and therefore surface tensions. The resulting surface tension gradient gives rise to a Marangoni flow which, if sufficiently large, can displace the droplet. In order to understand, the flow dynamics arising during the coalescence of droplets of different fluids, a model has been developed in the lubrication framework. The numerical results confirm the existence of a self-propulsion window which depends on two dimensionless groups representing competing effects during the coalescence: the surface tension contrast between the droplets which promotes actuation and species diffusion which tends to make the mixture uniform thereby anihilating Marangoni flow and droplet motion. In parallel, experiments have been conducted to confirm this self-propulsion behaviour. The experiment consists in depositing a droplet of distilled water on a ``hydrophilic highway.'' This stripe was obtained by plasma-treating a piece of PDMS shielded in some parts by glass coverslips. This surface functionalization was found to be the most convenient way to control the coalescence. When a droplet of ethanol is deposited near the ``water slug,'' coalescence occurs and a rapid motion of the resulting mixture is observed. The support of the Dumont d'Urville NZ-France Science & Technology program is gratefully acknowledged.

  13. Magnetically Actuated Seal

    NASA Technical Reports Server (NTRS)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  14. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III

    1994-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The linear proof mass actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (mass, upper housing, lower housing, and center support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operating testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  15. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, S. E., III

    1995-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The Linear Proof Mass Actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (Mass, Upper Housing, Lower Housing, and Center Support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operational testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  16. Small Business Innovations (Robotic Wrist)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Under a Langley Research Center Small Business Innovation Research (SBIR) contract, Ross-Hime Designs, Inc. Minneapolis, MN, developed the Omni-Wrist actuator, which has a 25-pound capacity, 180 degrees of pitch/yaw, and 360 degrees of roll. Company literature calls it "the first successful singularity-free high-precision (robotic) wrist." Applications include spray painting, sealing, ultrasonic testing, welding and a variety of nuclear industry, aerospace and military uses.

  17. Inertial Linear Actuators

    NASA Technical Reports Server (NTRS)

    Laughlin, Darren

    1995-01-01

    Inertial linear actuators developed to suppress residual accelerations of nominally stationary or steadily moving platforms. Function like long-stroke version of voice coil in conventional loudspeaker, with superimposed linear variable-differential transformer. Basic concept also applicable to suppression of vibrations of terrestrial platforms. For example, laboratory table equipped with such actuators plus suitable vibration sensors and control circuits made to vibrate much less in presence of seismic, vehicular, and other environmental vibrational disturbances.

  18. Laser Initiated Actuator study

    SciTech Connect

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  19. Modeling of robotic fish propelled by an ionic polymer-metal composite caudal fin

    NASA Astrophysics Data System (ADS)

    Chen, Zheng; Shatara, Stephan; Tan, Xiaobo

    2009-03-01

    In this paper, a model is proposed for a biomimetic robotic fish propelled by an ionic polymer metal composite (IPMC) actuator with a rigid passive fin at the end. The model incorporates both IPMC actuation dynamics and the hydrodynamics, and predicts the steady-state speed of the robot under a periodic actuation voltage. Experimental results have shown that the proposed model can predict the fish motion for different tail dimensions. Since its parameters are expressed in terms of physical properties and geometric dimensions, the model is expected to be instrumental in optimal design of the robotic fish.

  20. Robotic Surveying

    SciTech Connect

    Suzy Cantor-McKinney; Michael Kruzic

    2007-03-01

    ZAPATA ENGINEERING challenged our engineers and scientists, which included robotics expertise from Carnegie Mellon University, to design a solution to meet our client's requirements for rapid digital geophysical and radiological data collection of a munitions test range with no down-range personnel. A prime concern of the project was to minimize exposure of personnel to unexploded ordnance and radiation. The field season was limited by extreme heat, cold and snow. Geographical Information System (GIS) tools were used throughout this project to accurately define the limits of mapped areas, build a common mapping platform from various client products, track production progress, allocate resources and relate subsurface geophysical information to geographical features for use in rapidly reacquiring targets for investigation. We were hopeful that our platform could meet the proposed 35 acres per day, towing both a geophysical package and a radiological monitoring trailer. We held our breath and crossed our fingers as the autonomous Speedrower began to crawl across the playa lakebed. We met our proposed production rate, and we averaged just less than 50 acres per 12-hour day using the autonomous platform with a path tracking error of less than +/- 4 inches. Our project team mapped over 1,800 acres in an 8-week (4 days per week) timeframe. The expertise of our partner, Carnegie Mellon University, was recently demonstrated when their two autonomous vehicle entries finished second and third at the 2005 Defense Advanced Research Projects Agency (DARPA) Grand Challenge. 'The Grand Challenge program was established to help foster the development of autonomous vehicle technology that will some day help save the lives of Americans who are protecting our country on the battlefield', said DARPA Grand Challenge Program Manager, Ron Kurjanowicz. Our autonomous remote-controlled vehicle (ARCV) was a modified New Holland 2550 Speedrower retrofitted to allow the machine-actuated

  1. Compact electrostatic comb actuator

    DOEpatents

    Rodgers, M. Steven; Burg, Michael S.; Jensen, Brian D.; Miller, Samuel L.; Barnes, Stephen M.

    2000-01-01

    A compact electrostatic comb actuator is disclosed for microelectromechanical (MEM) applications. The actuator is based upon a plurality of meshed electrostatic combs, some of which are stationary and others of which are moveable. One or more restoring springs are fabricated within an outline of the electrostatic combs (i.e. superposed with the moveable electrostatic combs) to considerably reduce the space required for the actuator. Additionally, a truss structure is provided to support the moveable electrostatic combs and prevent bending or distortion of these combs due to unbalanced electrostatic forces or external loading. The truss structure formed about the moveable electrostatic combs allows the spacing between the interdigitated fingers of the combs to be reduced to about one micron or less, thereby substantially increasing the number of active fingers which can be provided in a given area. Finally, electrostatic shields can be used in the actuator to substantially reduce unwanted electrostatic fields to further improve performance of the device. As a result, the compact electrostatic comb actuator of the present invention occupies only a fraction of the space required for conventional electrostatic comb actuators, while providing a substantial increase in the available drive force (up to one-hundred times).

  2. Backed Bending Actuator

    NASA Technical Reports Server (NTRS)

    Costen, Robert C.; Su, Ji

    2004-01-01

    Bending actuators of a proposed type would partly resemble ordinary bending actuators, but would include simple additional components that would render them capable of exerting large forces at small displacements. Like an ordinary bending actuator, an actuator according to the proposal would include a thin rectangular strip that would comprise two bonded layers (possibly made of electroactive polymers with surface electrodes) and would be clamped at one end in the manner of a cantilever beam. Unlike an ordinary bending actuator, the proposed device would include a rigid flat backplate that would support part of the bending strip against backward displacement; because of this feature, the proposed device is called a backed bending actuator. When an ordinary bending actuator is inactive, the strip typically lies flat, the tip displacement is zero, and the force exerted by the tip is zero. During activation, the tip exerts a transverse force and undergoes a bending displacement that results from the expansion or contraction of one or more of the bonded layers. The tip force of an ordinary bending actuator is inversely proportional to its length; hence, a long actuator tends to be weak. The figure depicts an ordinary bending actuator and the corresponding backed bending actuator. The bending, the tip displacement (d(sub t)), and the tip force (F) exerted by the ordinary bending actuator are well approximated by the conventional equations for the loading and deflection of a cantilever beam subject to a bending moment which, in this case, is applied by the differential expansion or contraction of the bonded layers. The bending, displacement, and tip force of the backed bending actuator are calculated similarly, except that it is necessary to account for the fact that the force F(sub b) that resists the displacement of the tip could be sufficient to push part of the strip against the backplate; in such a condition, the cantilever beam would be effectively shortened

  3. Determining robot actions for tasks requiring sensor interaction

    NASA Technical Reports Server (NTRS)

    Budenske, John; Gini, Maria

    1989-01-01

    The performance of non-trivial tasks by a mobile robot has been a long term objective of robotic research. One of the major stumbling blocks to this goal is the conversion of the high-level planning goals and commands into the actuator and sensor processing controls. In order for a mobile robot to accomplish a non-trivial task, the task must be described in terms of primitive actions of the robot's actuators. Most non-trivial tasks require the robot to interact with its environment; thus necessitating coordination of sensor processing and actuator control to accomplish the task. The main contention is that the transformation from the high level description of the task to the primitive actions should be performed primarily at execution time, when knowledge about the environment can be obtained through sensors. It is proposed to produce the detailed plan of primitive actions by using a collection of low-level planning components that contain domain specific knowledge and knowledge about the available sensors, actuators, and sensor/actuator processing. This collection will perform signal and control processing as well as serve as a control interface between an actual mobile robot and a high-level planning system. Previous research has shown the usefulness of high-level planning systems to plan the coordination of activities such to achieve a goal, but none have been fully applied to actual mobile robots due to the complexity of interacting with sensors and actuators. This control interface is currently being implemented on a LABMATE mobile robot connected to a SUN workstation and will be developed such to enable the LABMATE to perform non-trivial, sensor-intensive tasks as specified by a planning system.

  4. Autonomous undulatory serpentine locomotion utilizing body dynamics of a fluidic soft robot.

    PubMed

    Onal, Cagdas D; Rus, Daniela

    2013-06-01

    Soft robotics offers the unique promise of creating inherently safe and adaptive systems. These systems bring man-made machines closer to the natural capabilities of biological systems. An important requirement to enable self-contained soft mobile robots is an on-board power source. In this paper, we present an approach to create a bio-inspired soft robotic snake that can undulate in a similar way to its biological counterpart using pressure for actuation power, without human intervention. With this approach, we develop an autonomous soft snake robot with on-board actuation, power, computation and control capabilities. The robot consists of four bidirectional fluidic elastomer actuators in series to create a traveling curvature wave from head to tail along its body. Passive wheels between segments generate the necessary frictional anisotropy for forward locomotion. It takes 14 h to build the soft robotic snake, which can attain an average locomotion speed of 19 mm s(-1).

  5. Time optimal movement of cooperating robots

    NASA Technical Reports Server (NTRS)

    Mccarthy, J. M.; Bobrow, J. E.

    1989-01-01

    The maximization of the speed of movement along a prescribed path, of the system formed by a set of robot arms and the object they hold is examined. The actuator torques that maximize the acceleration of the system are shown to be determined by the solution to a standard linear programming problem. The combination of this result with the known control strategy for time optimal movement of a single robot arm yields an algorithm for time optimal movement of multiple robot arms holding the same workpiece.

  6. Aerial Robotic System for Transportation and Logistics

    NASA Astrophysics Data System (ADS)

    Iwata, Kakuya; Hashimoto, Naohisa; Komoriya, Kiyoshi

    The status quo of a research on a novel aerial robotic system for transportation and logistics is presented. Under a new concept for an aerial robotic transportation system, three-Dimensional Transportation Robots (3DTR) were constructed with twin turbojet engines equipped by high performance noise reduction system and a flexibly jointed delta wing controlled by 2-axis actuators. This vehicle is also stable in the air due to its pendulum structure. The first flight was successfully conducted on November 22, 2005. Flight examination of 3DTR indicates its short take-off and landing (STOL) capability.

  7. A Hybrid Multi-Robot Control Architecture

    DTIC Science & Technology

    2007-12-01

    System (PRS), and topological planning [32]. The sen- sor processing, actuator output, and LPS could all reclassify as the Controller Layer, 10...13. Camacho, David, Fernando Fernández, and Miguel A. Rodelgo. “Roboskeleton: An architecture for coordinating robot soccer agents”. Engineering

  8. Grasping with a soft glove: intrinsic impedance control in pneumatic actuators.

    PubMed

    Paoletti, P; Jones, G W; Mahadevan, L

    2017-03-01

    The interaction of a robotic manipulator with unknown soft objects represents a significant challenge for traditional robotic platforms because of the difficulty in controlling the grasping force between a soft object and a stiff manipulator. Soft robotic actuators inspired by elephant trunks, octopus limbs and muscular hydrostats are suggestive of ways to overcome this fundamental difficulty. In particular, the large intrinsic compliance of soft manipulators such as 'pneu-nets'-pneumatically actuated elastomeric structures-makes them ideal for applications that require interactions with an uncertain mechanical and geometrical environment. Using a simple theoretical model, we show how the geometric and material nonlinearities inherent in the passive mechanical response of such devices can be used to grasp soft objects using force control, and stiff objects using position control, without any need for active sensing or feedback control. Our study is suggestive of a general principle for designing actuators with autonomous intrinsic impedance control.

  9. Fabrication of wrist-like SMA-based actuator by double smart soft composite casting

    NASA Astrophysics Data System (ADS)

    Rodrigue, Hugo; Wei, Wang; Bhandari, Binayak; Ahn, Sung-Hoon

    2015-12-01

    A new manufacturing method for smart soft composite (SSC) actuators that consists of double casting a SSC actuator to produce an actuator with non-linear shape memory alloy (SMA) wire positioning is proposed. This method is used to manufacture a tube-shaped SSC actuator in which the SMA wires follow the curvature of the tube and is capable of pure-twisting deformations while sustaining a cantilever load. The concept is tested by measuring the maximum twisting angle and a simple control method is proposed to control the twisting angle of the actuator. Then, a soft robotic wrist with a length of 18 cm is built, its load-carrying capability is tested by measuring the cantilever force required for deforming the actuator, and its load-carrying capability during actuation is tested by loading one end with different objects and actuating the actuator. This wrist actuator shows good repeatability, is capable of twisting deformations up to 25° while holding objects weighing 100 g, and can sustain loads above 2 N without undergoing buckling.

  10. Non-collinear valve actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2012-01-01

    A non-collinear valve actuator includes a primary actuating system and a return spring system with each applying forces to a linkage system in order to regulate the flow of a quarter-turn valve. The primary actuating system and return spring system are positioned non-collinearly, which simply means the primary actuating system and return spring system are not in line with each other. By positioning the primary actuating system and return spring system in this manner, the primary actuating system can undergo a larger stroke while the return spring system experiences significantly less displacement. This allows the length of the return spring to be reduced due to the minimization of displacement thereby reducing the weight of the return spring system. By allowing the primary actuating system to undergo longer strokes, the weight of the primary actuating system may also be reduced. Accordingly, the weight of the non-collinear valve actuator is reduced.

  11. Biologically inspired hexapedal robot using field-effect electroactive elastomer artificial muscles

    NASA Astrophysics Data System (ADS)

    Eckerle, Joseph; Stanford, Scott; Marlow, John; Schmidt, Roger; Oh, Seajin; Low, Thomas; Shastri, Subramanian V.

    2001-06-01

    Small, autonomous mobile robots are needed for applications such as reconnaissance over difficult terrain or internal inspection of large industrial systems. Previous work in experimental biology and with legged robots has revealed the advantages of using leg actuators with inherent compliance for robust, autonomous locomotion over uneven terrain. Recently developed field-effect electroactive elastomer artificial muscle actuators offer such compliance as well as attractive performance parameters such as force/weight and efficiency, so we developed a small (670 g) six-legged robot, FLEX, using AM actuators. Electrically, AM actuators are a capacitive, high-impedance load similar to piezoelectrics, which makes them difficult to rive optimally with conventional circuitry. Still, we were able to devise a modular, microprocessor-based control system capable of driving 12 muscles with up to 5,000 V, operating form an on- board battery. The artificial muscle actuators had excellent compliance and peak performance, but suffered from poor uniformity and degradation over time. FLEX is the first robot of its kind. While there is room for improvement in some of the robot systems such as actuators and their drivers, this work has validated the idea of using artificial muscle actuators in biologically inspired walking robots.

  12. Turtle mimetic soft robot with two swimming gaits.

    PubMed

    Song, Sung-Hyuk; Kim, Min-Soo; Rodrigue, Hugo; Lee, Jang-Yeob; Shim, Jae-Eul; Kim, Min-Cheol; Chu, Won-Shik; Ahn, Sung-Hoon

    2016-05-04

    This paper presents a biomimetic turtle flipper actuator consisting of a shape memory alloy composite structure for implementation in a turtle-inspired autonomous underwater vehicle. Based on the analysis of the Chelonia mydas, the flipper actuator was divided into three segments containing a scaffold structure fabricated using a 3D printer. According to the filament stacking sequence of the scaffold structure in the actuator, different actuating motions can be realized and three different types of scaffold structures were proposed to replicate the motion of the different segments of the flipper of the Chelonia mydas. This flipper actuator can mimic the continuous deformation of the forelimb of Chelonia mydas which could not be realized in previous motor based robot. This actuator can also produce two distinct motions that correspond to the two different swimming gaits of the Chelonia mydas, which are the routine and vigorous swimming gaits, by changing the applied current sequence of the SMA wires embedded in the flipper actuator. The generated thrust and the swimming efficiency in each swimming gait of the flipper actuator were measured and the results show that the vigorous gait has a higher thrust but a relatively lower swimming efficiency than the routine gait. The flipper actuator was implemented in a biomimetic turtle robot, and its average swimming speed in the routine and vigorous gaits were measured with the vigorous gait being capable of reaching a maximum speed of 11.5 mm s(-1).

  13. Materials science. Materials that couple sensing, actuation, computation, and communication.

    PubMed

    McEvoy, M A; Correll, N

    2015-03-20

    Tightly integrating sensing, actuation, and computation into composites could enable a new generation of truly smart material systems that can change their appearance and shape autonomously. Applications for such materials include airfoils that change their aerodynamic profile, vehicles with camouflage abilities, bridges that detect and repair damage, or robotic skins and prosthetics with a realistic sense of touch. Although integrating sensors and actuators into composites is becoming increasingly common, the opportunities afforded by embedded computation have only been marginally explored. Here, the key challenge is the gap between the continuous physics of materials and the discrete mathematics of computation. Bridging this gap requires a fundamental understanding of the constituents of such robotic materials and the distributed algorithms and controls that make these structures smart.

  14. Moisture-driven actuators inspired by motility of plants

    NASA Astrophysics Data System (ADS)

    Shin, Beomjune; Lee, Minhee; Kim, Ho-Young

    2015-11-01

    We report design and fabrication of moisture-driven actuators mimicking pine cones, wild wheats and seeds of Erodium cicutarium, which can bend and even helically coil with variation of environmental humidity. The actuators adopt a bilayer configuration, one of whose layers is hygroscopically active while the other is inactive. In order to enhance the degree and speed of deformation which critically depends on moisture-responsivity of the active layer, nanofibers of hydrogel are directionally deposited on the inactive layer via electrospinning. As a result, several designs of soft robots are demonstrated which are capable of locomotion by harvesting environmental humidity energy. The dynamics of the robots are analyzed by coupling moisture diffusion kinetics and elastic theory of multi-layer bending. The theoretical predictions are compared with the experimental results, to lead to the optimal design to maximize the locomotion speed measured by travel distance normalized by body length per unit time.

  15. Converging the capabilities of EAP artificial muscles and the requirements of bio-inspired robotics

    NASA Astrophysics Data System (ADS)

    Hanson, David F.; White, Victor

    2004-07-01

    The characteristics of Electro-actuated polymers (EAP) are typically considered inadequate for applications in robotics. But in recent years, there has been both dramatic increases in EAP technological capbilities and reductions in power requirements for actuating bio-inspired robotics. As the two trends continue to converge, one may anticipate that dramatic breakthroughs in biologically inspired robotic actuation will result due to the marraige of these technologies. This talk will provide a snapshot of how EAP actuator scientists and roboticists may work together on a common platform to accelerate the growth of both technologies. To demonstrate this concept of a platform to accelerate this convergence, the authors will discuss their work in the niche application of robotic facial expression. In particular, expressive robots appear to be within the range of EAP actuation, thanks to their low force requirements. Several robots will be shown that demonstrate realistic expressions with dramatically decreased force requirements. Also, detailed descriptions will be given of the engineering innovations that have enabled these robotics advancements-most notably, Structured-Porosity Elastomer Materials (SPEMs). SPEM manufacturing techniques create delicate cell-structures in a variety of elastomers that maintain the high elongation characteristics of the mother material, but because of the porisity, behave as sponge-materials, thus lower the force required to emulate facial expressions to levels output by several extant EAP actuators.

  16. Bending fluidic actuator for smart structures

    NASA Astrophysics Data System (ADS)

    Che-Ming Chang, Benjamin; Berring, John; Venkataram, Manu; Menon, Carlo; Parameswaran, M.

    2011-03-01

    This paper presents a novel silicone-based, millimeter-scale, bending fluidic actuator (BFA). Its unique parallel micro-channel design enables, for the first time, operation at low working pressure while at the same time having a very limited thickness expansion during pressurization. It also enables the actuator to have the highest ratios of angular displacement over length and torque over volume among previously proposed BFAs. In this work, this parallel micro-channel design is implemented by embedding the BFA with an innovative single winding conduit, which yields a simple, single-component configuration suitable for low-cost production and reliable performance. The BFA design can be easily scaled down to smaller dimensions and can be adapted to applications in restricted space, particularly minimally invasive surgery. In this work, the actuator is manufactured in TC-silicone through poly(methyl methacrylate) molds obtained by using laser cutting technology. Repeated angular displacement measurements on multiple prototypes having different stiffness are carried out. The experimental results are compared with an analytical model, which accurately predicts the performance of the device.

  17. Digital Actuator Technology

    SciTech Connect

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst

    2014-09-01

    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator

  18. CASSY Robot

    NASA Astrophysics Data System (ADS)

    Pittman, Anna; Wright, Ann; Rice, Aaron; Shyaka, Claude

    2014-03-01

    The CASSY Robot project involved two square robots coded in RobotC. The goal was to code a robot to do a certain set of tasks autonomously. To begin with, our task was to code the robot so that it would roam a certain area, marked off by black tape. When the robot hit the black tape, it knew to back up and turn around. It was able to do this thanks to the light sensor that was attached to the bottom of the robot. Also, whenever the robot hit an obstacle, it knew to stop, back up, and turn around. This was primarily to prevent the robot from hurting itself if it hit an obstacle. This was accomplished by using touch sensors set up as bumpers. Once that was accomplished, we attached sonar sensors and created code so that one robot was able to find and track the other robot in a sort of intruder/police scenario. The overall goal of this project was to code the robot so that we can test it against a robot coded exactly the same, but using Layered Mode Selection Logic. Professor.

  19. A Passive Parallel Master-Slave Mechanism for Magnetic Resonance Imaging-Guided Interventions.

    PubMed

    Elayaperumal, Santhi; Cutkosky, Mark R; Renaud, Pierre; Daniel, Bruce L

    2015-03-01

    A passive, parallel master-slave mechanism is presented for magnetic resonance imaging (MRI)-guided interventions in the pelvis. The mechanism allows a physician to stand outside the MRI scanner while manipulating a needle inside the bore and, unlike a powered robot, does not place actuators in proximity to the patient. The manipulator combines two parallel mechanisms based on the Delta robot architecture. The mechanism also includes a two-axis gimbal to allow for tool angulation, giving a total of five degrees of freedom so that the physician can insert and steer a needle using continuous natural arm and wrist movements, unlike simple needle guides. The need for access between the patient's legs and within the MRI scanner leads to an unusual asymmetric design in which the sliding prismatic joints form the vertices of an isosceles triangle. Kinematic analysis shows that the dexterity index of this design is improved over the desired workspace, as compared to an equilateral design. The analysis is extended to estimate the effect of friction and model the input:output force transmission. Prototypes, with final dimensions selected for transperineal prostate interventions, showed force transmission behavior as predicted by simulation, and easily withstood maximum forces required for tool insertion.

  20. From Autonomous Robots to Artificial Ecosystems

    NASA Astrophysics Data System (ADS)

    Mastrogiovanni, Fulvio; Sgorbissa, Antonio; Zaccaria, Renato

    During the past few years, starting from the two mainstream fields of Ambient Intelligence [2] and Robotics [17], several authors recognized the benefits of the socalled Ubiquitous Robotics paradigm. According to this perspective, mobile robots are no longer autonomous, physically situated and embodied entities adapting themselves to a world taliored for humans: on the contrary, they are able to interact with devices distributed throughout the environment and get across heterogeneous information by means of communication technologies. Information exchange, coupled with simple actuation capabilities, is meant to replace physical interaction between robots and their environment. Two benefits are evident: (i) smart environments overcome inherent limitations of mobile platforms, whereas (ii) mobile robots offer a mobility dimension unknown to smart environments.

  1. SMARBot: a modular miniature mobile robot platform

    NASA Astrophysics Data System (ADS)

    Meng, Yan; Johnson, Kerry; Simms, Brian; Conforth, Matthew

    2008-04-01

    Miniature robots have many advantages over their larger counterparts, such as low cost, low power, and easy to build a large scale team for complex tasks. Heterogeneous multi miniature robots could provide powerful situation awareness capability due to different locomotion capabilities and sensor information. However, it would be expensive and time consuming to develop specific embedded system for different type of robots. In this paper, we propose a generic modular embedded system architecture called SMARbot (Stevens Modular Autonomous Robot), which consists of a set of hardware and software modules that can be configured to construct various types of robot systems. These modules include a high performance microprocessor, a reconfigurable hardware component, wireless communication, and diverse sensor and actuator interfaces. The design of all the modules in electrical subsystem, the selection criteria for module components, and the real-time operating system are described. Some proofs of concept experimental results are also presented.

  2. Robot manipulator technologies for planetary exploration

    NASA Astrophysics Data System (ADS)

    Das, Hari; Bao, Xiaoqi; Bar-Cohen, Yoseph; Bonitz, Robert; Lindemann, Randall A.; Maimone, Mark; Nesnas, Issa A.; Voorhees, Christopher J.

    1999-06-01

    NASA exploration missions to Mars, initiated by the Mars Pathfinder mission in July 1997, will continue over the next decade. The missions require challenging innovations in robot design and improvements in autonomy to meet ambitious objectives under tight budget and time constraints. The authors are developing design tools, component technologies and capabilities to address these needs for manipulation with robots for planetary exploration. The specific developments are: (1) a software analysis tool to reduce robot design iteration cycles and optimize on design solutions, (2) new piezoelectric ultrasonic motors for light-weight and high torque actuation in planetary environments, (3) use of advanced materials and structures for strong and light-weight robot arms and (4) intelligent camera-image coordinated autonomous control of robot arms for instrument placement and sample acquisition from a rover vehicle.

  3. Potential of industrial robotics in physical rehabilitation

    SciTech Connect

    Carlisle, B.R.

    1983-01-01

    Industrial robots have evolved from simple devices used for heavy jobs requiring little accuracy and sensing, to sophisticated, computer-controlled machines capable of using sensory feedback and complex decision strategies to complete their tasks. Large amounts of effort are now being expended on sensor development, sensor controlled actions, task planning, actuator improvement, and structural design. Smaller efforts are focusing on dexterous hands, mobility, two arm coordination and obstacle avoidance. The long term goal of these efforts is to allow the robot to work in an unstructured environment. It is likely that the technology to develop a simple household robot will exist within ten years. This technology will be capable of providing manipulation to a disabled individual. It is likely that the most difficult problem will not be the basic robot abilities, but rather devising an effective means of communication between the robot and the person.

  4. Development and Analysis of Bending Actuator Using McKibben Artificial Muscle

    NASA Astrophysics Data System (ADS)

    Zhao, Feifei; Dohta, Shujiro; Akagi, Tetsuya

    Recent years, the number of nuclear families is rapidly growing. So the development of a human-friendly-robot which can take care of human daily life is strongly desired. This robot has to work just like a human, so, it is needed to have a dexterous soft hand in the robot. Therefore, we have developed an artificial soft gripper. This robot hand which has five fingers is made of silicone rubber. We also developed the hand which could be used to achieve several works just like a human hand. For example, it can grasp some objects that have the different shape and stiffness. Since it is made of silicone rubber, there is little damage to the object. However, the finger could not generate a larger force, less than 3N. In addition, it needs a skill and time to make the finger. In this study, we proposed and tested a bending actuator that could be easily constructed by putting the McKibben artificial muscle into the flexible tube. We also investigated the generated force and bending angle of the actuator. As a result, the generated force of the actuator was improved about 8.5 times as large as previous one. We also improved the bending actuator by changing the tube and the slit of the flexible tube. And the analytical model for the bending actuator was proposed and the calculated results were compared with the experimental ones.

  5. Interactive robot control system and method of use

    NASA Technical Reports Server (NTRS)

    Sanders, Adam M. (Inventor); Reiland, Matthew J. (Inventor); Abdallah, Muhammad E. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert (Inventor)

    2012-01-01

    A robotic system includes a robot having joints, actuators, and sensors, and a distributed controller. The controller includes command-level controller, embedded joint-level controllers each controlling a respective joint, and a joint coordination-level controller coordinating motion of the joints. A central data library (CDL) centralizes all control and feedback data, and a user interface displays a status of each joint, actuator, and sensor using the CDL. A parameterized action sequence has a hierarchy of linked events, and allows the control data to be modified in real time. A method of controlling the robot includes transmitting control data through the various levels of the controller, routing all control and feedback data to the CDL, and displaying status and operation of the robot using the CDL. The parameterized action sequences are generated for execution by the robot, and a hierarchy of linked events is created within the sequence.

  6. An intrinsically compliant robotic orthosis for treadmill training.

    PubMed

    Hussain, Shahid; Xie, Sheng Quan; Jamwal, Prashant K; Parsons, John

    2012-12-01

    A new intrinsically compliant robotic orthosis powered by pneumatic muscle actuators (PMA) was developed for treadmill training of neurologically impaired subjects. The robotic orthosis has hip and knee sagittal plane rotations actuated by antagonistic configuration of PMA. The orthosis has passive mechanisms to allow vertical and lateral translations of the trunk and a passive hip abduction/adduction joint. A foot lifter having a passive spring mechanism was used to ensure sufficient foot clearance during swing phase. A trajectory tracking controller was implemented to evaluate the performance of the robotic orthosis on a healthy subject. The results show that the robotic orthosis is able to perform the treadmill training task by providing sufficient torques to achieve physiological gait patterns and a realistic stepping experience. The orthosis is a new addition to the rapidly advancing field of robotic orthoses for treadmill training.

  7. Visual perception system and method for a humanoid robot

    NASA Technical Reports Server (NTRS)

    Wells, James W. (Inventor); Mc Kay, Neil David (Inventor); Chelian, Suhas E. (Inventor); Linn, Douglas Martin (Inventor); Wampler, II, Charles W. (Inventor); Bridgwater, Lyndon (Inventor)

    2012-01-01

    A robotic system includes a humanoid robot with robotic joints each moveable using an actuator(s), and a distributed controller for controlling the movement of each of the robotic joints. The controller includes a visual perception module (VPM) for visually identifying and tracking an object in the field of view of the robot under threshold lighting conditions. The VPM includes optical devices for collecting an image of the object, a positional extraction device, and a host machine having an algorithm for processing the image and positional information. The algorithm visually identifies and tracks the object, and automatically adapts an exposure time of the optical devices to prevent feature data loss of the image under the threshold lighting conditions. A method of identifying and tracking the object includes collecting the image, extracting positional information of the object, and automatically adapting the exposure time to thereby prevent feature data loss of the image.

  8. Mechanical design of a shape memory alloy actuated prosthetic hand.

    PubMed

    De Laurentis, Kathryn J; Mavroidis, Constantinos

    2002-01-01

    This paper presents the mechanical design for a new five fingered, twenty degree-of-freedom dexterous hand patterned after human anatomy and actuated by Shape Memory Alloy artificial muscles. Two experimental prototypes of a finger, one fabricated by traditional means and another fabricated by rapid prototyping techniques, are described and used to evaluate the design. An important aspect of the Rapid Prototype technique used here is that this multi-articulated hand will be fabricated in one step, without requiring assembly, while maintaining its desired mobility. The use of Shape Memory Alloy actuators combined with the rapid fabrication of the non-assembly type hand, reduce considerably its weight and fabrication time. Therefore, the focus of this paper is the mechanical design of a dexterous hand that combines Rapid Prototype techniques and smart actuators. The type of robotic hand described in this paper can be utilized for applications requiring low weight, compactness, and dexterity such as prosthetic devices, space and planetary exploration.

  9. Artificial muscles versus natural actuators from frogs to flies

    NASA Astrophysics Data System (ADS)

    Full, Robert J.; Meijer, Kenneth

    2000-06-01

    When is a human-made actuator an artificial muscle. Natural actuators in the animal kingdom vary greatly in their capacity and role. Maximum stress variety by 100-fold as does the velocity at which muscles contract. Some muscles generate near maximum force over broad strain ranges, while others function over only the narrowest ranges. Frequencies of operation range from less than 1 Hz to 1000 Hz. Mass- specific power output can reach over 250 W/kg muscle. Muscles function not simply as force generators, but as springs and dampers. Our isolated muscle experiments on insects show that some muscles function primarily as energy absorber sand have a role in control, while others are effective at power generation. At present, we are evaluating EAPs to see where these actuators fit in the functional space of nature's muscles. EAPs appear particularly promising as artificial muscles for insect-sized robots.

  10. Design and development of magnetorheological fluid-based passive actuator.

    PubMed

    Shokrollahi, Elnaz; Price, Karl; Drake, James M; Goldenberg, Andrew A

    2015-08-01

    We present the design and experimental validation of a magnetorheological (MR) fluid-based passive actuator for tele-robotic bone biopsy procedures. With Finite Element Method Magnet (FEMM) software, the required uniform magnetic field circuit design was simulated. An 1100 turn 24 AWG copper wire coil wrapped around a magnetic core was used to create a magnetic field. The field strength was measured with a Hall effect sensor, and compared to the simulation. The maximum magnetic field flux produced by a constant current of 1.4 A was 0.2 T, similar to the simulation results. A series of quasi-static experiments were conducted to characterize the forces generated by the MR fluid-based actuator under various currents up to 12 N. An analytical model was developed to validate the measurements from the passive actuator.

  11. Study on Multi-DOF Ultrasonic Actuator for Laparoscopic Instrument

    NASA Astrophysics Data System (ADS)

    Park, Shinsuk; Takemura, Kenjiro; Maeno, Takashi

    In surgical robots, compact manipulators with multi-degree-of-freedom (DOF) are essential owing to a small work volume in the patient body. Conventional single-DOF actuators such as electromagnetic motors require a multiple number of actuators to generate multi-DOF motion, which in turn results in bulky mechanism combined with transmission device. Our previous work has developed a compact ultrasonic motor capable of generating a multi-DOF rotation of a spherical rotor utilizing three natural vibration modes of a bar-shaped stator. The present study designs and builds a novel multi-DOF master-slave system for laparoscopic surgical procedures, using a single ultrasonic actuator. The system consists of surgical forceps on multi-DOF wrist with joystick controller. Experimental results have confirmed high responsiveness and precise position control of the master-slave system.

  12. The universal robot

    NASA Technical Reports Server (NTRS)

    Moravec, Hans

    1993-01-01

    Our artifacts are getting smarter, and a loose parallel with the evolution of animal intelligence suggests one future course for them. Computerless industrial machinery exhibits the behavioral flexibility of single-celled organisms. Today's best computer-controlled robots are like the simpler invertebrates. A thousand-fold increase in computer power in the next decade should make possible machines with reptile-like sensory and motor competence. Properly configured, such robots could do in the physical world what personal computers now do in the world of data - act on our behalf as literal-minded slaves. Growing computer power over the next half-century will allow this reptile stage to be surpassed, in stages producing robots that learn like mammals, model their world like primates, and eventually reason like humans. Depending on your point of view, humanity will then have produced a worthy successor, or transcended some of its inherited limitations and so transformed itself into something quite new.

  13. The universal robot

    NASA Astrophysics Data System (ADS)

    Moravec, Hans

    1993-12-01

    Our artifacts are getting smarter, and a loose parallel with the evolution of animal intelligence suggests one future course for them. Computerless industrial machinery exhibits the behavioral flexibility of single-celled organisms. Today's best computer-controlled robots are like the simpler invertebrates. A thousand-fold increase in computer power in the next decade should make possible machines with reptile-like sensory and motor competence. Properly configured, such robots could do in the physical world what personal computers now do in the world of data - act on our behalf as literal-minded slaves. Growing computer power over the next half-century will allow this reptile stage to be surpassed, in stages producing robots that learn like mammals, model their world like primates, and eventually reason like humans. Depending on your point of view, humanity will then have produced a worthy successor, or transcended some of its inherited limitations and so transformed itself into something quite new.

  14. Towards A Modular Robotic Architecture

    NASA Astrophysics Data System (ADS)

    Aviles, Walter A.; Laird, Robin T.; Myers, Margaret E.

    1989-03-01

    Despite the seemingly dramatic differences in the con-figuration of individual robots, all mobile platforms are required to perform the same basic tasks and gather certain basic types of information about their environment. In recognition of this fact, work has been initiated on a high-level robotic control and integration architecture known as the Generic Robotic Processing Architecture (GRPA). GRPA is designed to provide a flexible, standard interface between users and a wide variety of robotic processing sys-tems. Under GRPA, the user is able to "compile" a hardware description of a particular robot into data struc-tures used by its Virtual Systems Interface (VSI). Through the VSI disparate types of sensors and actuators can be addressed in a consistent manner. Changing a data object in the VSI initiates a corresponding change in the physical world. On top of the VSI are Teleoperated, Supervisory, Autonomous and Reflexive control levels. Within each con-trol level, GRPA provides standardized, device independent routines which interact with the the VSI to affect changes in the robot.

  15. Dynamic analysis and control of lightweight manipulators with flexible parallel link mechanisms

    NASA Technical Reports Server (NTRS)

    Lee, Jeh Won

    1991-01-01

    The flexible parallel link mechanism is designed for increased rigidity to sustain the buckling when it carries a heavy payload. Compared to a one link flexible manipulator, a two link flexible manipulator, especially the flexible parallel mechanism, has more complicated characteristics in dynamics and control. The objective of this research is the theoretical analysis and the experimental verification of dynamics and control of a two link flexible manipulator with a flexible parallel link mechanism. Nonlinear equations of motion of the lightweight manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. A manipulator with a flexible parallel link mechanism is a constrained dynamic system whose equations are sensitive to numerical integration error. This constrained system is solved using singular value decomposition of the constraint Jacobian matrix. The discrepancies between the analytical model and the experiment are explained using a simplified and a detailed finite element model. The step response of the analytical model and the TREETOPS model match each other well. The nonlinear dynamics is studied using a sinusoidal excitation. The actuator dynamic effect on a flexible robot was investigated. The effects are explained by the root loci and the Bode plot theoretically and experimentally. For the base performance for the advanced control scheme, a simple decoupled feedback scheme is applied.

  16. Consensus control of flexible-joint robots

    NASA Astrophysics Data System (ADS)

    Avila-Becerril, Sofía; Espinosa-Pérez, Gerardo; Panteley, Elena; Ortega, Romeo

    2015-06-01

    Synchronisation of networks composed by fully actuated robot manipulators has received a lot of attention from the control theory community. Unfortunately, the case of under-actuated robots has not been deeply studied. The aim of this paper is to extend previous results reported by the authors addressing the particular (but of practical interest) case of networks composed by flexible-joint robots. The main feature of the contribution is to consider a change of coordinates, first introduced in Nuno, Ortega, Basanes and Hill, to solve the consensus problem assuming the existence of unknown delays in the communication channels. The extension is twofold, namely: the presentation of a control scheme that, in contrast to the one considered in Avila-Becerril and Espinosa-Perez, does not require knowledge of the initial conditions and the proof that the controller can also be implemented in Cartesian coordinates. The usefulness of the contribution is illustrated through numerical simulations.

  17. Control of robot dynamics using acceleration control

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Prateru, S.; Li, W.; Hinman, Elaine

    1992-01-01

    Acceleration control of robotic devices can provide improvements to many space-based operations using flexible manipulators and to ground-based operations requiring better precision and efficiency than current industrial robots can provide. This paper reports on a preliminary study of acceleration measurement on robotic motion during parabolic flights on the NASA KC-135 and a parallel study of accelerations with and without gravity arising from computer simulated motions using TREETOPS software.

  18. Steerable vertical to horizontal energy transducer for mobile robots

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Feddema, John T.

    2001-01-01

    The present invention provides a steerable vertical to horizontal energy transducer for mobile robots that less complex and requires less power than two degree of freedom tilt mechanisms. The present invention comprises an end effector that, when mounted with a hopping actuator, translates along axis (typically vertical) actuation into combined vertical and horizontal motion. The end effector, or foot, mounts with an end of the actuator that moves toward the support surface (typically a floor or the earth). The foot is shaped so that the first contact with the support surface is off the axis of the actuator. Off-axis contact with the support surface generates an on-axis force (typically resulting in vertical motion) and a moment orthogonal to the axis. The moment initiates a horizontal tumbling motion, and tilts the actuator so that its axis is oriented with a horizontal component and continued actuation generates both vertical and horizontal force.

  19. Army Robotics

    DTIC Science & Technology

    2009-10-07

    Army Robotics 07 October 2009 Dr. Grant Gerhart, Senior Research Scientist Bernard Theisen, Joint Center for Robotics DISTRIBUTION STATEMENT A... Robots 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Grant Gerhart; Bernard Theisen 5d. PROJECT NUMBER 5e. TASK...CBRNE • IED Defeat Systems • Disarm / Disrupt • Reconnaissance • Investigation • Explosive Sniffer • Common Robotic Kit • EOD • Convoy • Log

  20. Space Robotics

    DTIC Science & Technology

    1982-08-01

    ACCESSION NO 3. RECIPIENTS CATALOG NUIA3.R CMU-RI-TR-82-10 I4 1 (. 4. ;,;-LL (and Sublitle) S. TYPE OF REPORT & PERIOD CovEREO SPACE ROBOTICS Interim... Robotics Institute Pittsburgh, PA. 15213 It. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Office of Naval Research -August 1982 Arlington, VA 22217...SXnet.eE . Space Robotics Richard E. Korf Department of Computer Science and The Robotics Institute Carnegie-Mellon University Pittsburgh, Oetusylvania

  1. TARDEC Robotics

    DTIC Science & Technology

    2010-01-12

    unclassified TARDEC Robotics Dr. James L. Overholt Director, Joint Center for Robotics US Army TARDEC Report Documentation Page Form ApprovedOMB No...COVERED - 4. TITLE AND SUBTITLE TARDEC Robotics 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) James L. Overholt... Robotics , Network and Control Components with a Focus on Customer Driven Requirements to Provide Full System Solutions to the War Fighter Technology

  2. Teleoperation System with Hybrid Pneumatic-Piezoelectric Actuation for MRI-Guided Needle Insertion with Haptic Feedback.

    PubMed

    Shang, Weijian; Su, Hao; Li, Gang; Fischer, Gregory S

    2013-01-01

    This paper presents a surgical master-slave tele-operation system for percutaneous interventional procedures under continuous magnetic resonance imaging (MRI) guidance. This system consists of a piezoelectrically actuated slave robot for needle placement with integrated fiber optic force sensor utilizing Fabry-Perot interferometry (FPI) sensing principle. The sensor flexure is optimized and embedded to the slave robot for measuring needle insertion force. A novel, compact opto-mechanical FPI sensor interface is integrated into an MRI robot control system. By leveraging the complementary features of pneumatic and piezoelectric actuation, a pneumatically actuated haptic master robot is also developed to render force associated with needle placement interventions to the clinician. An aluminum load cell is implemented and calibrated to close the impedance control loop of the master robot. A force-position control algorithm is developed to control the hybrid actuated system. Teleoperated needle insertion is demonstrated under live MR imaging, where the slave robot resides in the scanner bore and the user manipulates the master beside the patient outside the bore. Force and position tracking results of the master-slave robot are demonstrated to validate the tracking performance of the integrated system. It has a position tracking error of 0.318mm and sine wave force tracking error of 2.227N.

  3. Teleoperation System with Hybrid Pneumatic-Piezoelectric Actuation for MRI-Guided Needle Insertion with Haptic Feedback

    PubMed Central

    Shang, Weijian; Su, Hao; Li, Gang; Fischer, Gregory S.

    2014-01-01

    This paper presents a surgical master-slave tele-operation system for percutaneous interventional procedures under continuous magnetic resonance imaging (MRI) guidance. This system consists of a piezoelectrically actuated slave robot for needle placement with integrated fiber optic force sensor utilizing Fabry-Perot interferometry (FPI) sensing principle. The sensor flexure is optimized and embedded to the slave robot for measuring needle insertion force. A novel, compact opto-mechanical FPI sensor interface is integrated into an MRI robot control system. By leveraging the complementary features of pneumatic and piezoelectric actuation, a pneumatically actuated haptic master robot is also developed to render force associated with needle placement interventions to the clinician. An aluminum load cell is implemented and calibrated to close the impedance control loop of the master robot. A force-position control algorithm is developed to control the hybrid actuated system. Teleoperated needle insertion is demonstrated under live MR imaging, where the slave robot resides in the scanner bore and the user manipulates the master beside the patient outside the bore. Force and position tracking results of the master-slave robot are demonstrated to validate the tracking performance of the integrated system. It has a position tracking error of 0.318mm and sine wave force tracking error of 2.227N. PMID:25126446

  4. Fault tolerant linear actuator

    DOEpatents

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  5. Hydraulic involute cam actuator

    DOEpatents

    Love, Lonnie J [Knoxville, TN; Lind, Randall F [Loudon, TX

    2011-11-01

    Mechanical joints are provided in which the angle between a first coupled member and a second coupled member may be varied by mechanical actuators. In some embodiments the angle may be varied around a pivot axis in one plane and in some embodiments the angle may be varied around two pivot axes in two orthogonal planes. The joints typically utilize a cam assembly having two lobes with an involute surface. Actuators are configured to push against the lobes to vary the rotation angle between the first and second coupled member.

  6. Tetherless thermobiochemically actuated microgrippers

    PubMed Central

    Leong, Timothy G.; Randall, Christina L.; Benson, Bryan R.; Bassik, Noy; Stern, George M.; Gracias, David H.

    2009-01-01

    We demonstrate mass-producible, tetherless microgrippers that can be remotely triggered by temperature and chemicals under biologically relevant conditions. The microgrippers use a self-contained actuation response, obviating the need for external tethers in operation. The grippers can be actuated en masse, even while spatially separated. We used the microgrippers to perform diverse functions, such as picking up a bead on a substrate and the removal of cells from tissue embedded at the end of a capillary (an in vitro biopsy). PMID:19139411

  7. Rover Wheel-Actuated Tool Interface

    NASA Technical Reports Server (NTRS)

    Matthews, Janet; Ahmad, Norman; Wilcox, Brian

    2007-01-01

    A report describes an interface for utilizing some of the mobility features of a mobile robot for general-purpose manipulation of tools and other objects. The robot in question, now undergoing conceptual development for use on the Moon, is the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) rover, which is designed to roll over gentle terrain or walk over rough or steep terrain. Each leg of the robot is a six-degree-of-freedom general purpose manipulator tipped by a wheel with a motor drive. The tool interface includes a square cross-section peg, equivalent to a conventional socket-wrench drive, that rotates with the wheel. The tool interface also includes a clamp that holds a tool on the peg, and a pair of fold-out cameras that provides close-up stereoscopic images of the tool and its vicinity. The field of view of the imagers is actuated by the clamp mechanism and is specific to each tool. The motor drive can power any of a variety of tools, including rotating tools for helical fasteners, drills, and such clamping tools as pliers. With the addition of a flexible coupling, it could also power another tool or remote manipulator at a short distance. The socket drive can provide very high torque and power because it is driven by the wheel motor.

  8. (Robotic hands)

    SciTech Connect

    Mann, R.C.

    1988-09-23

    The traveler attended the International Workshop on Robot Hands at the Palace Hotel in Dubrovnik, Yugoslavia. The traveler presented a lecture on An integrated sensor system for the ORNL mobile robot.'' The traveler obtained important information on current R D efforts in multi-fingered robot hands and object recognition using touch sensing.

  9. Basic Robotics.

    ERIC Educational Resources Information Center

    Mullen, Frank

    This curriculum outline consists of instructional materials and information concerning resources for use in teaching a course in robotics. Addressed in the individual sections of the outline are the following topics: the nature of an industrial robot; the parts of an industrial robot (the manipulator, the power structure, and the control system);…

  10. Industrial Robots.

    ERIC Educational Resources Information Center

    Reed, Dean; Harden, Thomas K.

    Robots are mechanical devices that can be programmed to perform some task of manipulation or locomotion under automatic control. This paper discusses: (1) early developments of the robotics industry in the United States; (2) the present structure of the industry; (3) noneconomic factors related to the use of robots; (4) labor considerations…

  11. An Unconventional Inchworm Actuator Based on PZT/ERFs Control Technology

    PubMed Central

    Liu, Guojun; Zhang, Yanyan; Liu, Jianfang; Li, Jianqiao; Tang, Chunxiu; Wang, Tengfei; Yang, Xuhao

    2016-01-01

    An unconventional inchworm actuator for precision positioning based on piezoelectric (PZT) actuation and electrorheological fluids (ERFs) control technology is presented. The actuator consists of actuation unit (PZT stack pump), fluid control unit (ERFs valve), and execution unit (hydraulic actuator). In view of smaller deformation of PZT stack, a new structure is designed for actuation unit, which integrates the advantages of two modes (namely, diaphragm type and piston type) of the volume changing of pump chamber. In order to improve the static shear yield strength of ERFs, a composite ERFs valve is designed, which adopts the series-parallel plate compound structure. The prototype of the inchworm actuator has been designed and manufactured in the lab. Systematic test results indicate that the displacement resolution of the unconventional inchworm actuator reaches 0.038 μm, and the maximum driving force and velocity are 42 N, 14.8 mm/s, respectively. The optimal working frequency for the maximum driving velocity is 120 Hz. The complete research and development processes further confirm the feasibility of developing a new type of inchworm actuator with high performance based on PZT actuation and ERFs control technology, which provides a reference for the future development of a new type of actuator. PMID:27022234

  12. An Unconventional Inchworm Actuator Based on PZT/ERFs Control Technology.

    PubMed

    Liu, Guojun; Zhang, Yanyan; Liu, Jianfang; Li, Jianqiao; Tang, Chunxiu; Wang, Tengfei; Yang, Xuhao

    2016-01-01

    An unconventional inchworm actuator for precision positioning based on piezoelectric (PZT) actuation and electrorheological fluids (ERFs) control technology is presented. The actuator consists of actuation unit (PZT stack pump), fluid control unit (ERFs valve), and execution unit (hydraulic actuator). In view of smaller deformation of PZT stack, a new structure is designed for actuation unit, which integrates the advantages of two modes (namely, diaphragm type and piston type) of the volume changing of pump chamber. In order to improve the static shear yield strength of ERFs, a composite ERFs valve is designed, which adopts the series-parallel plate compound structure. The prototype of the inchworm actuator has been designed and manufactured in the lab. Systematic test results indicate that the displacement resolution of the unconventional inchworm actuator reaches 0.038 μm, and the maximum driving force and velocity are 42 N, 14.8 mm/s, respectively. The optimal working frequency for the maximum driving velocity is 120 Hz. The complete research and development processes further confirm the feasibility of developing a new type of inchworm actuator with high performance based on PZT actuation and ERFs control technology, which provides a reference for the future development of a new type of actuator.

  13. Computational motor control in humans and robots.

    PubMed

    Schaal, Stefan; Schweighofer, Nicolas

    2005-12-01

    Computational models can provide useful guidance in the design of behavioral and neurophysiological experiments and in the interpretation of complex, high dimensional biological data. Because many problems faced by the primate brain in the control of movement have parallels in robotic motor control, models and algorithms from robotics research provide useful inspiration, baseline performance, and sometimes direct analogs for neuroscience.

  14. Robopedia: Leveraging Sensorpedia for Web-Enabled Robot Control

    SciTech Connect

    Resseguie, David R

    2010-01-01

    There is a growing interest in building Internetscale sensor networks that integrate sensors from around the world into a single unified system. In contrast, robotics application development has primarily focused on building specialized systems. These specialized systems take scalability and reliability into consideration, but generally neglect exploring the key components required to build a large scale system. Integrating robotic applications with Internet-scale sensor networks will unify specialized robotics applications and provide answers to large scale implementation concerns. We focus on utilizing Internet-scale sensor network technology to construct a framework for unifying robotic systems. Our framework web-enables a surveillance robot s sensor observations and provides a webinterface to the robot s actuators. This lets robots seamlessly integrate into web applications. In addition, the framework eliminates most prerequisite robotics knowledge, allowing for the creation of general web-based robotics applications. The framework also provides mechanisms to create applications that can interface with any robot. Frameworks such as this one are key to solving large scale mobile robotics implementation problems. We provide an overview of previous Internetscale sensor networks, Sensorpedia (an ad-hoc Internet-scale sensor network), our framework for integrating robots with Sensorpedia, two applications which illustrate our frameworks ability to support general web-based robotic control, and offer experimental results that illustrate our framework s scalability, feasibility, and resource requirements.

  15. System and method for controlling a vision guided robot assembly

    DOEpatents

    Lin, Yhu-Tin; Daro, Timothy; Abell, Jeffrey A.; Turner, III, Raymond D.; Casoli, Daniel J.

    2017-03-07

    A method includes the following steps: actuating a robotic arm to perform an action at a start position; moving the robotic arm from the start position toward a first position; determining from a vision process method if a first part from the first position will be ready to be subjected to a first action by the robotic arm once the robotic arm reaches the first position; commencing the execution of the visual processing method for determining the position deviation of the second part from the second position and the readiness of the second part to be subjected to a second action by the robotic arm once the robotic arm reaches the second position; and performing a first action on the first part using the robotic arm with the position deviation of the first part from the first position predetermined by the vision process method.

  16. Fluid logic control circuit operates nutator actuator motor

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Fluid logic control circuit operates a pneumatic nutator actuator motor. It has no moving parts and consists of connected fluid interaction devices. The operation of this circuit demonstrates the ability of fluid interaction devices to operate in a complex combination of series and parallel logic sequence.

  17. Multiplexed hydraulic valve actuation using ionic liquid filled soft channels and Braille displays

    NASA Astrophysics Data System (ADS)

    Gu, Wei; Chen, Hao; Tung, Yi-Chung; Meiners, Jens-Christian; Takayama, Shuichi

    2007-01-01

    Pneumatic actuation with multilayer soft lithography enables operation of up to thousands of valves in parallel using far fewer control lines. However, it is dependent on macroscopic switches and external pressure sources that require interconnects and limit portability. The authors present a more portable and multiplexed valve actuation strategy that uses a grid of mechanically actuated Braille pins to hydraulically, rather than pneumatically, deform elastic actuation channels that act as valves. Experimental and theoretical analyses show that the key to reliable operation of the hydraulic system is the use of nonvolatile ionic liquids as the hydraulic fluid.

  18. Fabrication of Polyurethane Dielectric Actuators

    DTIC Science & Technology

    2005-01-01

    a summary of a 3 year Technology Investment Fund Project entitled “Dielectric Polymer Actuators for Active/ Passive Vibration Isolation”, which was...completed in March 2005. The purpose of this project was to investigate dielectric polymer materials for potential use in active/ passive vibration...devices and systems based on dielectric polymer actuators. Keywords: dielectric actuators, electroactive polymers , Technology Investment Fund 1

  19. Tactile Robotic Topographical Mapping Without Force or Contact Sensors

    NASA Technical Reports Server (NTRS)

    Burke, Kevin; Melko, Joseph; Krajewski, Joel; Cady, Ian

    2008-01-01

    A method of topographical mapping of a local solid surface within the range of motion of a robot arm is based on detection of contact between the surface and the end effector (the fixture or tool at the tip of the robot arm). The method was conceived to enable mapping of local terrain by an exploratory robot on a remote planet, without need to incorporate delicate contact switches, force sensors, a vision system, or other additional, costly hardware. The method could also be used on Earth for determining the size and shape of an unknown surface in the vicinity of a robot, perhaps in an unanticipated situation in which other means of mapping (e.g., stereoscopic imaging or laser scanning with triangulation) are not available. The method uses control software modified to utilize the inherent capability of the robotic control system to measure the joint positions, the rates of change of the joint positions, and the electrical current demanded by the robotic arm joint actuators. The system utilizes these coordinate data and the known robot-arm kinematics to compute the position and velocity of the end effector, move the end effector along a specified trajectory, place the end effector at a specified location, and measure the electrical currents in the joint actuators. Since the joint actuator current is approximately proportional to the actuator forces and torques, a sudden rise in joint current, combined with a slowing of the joint, is a possible indication of actuator stall and surface contact. Hence, even though the robotic arm is not equipped with contact sensors, it is possible to sense contact (albeit with reduced sensitivity) as the end effector becomes stalled against a surface that one seeks to measure.

  20. Electrically controllable twisted-coiled artificial muscle actuators using surface-modified polyester fibers

    NASA Astrophysics Data System (ADS)

    Park, Jungwoo; Yoo, Ji Wang; Seo, Hee Won; Lee, Youngkwan; Suhr, Jonghwan; Moon, Hyungpil; Koo, Ja Choon; Ryeol Choi, Hyouk; Hunt, Robert; Kim, Kwang Jin; Kim, Soo Hyun; Nam, Jae-Do

    2017-03-01

    As a new class of thermally activated actuators based on polymeric fibers, we investigated polyethylene terephthalate (PET) yarns for the development of a twisted-coiled polymer fiber actuator (TCA). The PET yarn TCA exhibited the maximum linear actuation up to 8.9% by external heating at above the glass transition temperature, 160 °C–180 °C. The payload of the actuator was successfully correlated with the preload and training-load conditions by an empirical equation. Furthermore, the PET-based TCA was electrically driven by Joule heating after the PET surface was metallization with silver. For the fast and precise control of PET yarn TCA, electroless silver plating was conducted to form electrical conductive layers on the PET fiber surface. The silver plated PET-based TCA was tested by Joule heating and the tensile actuation was increased up to 12.1% (6 V) due to the enhanced surface hardness and slippage of PET fibers. Overall, silver plating of the polymeric yarn provided a fast actuation speed and enhanced actuation performance of the TCA actuator by Joule heating, providing a great potential for being used in artificial muscle for biomimetic machines including robots, industrial actuators and powered exoskeletons.

  1. Automatic design of fiber-reinforced soft actuators for trajectory matching

    NASA Astrophysics Data System (ADS)

    Connolly, Fionnuala; Walsh, Conor J.; Bertoldi, Katia

    2017-01-01

    Soft actuators are the components responsible for producing motion in soft robots. Although soft actuators have allowed for a variety of innovative applications, there is a need for design tools that can help to efficiently and systematically design actuators for particular functions. Mathematical modeling of soft actuators is an area that is still in its infancy but has the potential to provide quantitative insights into the response of the actuators. These insights can be used to guide actuator design, thus accelerating the design process. Here, we study fluid-powered fiber-reinforced actuators, because these have previously been shown to be capable of producing a wide range of motions. We present a design strategy that takes a kinematic trajectory as its input and uses analytical modeling based on nonlinear elasticity and optimization to identify the optimal design parameters for an actuator that will follow this trajectory upon pressurization. We experimentally verify our modeling approach, and finally we demonstrate how the strategy works, by designing actuators that replicate the motion of the index finger and thumb.

  2. Robots for manipulation in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Quinn, R. D.; Lawrence, C.

    1988-01-01

    This paper is concerned with the development of control strategies and mechanisms for robots operating in the micro-gravity environment of Space Station. These robots must be capable of conducting experiments and manufacturing processes without disturbing the micro-gravity environment through base reactions/motions. Approaches discussed for controlling the robot base reactions/motions include strategies making use of manipulators with redundant degrees of freedon, actuators at the robot base, and a redundant (balancing) arm. Two degree-of-freedom, traction-drive joints are discussed as well as the conceptual design for a traction-driven manipulator.

  3. Large-Deformation Curling Actuators Based on Carbon Nanotube Composite: Advanced-Structure Design and Biomimetic Application.

    PubMed

    Chen, Luzhuo; Weng, Mingcen; Zhou, Zhiwei; Zhou, Yi; Zhang, Lingling; Li, Jiaxin; Huang, Zhigao; Zhang, Wei; Liu, Changhong; Fan, Shoushan

    2015-12-22

    In recent years, electroactive polymers have been developed as actuator materials. As an important branch of electroactive polymers, electrothermal actuators (ETAs) demonstrate potential applications in the fields of artificial muscles, biomimetic devices, robotics, and so on. Large-shape deformation, low-voltage-driven actuation, and ultrafast fabrication are critical to the development of ETA. However, a simultaneous optimization of all of these advantages has not been realized yet. Practical biomimetic applications are also rare. In this work, we introduce an ultrafast approach to fabricate a curling actuator based on a newly designed carbon nanotube and polymer composite, which completely realizes all of the above required advantages. The actuator shows an ultralarge curling actuation with a curvature greater than 1.0 cm(-1) and bending angle larger than 360°, even curling into a tubular structure. The driving voltage is down to a low voltage of 5 V. The remarkable actuation is attributed not only to the mismatch in the coefficients of thermal expansion but also to the mechanical property changes of materials during temperature change. We also construct an S-shape actuator to show the possibility of building advanced-structure actuators. A weightlifting walking robot is further designed that exhibits a fast-moving motion while lifting a sample heavier than itself, demonstrating promising biomimetic applications.

  4. "Mighty Worm" Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Bamford, Robert M.; Wada, Ben K.; Moore, Donald M.

    1994-01-01

    "Mighty Worm" piezoelectric actuator used as adjustable-length structural member, active vibrator or vibration suppressor, and acts as simple (fixed-length) structural member when inactive. Load force not applied to piezoelectric element in simple-structural-member mode. Piezoelectric element removed from load path when not in use.

  5. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  6. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2000-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  7. Electromechanical flight control actuator

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The feasibility of using an electromechanical actuator (EMA) as the primary flight control equipment in aerospace flight is examined. The EMA motor design is presented utilizing improved permanent magnet materials. The necessary equipment to complete a single channel EMA using the single channel power electronics breadboard is reported. The design and development of an improved rotor position sensor/tachometer is investigated.

  8. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, James G.

    1999-01-01

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing.

  9. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, J.G.

    1999-02-02

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing. 49 figs.

  10. Piezoelectric actuator renaissance

    NASA Astrophysics Data System (ADS)

    Uchino, Kenji

    2015-03-01

    This paper resumes the content of the invited talk of the author, read at the occasion of the International Workshop on Relaxor Ferroelectrics, IWRF 14, held on October 12-16, 2014 in Stirin, Czech Republic. It reviews the recent advances in materials, designing concepts, and new applications of piezoelectric actuators, as well as the future perspectives of this area.

  11. Kinesthetic Feedback during 2DOF Wrist Movements via a Novel MR-Compatible Robot.

    PubMed

    Erwin, Andrew; O'Malley, Marcia; Ress, David; Sergi, Fabrizio

    2016-12-01

    We demonstrate the interaction control capabilities of the MR-SoftWrist, a novel MR-compatible robot capable of applying accurate kinesthetic feedback to wrist pointing movements executed during fMRI. The MR-SoftWrist, based on a novel design that combines parallel piezoelectric actuation with compliant force feedback, is capable of delivering 1.5 N·m of torque to the wrist of an interacting subject about the flexion/extension and radial/ulnar axes. The robot workspace, defined by admissible wrist rotation angles, fully includes a circle with a 20 deg radius. Via dynamic characterization, we demonstrate capability for transparent operation with low (10% of maximum torque output) backdrivability torques at nominal speeds. Moreover, we demonstrate a 5.5 Hz stiffness control bandwidth for a 14 dB range of virtual stiffness values, corresponding to 25-125% of the device's physical reflected stiffness in the nominal configuration. We finally validate the possibility of operation during fMRI via a case study involving one healthy subject. Our validation experiment demonstrates the capability of the device to apply kinesthetic feedback to elicit distinguishable kinetic and neural responses without significant degradation of image quality or task-induced head movements. With this study, we demonstrate the feasibility of MR-compatible devices like the MR-SoftWrist to be used in support of motor control experiments investigating wrist pointing under robot-applied force fields. Such future studies may elucidate fundamental neural mechanisms enabling robot-assisted motor skill learning, which is crucial for robot-aided neurorehabilitation.

  12. Thermally Actuated Hydraulic Pumps

    NASA Technical Reports Server (NTRS)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  13. Compact, Low-Force, Low-Noise Linear Actuator

    NASA Technical Reports Server (NTRS)

    Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph

    2012-01-01

    Actuators are critical to all the robotic and manipulation mechanisms that are used in current and future NASA missions, and are also needed for many other industrial, aeronautical, and space activities. There are many types of actuators that were designed to operate as linear or rotary motors, but there is still a need for low-force, low-noise linear actuators for specialized applications, and the disclosed mechanism addresses this need. A simpler implementation of a rotary actuator was developed where the end effector controls the motion of a brush for cleaning a thermal sensor. The mechanism uses a SMA (shape-memory alloy) wire for low force, and low noise. The linear implementation of the actuator incorporates a set of springs and mechanical hard-stops for resetting and fault tolerance to mechanical resistance. The actuator can be designed to work in a pull or push mode, or both. Depending on the volume envelope criteria, the actuator can be configured for scaling its volume down to 4x2x1 cu cm. The actuator design has an inherent fault tolerance to mechanical resistance. The actuator has the flexibility of being designed for both linear and rotary motion. A specific configuration was designed and analyzed where fault-tolerant features have been implemented. In this configuration, an externally applied force larger than the design force does not damage the active components of the actuator. The actuator housing can be configured and produced using cost-effective methods such as injection molding, or alternatively, its components can be mounted directly on a small circuit board. The actuator is driven by a SMA -NiTi as a primary active element, and it requires energy on the order of 20 Ws(J) per cycle. Electrical connections to points A and B are used to apply electrical power in the resistive NiTi wire, causing a phase change that contracts the wire on the order of 5%. The actuation period is of the order of a second for generating the stroke, and 4 to 10

  14. Compact, Low-Force, Low-Noise Linear Actuator

    NASA Technical Reports Server (NTRS)

    Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph

    2012-01-01

    Actuators are critical to all the robotic and manipulation mechanisms that are used in current and future NASA missions, and are also needed for many other industrial, aeronautical, and space activities. There are many types of actuators that were designed to operate as linear or rotary motors, but there is still a need for low-force, low-noise linear actuators for specialized applications, and the disclosed mechanism addresses this need. A simpler implementation of a rotary actuator was developed where the end effector controls the motion of a brush for cleaning a thermal sensor. The mechanism uses a SMA (shape-memory alloy) wire for low force, and low noise. The linear implementation of the actuator incorporates a set of springs and mechanical hard-stops for resetting and fault tolerance to mechanical resistance. The actuator can be designed to work in a pull or push mode, or both. Depending on the volume envelope criteria, the actuator can be configured for scaling its volume down to 4 2 1 cm3. The actuator design has an inherent fault tolerance to mechanical resistance. The actuator has the flexibility of being designed for both linear and rotary motion. A specific configuration was designed and analyzed where fault-tolerant features have been implemented. In this configuration, an externally applied force larger than the design force does not damage the active components of the actuator. The actuator housing can be configured and produced using cost-effective methods such as injection molding, or alternatively, its components can be mounted directly on a small circuit board. The actuator is driven by a SMA -NiTi as a primary active element, and it requires energy on the order of 20 Ws(J) per cycle. Electrical connections to points A and B are used to apply electrical power in the resistive NiTi wire, causing a phase change that contracts the wire on the order of 5%. The actuation period is of the order of a second for generating the stroke, and 4 to 10 seconds

  15. Dynamic legged locomotion for palm-size robots

    NASA Astrophysics Data System (ADS)

    Zarrouk, David; Haldane, Duncan W.; Fearing, Ronald S.

    2015-05-01

    Minimally-actuated palm-size robots are capable of running at speeds greater than 2 meters per second (20 body lengths per second), with leg stride rates of greater than 20 Hz. In this dynamic regime, passive stabilization is needed for roll-and-pitch instability. However, we have found that certain roll-oscillation modes can be used for continuous high speed turning. Other continuous turning modes have also been identified, such as modulating foot contact location through foot compliance, and controlling differential leg velocity. For the small minimally actuated robots examined, the dynamically enhanced roll-steer mode showed the best turning rate, of over 8 degrees per step, but only appears at certain running frequencies. Interstride phase and velocity control appears promising as a mode for in-plane maneuverability for under-actuated robots.

  16. Parylene coated carbon nanotube actuators for tactile stimulation

    NASA Astrophysics Data System (ADS)

    Bubak, Grzegorz; Ansaldo, Alberto; Gendron, David; Brayda, Luca; Ceseracciu, Luca; Ricci, Davide

    2015-04-01

    Ionic liquid/carbon nanotube based actuators have been constantly improved in recent years owing to their suitability for applications related to human-machine interaction and robotics thanks to their light-weight and low voltage operation. However, while great attention has been paid to the development of better electrodes and electrolytes, no adequate efforts were made to develop actuators to be used in direct contact with the human skin. Herein, we present our approach, based on the use of parylene-C coating. Indeed, owning to its physicochemical properties such as high dielectric strength, resistance to solvents, biological and chemical inactivity/inertness, parylene fulfils the requirements for use in biocompatible actuator fabrication. In this paper, we study the influence of the parylene coating on the actuator performance. To do so, we analyzed its mechanical and electrochemical properties. We looked into the role of parylene as a protection layer that can prevent alteration of the actuator performance likely caused by external conditions. In order to complete our study, we designed a haptic device and investigated the generated force, displacement and energy usage.

  17. Parallel Assembly of LIGA Components

    SciTech Connect

    Christenson, T.R.; Feddema, J.T.

    1999-03-04

    In this paper, a prototype robotic workcell for the parallel assembly of LIGA components is described. A Cartesian robot is used to press 386 and 485 micron diameter pins into a LIGA substrate and then place a 3-inch diameter wafer with LIGA gears onto the pins. Upward and downward looking microscopes are used to locate holes in the LIGA substrate, pins to be pressed in the holes, and gears to be placed on the pins. This vision system can locate parts within 3 microns, while the Cartesian manipulator can place the parts within 0.4 microns.

  18. Robotic tentacles with three-dimensional mobility based on flexible elastomers.

    PubMed

    Martinez, Ramses V; Branch, Jamie L; Fish, Carina R; Jin, Lihua; Shepherd, Robert F; Nunes, Rui M D; Suo, Zhigang; Whitesides, George M

    2013-01-11

    Soft robotic tentacles that move in three dimensions upon pressurization are fabricated by composing flexible elastomers with different tensile strengths using soft lithographic molding. These actuators are able to grip complex shapes and manipulate delicate objects. Embedding functional components into these actuators (for example, a needle for delivering fluid, a video camera, and a suction cup) extends their capabilities.

  19. Adaptive impedance control of a robotic orthosis for gait rehabilitation.

    PubMed

    Hussain, Shahid; Xie, Sheng Q; Jamwal, Prashant K

    2013-06-01

    Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis with two actuated and four passive degrees of freedom (DOFs) is proposed. The actuated DOFs were powered by pneumatic muscle actuators. An AAN gait training paradigm based on adaptive impedance control was developed to provide interactive robotic gait training. The proposed adaptive impedance control scheme adapts the robotic assistance according to the disability level and voluntary participation of human subjects. The robotic orthosis was operated in two gait training modes, namely, inactive mode and active mode, to evaluate the performance of the proposed control scheme. The adaptive impedance control scheme was evaluated on ten neurologically intact subjects. The experimental results demonstrate that an increase in voluntary participation of human subjects resulted in a decrease of the robotic assistance and vice versa. Further clinical evaluations with neurologically impaired subjects are required to establish the therapeutic efficacy of the adaptive-impedance-control-based AAN gait training strategy.

  20. Dielectric Actuation of Polymers

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  1. Controlling Tensegrity Robots Through Evolution

    NASA Technical Reports Server (NTRS)

    Iscen, Atil; Agogino, Adrian; SunSpiral, Vytas; Tumer, Kagan

    2013-01-01

    Tensegrity structures (built from interconnected rods and cables) have the potential to offer a revolutionary new robotic design that is light-weight, energy-efficient, robust to failures, capable of unique modes of locomotion, impact tolerant, and compliant (reducing damage between the robot and its environment). Unfortunately robots built from tensegrity structures are difficult to control with traditional methods due to their oscillatory nature, nonlinear coupling between components and overall complexity. Fortunately this formidable control challenge can be overcome through the use of evolutionary algorithms. In this paper we show that evolutionary algorithms can be used to efficiently control a ball-shaped tensegrity robot. Experimental results performed with a variety of evolutionary algorithms in a detailed soft-body physics simulator show that a centralized evolutionary algorithm performs 400 percent better than a hand-coded solution, while the multi-agent evolution performs 800 percent better. In addition, evolution is able to discover diverse control solutions (both crawling and rolling) that are robust against structural failures and can be adapted to a wide range of energy and actuation constraints. These successful controls will form the basis for building high-performance tensegrity robots in the near future.

  2. Design of a small animal biopsy robot.

    PubMed

    Bebek, Ozkan; Hwang, Myun Joong; Fei, Baowei; Cavusoglu, M

    2008-01-01

    Small animals are widely used in biomedical research studies. They have compact anatomy and small organs. Therefore it is difficult to perceive tumors or cells and perform biopsies manually. Robotics technology offers a convenient and reliable solution for accurate needle insertion. In this paper, a novel 5 degrees of freedom (DOF) robot design for inserting needles into small animal subjects is proposed. The design has a compact size, is light weight, and has high resolution. Parallel mechanisms are used in the design for stable and reliable operation. The proposed robot has two gimbal joints that carry the needle mechanism. The robot can realize dexterous alignment of the needle before insertion.

  3. Robot tongues in space: continuum surfaces for robotic grasping and manipulation

    NASA Astrophysics Data System (ADS)

    Cohen, Caleb; Hiott, Brandon; Kapadia, Apoorva D.; Walker, Ian D.

    2016-05-01

    In this paper, we introduce a novel, continuously bending "robot tongue." The tongue replaces the existing parallel jaw gripper at the end of a KUKA industrial robot manipulator. The resulting system augments the precise positioning of the KUKA with unique capabilities for adaptive grasping afforded by the new robot tongue. We demonstrate the ability of the system to grasp and manipulate objects over a wide range of scales and geometries and evaluate the potential for use of such tongues in various applications.

  4. Electromechanical actuator with controllable motion, fast response rate, and high-frequency resonance based on graphene and polydiacetylene.

    PubMed

    Liang, Jiajie; Huang, Lu; Li, Na; Huang, Yi; Wu, Yingpeng; Fang, Shaoli; Oh, Jiyoung; Kozlov, Mikhail; Ma, Yanfeng; Li, Feifei; Baughman, Ray; Chen, Yongsheng

    2012-05-22

    Although widely investigated, novel electromechanical actuators with high overall actuation performance are still in urgent need for various practical and scientific applications, such as robots, prosthetic devices, sensor switches, and sonar projectors. In this work, combining the properties of unique environmental perturbations-actuated deformational isomerization of polydiacetylene (PDA) and the outstanding intrinsic features of graphene together for the first time, we design and fabricate an electromechanical bimorph actuator composed of a layer of PDA crystal and a layer of flexible graphene paper through a simple yet versatile solution approach. Under low applied direct current (dc), the graphene-PDA bimorph actuator with strong mechanical strength can generate large actuation motion (curvature is about 0.37 cm(-1) under a current density of 0.74 A/mm(2)) and produce high actuation stress (more than 160 MPa/g under an applied dc of only 0.29 A/mm(2)). When applying alternating current (ac), this actuator can display reversible swing behavior with long cycle life under high frequencies even up to 200 Hz; significantly, while the frequency and the value of applied ac and the state of the actuators reach an appropriate value, the graphene-PDA actuator can produce a strong resonance and the swing amplitude will jump to a peak value. Moreover, this stable graphene-PDA actuator also demonstrates rapidly and partially reversible electrochromatic phenomenon when applying an ac. Two mechanisms-the dominant one, electric-induced deformation, and a secondary one, thermal-induced expansion of PDA-are proposed to contribute to these interesting actuation performances of the graphene-PDA actuators. On the basis of these results, a mini-robot with controllable direction of motion based on the graphene-PDA actuator is designed to illustrate the great potential of our discoveries for practical use. Combining the unique actuation mechanism and many outstanding properties of

  5. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, M.A.; Ciarlo, D.R.; Lee, A.P.; Krulevitch, P.A.

    1997-07-08

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The ``micro`` size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed. 22 figs.

  6. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, Milton A.; Ciarlo, Dino R.; Lee, Abraham P.; Krulevitch, Peter A.

    1997-01-01

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The "micro" size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed.

  7. Electrical Actuation Technology Bridging

    NASA Technical Reports Server (NTRS)

    Hammond, Monica (Compiler); Sharkey, John (Compiler)

    1993-01-01

    This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

  8. Microfabricated therapeutic actuators

    DOEpatents

    Lee, Abraham P.; Northrup, M. Allen; Ciarlo, Dino R.; Krulevitch, Peter A.; Benett, William J.

    1999-01-01

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.

  9. Microfabricated therapeutic actuators

    DOEpatents

    Lee, A.P.; Northrup, M.A.; Ciarlo, D.R.; Krulevitch, P.A.; Benett, W.J.

    1999-06-15

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. 8 figs.

  10. Scissor thrust valve actuator

    DOEpatents

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  11. A novel microgripper hybrid driven by a piezoelectric stack actuator and piezoelectric cantilever actuators.

    PubMed

    Chen, Weilin; Zhang, Xianmin; Fatikow, Sergej

    2016-11-01

    For the piezo-driven microgripper, one issue is to enlarge the grasping stroke and realize parallel grasping movement in the compact design. Piezoelectric stack actuator (PSA) and piezoelectric cantilever actuator (PCA) are two kinds of typical piezoelectric actuators. In this study, a novel microgripper hybrid driven by a PSA and two PCAs is proposed, which can be a better solution for the issue, compared with the previous microgripper using PSA-driven multi-stages displacement amplification mechanism (DAM) or using longer and narrower PCAs. A compact one-stage orthogonal DAM is proposed for the PSA in the microgripper, which can enlarge the grasping stroke and realize parallel grasping movement. The proposed orthogonal DAM is a triangulation amplification-based mechanism with undetermined structural parameters. Bidirectional symmetric input forces/displacements are not required in the proposed design. The number of the undetermined parameters and the solution principle are analyzed. Finite element analysis is used to verify the proposed DAM. The gripper arms are designed as two PCAs, for which the grasping and parasitic movements of the free end are modeled. Piezoelectric-static coupling finite element analysis is used to verify the models. The PCAs-driven grasping with considerable parasitic movement can be used in the coarse positioning. The integration of the hybrid-driven microgripper is presented, and its performances are presented and verified by experiments.

  12. A novel microgripper hybrid driven by a piezoelectric stack actuator and piezoelectric cantilever actuators

    NASA Astrophysics Data System (ADS)

    Chen, Weilin; Zhang, Xianmin; Fatikow, Sergej

    2016-11-01

    For the piezo-driven microgripper, one issue is to enlarge the grasping stroke and realize parallel grasping movement in the compact design. Piezoelectric stack actuator (PSA) and piezoelectric cantilever actuator (PCA) are two kinds of typical piezoelectric actuators. In this study, a novel microgripper hybrid driven by a PSA and two PCAs is proposed, which can be a better solution for the issue, compared with the previous microgripper using PSA-driven multi-stages displacement amplification mechanism (DAM) or using longer and narrower PCAs. A compact one-stage orthogonal DAM is proposed for the PSA in the microgripper, which can enlarge the grasping stroke and realize parallel grasping movement. The proposed orthogonal DAM is a triangulation amplification-based mechanism with undetermined structural parameters. Bidirectional symmetric input forces/displacements are not required in the proposed design. The number of the undetermined parameters and the solution principle are analyzed. Finite element analysis is used to verify the proposed DAM. The gripper arms are designed as two PCAs, for which the grasping and parasitic movements of the free end are modeled. Piezoelectric-static coupling finite element analysis is used to verify the models. The PCAs-driven grasping with considerable parasitic movement can be used in the coarse positioning. The integration of the hybrid-driven microgripper is presented, and its performances are presented and verified by experiments.

  13. Method and System for Controlling a Dexterous Robot Execution Sequence Using State Classification

    NASA Technical Reports Server (NTRS)

    Sanders, Adam M. (Inventor); Platt, Robert J., Jr. (Inventor); Quillin, Nathaniel (Inventor); Permenter, Frank Noble (Inventor); Pfeiffer, Joseph (Inventor)

    2014-01-01

    A robotic system includes a dexterous robot and a controller. The robot includes a plurality of robotic joints, actuators for moving the joints, and sensors for measuring a characteristic of the joints, and for transmitting the characteristics as sensor signals. The controller receives the sensor signals, and is configured for executing instructions from memory, classifying the sensor signals into distinct classes via the state classification module, monitoring a system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the system state. A method for controlling the robot in the above system includes receiving the signals via the controller, classifying the signals using the state classification module, monitoring the present system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the present system state.

  14. Dissolution actuated sample container

    SciTech Connect

    Nance, Thomas A.; McCoy, Frank T.

    2013-03-26

    A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

  15. Shape memory alloy actuator

    DOEpatents

    Varma, Venugopal K.

    2001-01-01

    An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

  16. Thermally actuated thermionic switch

    DOEpatents

    Barrus, Donald M.; Shires, Charles D.

    1988-01-01

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  17. Thermally actuated thermionic switch

    DOEpatents

    Barrus, D.M.; Shires, C.D.

    1982-09-30

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  18. Shape Memory Actuator System

    DTIC Science & Technology

    1998-07-31

    The advantage in utilizing 15 shape-memory cables made of Nitinol for size reduction of the remote control actuator system is 1 Fi well suited for...a submarine environment because of its non-magnetic and corrosion resistance 17 properties. Use of thermoelastic Nitinol introduces other...problems because of the cooling and 18 resetting properties of Nitinol cables. It is therefore an important object of the present invention 19 on to

  19. Passively actuated valve

    SciTech Connect

    Modro, S. Michael; Ougouag, Abderrafi M.

    2005-09-20

    A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

  20. Linear mass actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

    1992-01-01

    A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.