Science.gov

Sample records for actuated parallel robot

  1. Validation and verification of a high-fidelity computational model for a bounding robot's parallel actuated elastic spine

    NASA Astrophysics Data System (ADS)

    Pusey, Jason L.; Yoo, Jin-Hyeong

    2014-06-01

    We document the design and preliminary numerical simulation study of a high fidelity model of Canid, a recently introduced bounding robot. Canid is a free-standing, power-autonomous quadrupedal machine constructed from standard commercially available electromechanical and structural elements, incorporating compliant C-shaped legs like those of the decade old RHex design, but departing from that standard (and, to the best of our knowledge, from any prior) robot platform in its parallel actuated elastic spine. We have used a commercial modeling package to develop a finite-element model of the actuated, cable-driven, rigid-plate-reinforced harness for the carbon-fiber spring that joins the robot's fore- and hind-quarters. We compare a numerical model of this parallel actuated elastic spine with empirical data from preliminary physical experiments with the most important component of the spine assembly: the composite leaf spring. Specifically, we report our progress in tuning the mechanical properties of a standard modal approximation to a conventional compliant beam model whose boundary conditions represent constraints imposed by the actuated cable driven vertebral plates that comprise the active control affordance over the spine. We conclude with a brief look ahead at near-term future experiments that will compare predictions of this fitted composite spring model with data taken from the physical spine flexed in isolation from the actuated harness.

  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. Soft mobile robots driven by foldable dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Sun, Wenjie; Liu, Fan; Ma, Ziqi; Li, Chenghai; Zhou, Jinxiong

    2016-08-01

    A cantilever beam with elastic hinge pulled antagonistically by two dielectric elastomer (DE) membranes in tension forms a foldable actuator if one DE membrane is subject to a voltage and releases part of tension. Simply placing parallel rigid bars on the prestressed DE membranes results in enhanced actuators working in a pure shear state. We report design, analysis, fabrication, and experiment of soft mobile robots that are moved by such foldable DE actuators. We describe systematic measurement of the foldable actuators and perform theoretical analysis of such actuators based on minimization of total energy, and a good agreement is achieved between model prediction and measurement. We develop two versions of prototypes of soft mobile robots driven either by two sets of DE membranes or one DE membrane and elastic springs. We demonstrate locomotion of these soft mobile robots and highlight several key design parameters that influence locomotion of the robots. A 45 g soft robot driven by a cyclic triangle voltage with amplitude 7.4 kV demonstrates maximal stroke 160 mm or maximal rolling velocity 42 mm/s. The underlying mechanics and physics of foldable DE actuators can be leveraged to develop other soft machines for various applications.

  5. 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.

  6. 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

  7. Soft Robots: Manipulation, Mobility, and Fast Actuation

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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. PMID:24110322

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. An arm wrestling robot driven by dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Kovacs, Gabor; Lochmatter, Patrick; Wissler, Michael

    2007-04-01

    The first arm wrestling match between a human arm and a robotic arm driven by electroactive polymers (EAP) was held at the EAPAD conference in 2005. The primary objective was to demonstrate the potential of the EAP actuator technology for applications in the field of robotics and bioengineering. The Swiss Federal Laboratories for Materials Testing and Research (Empa) was one of the three organizations participating in this competition. The robot presented by Empa was driven by a system of rolled dielectric elastomer (DE) actuators. Based on the calculated stress condition in the rolled actuator, a low number of pre-strained DE film wrappings were found to be preferential for achieving the best actuator performance. Because of the limited space inside the robot body, more than 250 rolled actuators with small diameters were arranged in two groups according to the human agonist-antagonist muscle configuration in order to achieve an arm-like bidirectional rotation movement. The robot was powered by a computer-controlled high voltage amplifier. The rotary motion of the arm was activated and deactivated electrically by corresponding actuator groups. The entire development process of the robot is presented in this paper where the design of the DE actuators is of primary interest. Although the robot lost the arm wrestling contest against the human opponent, the DE actuators have demonstrated very promising performance as artificial muscles. The scientific knowledge gained during the development process of the robot has pointed out the challenges to be addressed for future improvement in the performance of rolled dielectric elastomer actuators.

  2. Printing 3D dielectric elastomer actuators for soft robotics

    NASA Astrophysics Data System (ADS)

    Rossiter, Jonathan; Walters, Peter; Stoimenov, Boyko

    2009-03-01

    We present a new approach to the fabrication of soft dielectric elastomer actuators using a 3D printing process. Complete actuators including active membranes and support structures can be 3D printed in one go, resulting in a great improvement in fabrication speed and increases in accuracy and consistency. We describe the fabrication process and present force and displacement results for a double-membrane antagonistic actuator. In this structure controlled prestrain is applied by the simple process of pressing together two printed actuator halves. The development of 3D printable soft actuators will have a large impact on many application areas including engineering, medicine and the emerging field of soft robotics.

  3. Climbing robot actuated by meso-hydraulic artificial muscles

    NASA Astrophysics Data System (ADS)

    Bryant, Matthew; Fitzgerald, Jason; Miller, Samuel; Saltzman, Jonah; Kim, Sangkyu; Lin, Yong; Garcia, Ephrahim

    2014-03-01

    This paper presents the design, construction, experimental characterization, and system testing of a legged, wall-climbing robot actuated by meso-scale hydraulic artificial muscles. While small wall-climbing robots have seen increased research attention in recent years, most authors have primarily focused on designs for the gripping and adhesion of the robot to the wall, while using only standard DC servo-motors for actuation. This project seeks to explore and demonstrate a different actuation mechanism that utilizes hydraulic artificial muscles. A four-limb climbing robot platform that includes a full closed-loop hydraulic power and control system, custom hydraulic artificial muscles for actuation, an on-board microcontroller and RF receiver for control, and compliant claws with integrated sensing for gripping a variety of wall surfaces has been constructed and is currently being tested to investigate this actuation method. On-board power consumption data-logging during climbing operation, analysis of the robot kinematics and climbing behavior, and artificial muscle force-displacement characterization are presented to investigate and this actuation method.

  4. 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.

  5. 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

  6. A design concept of parallel elasticity extracted from biological muscles for engineered actuators.

    PubMed

    Chen, Jie; Jin, Hongzhe; Iida, Fumiya; Zhao, Jie

    2016-01-01

    Series elastic actuation that takes inspiration from biological muscle-tendon units has been extensively studied and used to address the challenges (e.g. energy efficiency, robustness) existing in purely stiff robots. However, there also exists another form of passive property in biological actuation, parallel elasticity within muscles themselves, and our knowledge of it is limited: for example, there is still no general design strategy for the elasticity profile. When we look at nature, on the other hand, there seems a universal agreement in biological systems: experimental evidence has suggested that a concave-upward elasticity behaviour is exhibited within the muscles of animals. Seeking to draw possible design clues for elasticity in parallel with actuators, we use a simplified joint model to investigate the mechanisms behind this biologically universal preference of muscles. Actuation of the model is identified from general biological joints and further reduced with a specific focus on muscle elasticity aspects, for the sake of easy implementation. By examining various elasticity scenarios, one without elasticity and three with elasticity of different profiles, we find that parallel elasticity generally exerts contradictory influences on energy efficiency and disturbance rejection, due to the mechanical impedance shift thus caused. The trade-off analysis between them also reveals that concave parallel elasticity is able to achieve a more advantageous balance than linear and convex ones. It is expected that the results could contribute to our further understanding of muscle elasticity and provide a theoretical guideline on how to properly design parallel elasticity behaviours for engineering systems such as artificial actuators and robotic joints. PMID:27550947

  7. 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.

  8. A novel compact compliant actuator design for rehabilitation robots.

    PubMed

    Yu, Haoyong; Huang, Sunan; Thakor, Nitish V; Chen, Gong; Toh, Siew-Lok; Sta Cruz, Manolo; Ghorbel, Yassine; Zhu, Chi

    2013-06-01

    Rehabilitation robots have direct physical interaction with human body. Ideally, actuators for rehabilitation robots should be compliant, force controllable, and back drivable due to safety and control considerations. Various designs of Series Elastic Actuators (SEA) have been developed for these applications. However, current SEA designs face a common performance limitation due to the compromise on the spring stiffness selection. This paper presents a novel compact compliant force control actuator design for portable rehabilitation robots to overcome the performance limitations in current SEAs. Our design consists of a servomotor, a ball screw, a torsional spring between the motor and the ball screw, and a set of translational springs between the ball screw nut and the external load. The soft translational springs are used to handle the low force operation and reduce output impedance, stiction, and external shock load. The torsional spring, being in the high speed range, has high effective stiffness and improves the system bandwidth in large force operation when the translational springs are fully compressed. This design is also more compact due to the smaller size of the springs. We explain the construction and the working principle of our new design, followed by the dynamic modeling and analysis of the actuator. We also show the preliminary testing results of a prototype actuator designed for a lower limb exoskeleton for gait rehabilitation.

  9. A swimming robot actuated by living muscle tissue.

    PubMed

    Herr, Hugh; Dennis, Robert G

    2004-10-28

    Biomechatronics is the integration of biological components with artificial devices, in which the biological component confers a significant functional capability to the system, and the artificial component provides specific cellular and tissue interfaces that promote the maintenance and functional adaptation of the biological component. Based upon functional performance, muscle is potentially an excellent mechanical actuator, but the larger challenge of developing muscle-actuated, biomechatronic devices poses many scientific and engineering challenges. As a demonstratory proof of concept, we designed, built, and characterized a swimming robot actuated by two explanted frog semitendinosus muscles and controlled by an embedded microcontroller. Using open loop stimulation protocols, the robot performed basic swimming maneuvers such as starting, stopping, turning (turning radius ~400 mm) and straight-line swimming (max speed >1/3 body lengths/second). A broad spectrum antibiotic/antimycotic ringer solution surrounded the muscle actuators for long term maintenance, ex vivo. The robot swam for a total of 4 hours over a 42 hour lifespan (10% duty cycle) before its velocity degraded below 75% of its maximum. The development of functional biomechatronic prototypes with integrated musculoskeletal tissues is the first critical step toward the long term objective of controllable, adaptive and robust biomechatronic robots and prostheses.

  10. Artificial heart for humanoid robot using coiled SMA actuators

    NASA Astrophysics Data System (ADS)

    Potnuru, Akshay; Tadesse, Yonas

    2015-03-01

    Previously, we have presented the design and characterization of artificial heart using cylindrical shape memory alloy (SMA) actuators for humanoids [1]. The robotic heart was primarily designed to pump a blood-like fluid to parts of the robot such as the face to simulate blushing or anger by the use of elastomeric substrates for the transport of fluids. It can also be used for other applications. In this paper, we present an improved design by using high strain coiled SMAs and a novel pumping mechanism that uses sequential actuation to create peristalsis-like motions, and hence pump the fluid. Various placements of actuators will be investigated with respect to the silicone elastomeric body. This new approach provides a better performance in terms of the fluid volume pumped.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Modeling liquid crystal elastomers: actuators, pumps, and robots

    NASA Astrophysics Data System (ADS)

    Selinger, Robin L. B.; Mbanga, Badel L.; Selinger, Jonathan V.

    2008-02-01

    We model the dynamics of shape evolution of liquid crystal elastomers (LCE) in three dimensions using finite element elastodynamics. The model predicts the macroscopic mechanical response induced by changes in nematic order, e.g. by heating or cooling through the isotropic/nematic transition or, in azo-doped materials, by exposure to light. We model the performance of LCE actuator devices including multicomponent actuators, peristaltic pumps and self-propelled robots. The goal of this work is to build a bridge between basic soft matter theory and practical materials engineering/device design. Supported by NSF-DMR-0605889.

  17. 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.

  18. 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.

  19. 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

  20. 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. PMID:26406072

  1. 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.

  2. A small biomimetic quadruped robot driven by multistacked dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Nguyen, Canh Toan; Phung, Hoa; Dat Nguyen, Tien; Lee, Choonghan; Kim, Uikyum; Lee, Donghyouk; Moon, Hyungpil; Koo, Jachoon; Nam, Jae-do; Ryeol Choi, Hyouk

    2014-06-01

    A kind of dielectric elastomer (DE) material, called ‘synthetic elastomer’, has been developed based on acrylonitrile butadiene rubber (NBR) to be used as a dielectric elastomer actuator (DEA). By stacking single layers of synthetic elastomer, a linear actuator, called a multistacked actuator, is produced, and used by mechatronic and robotic systems to generate linear motion. In this paper, we demonstrate the application of the multistacked dielectric elastomer actuator in a biomimetic legged robot. A miniature robot driven by a biomimetic actuation system with four 2-DOF (two-degree-of-freedom) legged mechanisms is realized. Based on the experimental results, we evaluate the performance of the proposed robot and validate the feasibility of the multistacked actuator in a locomotion system as a replacement for conventional actuators.

  3. EAP actuator design for biologically inspired face-based communication robots

    NASA Astrophysics Data System (ADS)

    Hanson, David F.

    2003-07-01

    This paper examines methods of developing electroactive polymer (EAP) actuators for actuating human-like facial expressions in sociable robots. EAP actuators could improve such robots in several ways - they could reduce the mechanical complexity of the robots and the robots' weight and power requirements, potentially leading to robots that are more robust, more easily manufactured and ideal for autonomous mobility. After a discussion of the state of the technique in UTD's face-based communication robots (the Identity Emulation robots project), this paper considers various EAP actuation technologies, and ways of adapting them towards use in these robots. Applications of this class of human-robot interface devices will rise in relevance as humans and robots begin to have more sociable encounters in the coming years. Key to success in this undertaking is the multi-modal integration of mechanics, sociable intelligence, and design aesthestics and dynamic stable mobility, and the innovation of skin materials that are lighter in weight and deformed with less force. Recent innovations in urethane polymers, described in this paper, have resulted in a humanoid facial skin that is actuated by considerably reduced force (16 to 20 oz.), relative to previously available skin polymers. These actuation requirements may put this facial expression technology within the capabilities of existing EAP actuation technologies.

  4. 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. PMID:21852714

  5. PD control for robot manipulators actuated by switched reluctance motors

    NASA Astrophysics Data System (ADS)

    Hernández-Guzmán, Victor M.; Carrillo-Serrano, Roberto V.; Silva-Ortigoza, Ramón

    2013-03-01

    This article is concerned with position regulation in direct-drive n degrees of freedom rigid robots equipped only with revolute joints when actuated by switched reluctance motors. Our controller represents an extension to this case of a previous work in the literature which was proposed for a single-switched reluctance motor when moving a simple linear mechanical load. We show how to avoid a singularity present in such a previous controller. We also introduce some simplifications since the number of terms to be fedback is smaller. Further, a linear proportional inner electric current loop is included instead of a velocity dependent one.

  6. 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. PMID:26923385

  7. 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.

  8. 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.

  9. 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.

  10. 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

  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.

  12. Comparison of parallel kinematic machines with three translational degrees of freedom and linear actuation

    NASA Astrophysics Data System (ADS)

    Prause, Isabel; Charaf Eddine, Sami; Corves, Burkhard

    2015-07-01

    The development of new robot structures, in particular of parallel kinematic machines(PKM), is widely systematized by different structure synthesis methods. Recent research increasingly focuses on PKM with less than six degrees of freedom(DOF). However, an overall comparison and evaluation of these structures is missing. In order to compare symmetrical PKM with three translational DOF, different evaluation criteria are used. Workspace, maximum actuation forces and velocities, power, actuator stiffness, accuracy and transmission behavior are taken into account to investigate strengths and weaknesses of the PKMs. A selection scheme based on possible configurations of translational PKM including different frame configurations is presented. Moreover, an optimization method based on a genetic algorithm is described to determine the geometric parameters of the selected PKM for an exemplary load case and a prescribed workspace. The values of the mentioned criteria are determined for all considered PKM with respect to certain boundary conditions. The distribution and spreading of these values within the prescribed workspace is presented by using box plots for each criterion. Thereby, the performance characteristics of the different structures can be compared directly. The results show that there is no "best" PKM. Further inquiries such as dynamic or stiffness analysis are necessary to extend the comparison and to finally select a PKM.

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

    PubMed Central

    Zheng, Hao; Shen, Xiangrong

    2014-01-01

    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. PMID:25264492

  14. 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.

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

    PubMed

    Raj, Aditi; Thakur, Atul

    2016-06-01

    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. PMID:27073001

  16. 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.

  17. 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. PMID:22550128

  18. 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.

  19. 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.

  20. Human-robot-interaction control for orthoses with pneumatic soft-actuators--concept and initial trails.

    PubMed

    Baiden, David; Ivlev, Oleg

    2013-06-01

    The purpose of this paper is to present a concept of human-robot-interaction control for robots with compliant pneumatic soft-actuators which are directly attached to the human body. Backdrivability of this type of actuators is beneficial for comfort and safety and they are well suitable to design rehabilitation robots for training of activities of daily living (ADL). The concept is verified with an application example of sit-to-stand tasks taking conventional treatment in neurology as reference. The focus is on stroke patients with a target group suffering from hemiplegia and paralysis in one half of the body. A 2 DOF exoskeleton robot was used as testbed to implement the control concept for supporting rising based on a master-slave position control such that movements from the fit leg are transferred to the affected leg. Furthermore the wearer of the robot has the possibility to adjust support for stabilizing the knee joint manually. Preliminary results are presented.

  1. 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.

  2. 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.

  3. 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.

  4. Trajectory control of an articulated robot with a parallel drive arm based on splines under tension

    NASA Astrophysics Data System (ADS)

    Yi, Seung-Jong

    Today's industrial robots controlled by mini/micro computers are basically simple positioning devices. The positioning accuracy depends on the mathematical description of the robot configuration to place the end-effector at the desired position and orientation within the workspace and on following the specified path which requires the trajectory planner. In addition, the consideration of joint velocity, acceleration, and jerk trajectories are essential for trajectory planning of industrial robots to obtain smooth operation. The newly designed 6 DOF articulated robot with a parallel drive arm mechanism which permits the joint actuators to be placed in the same horizontal line to reduce the arm inertia and to increase load capacity and stiffness is selected. First, the forward kinematic and inverse kinematic problems are examined. The forward kinematic equations are successfully derived based on Denavit-Hartenberg notation with independent joint angle constraints. The inverse kinematic problems are solved using the arm-wrist partitioned approach with independent joint angle constraints. Three types of curve fitting methods used in trajectory planning, i.e., certain degree polynomial functions, cubic spline functions, and cubic spline functions under tension, are compared to select the best possible method to satisfy both smooth joint trajectories and positioning accuracy for a robot trajectory planner. Cubic spline functions under tension is the method selected for the new trajectory planner. This method is implemented for a 6 DOF articulated robot with a parallel drive arm mechanism to improve the smoothness of the joint trajectories and the positioning accuracy of the manipulator. Also, this approach is compared with existing trajectory planners, 4-3-4 polynomials and cubic spline functions, via circular arc motion simulations. The new trajectory planner using cubic spline functions under tension is implemented into the microprocessor based robot controller and

  5. Design and development of miniature parallel robot for eye surgery.

    PubMed

    Sakai, Tomoya; Harada, Kanako; Tanaka, Shinichi; Ueta, Takashi; Noda, Yasuo; Sugita, Naohiko; Mitsuishi, Mamoru

    2014-01-01

    A five degree-of-freedom (DOF) miniature parallel robot has been developed to precisely and safely remove the thin internal limiting membrane in the eye ground during vitreoretinal surgery. A simulator has been developed to determine the design parameters of this robot. The developed robot's size is 85 mm × 100 mm × 240 mm, and its weight is 770 g. This robot incorporates an emergency instrument retraction function to quickly remove the instrument from the eye in case of sudden intraoperative complications such as bleeding. Experiments were conducted to evaluate the robot's performance in the master-slave configuration, and the results demonstrated that it had a tracing accuracy of 40.0 μm.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Differential-damper topologies for actuators in rehabilitation robotics.

    PubMed

    Tucker, Michael R; Gassert, Roger

    2012-01-01

    Differential-damper (DD) elements can provide a high bandwidth means for decoupling a high inertia, high friction, non-backdrivable actuator from its output and can enable high fidelity force control. In this paper, a port-based decomposition is used to analyze the energetic behavior of such actuators in various physical domains. The general concepts are then applied to a prototype DD actuator for illustration and discussion. It is shown that, within physical bounds, the output torque from a DD actuator can be controlled independently from the input speed. This concept holds the potential to be scaled up and integrated in a compact and lightweight package powerful enough for incorporation with a portable lower limb orthotic or prosthetic device. PMID:23366576

  11. Analysing the reliability of actuation elements in series and parallel configurations for high-redundancy actuation

    NASA Astrophysics Data System (ADS)

    Steffen, Thomas; Schiller, Frank; Blum, Michael; Dixon, Roger

    2013-08-01

    A high-redundancy actuator (HRA) is an actuation system composed of a high number of actuation elements, increasing both travel and force above the capability of an individual element. This approach provides inherent fault tolerance: if one of the elements fails, the capabilities of the whole actuator may be reduced, but it retains core functionality. Many different configurations are possible, with different implications for the actuator capability and reliability. This article analyses the reliability of the HRA based on the likelihood of an unacceptable reduction in capability. The analysis of the HRA is a highly structured problem, but it does not fit into known reliability categories (such as the k-out-of-n system), and a fault-tree analysis becomes prohibitively large. Instead, a multi-state systems approach is pursued here, which provides an easy, concise and efficient reliability analysis of the HRA. The resulting probability distribution can be used to find the optimal configuration of an HRA for a given set of requirements.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

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

    PubMed

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

    2016-01-01

    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. PMID:27367548

  20. 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.

  1. 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.

  2. Pre-distorted sinewave-driven parallel-plate electrostatic actuator for harmonic displacement

    NASA Astrophysics Data System (ADS)

    de Graaf, G.; Mol, L.; Rocha, L. A.; Cretu, E.; Wolffenbuttel, R. F.

    2005-07-01

    Harmonic displacement of a parallel-plate electrostatic actuator up to 50% of the static pull-in displacement has been achieved despite the non-linear voltage-to-displacement function using a driving voltage with a pre-distorted waveform. The microstructure is fabricated in an epi-poly process and the circuit is implemented in a CMOS process and designed for operation of the MEMS in a frequency range up to 1 kHz. The pre-distorted waveform is synthesized using 16 samples per period with 16 non-uniformly spaced quantization levels, using a ladder with accurately scaled resistors. Harmonic actuation has been demonstrated with 34 dB reduction of second-order distortion compared to systems with sinusoidal actuation. The residual second harmonic content in the harmonic displacement is typically -42 dB.

  3. A starfish robot based on soft and smart modular structure (SMS) actuated by SMA wires.

    PubMed

    Jin, Hu; Dong, Erbao; Alici, Gursel; Mao, Shixin; Min, Xu; Liu, Chunshan; Low, K H; Yang, Jie

    2016-09-09

    This paper describes the design, fabrication and locomotion of a starfish robot whose locomotion principle is derived from a starfish. The starfish robot has a number of tentacles or arms extending from its central body in the form of a disk, like the topology of a real starfish. The arm, which is a soft and composite structure (which we call the smart modular structure (SMS)) generating a planar reciprocal motion with a high speed of response upon the actuation provided by the shape memory alloy (SMA) wires, is fabricated from soft and smart materials. Based on the variation in the resistance of the SMA wires during their heating, an adaptive regulation (AR) heating strategy is proposed to (i) avoid overheating of the SMA wires, (ii) provide bending range control and (iii) achieve a high speed of response favorable to successfully propelling the starfish robot. Using a finite-segment method, a thermal dynamic model of the SMS is established to describe its thermal behavior under the AR and a constant heating strategy. A starfish robot with five SMS tentacles was tested with different control parameters to optimize its locomotion speed. As demonstrated in the accompanying video file, the robot successfully propelled in semi-submerged and underwater environments show its locomotion ability in the multi-media, like a real starfish. The propulsion speed of the starfish robot is at least an order of magnitude higher than that of those reported in the literature-thanks to the SMS controlled with the AR strategy.

  4. 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.

  5. A starfish robot based on soft and smart modular structure (SMS) actuated by SMA wires.

    PubMed

    Jin, Hu; Dong, Erbao; Alici, Gursel; Mao, Shixin; Min, Xu; Liu, Chunshan; Low, K H; Yang, Jie

    2016-01-01

    This paper describes the design, fabrication and locomotion of a starfish robot whose locomotion principle is derived from a starfish. The starfish robot has a number of tentacles or arms extending from its central body in the form of a disk, like the topology of a real starfish. The arm, which is a soft and composite structure (which we call the smart modular structure (SMS)) generating a planar reciprocal motion with a high speed of response upon the actuation provided by the shape memory alloy (SMA) wires, is fabricated from soft and smart materials. Based on the variation in the resistance of the SMA wires during their heating, an adaptive regulation (AR) heating strategy is proposed to (i) avoid overheating of the SMA wires, (ii) provide bending range control and (iii) achieve a high speed of response favorable to successfully propelling the starfish robot. Using a finite-segment method, a thermal dynamic model of the SMS is established to describe its thermal behavior under the AR and a constant heating strategy. A starfish robot with five SMS tentacles was tested with different control parameters to optimize its locomotion speed. As demonstrated in the accompanying video file, the robot successfully propelled in semi-submerged and underwater environments show its locomotion ability in the multi-media, like a real starfish. The propulsion speed of the starfish robot is at least an order of magnitude higher than that of those reported in the literature-thanks to the SMS controlled with the AR strategy. PMID:27609700

  6. 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.

  7. A 3-DOF parallel robot with spherical motion for the rehabilitation and evaluation of balance performance.

    PubMed

    Patanè, Fabrizio; Cappa, Paolo

    2011-04-01

    In this paper a novel electrically actuated parallel robot with three degrees-of-freedom (3 DOF) for dynamic postural studies is presented. The design has been described, the solution to the inverse kinematics has been found, and a numerical solution for the direct kinematics has been proposed. The workspace of the implemented robot is characterized by an angular range of motion of about ±10° for roll and pitch when yaw is in the range ±15°. The robot was constructed and the orientation accuracy was tested by means of an optoelectronic system and by imposing a sinusoidal input, with a frequency of 1 Hz and amplitude of 10°, along the three axes, in sequence. The collected data indicated a phase delay of 1° and an amplitude error of 0.5%-1.5%; similar values were observed for cross-axis sensitivity errors. We also conducted a clinical application on a group of normal subjects, who were standing in equilibrium on the robot base with eyes open (EO) and eyes closed (EC), which was rotated with a tri-axial sinusoidal trajectory with a frequency of 0.5 Hz and amplitude 5° for roll and pitch and 10° for the yaw. The postural configuration of the subjects was recorded with an optoelectronic system. However, due to the mainly technical nature of this paper, only initial validation outcomes are reported here. The clinical application showed that only the tilt and displacement on the sagittal pane of head, trunk, and pelvis in the trials conducted with eyes closed were affected by drift and that the reduction of the yaw rotation and of the mediolateral translation was not a controlled parameter, as happened, instead, for the other anatomical directions.

  8. 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.

  9. 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.

  10. Reproduction of in vivo motion using a parallel robot.

    PubMed

    Howard, Ryan A; Rosvold, Joshua M; Darcy, Shon P; Corr, David T; Shrive, Nigel G; Tapper, Janet E; Ronsky, Janet L; Beveridge, Jillian E; Marchuk, Linda L; Frank, Cyril B

    2007-10-01

    Although alterations in knee joint loading resulting from injury have been shown to influence the development of osteoarthritis, actual in vivo loading conditions of the joint remain unknown. A method for determining in vivo ligament loads by reproducing joint specific in vivo kinematics using a robotic testing apparatus is described. The in vivo kinematics of the ovine stifle joint during walking were measured with 3D optical motion analysis using markers rigidly affixed to the tibia and femur. An additional independent single degree of freedom measuring device was also used to record a measure of motion. Following sacrifice, the joint was mounted in a robotic/universal force sensor test apparatus and referenced using a coordinate measuring machine. A parallel robot configuration was chosen over the conventional serial manipulator because of its greater accuracy and stiffness. Median normal gait kinematics were applied to the joint and the resulting accuracy compared. The mean error in reproduction as determined by the motion analysis system varied between 0.06 mm and 0.67 mm and 0.07 deg and 0.74 deg for the two individual tests. The mean error measured by the independent device was found to be 0.07 mm and 0.83 mm for the two experiments, respectively. This study demonstrates the ability of this system to reproduce in vivo kinematics of the ovine stifle joint in vitro. The importance of system stiffness is discussed to ensure accurate reproduction of joint motion. PMID:17887900

  11. Use of spring-roll EAP actuator applied as end-effector of a hyper-redundant robot

    NASA Astrophysics Data System (ADS)

    Errico, Gianmarco; Fava, Victor; Resta, Ferruccio; Ripamonti, Francesco

    2015-04-01

    This paper presents a hyper-redundant continuous robot used to perform work in places which humans can not reach. This type of robot is generally a bio-inspired solution, it is composed by a lot of flexible segments driven by multiple actuators and its dynamics is described by a lot degrees of freedom. In this paper a model composed of some rigid links connected to each other by revolution joint is presented. In each link a torsional spring is added in order to simulate the resistant torque between the links and the interactions among the cables and the robot during the relative rotation. Moreover a type of EAP actuator, called spring roll, is used as the end-effector of the robot. Through a suitable sensor, such as a camera, the spring roll allows to track a target and it closes the control loop on the robot to follow it.

  12. 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. PMID:22254624

  13. 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.

  14. Microfabrication of Three-Axis Tactile Feedback Actuator for Robot-Assisted Surgery

    NASA Astrophysics Data System (ADS)

    Doh, Eunhyup; Yoo, Jihyung; Lee, Hyungkew; Park, Joonah; Yun, Kwang-Seok

    2013-01-01

    In this paper, we propose and demonstrate a three-axis tactile feedback actuator using pneumatic balloons for human perception applications such as robot-assisted surgery systems. A tactile actuator is composed of a center structure having four balloons, sidewalls with one lateral balloon on each sidewall, and a bottom structure supporting the center structure. We fabricated the proposed device using flexible poly(dimethylsiloxane) and hard polyurethane with final dimensions of 18 ×18 ×18 mm3. The four balloons on the center structure produce normal tactile display during pneumatic-pressure-assisted inflation. The lateral movement of the center structure driven by sidewall balloons generates a shear tactile display on fingertips. The center deflections of the circular and rectangular balloons were calculated and measured experimentally.

  15. 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.

  16. Mesoscale MEMS motion transformer and amplifier electrostatically actuated by parallel plate electrodes

    NASA Astrophysics Data System (ADS)

    Gerson, Y.; Nachmias, T.; Maimon, R.; Krylov, S.

    2015-05-01

    We report on the design, fabrication and characterization of a mesoscale microelectromechanical motion transformer and amplifier with integrated actuation. The device incorporates an electrostatic transducer with multiple parallel plate electrodes and an elastic suspension realized as a compliant mechanism, which converts small linear motion of the transducer into mechanically amplified angular motion of a rotating lever. By combining highly efficient small-gap actuation with the motion amplification the device is designed to provide a large, more than 60 µm, lever tip displacement along with a calculated blocking force increasing from the initial value of 0.8 mN up to 26 mN in the maximal stroke configuration when actuated at 150 V. The devices were fabricated from a silicon on insulator (SOI) wafer with (1 1 1) front surface orientation and a 150 µm thick device layer using deep reactive ion etching (DRIE) and their functionality was demonstrated experimentally. Good agreement between the results provided by finite elements analysis and the experimental data was observed. Our results demonstrate an ability to achieve both large displacements and high blocking forces in an electrostatically actuated mesoscale compliant mechanisms.

  17. 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.

  18. 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.

  19. 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.

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

    PubMed Central

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

    2016-01-01

    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.

  1. 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.

  2. 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).

  3. 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

  4. 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

  5. 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.

  6. A jellyfish-inspired jet propulsion robot actuated by an iris mechanism

    NASA Astrophysics Data System (ADS)

    Marut, Kenneth; Stewart, Colin; Michael, Tyler; Villanueva, Alex; Priya, Shashank

    2013-09-01

    A jellyfish-inspired jet propulsion robot (JetPRo) is designed, fabricated, and characterized with the objective of creating a fast-swimming uncrewed undersea vehicle. JetPRo measures 7.9 cm in height, 5.7 cm in diameter and is designed to mimic the proficient jetting propulsion mechanism used by the hydromedusa Sarsia tubulosa, which measures approximately 1 cm in diameter. In order to achieve the uniform-bell contraction used by S. tubulosa, we develop a novel circumferential actuation technique based on a mechanical iris diaphragm. When triggered, this mechanism induces a volumetric change of a deformable silicone cavity to expel a jet of fluid and produces positive thrust. A theoretical jetting model is used to optimize JetPRo’s gait for maximum steady-state swimming velocity, a result achieved by minimizing the timing between the contraction and relaxation phases. We validate this finding empirically and quantify the swimming performance of the robot using video tracking and time resolved digital particle image velocimetry. JetPRo was able to produce discrete vortex rings shed before pinch off and swim upwards with a maximum steady-state velocity of 11.6 cm s-1, outperforming current state-of-the-art robotic jellyfish in velocity as well as diameter-normalized velocity.

  7. Piezo-actuated parallel mechanism for biological cell release at high speed.

    PubMed

    Avci, Ebubekir; Hattori, Takayuki; Kamiyama, Kazuto; Kojima, Masaru; Horade, Mitsuhiro; Mae, Yasushi; Arai, Tatsuo

    2015-10-01

    In this paper, a dynamic releasing approach is proposed for high-speed biological cell manipulation. A compact parallel mechanism for grasping and releasing microobjects is used to generate controllable vibration to overcome the strong adhesion forces between the end effector and the manipulated object. To reach the required acceleration of the end effector, which is necessary for the detachment of the target object by overcoming adhesion forces, vibration in the end effector is generated by applying sinusoidal voltage to the PZT actuator of the parallel mechanism. For the necessary acceleration, we focus on the possible range of the frequency of the PZT-actuator-induced vibration, while minimizing the amplitude of the vibration (14 nm) to achieve precise positioning. The effect of the air and liquid environments on the required vibration frequency for successful release is investigated. For the first time, release results of microbeads and biological cells are compared. Release of the biological cells with 100 % success rate suggests that the proposed active release method is an appropriate solution for adhered biological cells during the release task.

  8. Numerical Simulations of Level-Ground Walking Based on Passive Walk for Planar Biped Robots with Torso by Hip Actuators

    NASA Astrophysics Data System (ADS)

    Narukawa, Terumasa; Takahashi, Masaki; Yoshida, Kazuo

    This study aims at a design technique of energy-efficient biped walking robots on level ground with simple mechanisms. To do this, we focus on the passive dynamic walkers which can walk stably down a shallow slope without actuators and controllers. On level ground, active walking should be studied because the mechanical energy is mainly lost through the swing-leg impacts with the ground. In this paper, numerical simulations show that planar biped robots with torso can walk efficiently on level ground over a wide range of speed by only using hip actuators. The hip actuators are used for a torso and swing-leg control based on passive-dynamic walking. The torso is used to generate active power replacing gravity used in the case of the passive walk. The swing-leg control is introduced to walk stably over a wide range of speed.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Modeling and motion compensation of a bidirectional tendon-sheath actuated system for robotic endoscopic surgery.

    PubMed

    Sun, Zhenglong; Wang, Zheng; Phee, Soo Jay

    2015-04-01

    Recent study shows that tendon-sheath system (TSS) has great potential in the development of surgical robots for endoscopic surgery. It is able to deliver adequate power in a light-weight and compact package. And the flexibility and compliance of the tendon-sheath system make it capable of adapting to the long and winding path in the flexible endoscope. However, the main difficulties in precise control of such system fall on the nonlinearities of the system behavior and absence of necessary sensory feedback at the surgical end-effectors. Since accurate position control of the tool is a prerequisite for efficacy, safety and intuitive user-experience in robotic surgery, in this paper we propose a system modeling approach for motion compensation. Based on a bidirectional actuated system using two separate tendon-sheaths, motion transmission is firstly characterized. Two types of positional errors due to system backlash and environment loading are defined and modeled. Then a model-based feedforward compensation method is proposed for open-loop control, giving the system abilities to adjust according to changes in the transmission route configuration without any information feedback from the distal end. A dedicated experimental platform emulating a bidirectional TSS robotic system for endoscopic surgery is built for testing. Proposed positional errors are identified and verified. The performance of the proposed motion compensation is evaluated by trajectory tracking under different environment loading conditions. And the results demonstrate that accurate position control can be achieved even if the transmission route configuration is updated. PMID:25819033

  14. Possibility of application of small-size robots with vibratory piezoelectric actuators for inspection of physical state of surfaces

    NASA Astrophysics Data System (ADS)

    Stepanenko, D. A.; Minchenya, V. T.; Asimov, R. M.; Zimmermann, K.

    2012-05-01

    The article describes design and principle of control of small-size inspection robot with vibratory piezoelectric actuator and possibility of its application for non-destructive evaluation (NDE). Controlled movement of robot is implemented using single bimorph piezoelement by means of frequency control of electric voltage applied to piezoelement. Such scheme of control is realized as a result of application of structural asymmetry principle consisting in relative shift of resonant characteristics of robot supporting elements (legs) by means of imparting geometric asymmetry to them. During movement of robot upon inspected surface each of its legs excites in substrate elastic waves which can be registered by another robot as a consequence of piezoelectric effect reversibility. As a result group of communicating robots (robotic swarm) will be able to distribute over the surface of inspected object and perform its multiagent control. This will give possibility to accelerate and simplify inspection of large and geometrically-complex objects. Autonomy and compactness of the described robots will also make reasonable their application for NDE of hard-to-access surfaces and potentially hazardous objects.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Error modeling and sensitivity analysis of a parallel robot with SCARA(selective compliance assembly robot arm) motions

    NASA Astrophysics Data System (ADS)

    Chen, Yuzhen; Xie, Fugui; Liu, Xinjun; Zhou, Yanhua

    2014-07-01

    Parallel robots with SCARA(selective compliance assembly robot arm) motions are utilized widely in the field of high speed pick-and-place manipulation. Error modeling for these robots generally simplifies the parallelogram structures included by the robots as a link. As the established error model fails to reflect the error feature of the parallelogram structures, the effect of accuracy design and kinematic calibration based on the error model come to be undermined. An error modeling methodology is proposed to establish an error model of parallel robots with parallelogram structures. The error model can embody the geometric errors of all joints, including the joints of parallelogram structures. Thus it can contain more exhaustively the factors that reduce the accuracy of the robot. Based on the error model and some sensitivity indices defined in the sense of statistics, sensitivity analysis is carried out. Accordingly, some atlases are depicted to express each geometric error's influence on the moving platform's pose errors. From these atlases, the geometric errors that have greater impact on the accuracy of the moving platform are identified, and some sensitive areas where the pose errors of the moving platform are extremely sensitive to the geometric errors are also figured out. By taking into account the error factors which are generally neglected in all existing modeling methods, the proposed modeling method can thoroughly disclose the process of error transmission and enhance the efficacy of accuracy design and calibration.

  1. Validation of computational models and a new experimental facility of a robot actuator using twin electro-rheological clutches

    NASA Astrophysics Data System (ADS)

    Johnson, Andrew R.; Stanway, Roger

    2005-05-01

    Flexibility and speed of response are two key requirements in the design of machinery for high-speed manufacturing operations. These two requirements are often conflicting and their resolution requires considerable ingenuity on the part of the designer. A novel actuator based upon the use of twin electro-rheological (ER) clutches is described together with its modification to control the motion (angular displacement, angular velocity) of a robot manipulator arm. The development of a new experimental facility involving the robot manipulator arm is described. In the basic twin ER clutch facility, the motion of a toothed belt is controlled by manipulating the electric field applied to each ER clutch. The belt, in turn, controls the angular position and velocity of the robot arm. The use of twin clutches allows motion to be imparted in opposite directions without the need for return springs or similar mechanisms. To improve the positional performance an ER brake is added to the robot arm mechanism. The extension to the dynamic model for the ER clutch mechanism to incorporate the robot arm and ER brake is outlined and is validated experimentally. The displacement response of the robot arm is then examined as a trend study using different motor driving speeds. The positional accuracy of the robot arm and its repeatability is then demonstrated.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    Lee, J.; Kim, K.

    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.

  8. 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.

  9. 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.

  10. 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.

  11. New methods in combinatorial chemistry-robotics and parallel synthesis.

    PubMed

    Cargill, J F; Lebl, M

    1997-06-01

    Technological advances in the automation of parallel synthesis are following the model set by the semiconductor industry: miniaturization, increasing speed, lower costs. Recent work includes preparation of high-density reaction blocks, development of ink-jet dispensing to polypropylene sheets and synthesis inside customized microchips.

  12. The parallel approach to force/position control of robotic manipulators

    SciTech Connect

    Chiaverini, S.; Sciavicco, L.

    1993-08-01

    Force/position control strategies provide an effective framework to deal with tasks involving interaction with the environment. In this paper the parallel approach to force/position control of robotic manipulators is presented. It allows a complete use of the available sensor measurements by operating the control action in a full-dimensional space without using selection matrices. Conflicting situations between the position and force tasks are managed using a priority strategy: the force control loop is designed to prevail over the position control loop. This choice ensures limited deviations from the prescribed force trajectory in every situation, guaranteeing automatic recovery from unplanned collisions. A dynamic force/position parallel control law is presented and its performance in presence of an elastic environment is analyzed; simplification of the dynamic control law is also discussed leading to a PID-type parallel controller. Two case studies are worked out that show the effectiveness of the approach in application to an industrial robot.

  13. 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.

  14. 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.

  15. 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.

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

    PubMed

    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

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

    PubMed

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

    2015-12-03

    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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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. PMID:23366645

  3. 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.

  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. 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.

  6. Robot-assisted ultrasound imaging: overview and development of a parallel telerobotic system.

    PubMed

    Monfaredi, Reza; Wilson, Emmanuel; Azizi Koutenaei, Bamshad; Labrecque, Brendan; Leroy, Kristen; Goldie, James; Louis, Eric; Swerdlow, Daniel; Cleary, Kevin

    2015-02-01

    Ultrasound imaging is frequently used in medicine. The quality of ultrasound images is often dependent on the skill of the sonographer. Several researchers have proposed robotic systems to aid in ultrasound image acquisition. In this paper we first provide a short overview of robot-assisted ultrasound imaging (US). We categorize robot-assisted US imaging systems into three approaches: autonomous US imaging, teleoperated US imaging, and human-robot cooperation. For each approach several systems are introduced and briefly discussed. We then describe a compact six degree of freedom parallel mechanism telerobotic system for ultrasound imaging developed by our research team. The long-term goal of this work is to enable remote ultrasound scanning through teleoperation. This parallel mechanism allows for both translation and rotation of an ultrasound probe mounted on the top plate along with force control. Our experimental results confirmed good mechanical system performance with a positioning error of < 1 mm. Phantom experiments by a radiologist showed promising results with good image quality.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Characterization of robotics parallel algorithms and mapping onto a reconfigurable SIMD machine

    NASA Technical Reports Server (NTRS)

    Lee, C. S. G.; Lin, C. T.

    1989-01-01

    The kinematics, dynamics, Jacobian, and their corresponding inverse computations are six essential problems in the control of robot manipulators. Efficient parallel algorithms for these computations are discussed and analyzed. Their characteristics are identified and a scheme on the mapping of these algorithms to a reconfigurable parallel architecture is presented. Based on the characteristics including type of parallelism, degree of parallelism, uniformity of the operations, fundamental operations, data dependencies, and communication requirement, it is shown that most of the algorithms for robotic computations possess highly regular properties and some common structures, especially the linear recursive structure. Moreover, they are well-suited to be implemented on a single-instruction-stream multiple-data-stream (SIMD) computer with reconfigurable interconnection network. The model of a reconfigurable dual network SIMD machine with internal direct feedback is introduced. A systematic procedure internal direct feedback is introduced. A systematic procedure to map these computations to the proposed machine is presented. A new scheduling problem for SIMD machines is investigated and a heuristic algorithm, called neighborhood scheduling, that reorders the processing sequence of subtasks to reduce the communication time is described. Mapping results of a benchmark algorithm are illustrated and discussed.

  12. 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.

  13. New methodology for multi-dimensional spinal joint testing with a parallel robot.

    PubMed

    Walker, Matthew R; Dickey, James P

    2007-03-01

    Six degree-of-freedom (6DOF) robots can be used to examine joints and their mechanical properties with the spatial freedom encountered physiologically. Parallel robots are capable of 6DOF motion under large payloads making them ideal for joint testing. This study developed and assessed novel methods for spinal joint testing with a custom-built parallel robot implementing hybrid load-position control. We hypothesized these methods would allow multi-dimensional control of joint loading scenarios, resulting in physiological joint motions. Tests were performed in 3DOF and 6DOF. 3DOF methods controlled the forces and the principal moment within +/-10 N and 0.25 N m under combined bending and compressive loads. 6DOF tests required larger tolerances for convergence due to machine compliance, however expected motion patterns were still observed. The unique mechanism and control approaches show promise for enabling complex three-dimensional loading patterns for in vitro joint biomechanics, and could facilitate research using specimens with unknown, changing, or nonlinear load-deformation properties. PMID:17235615

  14. 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).

  15. 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). PMID:22535882

  16. Gait simulation via a 6-DOF parallel robot with iterative learning control.

    PubMed

    Aubin, Patrick M; Cowley, Matthew S; Ledoux, William R

    2008-03-01

    We have developed a robotic gait simulator (RGS) by leveraging a 6-degree of freedom parallel robot, with the goal of overcoming three significant challenges of gait simulation, including: 1) operating at near physiologically correct velocities; 2) inputting full scale ground reaction forces; and 3) simulating motion in all three planes (sagittal, coronal and transverse). The robot will eventually be employed with cadaveric specimens, but as a means of exploring the capability of the system, we have first used it with a prosthetic foot. Gait data were recorded from one transtibial amputee using a motion analysis system and force plate. Using the same prosthetic foot as the subject, the RGS accurately reproduced the recorded kinematics and kinetics and the appropriate vertical ground reaction force was realized with a proportional iterative learning controller. After six gait iterations the controller reduced the root mean square (RMS) error between the simulated and in situ; vertical ground reaction force to 35 N during a 1.5 s simulation of the stance phase of gait with a prosthetic foot. This paper addresses the design, methodology and validation of the novel RGS. PMID:18334421

  17. Gait simulation via a 6-DOF parallel robot with iterative learning control.

    PubMed

    Aubin, Patrick M; Cowley, Matthew S; Ledoux, William R

    2008-03-01

    We have developed a robotic gait simulator (RGS) by leveraging a 6-degree of freedom parallel robot, with the goal of overcoming three significant challenges of gait simulation, including: 1) operating at near physiologically correct velocities; 2) inputting full scale ground reaction forces; and 3) simulating motion in all three planes (sagittal, coronal and transverse). The robot will eventually be employed with cadaveric specimens, but as a means of exploring the capability of the system, we have first used it with a prosthetic foot. Gait data were recorded from one transtibial amputee using a motion analysis system and force plate. Using the same prosthetic foot as the subject, the RGS accurately reproduced the recorded kinematics and kinetics and the appropriate vertical ground reaction force was realized with a proportional iterative learning controller. After six gait iterations the controller reduced the root mean square (RMS) error between the simulated and in situ; vertical ground reaction force to 35 N during a 1.5 s simulation of the stance phase of gait with a prosthetic foot. This paper addresses the design, methodology and validation of the novel RGS.

  18. Graphene fibers with predetermined deformation as moisture-triggered actuators and robots.

    PubMed

    Cheng, Huhu; Liu, Jia; Zhao, Yang; Hu, Chuangang; Zhang, Zhipan; Chen, Nan; Jiang, Lan; Qu, Liangti

    2013-09-27

    Enough to make your hair curl! Moisture-responsive graphene (G) fibers can be prepared by the positioned laser reduction of graphene oxide (GO) counterparts. When exposed to moisture, the asymmetric G/GO fibers display complex, well-controlled motion/deformation in a predetermined manner. These fibers can function not only as a single-fiber walking robot under humidity alternation but also as a new platform for woven devices and smart textiles. PMID:23946272

  19. 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

  20. An inexpensive method for kinematic calibration of a parallel robot by using one hand-held camera as main sensor.

    PubMed

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

    2013-08-05

    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.

  1. A parallel expert system for the control of a robotic air vehicle

    NASA Technical Reports Server (NTRS)

    Shakley, Donald; Lamont, Gary B.

    1988-01-01

    Expert systems can be used to govern the intelligent control of vehicles, for example the Robotic Air Vehicle (RAV). Due to the nature of the RAV system the associated expert system needs to perform in a demanding real-time environment. The use of a parallel processing capability to support the associated expert system's computational requirement is critical in this application. Thus, algorithms for parallel real-time expert systems must be designed, analyzed, and synthesized. The design process incorporates a consideration of the rule-set/face-set size along with representation issues. These issues are looked at in reference to information movement and various inference mechanisms. Also examined is the process involved with transporting the RAV expert system functions from the TI Explorer, where they are implemented in the Automated Reasoning Tool (ART), to the iPSC Hypercube, where the system is synthesized using Concurrent Common LISP (CCLISP). The transformation process for the ART to CCLISP conversion is described. The performance characteristics of the parallel implementation of these expert systems on the iPSC Hypercube are compared to the TI Explorer implementation.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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

  8. A novel testing platform for assessing knee joint mechanics: a parallel robotic system combined with an instrumented spatial linkage.

    PubMed

    Atarod, Mohammad; Rosvold, Joshua M; Frank, Cyril B; Shrive, Nigel G

    2014-05-01

    Assessing joint function following trauma and its inter-relation with degenerative changes requires an understanding of the normal state of structural loading in the joint. Very few studies have attempted to reproduce joint specific in vivo motions in vitro to quantify the actual loads carried by different tissues within the knee joint. The most significant challenge in this area is the very high sensitivity of the loads in joint structures to motion reproduction accuracy. A novel testing platform for assessing knee joint mechanics is described, comprised of a highly accurate (0.3 ± 0.1 mm, 0.3 ± 0.1°) six-degree-of-freedom (6-DOF) instrumented spatial linkage (ISL) for in vivo joint kinematic assessments and a unique 6-DOF parallel robotic manipulator. A position feedback system (ISL and position controller) is used for accurate reproduction of in vivo joint motions and estimation of "in situ" joint/tissue loads. The parallel robotic manipulator provides excellent stiffness and repeatability in reproducing physiological motions in 6-DOF, compared to the commonly used serial robots. The position feedback system provides real-time feedback data to the robot to reproduce in vivo motions and significantly enhances motion reproduction accuracy by adjusting for robot end-effector movements. Using this combined robot-ISL system, in vivo motions can be reproduced in vitro with very high accuracy (0.1 mm, 0.1°). Our results indicate that this level of accuracy is essential for meaningful estimation of tissue loads during gait. Using this novel testing platform, we have determined the normal load-carrying characteristics of different tissues within the ovine knee joint. The application of this testing system will continue to increase our understanding of normal and pathological joint states. PMID:24519725

  9. 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.

  10. 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.

  11. Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device

    PubMed Central

    2011-01-01

    Background Variable structure parallel mechanisms, actuated with low-cost motors with serially added elasticity (series elastic actuator - SEA), has considerable potential in rehabilitation robotics. However, reflected masses of a SEA and variable structure parallel mechanism linked with a compliant actuator result in a potentially unstable coupled mechanical oscillator, which has not been addressed in previous studies. Methods The aim of this paper was to investigate through simulation, experimentation and theoretical analysis the necessary conditions that guarantee stability and passivity of a haptic device (based on a variable structure parallel mechanism driven by SEA actuators) when in contact with a human. We have analyzed an equivalent mechanical system where a dissipative element, a mechanical damper was placed in parallel to a spring in SEA. Results The theoretical analysis yielded necessary conditions relating the damping coefficient, spring stiffness, both reflected masses, controller's gain and desired virtual impedance that needs to be fulfilled in order to obtain stable and passive behavior of the device when in contact with a human. The validity of the derived passivity conditions were confirmed in simulations and experimentally. Conclusions These results show that by properly designing variable structure parallel mechanisms actuated with SEA, versatile and affordable rehabilitation robotic devices can be conceived, which may facilitate their wide spread use in clinical and home environments. PMID:21251299

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Applications of dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Pelrine, Ron; Sommer-Larsen, Peter; Kornbluh, Roy D.; Heydt, Richard; Kofod, Guggi; Pei, Qibing; Gravesen, Peter

    2001-07-01

    Dielectric elastomer actuators, based on the field-induced deformation of elastomeric polymers with compliant electrodes, can produce a large strain response, combined with a fast response time and high electromechanical efficiency. This unique performance, combined with other factors such as low cost, suggests many potential applications, a wide range of which are under investigation. Applications that effectively exploit the properties of dielectric elastomers include artificial muscle actuators for robots; low-cost, lightweight linear actuators; solid- state optical devices; diaphragm actuators for pumps and smart skins; acoustic actuators; and rotary motors. Issues that may ultimately determine the success or failure of the actuation technology for specific applications include the durability of the actuator, the performance of the actuator under load, operating voltage and power requirements, and electronic driving circuitry, to name a few.

  17. A pediatric robotic thumb exoskeleton for at-home rehabilitation: the Isolated Orthosis for Thumb Actuation (IOTA).

    PubMed

    Aubin, Patrick M; Sallum, Hani; Walsh, Conor; Stirling, Leia; Correia, Annette

    2013-06-01

    In this paper, we present the design of a thumb exoskeleton for pediatric at-home rehabilitation. Pediatric disorders, such as cerebral palsy (CP) and stroke, can result in thumb in palm deformity greatly limiting hand function. This not only limits children's ability to perform activities of daily living but also limits important motor skill development. Specifically, the device, dubbed IOTA (Isolated Orthosis for Thumb Actuation) is a 2-DOF thumb exoskeleton that can actuate the carpometacarpal (CMC) and metacarpalphalangeal (MCP) joints through ranges of motion required for activities of daily living. The device consists of a lightweight hand-mounted mechanism that can be custom secured and aligned to the wearer. The mechanism is actuated via flexible cables that connect to a portable control box. Embedded encoders and bend sensors monitor the two degrees of freedom of the thumb and flexion/extension of the wrist. Using this platform, a number of control modes can be implemented that will enable the device to be intuitively controlled by a patient to assist with opposition grasp, fine motor control, and ultimately facilitate motor recovery. We envision this at-home device augmenting the current in-clinic therapy and enabling tele-rehabilitation where a clinician can remotely monitor a patient's usage and performance.

  18. Anthropomorphic finger antagonistically actuated by SMA plates.

    PubMed

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

    2015-10-01

    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. PMID:26292164

  19. Using parallel evolutionary development for a biologically-inspired computer vision system for mobile robots.

    PubMed

    Wright, Cameron H G; Barrett, Steven F; Pack, Daniel J

    2005-01-01

    We describe a new approach to attacking the problem of robust computer vision for mobile robots. The overall strategy is to mimic the biological evolution of animal vision systems. Our basic imaging sensor is based upon the eye of the common house fly, Musca domestica. The computational algorithms are a mix of traditional image processing, subspace techniques, and multilayer neural networks.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Mechanical characterization of bone anchors used with a bone-attached, parallel robot for skull surgery.

    PubMed

    Kobler, Jan-Philipp; Prielozny, Lenka; Lexow, G Jakob; Rau, Thomas S; Majdani, Omid; Ortmaier, Tobias

    2015-05-01

    Bone-attached robots and microstereotactic frames, intended for deep brain stimulation and minimally invasive cochlear implantation, typically attach to a patient's skull via bone anchors. A rigid and reliable link between such devices and the skull is mandatory in order to fulfill the high accuracy demands of minimally invasive procedures while maintaining patient safety. In this paper, a method is presented to experimentally characterize the mechanical properties of the anchor-bone linkage. A custom-built universal testing machine is used to measure the pullout strength as well as the spring constants of bone anchors seated in four different bone substitutes as well as in human cranial bone. Furthermore, the angles at which forces act on the bone anchors are varied to simulate realistic conditions. Based on the experimental results, a substitute material that has mechanical properties similar to those of cranial bone is identified. The results further reveal that the pullout strength of the investigated anchor design is sufficient with respect to the proposed application. However, both the measured load capacity as well as the spring constants vary depending on the load angles. Based on these findings, an alternative bone anchor design is presented and experimentally validated. Furthermore, the results serve as a basis for stiffness simulation and optimization of bone-attached microstereotactic frames. PMID:25771430

  8. Mechanical characterization of bone anchors used with a bone-attached, parallel robot for skull surgery.

    PubMed

    Kobler, Jan-Philipp; Prielozny, Lenka; Lexow, G Jakob; Rau, Thomas S; Majdani, Omid; Ortmaier, Tobias

    2015-05-01

    Bone-attached robots and microstereotactic frames, intended for deep brain stimulation and minimally invasive cochlear implantation, typically attach to a patient's skull via bone anchors. A rigid and reliable link between such devices and the skull is mandatory in order to fulfill the high accuracy demands of minimally invasive procedures while maintaining patient safety. In this paper, a method is presented to experimentally characterize the mechanical properties of the anchor-bone linkage. A custom-built universal testing machine is used to measure the pullout strength as well as the spring constants of bone anchors seated in four different bone substitutes as well as in human cranial bone. Furthermore, the angles at which forces act on the bone anchors are varied to simulate realistic conditions. Based on the experimental results, a substitute material that has mechanical properties similar to those of cranial bone is identified. The results further reveal that the pullout strength of the investigated anchor design is sufficient with respect to the proposed application. However, both the measured load capacity as well as the spring constants vary depending on the load angles. Based on these findings, an alternative bone anchor design is presented and experimentally validated. Furthermore, the results serve as a basis for stiffness simulation and optimization of bone-attached microstereotactic frames.

  9. Applications of conducting polymers: robotic fins and other devices

    NASA Astrophysics Data System (ADS)

    Tangorra, James L.; Anquetil, Patrick A.; Weideman, Nathan S.; Fofonoff, Timothy; Hunter, Ian W.

    2007-04-01

    Conducting polymers are becoming viable engineering materials and are gradually being integrated into a wide range of devices. Parallel efforts conducted to characterize their electromechanical behavior, understand the factors that affect actuation performance, mechanically process films, and address the engineering obstacles that must be overcome to generate the forces and displacements required in real-world applications have made it possible to begin using conducting polymers in devices that cannot be made optimal using traditional actuators and materials. The use of conducting polymers has allowed us to take better advantage of biological architectures for robotic applications and has enabled us to pursue the development of novel sensors, motors, and medical diagnostic technologies. This paper uses the application of conducting polymer actuators to a biorobotic fin for unmanned undersea vehicles (UUVs) as a vehicle for discussing the efforts in our laboratory to develop conducting polymers into a suite of useful actuators and engineering components.

  10. Multigait soft robot

    PubMed Central

    Shepherd, Robert F.; Ilievski, Filip; Choi, Wonjae; Morin, Stephen A.; Stokes, Adam A.; Mazzeo, Aaron D.; Chen, Xin; Wang, Michael; Whitesides, George M.

    2011-01-01

    This manuscript describes a unique class of locomotive robot: A soft robot, composed exclusively of soft materials (elastomeric polymers), which is inspired by animals (e.g., squid, starfish, worms) that do not have hard internal skeletons. Soft lithography was used to fabricate a pneumatically actuated robot capable of sophisticated locomotion (e.g., fluid movement of limbs and multiple gaits). This robot is quadrupedal; it uses no sensors, only five actuators, and a simple pneumatic valving system that operates at low pressures (< 10 psi). A combination of crawling and undulation gaits allowed this robot to navigate a difficult obstacle. This demonstration illustrates an advantage of soft robotics: They are systems in which simple types of actuation produce complex motion. PMID:22123978

  11. Multigait soft robot.

    PubMed

    Shepherd, Robert F; Ilievski, Filip; Choi, Wonjae; Morin, Stephen A; Stokes, Adam A; Mazzeo, Aaron D; Chen, Xin; Wang, Michael; Whitesides, George M

    2011-12-20

    This manuscript describes a unique class of locomotive robot: A soft robot, composed exclusively of soft materials (elastomeric polymers), which is inspired by animals (e.g., squid, starfish, worms) that do not have hard internal skeletons. Soft lithography was used to fabricate a pneumatically actuated robot capable of sophisticated locomotion (e.g., fluid movement of limbs and multiple gaits). This robot is quadrupedal; it uses no sensors, only five actuators, and a simple pneumatic valving system that operates at low pressures (< 10 psi). A combination of crawling and undulation gaits allowed this robot to navigate a difficult obstacle. This demonstration illustrates an advantage of soft robotics: They are systems in which simple types of actuation produce complex motion.

  12. 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.

  13. New electrode materials for dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Yuan, Wei; Lam, Tuling; Biggs, James; Hu, Liangbing; Yu, Zhibin; Ha, Soonmok; Xi, Dongjuan; Senesky, Matthew K.; Grüner, George; Pei, Qibing

    2007-04-01

    Dielectric elastomer actuators exert strain due to an applied electric field. With advantageous properties such as high efficiency and their light weight, these actuators are attractive for a variety of applications ranging from biomimetic robots, medical prosthetics to conventional pumps and valves. The performance and reliability however, are limited by dielectric breakdown which occurs primarily from localized defects inherently present in the polymer film during actuation. These defects lead to electric arcing, causing a short circuit that shuts down the entire actuator and can lead to actuator failure at fields significantly lower than the intrinsic strength of the material. This limitation is particularly a problem in actuators using large-area films. Our recent studies have shown that the gap between the strength of the intrinsic material and the strength of large-area actuators can be reduced by electrically isolating defects in the dielectric film. As a result, the performance and reliability of dielectric elastomers actuators can be substantially improved.

  14. 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

  15. 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.

  16. Dielectric Elastomer Based "Grippers" for Soft Robotics.

    PubMed

    Shian, Samuel; Bertoldi, Katia; Clarke, David R

    2015-11-18

    The use of few stiff fibers to control the deformation of dielectric elastomer actuators, in particular to break the symmetry of equi-biaxial lateral strain in the absence of prestretch, is demonstrated. Actuators with patterned fibers are shown to evolve into unique shapes upon electrical actuation, enabling novel designs of gripping actuators for soft robotics. PMID:26418227

  17. 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.

  18. 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.

  19. A surface-matching technique for robot-assisted registration.

    PubMed

    Glozman, D; Shoham, M; Fischer, A

    2001-01-01

    Successful implementation of robot-assisted surgery (RAS) requires coherent integration of spatial image data with sensing and actuating devices, each having its own coordinate system. Hence, accurate estimation of the geometric relationships between relevant reference frames, known as registration, is a crucial procedure in all RAS applications. The purpose of this paper is to present a new registration scheme, along with the results of an experimental evaluation of a robot-assisted registration method for RAS applications in orthopedics. The accuracy of the proposed registration is appropriate for specified orthopedic surgical applications such as Total Knee Replacement. The registration method is based on a surface-matching algorithm that does not require marker implants, thereby reducing surgical invasiveness. Points on the bone surface are sampled by the robot, which in turn directs the surgical tool. This technique eliminates additional coordinate transformations to an external device (such as a digitizer), resulting in increased surgical accuracy. The registration technique was tested on an RSPR six-degrees-of-freedom parallel robot specifically designed for medical applications. A six-axis force sensor attached to the robot's moving platform enables fast and accurate acquisition of positions and surface normal directions at sampled points. Sampling with a robot probe was shown to be accurate, fast, and easy to perform. The whole procedure takes about 2 min, with the robot performing most of the registration procedures, leaving the surgeon's hands free. Robotic registration was shown to provide a flawless link between preoperative planning and robotic assistance during surgery.

  20. A surface-matching technique for robot-assisted registration.

    PubMed

    Glozman, D; Shoham, M; Fischer, A

    2001-01-01

    Successful implementation of robot-assisted surgery (RAS) requires coherent integration of spatial image data with sensing and actuating devices, each having its own coordinate system. Hence, accurate estimation of the geometric relationships between relevant reference frames, known as registration, is a crucial procedure in all RAS applications. The purpose of this paper is to present a new registration scheme, along with the results of an experimental evaluation of a robot-assisted registration method for RAS applications in orthopedics. The accuracy of the proposed registration is appropriate for specified orthopedic surgical applications such as Total Knee Replacement. The registration method is based on a surface-matching algorithm that does not require marker implants, thereby reducing surgical invasiveness. Points on the bone surface are sampled by the robot, which in turn directs the surgical tool. This technique eliminates additional coordinate transformations to an external device (such as a digitizer), resulting in increased surgical accuracy. The registration technique was tested on an RSPR six-degrees-of-freedom parallel robot specifically designed for medical applications. A six-axis force sensor attached to the robot's moving platform enables fast and accurate acquisition of positions and surface normal directions at sampled points. Sampling with a robot probe was shown to be accurate, fast, and easy to perform. The whole procedure takes about 2 min, with the robot performing most of the registration procedures, leaving the surgeon's hands free. Robotic registration was shown to provide a flawless link between preoperative planning and robotic assistance during surgery. PMID:11892002

  1. 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.

  2. 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.

  3. 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. PMID:26794489

  4. 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.

  5. Enhancing the force capability of permanent magnet latching actuators for electromechanical valve actuation systems

    NASA Astrophysics Data System (ADS)

    Rens, J.; Clark, R. E.; Jewell, G. W.; Howe, D.

    2005-05-01

    This article introduces a topology of parallel-polarized permanent magnet latching actuator for use in electromagnetic valve actuation systems for internal combustion engines. The actuator has a number of advantages over reluctance actuators, commonly employed in such systems, in terms of reduced starting currents and fail-safe capability. The influence of a number of design features on actuator performance, such as tooth tapering, additional magnets to improve the main magnet flux path and prevent the onset of saturation, and mechanical clearances required to protect the permanent magnet from shock loads are investigated. The design study findings are verified by measurements on a prototype actuator.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Position and torque tracking: series elastic actuation versus model-based-controlled hydraulic actuation.

    PubMed

    Otten, Alexander; van Vuuren, Wieke; Stienen, Arno; van Asseldonk, Edwin; Schouten, Alfred; van der Kooij, Herman

    2011-01-01

    Robotics used for diagnostic measurements on, e.g. stroke survivors, require actuators that are both stiff and compliant. Stiffness is required for identification purposes, and compliance to compensate for the robots dynamics, so that the subject can move freely while using the robot. A hydraulic actuator can act as a position (stiff) or a torque (compliant) actuator. The drawback of a hydraulic actuator is that it behaves nonlinear. This article examines two methods for controlling a nonlinear hydraulic actuator. The first method that is often applied uses an elastic element (i.e. spring) connected in series with the hydraulic actuator so that the torque can be measured as the deflection of the spring. This torque measurement is used for proportional integral control. The second method of control uses the inverse of the model of the actuator as a linearizing controller. Both methods are compared using simulation results. The controller designed for the series elastic hydraulic actuator is faster to implement, but only shows good performance for the working range for which the controller is designed due to the systems nonlinear behavior. The elastic element is a limiting factor when designing a position controller due to its low torsional stiffness. The model-based controller linearizes the nonlinear system and shows good performance when used for torque and position control. Implementing the model-based controller does require building and validating of the detailed model. PMID:22275654

  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. PMID:26192533

  12. 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

  13. Control of parallel manipulators using force feedback

    NASA Technical Reports Server (NTRS)

    Nanua, Prabjot

    1994-01-01

    Two control schemes are compared for parallel robotic mechanisms actuated by hydraulic cylinders. One scheme, the 'rate based scheme', uses the position and rate information only for feedback. The second scheme, the 'force based scheme' feeds back the force information also. The force control scheme is shown to improve the response over the rate control one. It is a simple constant gain control scheme better suited to parallel mechanisms. The force control scheme can be easily modified for the dynamic forces on the end effector. This paper presents the results of a computer simulation of both the rate and force control schemes. The gains in the force based scheme can be individually adjusted in all three directions, whereas the adjustment in just one direction of the rate based scheme directly affects the other two directions.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  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. Actuated atomizer

    NASA Technical Reports Server (NTRS)

    Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)

    2008-01-01

    An actuated atomizer is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated atomizer includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a magnetic field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the magnetic field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the atomizer from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the atomizer to release atomized fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the magnetic field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.

  1. Actuator mechanism

    NASA Technical Reports Server (NTRS)

    Stange, W. C. (Inventor)

    1978-01-01

    An actuator mechanism is described, having a frame with a rotatable shaft supported in the frame, a positioning mechanism coupled to the shaft for rotating the shaft in two rotary positions, disposed approximately 180 degrees apart, and a pair of plungers coupled to the shaft. Each plunger is responsive to a control signal for applying bi-directional rotation to the shaft.

  2. Conducting IPN actuators for biomimetic vision system

    NASA Astrophysics Data System (ADS)

    Festin, Nicolas; Plesse, Cedric; Chevrot, Claude; Teyssié, Dominique; Pirim, Patrick; Vidal, Frederic

    2011-04-01

    In recent years, many studies on electroactive polymer (EAP) actuators have been reported. One promising technology is the elaboration of electronic conducting polymers based actuators with Interpenetrating Polymer Networks (IPNs) architecture. Their many advantageous properties as low working voltage, light weight and high lifetime (several million cycles) make them very attractive for various applications including robotics. Our laboratory recently synthesized new conducting IPN actuators based on high molecular Nitrile Butadiene Rubber, poly(ethylene oxide) derivative and poly(3,4-ethylenedioxithiophene). The presence of the elastomer greatly improves the actuator performances such as mechanical resistance and output force. In this article we present the IPN and actuator synthesis, characterizations and design allowing their integration in a biomimetic vision system.

  3. Mesofluidic controlled robotic or prosthetic finger

    SciTech Connect

    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.

  4. 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.

  5. Rotary Actuators Based on Pneumatically Driven Elastomeric Structures.

    PubMed

    Gong, Xiangyu; Yang, Ke; Xie, Jingjin; Wang, Yanjun; Kulkarni, Parth; Hobbs, Alexander S; Mazzeo, Aaron D

    2016-09-01

    Unique elastomeric rotary actuators based on pneumatically driven peristaltic motion are demonstrated. Using silicone-based wheels, these motors enable a new class of soft locomotion not found in nature, which is capable of withstanding impact, traversing irregular terrain, and operating in water. For soft robotics, this work marks progress toward providing torque without bending actuators. PMID:27348794

  6. Robotic Tube-Gap Inspector

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.; Gutow, David A.; Maslakowski, John E.

    1993-01-01

    Robotic vision system measures small gaps between nearly parallel tubes. Robot-held video camera examines closely spaced tubes while computer determines gaps between tubes. Video monitor simultaneously displays data on gaps.

  7. 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. PMID:26227680

  8. 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.

  9. 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 software and teaching…

  10. Mechanochemically Active Soft Robots.

    PubMed

    Gossweiler, Gregory R; Brown, Cameron L; Hewage, Gihan B; Sapiro-Gheiler, Eitan; Trautman, William J; Welshofer, Garrett W; Craig, Stephen L

    2015-10-14

    The functions of soft robotics are intimately tied to their form-channels and voids defined by an elastomeric superstructure that reversibly stores and releases mechanical energy to change shape, grip objects, and achieve complex motions. Here, we demonstrate that covalent polymer mechanochemistry provides a viable mechanism to convert the same mechanical potential energy used for actuation in soft robots into a mechanochromic, covalent chemical response. A bis-alkene functionalized spiropyran (SP) mechanophore is cured into a molded poly(dimethylsiloxane) (PDMS) soft robot walker and gripper. The stresses and strains necessary for SP activation are compatible with soft robot function. The color change associated with actuation suggests opportunities for not only new color changing or camouflaging strategies, but also the possibility for simultaneous activation of latent chemistry (e.g., release of small molecules, change in mechanical properties, activation of catalysts, etc.) in soft robots. In addition, mechanochromic stress mapping in a functional robotic device might provide a useful design and optimization tool, revealing spatial and temporal force evolution within the robot in a way that might be coupled to autonomous feedback loops that allow the robot to regulate its own activity. The demonstration motivates the simultaneous development of new combinations of mechanophores, materials, and soft, active devices for enhanced functionality.

  11. Mechanochemically Active Soft Robots.

    PubMed

    Gossweiler, Gregory R; Brown, Cameron L; Hewage, Gihan B; Sapiro-Gheiler, Eitan; Trautman, William J; Welshofer, Garrett W; Craig, Stephen L

    2015-10-14

    The functions of soft robotics are intimately tied to their form-channels and voids defined by an elastomeric superstructure that reversibly stores and releases mechanical energy to change shape, grip objects, and achieve complex motions. Here, we demonstrate that covalent polymer mechanochemistry provides a viable mechanism to convert the same mechanical potential energy used for actuation in soft robots into a mechanochromic, covalent chemical response. A bis-alkene functionalized spiropyran (SP) mechanophore is cured into a molded poly(dimethylsiloxane) (PDMS) soft robot walker and gripper. The stresses and strains necessary for SP activation are compatible with soft robot function. The color change associated with actuation suggests opportunities for not only new color changing or camouflaging strategies, but also the possibility for simultaneous activation of latent chemistry (e.g., release of small molecules, change in mechanical properties, activation of catalysts, etc.) in soft robots. In addition, mechanochromic stress mapping in a functional robotic device might provide a useful design and optimization tool, revealing spatial and temporal force evolution within the robot in a way that might be coupled to autonomous feedback loops that allow the robot to regulate its own activity. The demonstration motivates the simultaneous development of new combinations of mechanophores, materials, and soft, active devices for enhanced functionality. PMID:26390078

  12. Control of Single Wheel Robots

    NASA Astrophysics Data System (ADS)

    Xu, Yangsheng; Ou, Yongsheng

    This monograph presents a novel concept of a mobile robot, which is a single-wheel, gyroscopically stabilized robot. The robot is balanced by a spinning wheel attached through a two-link manipulator at the wheel bearing, and actuated by a drive motor. This configuration conveys significant advantages including insensitivity to attitude disturbances, high maneuverability, low rolling resistance, ability to recover from falls, and amphibious capability for potential applications on both land and water.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Dynamic load-carrying capacity and inverse dynamics of multiple cooperating robotic manipulators

    SciTech Connect

    Wang, L.C.T.; Ming Jun Kuo . Dept. of Mechanical Engineering)

    1994-02-01

    A unified method for computing the dynamic load-carrying capacity (DLCC) and the inverse dynamics of multiple cooperating robotic manipulators is developed in this paper. In this method, the kinematic constraints and the governing dynamic equations of the multi-robot system are formulated in the joint space based on a coordinate partitioning technique and the generalized D'Alembert's principle. This approach not only gives the minimum number of equations but also allows separate computations of the dynamics of the robots and that of the payload. The upper limit of the DLCC at any points on a given trajectory is obtained by solving a small-size linear programming problem. An iterative algorithm for evaluating the maximum allowable DLCC of the trajectory is also developed. After the DLCC is determined, the optimum distribution of actuator torques are computed by using a quadratic programming technique. The proposed method is conceptually straightforward, and it is applicable to wide varieties of multi-robot systems as well as fully parallel robots with redundant actuators.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Carbon nanotube actuators

    PubMed

    Baughman; Cui; Zakhidov; Iqbal; Barisci; Spinks; Wallace; Mazzoldi; De Rossi D; Rinzler; Jaschinski; Roth; Kertesz

    1999-05-21

    Electromechanical actuators based on sheets of single-walled carbon nanotubes were shown to generate higher stresses than natural muscle and higher strains than high-modulus ferroelectrics. Like natural muscles, the macroscopic actuators are assemblies of billions of individual nanoscale actuators. The actuation mechanism (quantum chemical-based expansion due to electrochemical double-layer charging) does not require ion intercalation, which limits the life and rate of faradaic conducting polymer actuators. Unlike conventional ferroelectric actuators, low operating voltages of a few volts generate large actuator strains. Predictions based on measurements suggest that actuators using optimized nanotube sheets may eventually provide substantially higher work densities per cycle than any previously known technology.

  5. 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.

  6. 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.

  7. Biomimetic actuator

    NASA Astrophysics Data System (ADS)

    Bouda, Vaclav; Boudova, Lea; Haluzikova, Denisa

    2005-05-01

    The aim of the presentation is to propose an alternative model of mammalian skeletal muscle function, which reflects the simplicity of nature and can be applied in engineering. Van der Waals attractive and repulsive electrostatic forces are assumed to control the design of internal structures and functions of contractile units of the muscles - sarcomere. The role of myosin heads is crucial for the higher order formation. The model of the myosin head lattice is the working model for the sarcomere contraction interpretation. The contraction is interpreted as a calcium induced phase transition of the lattice, which results in relative actin-myosin sliding and/or force generation. The model should provide the engineering science with a simple analogy to technical actuators of high performance.

  8. Viselike Robotic Gripper

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1991-01-01

    Split-rail/roller bearing system minimizes both friction and jamming under side loads. Viselike, high-performance, general-purpose robot hand developed for use in both industry and outer space. Device, called "split-rail parallel gripper", is simple, compact, inexpensive, rugged, light enough to be used on small robots, strong enough to be used on large robots to lift loads up to 100 lbs, and capable of gripping objects up to 7 in. wide.

  9. 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.

  10. 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.

  11. 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

  12. 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. PMID:25020043

  13. Spiral lead platen robotic end effector

    NASA Technical Reports Server (NTRS)

    Beals, David C. (Inventor)

    1990-01-01

    A robotic end effector is disclosed which makes use of a rotating platen with spiral leads used to impact lateral motion to gripping fingers. Actuation is provided by the contact of rolling pins with the walls of the leads. The use of the disclosed method of actuation avoids jamming and provides excellent mechanical advantage while remaining light in weight and durable. The entire end effector is compact and easily adapted for attachment to robotic arms currently in use.

  14. 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.

  15. 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.

  16. Robotic penguin-like propulsor with novel spherical joint

    NASA Astrophysics Data System (ADS)

    Sudki, Bassem; Lauria, Michel; Noca, Flavio

    2013-11-01

    We have designed and manufactured an innovative spherical joint mechanism with three actuated degrees of freedom, aimed at mimicking a penguin shoulder and enabling a potential propulsion technology with high efficiency and maneuverability. In addition, the mechanism might also lead to propellers with directional thrusting capability. A parallel architecture was chosen for this type of mechanism in order to ensure rigidity as well high actuation frequencies and amplitudes. Indeed, as the motors are fixed, inertial forces are lower than for a serial robot. The resulting spherical parallel mechanism (SPM) with coaxial shafts was designed and manufactured with the following specifications: fixed center of rotation (spherical joint); working frequency of 2.5 Hz under charge; unlimited rotation about main axis; and arbitrary motion within a cone of 60 degrees. The equations for the inverse kinematics of the mechanism have been established and can yield the trajectories of each actuator for any desired motion applied to the oar or blade. The technology will be illustrated with preliminary experiments in a hydrodynamic channel at the University of Applied Sciences - hepia - Switzerland.

  17. 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.

  18. 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.

  19. Self sensing feedback for dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Gisby, Todd A.; O'Brien, Benjamin M.; Anderson, Iain A.

    2013-05-01

    Self sensing Dielectric Elastomer Actuator (DEA) artificial muscles will enable the creation of soft, lightweight robots with animal-like capabilities. We demonstrate a fast, accurate, and economic self sensing algorithm that enables an arbitrary voltage oscillation to be used to sense DEA capacitance during actuation in a manner that is robust to significant changes in electrode resistance and leakage current. Not only we can use this algorithm to emulate the proprioceptive feedback found in natural muscle but also we can use it for the online characterisation and analysis of DEA behavior.

  20. Microprocessor controlled force actuator

    NASA Technical Reports Server (NTRS)

    Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

    1986-01-01

    The mechanical and electrical design of a prototype force actuator for vibration control of large space structures (LSS) is described. The force actuator is an electromagnetic system that produces a force by reacting against a proof-mass. The actuator has two colocated sensors, a digital microcontroller, and a power amplifier. The total weight of actuator is .998 kg. The actuator has a steady state force output of approximately 2.75 N from approximately 2 Hz to well beyond 1000 Hz.

  1. 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…

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. The robotics review 1

    SciTech Connect

    Khatib, O.; Craig, J.J.; Lozano-Perez, T.

    1989-01-01

    Theoretical and implementation issues in robotics are discussed in reviews of recent investigations. Sections are devoted to programming, planning, and learning; sensing and perception; kinematics, dynamics, and design; and motion and force control. Particular attention is given to a robust layered control system for a mobile robot, camera calibration for three-dimensional machine vision, walking vehicles, design and control of direct-drive vehicles, an efficient parallel algorithm for robot inverse dynamics, stability problems in contact tasks, and kinematics and reaction-moment compensation for satellite-mounted robot manipulators.

  7. 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.

  8. 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.

  9. 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. PMID:26643022

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Design and real-time control of a robotic system for fracture manipulation.

    PubMed

    Dagnino, G; Georgilas, I; Tarassoli, P; Atkins, R; Dogramadzi, S

    2015-08-01

    This paper presents the design, development and control of a new robotic system for fracture manipulation. The objective is to improve the precision, ergonomics and safety of the traditional surgical procedure to treat joint fractures. The achievements toward this direction are here reported and include the design, the real-time control architecture and the evaluation of a new robotic manipulator system. The robotic manipulator is a 6-DOF parallel robot with the struts developed as linear actuators. The control architecture is also described here. The high-level controller implements a host-target structure composed by a host computer (PC), a real-time controller, and an FPGA. A graphical user interface was designed allowing the surgeon to comfortably automate and monitor the robotic system. The real-time controller guarantees the determinism of the control algorithms adding an extra level of safety for the robotic automation. The system's positioning accuracy and repeatability have been demonstrated showing a maximum positioning RMSE of 1.18 ± 1.14mm (translations) and 1.85 ± 1.54° (rotations). PMID:26737383

  15. Design and real-time control of a robotic system for fracture manipulation.

    PubMed

    Dagnino, G; Georgilas, I; Tarassoli, P; Atkins, R; Dogramadzi, S

    2015-08-01

    This paper presents the design, development and control of a new robotic system for fracture manipulation. The objective is to improve the precision, ergonomics and safety of the traditional surgical procedure to treat joint fractures. The achievements toward this direction are here reported and include the design, the real-time control architecture and the evaluation of a new robotic manipulator system. The robotic manipulator is a 6-DOF parallel robot with the struts developed as linear actuators. The control architecture is also described here. The high-level controller implements a host-target structure composed by a host computer (PC), a real-time controller, and an FPGA. A graphical user interface was designed allowing the surgeon to comfortably automate and monitor the robotic system. The real-time controller guarantees the determinism of the control algorithms adding an extra level of safety for the robotic automation. The system's positioning accuracy and repeatability have been demonstrated showing a maximum positioning RMSE of 1.18 ± 1.14mm (translations) and 1.85 ± 1.54° (rotations).

  16. 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.

  17. 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

    2016-01-01

    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

  18. 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.

  19. 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.

  20. 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.

  1. Robotic chair at steep and narrow stairways

    NASA Astrophysics Data System (ADS)

    Imazato, Masahiro; Yamaguchi, Masahiro; Moromugi, Shunji; Ishimatsu, Takakazu

    2007-12-01

    A robotic chair is developed to support mobility of elderly and disabled people living in the house where steep and narrow stairways are installed. In order to deal with such mobility problem the developed robotic chair has a compact original configuration. The robotic chair vertically moves by actuation of electric cylinders and horizontally moves by push-pull operation given by a care-giver. In order to navigate safely every action of the chair is checked by the operator. Up-and-down motions of the robotic chair on the stairway are executed through combinations of motor and cylinder actuations. Performance of the robotic chair was evaluated through two kinds of experiments. The excellent ability of the robotic chair could be confirmed through these experiments.

  2. 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.

  3. Human-robot interaction tests on a novel robot for gait assistance.

    PubMed

    Tagliamonte, Nevio Luigi; Sergi, Fabrizio; Carpino, Giorgio; Accoto, Dino; Guglielmelli, Eugenio

    2013-06-01

    This paper presents tests on a treadmill-based non-anthropomorphic wearable robot assisting hip and knee flexion/extension movements using compliant actuation. Validation experiments were performed on the actuators and on the robot, with specific focus on the evaluation of intrinsic backdrivability and of assistance capability. Tests on a young healthy subject were conducted. In the case of robot completely unpowered, maximum backdriving torques were found to be in the order of 10 Nm due to the robot design features (reduced swinging masses; low intrinsic mechanical impedance and high-efficiency reduction gears for the actuators). Assistance tests demonstrated that the robot can deliver torques attracting the subject towards a predicted kinematic status.

  4. Force control of ionic polymer-metal composite actuators with cellular actuator method

    NASA Astrophysics Data System (ADS)

    Inoue, Yushiro; Kamamichi, Norihiro

    2014-03-01

    Ionic polymer-metal composite (IPMC) is one of the electro-active polymer materials which respond to electric stimuli with shape change. IPMC actuators can be activated with simple driving circuit and common control approach; however, dynamic characteristics change from environmental conditions such as the temperature or humidity. The output force of IPMC is very small, and the stress relaxation exists depending on the type of the counter-ions in the electrolyte. Therefore, it is desirable to construct robust controllers and connection of multiple actuator units to obtain stable and large output force. In this study, we apply a control method for cellular actuators to solve above problems. The cellular actuator is a concept of the actuators which consist of multiple actuator units. The actuator units connect in parallel or series, and each unit is controlled by distributed controllers, which are switched ON/OFF state stochastically depending on the broadcast error signal which is generated in the central controller. In this paper, we verify the control performance of the cellular actuator method through numerical simulations. In the simulations, we assume that the one hundred units of IPMC connected in parallel, the output force is controlled to the desired value. The control performance is investigated in the case of some mixed ratio of units whose counter-ions are Sodium (Na) ion or Tetraethylammonium (TEA). As a result of simulation, it was confirmed that the tracking performance is improved by combining the fast response actuator units of Na ions and the large output actuator units of TEA ions.

  5. Segway robotic mobility platform

    NASA Astrophysics Data System (ADS)

    Nguyen, Hoa G.; Morrell, John; Mullens, Katherine D.; Burmeister, Aaron B.; Miles, Susan; Farrington, Nathan; Thomas, Kari M.; Gage, Douglas W.

    2004-12-01

    The Segway Robotic Mobility Platform (RMP) is a new mobile robotic platform based on the self-balancing Segway Human Transporter (HT). The Segway RMP is faster, cheaper, and more agile than existing comparable platforms. It is also rugged, has a small footprint, a zero turning radius, and yet can carry a greater payload. The new geometry of the platform presents researchers with an opportunity to examine novel topics, including people-height sensing and actuation modalities. This paper describes the history and development of the platform, its characteristics, and a summary of current research projects involving the platform at various institutions across the United States.

  6. 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.

  7. 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. …

  8. 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.

  9. 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.

  10. Subminiature hydraulic actuator

    NASA Technical Reports Server (NTRS)

    Sevart, F. D.

    1978-01-01

    Subminiature, single-vane rotary actuator for wind-tunnel test-model control-surface actuation systems presents severe torque and system band-pass requirements with stringent space and weight limitations. Actuator has very low leakage of fluid from one side to other, permitting use in precision position servo-systems.

  11. AMSD Cryo Actuator Testing

    NASA Technical Reports Server (NTRS)

    Mullette, Mark; Matthews, Gary; Russell, Kevin (Technical Monitor)

    2002-01-01

    The actuator technology required for AMSD and subsequently NGST are critical in the successful development for future cryogenic systems. Kodak has undertaken an extensive test plan to determine the performance of the force actuators developed under the AMSD program. These actuators are currently in testing at MSFC and are expected to finish this test cycle in early June 2002.

  12. Development of multilayer conducting polymer actuator for power application

    NASA Astrophysics Data System (ADS)

    Ikushima, Kimiya; Kudoh, Yuji; Hiraoka, Maki; Yokoyama, Kazuo; Nagamitsu, Sachio

    2009-03-01

    In late years many kinds of home-use robot have been developed to assist elderly care and housework. Most of these robots are designed with conventional electromagnetic motors. For safety it is desirable to replace these electromagnetic motors with artificial muscle. However, an actuator for such a robot is required to have simple structure, low driving voltage, high stress generation, high durability, and operability in the air. No polymer actuator satisfying all these requirements has been realized yet. To meet these we took following two approaches focusing on conducting polymer actuators which can output high power in the air. (Approach 1) We have newly developed an actuator by multiply laminating ionic liquid infiltrated separators and polypyrrole films. Compared with conventional actuator that is driven in a bath of ionic liquid, the new actuator can greatly increase generated stress since the total sectional area is tremendously small. In our experiment, the new actuator consists of minimum unit with thickness of 128um and has work/weight ratio of 0.92J/kg by laminating 9 units in 0.5Hz driving condition. In addition, the driving experiment has shown a stable driving characteristic even for 10,000 cycles durability test. Furthermore, from our design consideration, it has been found that the work/weight ratio can be improved up to 8J/kg (1/8 of mammalian muscle of 64J/kg) in 0.1Hz by reducing the thickness of each unit to 30um. (Approach 2) In order to realize a simplified actuator structure in the air without sealing, we propose the use of ionic liquid gel. The actuation characteristic of suggested multilayered actuator using ionic liquid gel is simulated by computer. The result shows that performance degradation due to the use of ionic liquid gel is negligible small when ionic liquid gel with the elasticity of 3kPa or less is used. From above two results it is concluded that the proposed multilayerd actuator is promising for the future robotic applications

  13. 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. PMID:24320195

  14. 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.

  15. Industrial robots and robotics

    SciTech Connect

    Kafrissen, S.; Stephens, M.

    1984-01-01

    This book discusses the study of robotics. It provides information of hardware, software, applications and economics. Eleven chapters examine the following: Minicomputers, Microcomputers, and Microprocessors; The Servo-Control System; The Activators; Robot Vision Systems; and Robot Workcell Environments. Twelve appendices supplement the data.

  16. Omnidirectional Actuator Handle

    NASA Technical Reports Server (NTRS)

    Moetteli, John B.

    1995-01-01

    Proposed actuator handle comprises two normally concentric rings, cables, and pulleys arranged such that relative displacement of rings from concentricity results in pulling of cable and consequent actuation of associated mechanism. Unlike conventional actuator handles like levers on farm implements, actuated from one or two directions only, proposed handle reached from almost any direction and actuated by pulling or pushing inner ring in any direction with respect to outer ring. Flanges installed on inner ring to cover gap between inner ring and housing to prevent clothing from being caught.

  17. 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.

  18. 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.

  19. Robotic surgery

    MedlinePlus

    Robot-assisted surgery; Robotic-assisted laparoscopic surgery; Laparoscopic surgery with robotic assistance ... Robotic surgery is similar to laparoscopic surgery. It can be performed through smaller cuts than open surgery. ...

  20. Coordination of multiple robot arms

    NASA Technical Reports Server (NTRS)

    Barker, L. K.; Soloway, D.

    1987-01-01

    Kinematic resolved-rate control from one robot arm is extended to the coordinated control of multiple robot arms in the movement of an object. The structure supports the general movement of one axis system (moving reference frame) with respect to another axis system (control reference frame) by one or more robot arms. The grippers of the robot arms do not have to be parallel or at any pre-disposed positions on the object. For multiarm control, the operator chooses the same moving and control reference frames for each of the robot arms. Consequently, each arm then moves as though it were carrying out the commanded motions by itself.

  1. Utilization of electroactive polymer actuators in micromixing and in extended-life biosensor applications

    NASA Astrophysics Data System (ADS)

    Ho, Vinh; Shimada, Mark; Szeto, David; Casadevall i Solvas, Xavier; Scott, Daniel; Dolci, Luisa Stella; Kulinsky, Lawrence; Daunert, Sylvia; Madou, Marc

    2010-04-01

    Polypyrrole (PPy)-based microactuators hold a promise for a wide variety of engineering applications from robotics and microassembly to biosensors and drug delivery systems. The main advantages of using PPy/Au actuator structures (vs competing solid-state actuator technologies) include ease of fabrication, low actuation energy, and large motion range of microactuators. We present advances in two areas of application - in the extended-life biosensor platform and in micromixers.

  2. 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.

  3. 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

  4. 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. PMID:22666004

  5. 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.

  6. 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.

  7. Fabrication and reliable implementation of an ionic polymer-metal composite (IPMC) biaxial bending actuator

    NASA Astrophysics Data System (ADS)

    Lee, Gil-Yong; Choi, Jung-Oh; Kim, Myeungseon; Ahn, Sung-Hoon

    2011-10-01

    Ionic polymer-metal composites (IPMCs) are one of the most popular types of electro-active polymer actuator, due to their low electric driving potential, large deformation range, and light weight. IPMCs have been used as actuators or sensors in many areas of biomedical and robotic engineering. In this research, IPMCs were studied as a biaxial bending actuator capable of smart and flexible motion. We designed and fabricated this bending actuator and implemented it to have a reliable actuating motion using a systematic approach. The resulting device was bar shaped with a square cross section and had four insulated electrodes on its surface. By applying different voltages to these four electrodes, a biaxial bending motion can be induced. To construct this actuator, several fabrication processes were considered. We modified the Nafion stacking method, and established a complete sequence of actuator fabrication processes. Using these processes, we were able to fabricate an IPMC biaxial bending actuator with both high actuating force and high flexibility. Several experiments were conducted to investigate and verify the performance of the actuator. The IPMC actuator system was modeled from experimentally measured data, and using this actuator model, a closed-loop proportional integral (PI) controller was designed. Reference position tracking performances of open-loop and closed-loop systems were compared. Finally, circular motion tracking performances of the actuator tip were tested under different rotation frequencies and radii of a reference trajectory circle.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Electropneumatic actuator, phase 1

    NASA Astrophysics Data System (ADS)

    Bloomfield, D. P.

    1989-10-01

    The program demonstrated the feasibility of an electropneumatic actuator which can be used in manufacturing applications. The electropneumatic actuator, an alternative to the electric, hydraulic, and pneumatic actuators used in industry, consists of an electrochemical compressor, a power supply, and an actuator. The electrochemical compressor working fluid is hydrogen and a solvent such as water or ammonia. The compressor has no moving parts and runs on low voltage DC. The actuator is a conventional, commercially available unit. Researchers designed, constructed, and tested the electrochemical compressor in conjunction with the actuator, power supply, and computerized control. The one inch actuator can lift a fifty pound weight a distance of ten inches in about 1.5 minutes. The electrochemically powered system is capable of driving its loaded actuator to a prescribed location at a controlled rate. A defined set of design changes will combine the compressor and actuator in the same housing, and will develop two orders of magnitude increased actuator speed at the same or higher force levels.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. A biomorphic origami actuator fabricated by folding a conducting paper

    NASA Astrophysics Data System (ADS)

    Okuzaki, H.; Saido, T.; Suzuki, H.; Hara, Y.; Yan, H.

    2008-08-01

    Cooperation between the electrical conductivity and hygroscopic nature of conducting polymers can provide an insight into the development of a new class of electro-active polymer (EAP) actuators or soft robots working in ambient air. In this paper, we describe an 'origami' actuator fabricated by folding a sheet of conducting 'paper'. The principle lies in the electrically induced changes in the elastic modulus of a humidosensitive conducting polymer film through reversible sorption and desorption of water vapor molecules, which is responsible for amplifying a contraction of the film (~ 1%) to more than a 100-fold expansion (> 100%) of the origami actuator. Utilizing the origami technique, we have fabricated a biomorphic origami robot by folding an electrochemically synthesized polypyrrole film into the figure of an accordion shape, which can move with a caterpillar-like motion by repeated expansion and contraction at a velocity of 2 cm min-1.

  2. 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.

  3. 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.

  4. Xurography actuated valving for centrifugal flow control.

    PubMed

    Kinahan, David J; Early, Philip L; Vembadi, Abhishek; MacNamara, Eoghan; Kilcawley, Niamh A; Glennon, Thomas; Diamond, Dermot; Brabazon, Dermot; Ducrée, Jens

    2016-09-21

    We introduce a novel instrument controlled valving scheme for centrifugal platforms which is based upon xurography. In a first approach, which is akin to previously presented event-triggered flow control, the valves are composed of a pneumatic chamber sealed by a dissolvable film (DF) and by a pierceable membrane. Liquid is initially prevented from wetting the DF by the counter pressure of a trapped gas. Via a channel, this pocket is pneumatically connected to a vent, sealed by the pierceable membrane, located on the top surface of the disc. By scouring the top surface of the disc, along a pre-defined track by a robotic knife-cutter, the trapped gas is released and so the liquid can wet and disintegrate the DF. In order to automate assay protocols without the need to integrate DFs, we extend this xurography-based flow control concept by selective venting of chambers subjected to pneumatic over-pressure or vacuum suction. Unlike most instrument controlled flow-control mechanisms, in this approach to valve actuation can occur during disc rotation. To demonstrate the potential of this flow control approach, we designed a disc architecture to automate the liquid handling as the backbone of a biplex liver assay panel. We demonstrate valve actuation during rotation, using the robotic arm, using this disc with visualisation via dyed water. We then demonstrate the biplex liver assay, using calibration reagent, by stopping the disc and manually piercing the membrane to actuate the same valves. PMID:27523628

  5. 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.

  6. Comprehensive piezoceramic actuator review

    NASA Astrophysics Data System (ADS)

    Taylor, Chris J.; Washington, Gregory N.

    2002-07-01

    Piezoceramic actuation has become an area of increased interest in the past ten years. Having been used for many years as sensors in such applications as pressure transducers and smoke detectors, piezoceramics are now being used as prime movers in fuel injectors and valve lifters. In an effort to aid the engineering community, this paper will conduct a comprehensive review of several piezoceramic actuators. Classical design parameters will be derived for each actuator such as blocked force and free stroke. In addition, more esoteric entities such as mechanical efficiency and energy density will also be derived. The result will be design metrics of popular piezoceramic actuators containing vital design equations, validated with empirical data. Of the many different configurations of piezoceramic actuators, this paper will investigate the bimorph and unimorph bender. These actuator types are finding increased use in semi-active structural damping, energy harvesting and vibration control. The work in this paper will show experimental verification of various actuator types as well as theoretical derivations. In addition to unimorphs, bimorphs and stack actuators a novel type of unimorph bender, the THUNDER actuator (developed and licensed by NASA) will be included in the review.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Actuating Fibers: Design and Applications.

    PubMed

    Stoychev, Georgi V; Ionov, Leonid

    2016-09-21

    Actuators are devices capable of moving or controlling objects and systems by applying mechanical force on them. Among all kinds of actuators with different shapes, fibrous ones deserve particular attention. In spite of their apparent simplicity, actuating fibers allow for very complex actuation behavior. This review discusses different approaches for the design of actuating fibers, and their advantages and disadvantages. We also discuss the prospects for the design of fibers with advanced architectures and complex actuation behavior. PMID:27571481

  12. 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.

  13. Lock for hydraulic actuators

    NASA Technical Reports Server (NTRS)

    Wood, R. H.

    1981-01-01

    Two clamps hold rod in fixed extension from cylinder even when power is off, converting actuator into stiff structural member. Locked actuator is useful as mechanical support or linkage or as fail-safe device in case of loss of hydraulic pressure. Potential applications include manufacturing processes and specialized handling and holding devices.

  14. Pressure-constrained, reduced-DOF, interconnected parallel manipulators with applications to space suit design

    NASA Astrophysics Data System (ADS)

    Jacobs, Shane Earl

    This dissertation presents the concept of a Morphing Upper Torso, an innovative pressure suit design that incorporates robotic elements to enable a resizable, highly mobile and easy to don/doff spacesuit. The torso is modeled as a system of interconnected, pressure-constrained, reduced-DOF, wire-actuated parallel manipulators, that enable the dimensions of the suit to be reconfigured to match the wearer. The kinematics, dynamics and control of wire-actuated manipulators are derived and simulated, along with the Jacobian transforms, which relate the total twist vector of the system to the vector of actuator velocities. Tools are developed that allow calculation of the workspace for both single and interconnected reduced-DOF robots of this type, using knowledge of the link lengths. The forward kinematics and statics equations are combined and solved to produce the pose of the platforms along with the link tensions. These tools allow analysis of the full Morphing Upper Torso design, in which the back hatch of a rear-entry torso is interconnected with the waist ring, helmet ring and two scye bearings. Half-scale and full-scale experimental models are used along with analytical models to examine the feasibility of this novel space suit concept. The analytical and experimental results demonstrate that the torso could be expanded to facilitate donning and doffng, and then contracted to match different wearer's body dimensions. Using the system of interconnected parallel manipulators, suit components can be accurately repositioned to different desired configurations. The demonstrated feasibility of the Morphing Upper Torso concept makes it an exciting candidate for inclusion in a future planetary suit architecture.

  15. 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.

  16. Modular robotic architecture

    NASA Astrophysics Data System (ADS)

    Smurlo, Richard P.; Laird, Robin T.

    1991-03-01

    The development of control architectures for mobile systems is typically a task undertaken with each new application. These architectures address different operational needs and tend to be difficult to adapt to more than the problem at hand. The development of a flexible and extendible control system with evolutionary growth potential for use on mobile robots will help alleviate these problems and if made widely available will promote standardization and cornpatibility among systems throughout the industry. The Modular Robotic Architecture (MRA) is a generic control systern that meets the above needs by providing developers with a standard set of software hardware tools that can be used to design modular robots (MODBOTs) with nearly unlimited growth potential. The MODBOT itself is a generic creature that must be customized by the developer for a particular application. The MRA facilitates customization of the MODBOT by providing sensor actuator and processing modules that can be configured in almost any manner as demanded by the application. The Mobile Security Robot (MOSER) is an instance of a MODBOT that is being developed using the MRA. Navigational Sonar Module RF Link Control Station Module hR Link Detection Module Near hR Proximi Sensor Module Fluxgate Compass and Rate Gyro Collision Avoidance Sonar Module Figure 1. Remote platform module configuration of the Mobile Security Robot (MOSER). Acoustical Detection Array Stereoscopic Pan and Tilt Module High Level Processing Module Mobile Base 566

  17. Robotic tool change mechanism

    NASA Technical Reports Server (NTRS)

    Voellmer, George M. (Inventor)

    1991-01-01

    An assembly of three major components is disclosed which included a wrist interface plate which is secured to the wrist joint of a robotic arm, a tool interface plate which is secured to each tool intended for use by the robotic arm, and a tool holster for each tool attached to the interface plate. The wrist interface plate and a selected tool interface plate are mutually connectable together through an opening or recess in the upper face of the interface plate by means of a notched tongue protruding from the front face of the wrist interface plate which engages a pair of spring-biased rotatable notched wheels located within the body of the tool interface plate. The tool holster captures and locks onto the tool interface plate by means of a pair of actuation claws including a locking tab and an unlocking wedge which operate respective actuation bosses on each of the notched wheels in response to a forward and backward motion of the tool interface plate as a result of motion of the robotic arm to either park the tool or use the tool.

  18. Actuators, biomedicine, and cell-biology

    NASA Astrophysics Data System (ADS)

    Jager, Edwin W. H.

    2012-04-01

    Conducting polymers such as polypyrrole are well-known for their volume changing capacity and their use as actuating material. Actuators based on polypyrrole have been demonstrated in dimensions ranging from centimetres down to micrometres as well as in linear strain and bending beam actuation modes. The polypyrrole (micro-)actuators can be operated in salt solutions including cell culture media and blood. In addition, polypyrrole is known to be biocompatible making them a good choice for applications within cell biology and medicine. Applications of polypyrrole actuators within micromechanical devices, such as microrobotics and valves, will be presented. Opportunities and devices for the medical device industry, especially vascular surgery will be shown. This includes a rotating PCTA balloon system, a steerable guide wire, and an implantable drug delivery system. In addition, novel mechanostimulation chips for cell biology will be introduced. Using these devices, we can stretch cells and show the cellular response to this mechanical stimulation. Since the dawn of eukaryotic cells many parallel molecular mechanisms that respond to mechanical stimuli have evolved. This technology allows us to begin the investigation of these mechanisms on a single cell level.

  19. 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.

  20. 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.

  1. A robot safety experiment varying robot speed and contrast with human decision cost.

    PubMed

    Etherton, J; Sneckenberger, J E

    1990-09-01

    An industrial robot safety experiment was performed to find out how quickly subjects responded to an unexpected robot motion at different speeds of the robot arm, and how frequently they failed to detect a motion that should have been detected. Robotics technicians risk being fatally injured if a robot should trap them against a fixed object. The value of the experimentation lies in its ability to show that this risk can be reduced by a design change. If the robot is moving at a slow speed, during programming and troubleshooting tasks, then the worker has sufficient time to actuate an emergency stop device before the robot can reach the person. The dependent variable in the experiment was the overrun distance (beyond an expected stopping point) that a robot arm travelled before a person actuated a stop pushbutton. Results of this experiment demonstrated that the speed of the robot arm and the implied decision cost for hitting an emergency stop button had a significant effect on human reaction time. At a fairly high level of ambient lighting (560 lux), fixed-level changes in the luminance contrast between the robot arm and its background did not significantly affect human reaction time.

  2. 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.

  3. Integrated smart actuator containing a monolithic coformed accelerometer

    NASA Astrophysics Data System (ADS)

    Corsaro, Robert D.; Houston, Brian H.; Klunder, Joseph D.

    1997-05-01

    A general need exists for inexpensive finite-area transducer arrays which intrinsically combine acoustic or vibration sensing with area actuation. Such combination transducers are particularly needed in active sound and vibration control and smart-materials applications. Commercial areas of interest include advanced underwater, aerospace or robotic-sensing applications. To be economically attractive they must be relatively simple to manufacture from reasonable cost materials. One promising new technology for such applications is injection-molded 1-3 composite piezo- ceramics, pioneered by Material Systems Inc. This transducer material is well suited for use as the low-cost actuator component of such a smart actuator. The challenge of this study was to design an inexpensive accelerometer which could be injection molded along with the actuator as an interspersed array. This paper describes a monolithic accelerometer which is suitable for fabrication by injection-molding as an integrated co-formed actuator component. Experimental results are presented for actuator/accelerometer arrays and issues related to the design and use of accelerometers in close proximity to an actuator are discussed.

  4. 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.

  5. 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

  6. MEMS Actuated Deformable Mirror

    SciTech Connect

    Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M

    2005-11-10

    This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. On The Control Of Robot Manipulator

    NASA Astrophysics Data System (ADS)

    Lee, C. S.

    1983-12-01

    The purpose of robot arm control is to maintain a prescribed motion for the manipulator along a desired trajectory by applying corrective compensation torques to the actuators to adjust for any deviations of the manipulator from the trajectory. This paper presents various control methods for industrial robots. It begins with the discussion of various dynamic models for manipulators and covers several existing control methods from simple servomechanism to advanced controls such as adaptive control with identification algorithm.

  15. 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.

  16. 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

    2016-01-01

    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. PMID:27545346

  17. 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.

  18. Electrothermal linear actuator

    NASA Technical Reports Server (NTRS)

    Derr, L. J.; Tobias, R. A.

    1969-01-01

    Converting electric power into powerful linear thrust without generation of magnetic fields is accomplished with an electrothermal linear actuator. When treated by an energized filament, a stack of bimetallic washers expands and drives the end of the shaft upward.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Robotic surgery.

    PubMed

    Oleynikov, Dmitry

    2008-10-01

    This article discusses the developments that led up to robotic surgical systems as well as what is on the horizon for new robotic technology. Topics include how robotics is enabling new types of procedures, including natural orifice endoscopic translumenal surgery in which one cannot reach by hand under any circumstances, and how these developments will drive the next generation of robots. PMID:18790158

  4. 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.

  5. Electrostatic Linear Actuator

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr.; Curry, Kenneth C.

    1990-01-01

    Electrically charged helices attract or repel each other. Proposed electrostatic linear actuator made with intertwined dual helices, which holds charge-bearing surfaces. Dual-helix configuration provides relatively large unbroken facing charged surfaces (relatively large electrostatic force) within small volume. Inner helix slides axially in outer helix in response to voltages applied to conductors. Spiral form also makes components more rigid. Actuator conceived to have few moving parts and to be operable after long intervals of inactivity.

  6. 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.

  7. Actuation of polypyrrole nanowires

    NASA Astrophysics Data System (ADS)

    Lee, Alexander S.; Peteu, Serban F.; Ly, James V.; Requicha, Aristides A. G.; Thompson, Mark E.; Zhou, Chongwu

    2008-04-01

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  8. Actuation of polypyrrole nanowires.

    PubMed

    Lee, Alexander S; Peteu, Serban F; Ly, James V; Requicha, Aristides A G; Thompson, Mark E; Zhou, Chongwu

    2008-04-23

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  9. 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.

  10. 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.

  11. 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

  12. Eclectic theory of intelligent robots

    NASA Astrophysics Data System (ADS)

    Hall, E. L.; Ghaffari, M.; Liao, X.; Ali, S. M. Alhaj; Sarkar, Saurabh; Reynolds, Scott; Mathur, Kovid

    2007-09-01

    The purpose of this paper is to introduce a concept of eclecticism for the design, development, simulation and implementation of a real time controller for an intelligent, vision guided robots. The use of an eclectic perceptual, creative controller that can select its own tasks and perform autonomous operations is illustrated. This eclectic controller is a new paradigm for robot controllers and is an attempt to simplify the application of intelligent machines in general and robots in particular. The idea is to uses a task control center and dynamic programming approach. However, the information required for an optimal solution may only partially reside in a dynamic database so that some tasks are impossible to accomplish. So a decision must be made about the feasibility of a solution to a task before the task is attempted. Even when tasks are feasible, an iterative learning approach may be required. The learning could go on forever. The dynamic database stores both global environmental information and local information including the kinematic and dynamic models of the intelligent robot. The kinematic model is very useful for position control and simulations. However, models of the dynamics of the manipulators are needed for tracking control of the robot's motions. Such models are also necessary for sizing the actuators, tuning the controller, and achieving superior performance. Simulations of various control designs are shown. Much of the model has also been used for the actual prototype Bearcat Cub mobile robot. This vision guided robot was designed for the Intelligent Ground Vehicle Contest. A novel feature of the proposed approach lies in the fact that it is applicable to both robot arm manipulators and mobile robots such as wheeled mobile robots. This generality should encourage the development of more mobile robots with manipulator capability since both models can be easily stored in the dynamic database. The multi task controller also permits wide

  13. Molecular level materials design for improvements of actuation properties of dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Kofod, G.; Stoyanov, H.; Kollosche, M.; Risse, S.; Ragusch, H.; McCarthy, D. N.; Waché, R.; Rychkov, D.; Dansachmüller, M.

    2011-04-01

    Dielectric elastomer actuators are soft electro-mechanical transducers with possible uses in robotic, orthopaedic and automotive applications. The active material must be soft and have a high ability to store electrical energy. Hence, three properties of the elastic medium in a dielectric elastomer actuator affect the actuation properties directly: dielectric constant, electric breakdown strength, and mechanical stiffness. The dielectric constant of a given elastomer can be improved by mixing it with other components with a higher dielectric constant, which can be classified as insulating or conducting. In this paper, an overview of all approaches proposed so far for dielectric constant improvement in these soft materials will be provided. Insulating particles such as TiO2 nanoparticles can raise the dielectric constant, but may also lead to stiffening of the composite, such that the overall actuation is lowered. It is shown here how a chemical coating of the TiO2 nanoparticles leads to verifiable improvements. Conducting material can also lead to improvements, as has been shown in several cases. Simple percolation, relying on the random distribution of conducting nanoparticles, commonly leads to drastic lowering of the breakdown strength. On the other hand, conducting polymer can also be employed, as has been demonstrated. We show here how an approach based on a specific chemical reaction between the conducting polymer and the elastomer network molecules solves the problem of premature breakdown which is otherwise typically found.

  14. Enhancement of EAP actuated facial expressions by designed chamber geometry in elastomers

    NASA Astrophysics Data System (ADS)

    Hanson, D.; Bergs, R.; Tadesse, Y.; White, V.; Priya, S.

    2006-03-01

    In this paper, the authors explore various ways that designed chambering of elastomers can enhance electroactive polymer (EAP) actuation. Such enhancements include structuring of chambers for various mechanical functions and advantages, boosting of surface area of a polymer for enhanced ionic migration, construction of advanced electret foams for sensing and for tunable hydrophobicity for micro/pumping action, and distribution of composite EAP devices throughout the chambered elastomer to achieve discrete controllability of electroactive polymer actuators. The authors also discuss the chambering of EAP materials themselves for enhanced actuation effects. With varied design of the chambers of the elastomer, the mechanical and structural properties of the elastomer can be tuned to greatly enhance EAP actuation. The chambers can be designed in accordion-like bellows to achieve extreme elongation with low forces, in spiral geometries to effect negative or neutral poisson's ratio under actuation, and with embedded fluidic bellows for fluidic actuation or sensing. These are but a few examples of the advantages that can be achieved via designed chambering of elastomers. The authors also discuss various application uses of the described chambering technologies. Such chambered elastomers, combined with advanced muscle-like actuators, can substantially benefit facelike robots (useful for entertainment and education etc), prosthetics, and numerous modalities of bio-inspired locomotion. In the efforts of the authors to generate facial expression robots with low-power lightweight actuators is described.

  15. 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.

  16. 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.

  17. 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).

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

    2016-06-01

    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). PMID:27145061

  3. 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).

  4. 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.

  5. Parallel micromanipulation method for microassembly

    NASA Astrophysics Data System (ADS)

    Sin, Jeongsik; Stephanou, Harry E.

    2001-09-01

    Microassembly deals with micron or millimeter scale objects where the tolerance requirements are in the micron range. Typical applications include electronics components (silicon fabricated circuits), optoelectronics components (photo detectors, emitters, amplifiers, optical fibers, microlenses, etc.), and MEMS (Micro-Electro-Mechanical-System) dies. The assembly processes generally require not only high precision but also high throughput at low manufacturing cost. While conventional macroscale assembly methods have been utilized in scaled down versions for microassembly applications, they exhibit limitations on throughput and cost due to the inherently serialized process. Since the assembly process depends heavily on the manipulation performance, an efficient manipulation method for small parts will have a significant impact on the manufacturing of miniaturized products. The objective of this study on 'parallel micromanipulation' is to achieve these three requirements through the handling of multiple small parts simultaneously (in parallel) with high precision (micromanipulation). As a step toward this objective, a new manipulation method is introduced. The method uses a distributed actuation array for gripper free and parallel manipulation, and a centralized, shared actuator for simplified controls. The method has been implemented on a testbed 'Piezo Active Surface (PAS)' in which an actively generated friction force field is the driving force for part manipulation. Basic motion primitives, such as translation and rotation of objects, are made possible with the proposed method. This study discusses the design of the proposed manipulation method PAS, and the corresponding manipulation mechanism. The PAS consists of two piezoelectric actuators for X and Y motion, two linear motion guides, two sets of nozzle arrays, and solenoid valves to switch the pneumatic suction force on and off in individual nozzles. One array of nozzles is fixed relative to the surface on

  6. Control of Compliant Anthropomimetic Robot Joint

    NASA Astrophysics Data System (ADS)

    Potkonjak, Veljko; Svetozarevic, Bratislav; Jovanovic, Kosta; Holland, Owen

    2010-09-01

    In this paper we propose a control strategy for a robot joint which fully mimics the typical human joint structure. The joint drive is based on two actuators (dc motors), agonist and antagonist, acting through compliant tendons and forming a nonlinear multi-input multi-output (MIMO) system. At any time, we consider one actuator, the puller, as being responsible for motion control, while the role of the other is to keep its tendon force at some appropriate low level. This human-like and energetically efficient approach requires the control of "switching", or exchanging roles between actuators. Moreover, an algorithm based on adaptive force reference is used to solve a problem of slacken tendons during the switching and to increase the energy efficiency. This approach was developed and evaluated on increasingly complex robot joint configurations, starting with linear and noncompliant system, and finishing with nonlinear and compliant system.

  7. Swarm Robotics

    NASA Astrophysics Data System (ADS)

    Şahin, Erol; Girgin, Sertan; Bayindir, Levent; Turgut, Ali Emre

    Swarm robotics is a novel approach to the coordination of large numbers of robots and has emerged as the application of swarm intelligence to multi-robot systems. Different from other swarm intelligence studies, swarm robotics puts emphases on the physical embodiment of individuals and realistic interactions among the individuals and between the individuals and the environment. In this chapter, we present a brief review of this new approach. We first present its definition, discuss the main motivations behind the approach, as well as its distinguishing characteristics and major coordination mechanisms. Then we present a brief review of swarm robotics research along four axes; namely design, modelling and analysis, robots and problems.

  8. Robotic surgery.

    PubMed

    Stoianovici, D

    2000-09-01

    The industrial revolution demonstrated the capability of robotic systems to facilitate and improve manufacturing. As a result, robotics extended to various other domains, including the delivery of health care. Hence, robots have been developed to assist hospital staff, to facilitate laboratory analyses, to augment patient rehabilitation, and even to advance surgical performance. As robotics lead usefulness and gain wider acceptance among the surgical community, the urologist should become familiar with this new interdisciplinary field and its "URobotics" subset: robotics applied to urology. This article reviews the current applications and experience, issues and debates in surgical robotics, and highlights future directions in the field.

  9. Toward a new generation of electrically controllable hygromorphic soft actuators.

    PubMed

    Taccola, Silvia; Greco, Francesco; Sinibaldi, Edoardo; Mondini, Alessio; Mazzolai, Barbara; Mattoli, Virgilio

    2015-03-11

    An innovative processing strategy for fabricating soft structures that possess electric- and humidity-driven active/passive actuation capabilities along with touch- and humidity-sensing properties is reported. The intrinsically multifunctional material comprises an active thin layer of poly(3,4-ethylenedioxythiophene):poly-(styrene sulfonate) in a double-layered structure with a silicone elastomer and provides an opportunity toward developing a new class of smart structures for soft robotics. PMID:25556552

  10. Torsional Ratcheting Actuating System

    SciTech Connect

    BARNES,STEPHEN MATTHEW; MILLER,SAMUEL L.; RODGERS,M. STEVEN; BITSIE,FERNANDO

    2000-01-24

    A new type of surface micromachined ratcheting actuation system has been developed at the Microelectronics Development Laboratory at Sandia National Laboratories. The actuator uses a torsional electrostatic comb drive that is coupled to an external ring gear through a ratcheting scheme. The actuator can be operated with a single square wave, has minimal rubbing surfaces, maximizes comb finger density, and can be used for open-loop position control. The prototypes function as intended with a minimum demonstrated operating voltage of 18V. The equations of motion are developed for the torsional electrostatic comb drive. The resonant frequency, voltage vs. displacement and force delivery characteristics are predicted and compared with the fabricated device's performance.

  11. Actuating critical care therapeutics.

    PubMed

    Stone, David J; Csete, Marie

    2016-10-01

    Viewing the intensive care unit (ICU) as a control system with inputs (patients) and outputs (outcomes), we focus on actuation (therapies) of the system and how to enhance our understanding of status of patients and their trajectory in the ICU. To incorporate the results of these analytics meaningfully, we feel that a reassessment of predictive scoring systems and of ways to optimally characterize and display the patient's "state space" to clinicians is important. Advances in sensing (diagnostics) and computation have not yet led to significantly better actuation, and so we focus on ways that data can be used to improve actuation in the ICU, in particular by following therapeutic burden along with disease severity. This article is meant to encourage discussion about how the critical care community can best deal with the data they see each day, and prepare for recommendations that will inevitably arise from application of major federal and state initiatives in big data analytics and precision medicine.

  12. 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. PMID:26737387

  13. 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.

  14. 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.

  15. 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.

  16. Hydraulic involute cam actuator

    DOEpatents

    Love, Lonnie J.; Lind, Randall F.

    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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Robotically assisted ultrasound interventions

    NASA Astrophysics Data System (ADS)

    Ding, Jienan; Swerdlow, Dan; Wang, Shuxin; Wilson, Emmanuel; Tang, Jonathan; Cleary, Kevin

    2008-03-01

    The goal of this project is to develop a robotic system to assist the physician in minimally invasive ultrasound interventions. In current practice, the physician must manually hold the ultrasound probe in one hand and manipulate the needle with the other hand, which can be challenging, particularly when trying to target small lesions. To assist the physician, the robot should not only be capable of providing the spatial movement needed, but also be able to control the contact force between the ultrasound probe and patient. To meet these requirements, we are developing a prototype system based on a six degree of freedom parallel robot. The system will provide high bandwidth, precision motion, and force control. In this paper we report on our progress to date, including the development of a PC-based control system and the results of our initial experiments.

  5. 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

  6. 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

  7. 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…

  8. 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);…

  9. (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.

  10. "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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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. PMID:26512734

  2. 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.

  3. Parallel computers

    SciTech Connect

    Treveaven, P.

    1989-01-01

    This book presents an introduction to object-oriented, functional, and logic parallel computing on which the fifth generation of computer systems will be based. Coverage includes concepts for parallel computing languages, a parallel object-oriented system (DOOM) and its language (POOL), an object-oriented multilevel VLSI simulator using POOL, and implementation of lazy functional languages on parallel architectures.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Robot programming

    SciTech Connect

    Lozano-Perez, T.

    1982-12-01

    The industrial robot's principal advantage over traditional automation is programmability. Robots can perform arbitrary sequences of pre-stored motions or of motions computed as functions of sensory input. This paper reviews requirements for and developments in robot programming systems. The key requirements for robot programming systems examined in the paper are in the areas of sensing, world modeling, motion specification, flow of control, and programming support. Existing and proposed robot programming systems fall into three broad categories: guiding systems in which the user leads a robot through the motions to be performed, robot-level programming systems in which the user writes a computer program specifying motion and sensing, and task-level programming systems in which the user writes a computer program specifying motion and sensing, and task-level programming systems in which the user specifies operations by their desired effect on objects. A representative sample of systems in each of these categories is surveyed in the paper.

  9. 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.

  10. 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

  11. Biomimetic soft robots with artificial muscles

    NASA Astrophysics Data System (ADS)

    Nakabo, Yoshihiro; Mukai, Toshiharu; Asaka, Kinji

    2004-02-01

    An artificial muscle is an ionic polymer-metal composite (IPMC) which is made out of a high polymer gel film whose surface is plated with gold. Our goal is to realize bio-inspired soft robots, for example, a snake-like swimming robot or multi-degree-of-freedom (DOF) micro-robot manipulator. To realize a snake-like or a multi-DOF bending motion, we cut electrodes on the surface of the actuator in order to control each segment individually. We have developed a variety of motions from this patterned actuator including a snake-like motion. We have also proposed kinematic modeling of the manipulator which simply describes various multi-DOF motions of the artificial muscle. This model is applied to visual feedback control of the manipulator system using a Jacobian control method. For the feedback control, we have developed a visual sensing system using a 1ms high-speed vision system which has a fast enough response to capture the fast actuator motion. We have also made the device swim freely forward and backward by finding the optimal voltage, phase and frequency. In this report, we show some results from simulations of the proposed manipulator control method and experimental results from visual sensing of the bending motion and snake-like swimming of the actuator.

  12. 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.

  13. Solar actuated drain system

    SciTech Connect

    Sarver, G. E.; Worstell, B. W.

    1985-04-30

    A temperature actuated drain system is provided that comprises a siphon that has an inlet end for immersing in a pool of water to be drained from a roof surface and a discharge end communicating with a pressure-responsive one-way valve. A solar actuated enclosed chamber that contains a solar heat energy collector is located on the roof surface and is in open communication with the siphon by means of a tubular member that has its inlet end positioned closely adjacent the bottom of the interior of the chamber. The arrangement causes any appreciable amounts of water that accumulate within the chamber to be discharged from the chamber during the pumping action created by the heating and cooling of air within the chamber.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Automatic rotary valve actuator

    SciTech Connect

    Cook, W.E.

    1985-03-28

    This report describes the design, construction, and operation of a microcomputer-controlled valve actuator for operating test valves requiring rotary motion of the valve stem. An AIM 65 microcomputer, using a FORTH language program, controls an air motor and air clutch mounted within an oven to accomplish testing at elevated temperatures. The valve actuator closes the test valve until a preset torque is reached and then opens the valve to its initial starting point. The number of cycles and extremes of rotation are tallied and printed as the test progresses. Provisions are made to accept remote signals to stop the test and to indicate to a remote device when the test has been stopped.

  19. 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.

  20. A compliant soft-actuator laterotactile display

    NASA Astrophysics Data System (ADS)

    Knoop, Espen; Rossiter, Jonathan

    2015-04-01

    Humans are extremely adept at eliciting useful information through touch, and the tactile domain has huge potential for handheld and wearable electronic devices. Smart materials may be central to exploiting this potential. The skin is highly sensitive to laterotactile stimulation, where tactile elements move laterally against the skin, and this modality is well suited for wearable devices. Wearable devices should be soft and compliant, in order to move with the user and be comfortable. We present and characterize a laterotactile display using soft and compliant dielectric elastomer actuators. We carry out an initial psychophysical study to determine the absolute sensitivity threshold of laterotactile stimulation, and find that at low frequencies sensitivity is higher than for normal tactile stimulation. Our results suggest that the mechanoreceptors close to the skin surface (SA1, FA1) have improved sensitivity to laterotactile stimulation. We believe our results lay the foundation for a range of new soft robotic human interface devices using smart materials.

  1. Dissolution actuated sample container

    DOEpatents

    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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Passively actuated valve

    DOEpatents

    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.

  7. Cylindrical Piezoelectric Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  8. Microelectromechanical (MEM) thermal actuator

    DOEpatents

    Garcia, Ernest J.; Fulcher, Clay W. G.

    2012-07-31

    Microelectromechanical (MEM) buckling beam thermal actuators are disclosed wherein the buckling direction of a beam is constrained to a desired direction of actuation, which can be in-plane or out-of-plane with respect to a support substrate. The actuators comprise as-fabricated, linear beams of uniform cross section supported above the substrate by supports which rigidly attach a beam to the substrate. The beams can be heated by methods including the passage of an electrical current through them. The buckling direction of an initially straight beam upon heating and expansion is controlled by incorporating one or more directional constraints attached to the substrate and proximal to the mid-point of the beam. In the event that the beam initially buckles in an undesired direction, deformation of the beam induced by contact with a directional constraint generates an opposing force to re-direct the buckling beam into the desired direction. The displacement and force generated by the movement of the buckling beam can be harnessed to perform useful work, such as closing contacts in an electrical switch.

  9. 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

  10. 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.

  11. Inverse dynamics: Simultaneous trajectory tracking and vibration reduction with distributed actuators

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh; Bayo, Eduardo

    1993-01-01

    This paper addresses the problem of inverse dynamics for articulated flexible structures with both lumped and distributed actuators. This problem arises, for example, in the combined vibration minimization and trajectory control of space robots and structures. A new inverse dynamics scheme for computing the nominal lumped and distributed inputs for tracking a prescribed trajectory is given.

  12. Assistive acting movement therapy devices with pneumatic rotary-type soft actuators.

    PubMed

    Wilkening, André; Baiden, David; Ivlev, Oleg

    2012-12-01

    Inherent compliance and assistive behavior are assumed to be essential properties for safe human-robot interaction. Rehabilitation robots demand the highest standards in this respect because the machine interacts directly with weak persons who are often sensitive to pain. Using novel soft fluidic actuators with rotary elastic chambers (REC actuators), compact, lightweight, and cost-effective therapeutic devices can be developed. This article describes modular design and control strategies for new assistive acting robotic devices for upper and lower extremities. Due to the inherent compliance and natural back-drivability of pneumatic REC actuators, these movement therapy devices provide gentle treatment, whereby the interaction forces between humans and the therapy device are estimated without the use of expensive force/torque sensors. An active model-based gravity compensation based on separated models of the robot and of the individual patient's extremity provides the basis for effective assistive control. The utilization of pneumatic actuators demands a special safety concept, which is merged with control algorithms to provide a sufficient level of safeness and to catch any possible system errors and/or emergency situations. A self-explanatory user interface allows for easy, intuitive handling. Prototypes are very comfortable for use due to several control routines that work in the background. Assistive devices have been tested extensively with several healthy persons; the knee/hip movement therapy device is now under clinical trials at the Clinic for Orthopaedics and Trauma Surgery at the Klinikum Stuttgart.

  13. Assistive acting movement therapy devices with pneumatic rotary-type soft actuators.

    PubMed

    Wilkening, André; Baiden, David; Ivlev, Oleg

    2012-12-01

    Inherent compliance and assistive behavior are assumed to be essential properties for safe human-robot interaction. Rehabilitation robots demand the highest standards in this respect because the machine interacts directly with weak persons who are often sensitive to pain. Using novel soft fluidic actuators with rotary elastic chambers (REC actuators), compact, lightweight, and cost-effective therapeutic devices can be developed. This article describes modular design and control strategies for new assistive acting robotic devices for upper and lower extremities. Due to the inherent compliance and natural back-drivability of pneumatic REC actuators, these movement therapy devices provide gentle treatment, whereby the interaction forces between humans and the therapy device are estimated without the use of expensive force/torque sensors. An active model-based gravity compensation based on separated models of the robot and of the individual patient's extremity provides the basis for effective assistive control. The utilization of pneumatic actuators demands a special safety concept, which is merged with control algorithms to provide a sufficient level of safeness and to catch any possible system errors and/or emergency situations. A self-explanatory user interface allows for easy, intuitive handling. Prototypes are very comfortable for use due to several control routines that work in the background. Assistive devices have been tested extensively with several healthy persons; the knee/hip movement therapy device is now under clinical trials at the Clinic for Orthopaedics and Trauma Surgery at the Klinikum Stuttgart. PMID:23241570

  14. 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.

  15. 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.

  16. 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.

  17. High power thrust vector actuation

    NASA Astrophysics Data System (ADS)

    Kittock, M. J.

    1993-06-01

    Modern missile programs are frequently favoring electro-mechanical (EM) thrust vector actuation (TVA) over hydraulic for a variety of reasons. However, actuation system performance requirements are not relaxed for EM systems. Thus the development of EM systems with greater power output is required. The configuration of EM actuator studied consists of a DC brushless motor driving a spur gear train, which drives a ballscrew that converts rotary motion to rectilinear motion. This design produces an actuator with high levels of performance in a compact mechanical package. Design for manufacturability and assembly (DFMA) was part of the design process, resulting in an actuator that can be assembled easily and will operate reliably. This paper will discuss the mechanical details of the resultant actuator and report test results on a prototype derivative.

  18. Controlling robot manipulators by dynamic programming

    NASA Astrophysics Data System (ADS)

    Richard, Marc J.; Cheng, Li

    1995-02-01

    A certain number of considerations should be taken into account in the dynamic control of robot manipulators as highly complex non-linear systems. In this article, we provide a detailed presentation of the mechanical and electrical implications of robots equipped with DC motor actuators. This model takes into account all non-linear aspects of the system. Then, we develop computational algorithms for optimal control based on dynamic programming. The robot's trajectory must be predefined, but performance criteria and constraints applying to the system are not limited and we may adapt them freely to the robot and the task being studied. As an example, a manipulator arm with 3 degress of freedom is analyzed.

  19. Evolving self-assembly in autonomous homogeneous robots: experiments with two physical robots.

    PubMed

    Ampatzis, Christos; Tuci, Elio; Trianni, Vito; Christensen, Anders Lyhne; Dorigo, Marco

    2009-01-01

    This research work illustrates an approach to the design of controllers for self-assembling robots in which the self-assembly is initiated and regulated by perceptual cues that are brought forth by the physical robots through their dynamical interactions. More specifically, we present a homogeneous control system that can achieve assembly between two modules (two fully autonomous robots) of a mobile self-reconfigurable system without a priori introduced behavioral or morphological heterogeneities. The controllers are dynamic neural networks evolved in simulation that directly control all the actuators of the two robots. The neurocontrollers cause the dynamic specialization of the robots by allocating roles between them based solely on their interaction. We show that the best evolved controller proves to be successful when tested on a real hardware platform, the swarm-bot. The performance achieved is similar to the one achieved by existing modular or behavior-based approaches, also due to the effect of an emergent recovery mechanism that was neither explicitly rewarded by the fitness function, nor observed during the evolutionary simulation. Our results suggest that direct access to the orientations or intentions of the other agents is not a necessary condition for robot coordination: Our robots coordinate without direct or explicit communication, contrary to what is assumed by most research works in collective robotics. This work also contributes to strengthening the evidence that evolutionary robotics is a design methodology that can tackle real-world tasks demanding fine sensory-motor coordination. PMID:19463056

  20. Linear Proof-Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III; Crossley, Edward A.; Miller, James B.; Jones, Irby W.; Davis, C. Calvin; Behun, Vaughn D.; Goodrich, Lewis R., Sr.

    1995-01-01

    Linear proof-mass actuator (LPMA) is friction-driven linear mass actuator capable of applying controlled force to structure in outer space to damp out oscillations. Capable of high accelerations and provides smooth, bidirectional travel of mass. Design eliminates gears and belts. LPMA strong enough to be used terrestrially where linear actuators needed to excite or damp out oscillations. High flexibility designed into LPMA by varying size of motors, mass, and length of stroke, and by modifying control software.

  1. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  2. Direct drive field actuator motors

    DOEpatents

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  3. Fault-tolerant rotary actuator

    DOEpatents

    Tesar, Delbert

    2006-10-17

    A fault-tolerant actuator module, in a single containment shell, containing two actuator subsystems that are either asymmetrically or symmetrically laid out is provided. Fault tolerance in the actuators of the present invention is achieved by the employment of dual sets of equal resources. Dual resources are integrated into single modules, with each having the external appearance and functionality of a single set of resources.

  4. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2016-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  5. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2014-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  6. Brachytherapy next generation: robotic systems

    PubMed Central

    Popescu, Tiberiu; Kacsó, Alex Cristian; Pisla, Doina

    2015-01-01

    In a field dominated by external beam radiation therapy (EBRT), both the therapeutic and technical possibilities of brachytherapy (BT) are underrated, shadowed by protons and intensity modulated radiotherapy. Decreasing expertise and indications, as well as increasing lack of specific BT training for radiation therapy (RT) residents led to the real need of shortening its learning curve and making it more popular. Developing robotic BT devices can be a way to mitigate the above issues. There are many teams working at custom-made robotic BT platforms to perfect and overcome the limitations of the existing systems. This paper provides a picture of the current state-of-the-art in robotic assisted BT, as it also conveys the author's solution to the problem, a parallel robot that uses CT-guidance. PMID:26816510

  7. Frequency-weighted feedforward control for dynamic compensation in ionic polymer-metal composite actuators

    NASA Astrophysics Data System (ADS)

    Shan, Yingfeng; Leang, Kam K.

    2009-12-01

    Ionic polymer-metal composites (IPMCs) are innovative materials that offer combined sensing and actuating ability in lightweight and flexible package. IPMCs have been exploited in robotics and a wide variety of biomedical devices, for example, as sensors for teleoperation, as actuators for positioning in active endoscopy, as fins for propelling aquatic robots, and as an injector for drug delivery. In the actuation mode, one of the main challenges is precise position control. In particular, IPMC actuators exhibit relaxation behavior and nonlinearities; and at relatively high operating frequencies dynamic effects limit accuracy and positioning bandwidth. A frequency-weighted feedforward controller is designed to account for the IPMC's structural dynamics to enable fast positioning. The control method is applied to a custom-made Nafion-based IPMC actuator. The controller takes into account the magnitude of the control input to avoid generating excessively large voltages which can damage the IPMC actuator. To account for unmodeled effects not captured by the dynamics model, a feedback controller is integrated with the feedforward controller. Experimental results show a significant improvement in the tracking performance when feedforward control is used. For instance, the feedforward controller shows over 75% reduction in the tracking error compared to the case without feedforward compensation. Finally, the integrated feedforward and feedback control system reduces the tracking error to less than 10% for tracking an 18-Hz triangle-like trajectory. Some of the advantages of feedforward control as well as its limitations are also discussed.

  8. Development of novel single-wall carbon nanotube epoxy composite ply actuators

    NASA Astrophysics Data System (ADS)

    Yun, Yeo-Heung; Shanov, Vesselin; Schulz, Mark J.; Narasimhadevara, Suhasini; Subramaniam, Srinivas; Hurd, Douglas; Boerio, F. J.

    2005-12-01

    This paper describes a carbon nanotube epoxy ply material that has electrochemical actuation properties. The material was formed by dispersing single-wall carbon nanotubes in a solvent and then solution casting a thin paper using a mold and vacuum oven. In order to take advantage of the high elastic modulus of carbon nanotubes for actuation, epoxy as a chemically inert polymer is considered. An epoxy layer was cast on the surface of the nanotube paper to make a two-layer ply. A wet electrochemical actuator was formed by placing the nanotube epoxy ply in a 2 M NaCl electrolyte solution. Electrochemical impedance spectroscopy and cyclic voltammetry were carried out to characterize the electrochemical properties of the actuator. The voltage-current relationship and power to drive the actuator material were also determined. Compared to previous single-wall carbon nanotube buckypaper tape actuators, which had poor adhesion between the nanotubes and tape, and other nanotube-thermal plastic polymer actuators, which could not provide high strength, the epoxy based actuator has a higher elastic modulus and strength, which will be useful for future structural applications. This demonstrates that a polymer layer can reinforce nanotube paper, which is an important step in building a new structural material that actuates. Further work is under way to develop a solid electrolyte to allow dry actuation. Finally, these actuator plies will be laminated to build a carbon nanocomposite material. This smart structural material will have potential applications that range from use in robotic surgical tools to use as structures that change shape.

  9. Highly parallel computer architecture for robotic computation

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    In a computer having a large number of single instruction multiple data (SIMD) processors, each of the SIMD processors has two sets of three individual processor elements controlled by a master control unit and interconnected among a plurality of register file units where data is stored. The register files input and output data in synchronism with a minor cycle clock under control of two slave control units controlling the register file units connected to respective ones of the two sets of processor elements. Depending upon which ones of the register file units are enabled to store or transmit data during a particular minor clock cycle, the processor elements within an SIMD processor are connected in rings or in pipeline arrays, and may exchange data with the internal bus or with neighboring SIMD processors through interface units controlled by respective ones of the two slave control units.

  10. Microbial-powered artificial muscles for autonomous robots

    NASA Astrophysics Data System (ADS)

    Ieropoulos, Ioannis; Anderson, Iain A.; Gisby, Todd; Wang, Cheng-Hung; Rossiter, Jonathan

    2009-03-01

    We consider the embodiment of a microbial fuel cell using artificial muscle actuators. The microbial fuel cell digests organic matter and generates electricity. This energy is stored in a capacitor bank until it is discharged to power one of two complimentary artificial muscle technologies: the dielectric elastomer actuator and the ionic-polymer metal composite. We study the ability of the fuel cell to generate useful actuation and consider appropriate configurations to maximally exploit both of these artificial muscle technologies. A prototype artificial sphincter is implemented using a dielectric elastomer actuator. Stirrer and cilia mechanisms motivate experimentation using ionic polymer metal composite actuators. The ability of the fuel cell to drive both of these technologies opens up new possibilities for truly biomimetic soft artificial robotic organisms.

  11. Complete modeling of rotary ultrasonic motors actuated by traveling flexural waves

    NASA Astrophysics Data System (ADS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph

    2000-06-01

    Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors are being adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and analytical tools for the design of efficient motors are being developed. A hybrid analytical model was developed to address a complete ultrasonic motor as a system. Included in this model is the influence of the rotor dynamics, which was determined experimentally to be important to the motor performance. The analysis employs a 3D finite element model to express the dynamic characteristics of the stator with piezoelectric elements and the rotor. The details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. are included to support practical USM designs. A brush model is used for the interface layer and Coulomb's law for the friction between the stator and the rotor. The theoretical predictions were corroborated experimentally for the motor. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.

  12. Application of robotics in gastrointestinal endoscopy: A review.

    PubMed

    Yeung, Baldwin Po Man; Chiu, Philip Wai Yan

    2016-02-01

    Multiple robotic flexible endoscope platforms have been developed based on cross specialty collaboration between engineers and medical doctors. However, significant number of these platforms have been developed for the natural orifice transluminal endoscopic surgery paradigm. Increasing amount of evidence suggest the focus of development should be placed on advanced endolumenal procedures such as endoscopic submucosal dissection instead. A thorough literature analysis was performed to assess the current status of robotic flexible endoscopic platforms designed for advanced endolumenal procedures. Current efforts are mainly focused on robotic locomotion and robotic instrument control. In the future, advances in actuation and servoing technology, optical analysis, augmented reality and wireless power transmission technology will no doubt further advance the field of robotic endoscopy. Globally, health systems have become increasingly budget conscious; widespread acceptance of robotic endoscopy will depend on careful design to ensure its delivery of a cost effective service. PMID:26855540

  13. Simulated Energy Usage for a Novel 6 DOF Articulated Robot

    NASA Astrophysics Data System (ADS)

    Shaik, A. A.; Tlale, N.; Bright, G.

    2014-07-01

    The serial robot architecture is widespread in modern day manufacturing, and over the last few decades the technology has matured and settled to its current state. One drawback from the architecture however is the location of motors and gearboxes which are either at the joint it controls or close by. A novel hybrid 6 DOF robot was designed to move all the actuators to the robot base, and to control the desired axis through a set of connected links and gears, while maintaining the same workspace and dexterity. This would reduce the inertia of the movable part of the robot and some of the moment arms on the 3 axes required for translation of the 3 DOF spherical wrist. Doing so would decrease the energy requirements when compared to a 6 DOF serial robot. This paper focuses on the mathematical modelling and simulation of the novel hybrid machine design and compares it to an equivalent serial robot.

  14. Application of robotics in gastrointestinal endoscopy: A review

    PubMed Central

    Yeung, Baldwin Po Man; Chiu, Philip Wai Yan

    2016-01-01

    Multiple robotic flexible endoscope platforms have been developed based on cross specialty collaboration between engineers and medical doctors. However, significant number of these platforms have been developed for the natural orifice transluminal endoscopic surgery paradigm. Increasing amount of evidence suggest the focus of development should be placed on advanced endolumenal procedures such as endoscopic submucosal dissection instead. A thorough literature analysis was performed to assess the current status of robotic flexible endoscopic platforms designed for advanced endolumenal procedures. Current efforts are mainly focused on robotic locomotion and robotic instrument control. In the future, advances in actuation and servoing technology, optical analysis, augmented reality and wireless power transmission technology will no doubt further advance the field of robotic endoscopy. Globally, health systems have become increasingly budget conscious; widespread acceptance of robotic endoscopy will depend on careful design to ensure its delivery of a cost effective service. PMID:26855540

  15. Remote operation of robotics systems using WLAN- and CORBA-based architecture

    NASA Astrophysics Data System (ADS)

    Tikanmaki, Antti; Riekki, Jukka P.; Roning, Juha

    2003-10-01

    Our work describes generic solutions for controlling various different robots through IEEE 802.11b Wireless LAN. Our goals have been to develop a remote-operating architecture for robots with different configurations of sensors and actuators, as well as, controlling multiple robots through a wireless network. Our earlier development work on network-distributed control architecture for mobile robots provides a suitable platform for remote operation. In CORBA based architecture, new sensors or actuators, and new automatic functionality are easy to append. In addition to functionality, we have been developing user interfaces that contain generally useful components for multiple purposes and a possibility to control different shapes of robots and multiple robots at the same time. As a basic idea, the user interface should always be easily customizable, platform portable and require only a minimum amount of installation packages.

  16. Piezoelectric actuated gimbal

    DOEpatents

    Tschaggeny, Charles W.; Jones, Warren F.; Bamberg, Eberhard

    2011-09-13

    A gimbal is described and which includes a fixed base member defining an axis of rotation; a second member concentrically oriented relative to the axis of rotation; a linear actuator oriented in immediate, adjoining force transmitting relation relative to the base member or to the second member, and which applies force along a linear axis which is tangential to the axis of rotation so as to cause the second member to rotate coaxially relative to the fixed base member; and an object of interest mounted to the second member such that the object of interest is selectively moved relative to the base member about the axis of rotation.

  17. Pneumatically actuated micropipetting device

    NASA Astrophysics Data System (ADS)

    Szita, Nicolas; Buser, Rudolf A.

    1998-03-01

    We have realized a valveless micropipetting device with an integrated sensor which can aspirate and dispense liquid volumes without any valves, hence without any reflow or dead volume. With an external pneumatic actuation, we have demonstrated aspirating and dispensing from 190nl of 6 (mu) l of water. Measurements showed a standard deviation of down to 1 percent. An integrated capacitive sensor will allow monitoring of the pressure throughout the pipetting process and detect malfunctions, e.g. clotting of the pipetting tip. It is our intention to use this demonstrated precise aspiration mechanism in combination with a micromachined reaction chamber and a miniaturized optical analysis system.

  18. Lead screw linear actuator

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A linear actuator which can apply high forces is described, which includes a reciprocating rod having a threaded portion engaged by a nut that is directly coupled to the rotor of an electric motor. The nut is connected to the rotor in a manner that minimizes loading on the rotor, by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded rod portion, with an oilcarrying groove in the nut being interrupted.

  19. "MRI Stealth" robot for prostate interventions.

    PubMed

    Stoianovici, Dan; Song, Danny; Petrisor, Doru; Ursu, Daniel; Mazilu, Dumitru; Muntener, Michael; Mutener, Michael; Schar, Michael; Patriciu, Alexandru

    2007-01-01

    The paper reports an important achievement in MRI instrumentation, a pneumatic, fully actuated robot located within the scanner alongside the patient and operating under remote control based on the images. Previous MRI robots commonly used piezoelectric actuation limiting their compatibility. Pneumatics is an ideal choice for MRI compatibility because it is decoupled from electromagnetism, but pneumatic actuators were hardly controllable. This achievement was possible due to a recent technology breakthrough, the invention of a new type of pneumatic motor, PneuStep 1, designed for the robot reported here with uncompromised MRI compatibility, high-precision, and medical safety. MrBot is one of the "MRI stealth" robots today (the second is described in this issue by Zangos et al.). Both of these systems are also multi-imager compatible, being able to operate with the imager of choice or cross-imaging modalities. For MRI compatibility the robot is exclusively constructed of nonmagnetic and dielectric materials such as plastics, ceramics, crystals, rubbers and is electricity free. Light-based encoding is used for feedback, so that all electric components are distally located outside the imager's room. MRI robots are modern, digital medical instruments in line with advanced imaging equipment and methods. These allow for accessing patients within closed bore scanners and performing interventions under direct (in scanner) imaging feedback. MRI robots could allow e.g. to biopsy small lesions imaged with cutting edge cancer imaging methods, or precisely deploy localized therapy at cancer foci. Our robot is the first to show the feasibility of fully automated in-scanner interventions. It is customized for the prostate and operates transperineally for needle interventions. It can accommodate various needle drivers for different percutaneous procedures such as biopsy, thermal ablations, or brachytherapy. The first needle driver is customized for fully automated low

  20. "MRI Stealth" robot for prostate interventions.

    PubMed

    Stoianovici, Dan; Song, Danny; Petrisor, Doru; Ursu, Daniel; Mazilu, Dumitru; Muntener, Michael; Mutener, Michael; Schar, Michael; Patriciu, Alexandru

    2007-01-01

    The paper reports an important achievement in MRI instrumentation, a pneumatic, fully actuated robot located within the scanner alongside the patient and operating under remote control based on the images. Previous MRI robots commonly used piezoelectric actuation limiting their compatibility. Pneumatics is an ideal choice for MRI compatibility because it is decoupled from electromagnetism, but pneumatic actuators were hardly controllable. This achievement was possible due to a recent technology breakthrough, the invention of a new type of pneumatic motor, PneuStep 1, designed for the robot reported here with uncompromised MRI compatibility, high-precision, and medical safety. MrBot is one of the "MRI stealth" robots today (the second is described in this issue by Zangos et al.). Both of these systems are also multi-imager compatible, being able to operate with the imager of choice or cross-imaging modalities. For MRI compatibility the robot is exclusively constructed of nonmagnetic and dielectric materials such as plastics, ceramics, crystals, rubbers and is electricity free. Light-based encoding is used for feedback, so that all electric components are distally located outside the imager's room. MRI robots are modern, digital medical instruments in line with advanced imaging equipment and methods. These allow for accessing patients within closed bore scanners and performing interventions under direct (in scanner) imaging feedback. MRI robots could allow e.g. to biopsy small lesions imaged with cutting edge cancer imaging methods, or precisely deploy localized therapy at cancer foci. Our robot is the first to show the feasibility of fully automated in-scanner interventions. It is customized for the prostate and operates transperineally for needle interventions. It can accommodate various needle drivers for different percutaneous procedures such as biopsy, thermal ablations, or brachytherapy. The first needle driver is customized for fully automated low

  1. Robotic system

    NASA Technical Reports Server (NTRS)

    Ambrose, Robert O. (Inventor)

    2003-01-01

    A robot having a plurality of interconnected sections is disclosed. Each of the sections includes components which are moveable relative to components of an adjacent section. A plurality of electric motors are operably connected to at least two of said relatively moveable components to effect relative movement. A fitted, removable protective covering surrounds the sections to protect the robot.

  2. Robotics 101

    ERIC Educational Resources Information Center

    Sultan, Alan

    2011-01-01

    Robots are used in all kinds of industrial settings. They are used to rivet bolts to cars, to move items from one conveyor belt to another, to gather information from other planets, and even to perform some very delicate types of surgery. Anyone who has watched a robot perform its tasks cannot help but be impressed by how it works. This article…

  3. Design of an innovative dielectric elastomer actuator for space applications

    NASA Astrophysics Data System (ADS)

    Branz, Francesco; Sansone, Francesco; Francesconi, Alessandro

    2014-03-01

    The capability of Dielectric Elastomers to show large deformations under high voltage loads has been deeply investigated to develop a number of actuators concepts. From a space systems point of view, the advantages introduced by this class of smart materials are considerable and include high conversion efficiency, distributed actuation, self-sensing capability, light weight and low cost. This paper focuses on the design of a solid-state actuator capable of high positioning resolution. The use of Electroactive Polymers makes this device interesting for space mechanisms applications, such as antenna and sensor pointing, solar array orientation, attitude control, adaptive structures and robotic manipulators. In particular, such actuation suffers neither wear, nor fatigue issues and shows highly damped vibrations, thus requiring no maintenance and transferring low disturbance to the surrounding structures. The main weakness of this actuator is the relatively low force/torque values available. The proposed geometry allows two rotational degrees of freedom, and simulations are performed to measure the expected instant angular deflection at zero load and the stall torque of the actuator under a given high voltage load. Several geometric parameters are varied and their influence on the device behaviour is studied. Simplified relations are extrapolated from the numerical results and represent useful predicting tools for design purposes. Beside the expected static performances, the dynamic behaviour of the device is also assessed and the input/output transfer function is estimated. Finally, a prototype design for laboratory tests is presented; the experimental activity aims to validate the preliminary results obtained by numerical analysis.

  4. Modelling and control of double-cone dielectric elastomer actuator

    NASA Astrophysics Data System (ADS)

    Branz, F.; Francesconi, A.

    2016-09-01

    Among various dielectric elastomer devices, cone actuators are of large interest for their multi-degree-of-freedom design. These objects combine the common advantages of dielectric elastomers (i.e. solid-state actuation, self-sensing capability, high conversion efficiency, light weight and low cost) with the possibility to actuate more than one degree of freedom in a single device. The potential applications of this feature in robotics are huge, making cone actuators very attractive. This work focuses on rotational degrees of freedom to complete existing literature and improve the understanding of such aspect. Simple tools are presented for the performance prediction of the device: finite element method simulations and interpolating relations have been used to assess the actuator steady-state behaviour in terms of torque and rotation as a function of geometric parameters. Results are interpolated by fit relations accounting for all the relevant parameters. The obtained data are validated through comparison with experimental results: steady-state torque and rotation are determined at a given high voltage actuation. In addition, the transient response to step input has been measured and, as a result, the voltage-to-torque and the voltage-to-rotation transfer functions are obtained. Experimental data are collected and used to validate the prediction capability of the transfer function in terms of time response to step input and frequency response. The developed static and dynamic models have been employed to implement a feedback compensator that controls the device motion; the simulated behaviour is compared to experimental data, resulting in a maximum prediction error of 7.5%.

  5. Genetic Optimization and Simulation of a Piezoelectric Pipe-Crawling Inspection Robot

    NASA Technical Reports Server (NTRS)

    Hollinger, Geoffrey A.; Briscoe, Jeri M.

    2004-01-01

    Using the DarwinZk development software, a genetic algorithm (GA) was used to design and optimize a pipe-crawling robot for parameters such as mass, power consumption, and joint extension to further the research of the Miniature Inspection Systems Technology (MIST) team. In an attempt to improve on existing designs, a new robot was developed, the piezo robot. The final proposed design uses piezoelectric expansion actuators to move the robot with a 'chimneying' method employed by mountain climbers and greatly improves on previous designs in load bearing ability, pipe traversing specifications, and field usability. This research shows the advantages of GA assisted design in the field of robotics.

  6. Robot Design

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Martin Marietta Aero and Naval Systems has advanced the CAD art to a very high level at its Robotics Laboratory. One of the company's major projects is construction of a huge Field Material Handling Robot for the Army's Human Engineering Lab. Design of FMR, intended to move heavy and dangerous material such as ammunition, was a triumph in CAD Engineering. Separate computer problems modeled the robot's kinematics and dynamics, yielding such parameters as the strength of materials required for each component, the length of the arms, their degree of freedom and power of hydraulic system needed. The Robotics Lab went a step further and added data enabling computer simulation and animation of the robot's total operational capability under various loading and unloading conditions. NASA computer program (IAC), integrated Analysis Capability Engineering Database was used. Program contains a series of modules that can stand alone or be integrated with data from sensors or software tools.

  7. Robotic Surgery

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Automated Endoscopic System for Optimal Positioning, or AESOP, was developed by Computer Motion, Inc. under a SBIR contract from the Jet Propulsion Lab. AESOP is a robotic endoscopic positioning system used to control the motion of a camera during endoscopic surgery. The camera, which is mounted at the end of a robotic arm, previously had to be held in place by the surgical staff. With AESOP the robotic arm can make more precise and consistent movements. AESOP is also voice controlled by the surgeon. It is hoped that this technology can be used in space repair missions which require precision beyond human dexterity. A new generation of the same technology entitled the ZEUS Robotic Surgical System can make endoscopic procedures even more successful. ZEUS allows the surgeon control various instruments in its robotic arms, allowing for the precision the procedure requires.

  8. Reversible thermosensitive biodegradable polymeric actuators based on confined crystallization.

    PubMed

    Stroganov, Vladislav; Al-Hussein, Mahmoud; Sommer, Jens-Uwe; Janke, Andreas; Zakharchenko, Svetlana; Ionov, Leonid

    2015-03-11

    We discovered a new and unexpected effect of reversible actuation of ultrathin semicrystalline polymer films. The principle was demonstrated on the example of thin polycaprolactone-gelatin bilayer films. These films are unfolded at room temperature, fold at temperature above polycaprolactone melting point, and unfold again at room temperature. The actuation is based on reversible switching of the structure of the hydrophobic polymer (polycaprolactone) upon melting and crystallization. We hypothesize that the origin of this unexpected behavior is the orientation of polycaprolactone chains parallel to the surface of the film, which is retained even after melting and crystallization of the polymer or the "crystallization memory effect". In this way, the crystallization generates a directed force, which causes bending of the film. We used this effect for the design of new generation of fully biodegradable thermoresponsive polymeric actuators, which are highly desirable for bionano-technological applications such as reversible encapsulation of cells and design of swimmers.

  9. Series elastic actuator control of a powered exoskeleton.

    PubMed

    Ragonesi, Daniel; Agrawal, Sunil; Sample, Whitney; Rahman, Tariq

    2011-01-01

    A motorized upper extremity orthosis based on the passive WREX system is being developed. The orthosis is a 4 dof arm controlled by user residual force inputs. The arm is intended for people with neuromuscular weakness due to muscular dystrophy or spinal muscular atrophy. Previous work determined that actuation in parallel with gravity balancing springs required less torque than actuation in series. Compliance is achieved by using a series elastic actuator (SEA) by placing torsional springs between the motors and the WREX. A torque control was implemented on the SEA at the joint level. The response of the control law was characterized without disturbances. The SEAs were then attached to the orthosis to test the response with disturbances, and the control provided accurate joint torques. PMID:22255098

  10. CPU-less robotics: distributed control of biomorphs

    NASA Astrophysics Data System (ADS)

    Etienne-Cummings, Ralph; Lewis, M. Anthony; Hartmann, Mitra; Cohen, Avis H.

    2000-11-01

    Traditional robotics revolves around the microprocessor. All well-known demonstrations of sensory guided motor control, such as jugglers and mobile robots, require at least one CPU. Recently, the availability of fast CPUs have made real-time sensory-motor control possible, however, problems with high power consumption and lack of autonomy still remain. In fact, the best examples of real-time robotics are usually tethered or require large batteries. We present a new paradigm for robotics control that uses no explicit CPU. We use computational sensors that are directly interfaced with adaptive actuation units. The units perform motor control and have learning capabilities. This architecture distributes computation over the entire body of the robot, in every sensor and actuator. Clearly, this is similar to biological sensory- motor systems. Some researchers have tried to model the latter in software, again using CPUs. We demonstrate this idea in with an adaptive locomotion controller chip. The locomotory controller for walking, running, swimming and flying animals is based on a Central Pattern Generator (CPG). CPGs are modeled as systems of coupled non-linear oscillators that control muscles responsible for movement. Here we describe an adaptive CPG model, implemented in a custom VLSI chip, which is used to control an under-actuated and asymmetric robotic leg.

  11. Dual independent displacement-amplified micropumps with a single actuator

    NASA Astrophysics Data System (ADS)

    Tracey, M. C.; Johnston, I. D.; Davis, J. B.; Tan, C. K. L.

    2006-08-01

    We report a dual-micropump structure operated by a single actuator element. The constituent micropumps are a form of micro throttle pump (MTP) comprising a narrow flow channel incorporating two microthrottles. We term this a 'linear MTP' (LMTP). The LMTP's narrowness, in conjunction with an elastomeric substrate, allows multiple, independent, LMTPs to be actuated by a single piezoelectric actuator thereby suiting it to parallel microfluidic architectures. Furthermore, LMTP elements can be combined into parallel or series composites yielding increased maximum pumping rates or back pressures, respectively, when compared to a single LMTP element. The LMTP's flow-channel-like, linear pump chamber minimizes the development of recirculatory flows associated with circular pump chambers which, in part, determine their frequency response and hence maximum pumping rates. We have modelled, fabricated and evaluated a dual-LMTP. We report operation in three modes: as two distinct pumps, as a series composite pump, and as a parallel composite pump. Operating at about 1.6 kHz, with both pumps under identical load conditions, each pump yielded maximum pumping rates of about 750 µl min-1 and back pressures of 18 kPa, both with close matching. Configured as a series composite, a 35 kPa back pressure was achieved, and configured as a parallel composite, a maximum pumping rate of 1.4 ml min-1 resulted. Images of 5 µm polystyrene beads flowing within an LMTP confirm minimal recirculatory behaviour consistent with the LMTP's increased operating frequencies compared to circular pump chamber MTPs.

  12. Multi-material additive manufacturing of robot components with integrated sensor arrays

    NASA Astrophysics Data System (ADS)

    Saari, Matt; Cox, Bryan; Galla, Matt; Krueger, Paul S.; Richer, Edmond; Cohen, Adam L.

    2015-06-01

    Fabricating a robotic component comprising 100s of distributed, connected sensors can be very difficult with current approaches. To address these challenges, we are developing a novel additive manufacturing technology to enable the integrated fabrication of robotic structural elements with distributed, interconnected sensors and actuators. The focus is on resistive and capacitive sensors and electromagnetic actuators, though others are anticipated. Anticipated applications beyond robotics include advanced prosthetics, wearable electronics, and defense electronics. This paper presents preliminary results for printing polymers and conductive material simultaneously to form small sensor arrays. Approaches to optimizing sensor performance are discussed.

  13. Parallel rendering

    NASA Technical Reports Server (NTRS)

    Crockett, Thomas W.

    1995-01-01

    This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering problem. We also explore concepts from computer graphics, such as coherence and projection, which have a significant impact on the structure of parallel rendering algorithms. Our survey covers a number of practical considerations as well, including the choice of architectural platform, communication and memory requirements, and the problem of image assembly and display. We illustrate the discussion with numerous examples from the parallel rendering literature, representing most of the principal rendering methods currently used in computer graphics.

  14. A family of asymptotically stable control laws for flexible robots based on a passivity approach

    NASA Technical Reports Server (NTRS)

    Lanari, Leonardo; Wen, John T.

    1991-01-01

    A general family of asymptotically stabilizing control laws is introduced for a class of nonlinear Hamiltonian systems. The inherent passivity property of this class of systems and the Passivity Theorem are used to show the closed-loop input/output stability which is then related to the internal state space stability through the stabilizability and detectability condition. Applications of these results include fully actuated robots, flexible joint robots, and robots with link flexibility.

  15. Actuator operated microvalves

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor)

    2008-01-01

    An actuator operated microvalve and the method of making same is disclosed and claimed. The microvalve comprises a SiC housing which includes a first lower portion and a second upper portion. The lower portion of the SiC housing includes a passageway therethrough, a microvalve seat, and a moveable SiC diaphragm. The SiC diaphragm includes a centrally located boss and radially extending corrugations which may be sinusoidally shaped. The boss of the SiC diaphragm moves and modulates in a range of positions between a closed position wherein the boss interengages said microvalve seat prohibiting communication of fluid through the passageway and a fully open position when the boss is spaced apart from the seat at its maximum permitting communication of fluid through said passageway. The actuator includes a SiC top plate affixed to the boss of the diaphragm and a first electrode and the second upper portion of the SiC housing further includes a second electrode.

  16. Exploring Toe Walking in a Bipedal Robot

    NASA Astrophysics Data System (ADS)

    Smith, James Andrew; Seyfarth, Andre

    The design and development of locomotory subsystems such as legs is a key issue in the broader topic of autonomous mobile systems. Simplification of substructures, sensing, actuation and control can aid to better understand the dynamics of legged locomotion and will make the implementation of legs in engineered systems more effective. This paper examines recent results in the development of toe walking on the JenaWalker II robot. The robot is shown, while supported on a treadmill, to be capable of accelerating from 0 to over 0.6 m/s without adjustment of control parameters such as hip actuator sweep frequency or amplitude. The resulting stable motion is due to the adaptability of the passive structures incorporated into the legs. The roles of the individual muscletendon groups are examined and a potential configuration for future heel-toe trials is suggested.

  17. Designing light responsive bistable arches for rapid, remotely triggered actuation

    NASA Astrophysics Data System (ADS)

    Smith, Matthew L.; Shankar, M. Ravi; Backman, Ryan; Tondiglia, Vincent P.; Lee, Kyung Min; McConney, Michael E.; Wang, David H.; Tan, Loon-Seng; White, Timothy J.

    2014-03-01

    Light responsive azobenzene functionalized polymer networks enjoy several advantages as actuator candidates including the ability to be remotely triggered and the capacity for highly tunable control via light intensity, polarization, wavelength and material alignments. One signi cant challenge hindering these materials from being employed in applications is their often relatively slow actuation rates and low power densities, especially in the absence of photo-thermal e ects. One well known strategy employed in nature for increasing actuation rate and power output is the storage and quick release of elastic energy (e.g., the Venus ytrap). Using nature as inspiration we have conducted a series of experiments and developed an equilibrium mechanics model for investigating remotely triggered snap-through of bistable light responsive arches made from glassy azobenzene functionalized polymers. After brie y discussing experimental observations we consider in detail a geometrically exact, planar rod model of photomechanical snap-through. Theoretical energy release characteristics and unique strain eld pro les provide insight toward design strategies for improved actuator performance. The bistable light responsive arches presented here are potentially a powerful option for remotely triggered, rapid motion from apparently passive structures in applications such as binary optical switches and positioners, surfaces with morphing topologies, and impulse locomotion in micro or millimeter scale robotics.

  18. Electro-active paper for a durable biomimetic actuator

    NASA Astrophysics Data System (ADS)

    Yun, Sung-Ryul; Yun, Gyu Young; Kim, Jung Hwan; Chen, Yi; Kim, Jaehwan

    2009-02-01

    Cellulose electro-active paper (EAPap), known as a smart material, has merits in terms of low voltage operation, light weight, dryness, low power consumption, biodegradability, abundance and low price. Since EAPap requires low power consumption, a remotely driven actuator has been proposed using microwave power transmission. This concept is attractive for many biomimetic systems such as crawling micro-insect robots, flying objects like dragon flies and smart wallpapers. However, the actuation performance of EAPap is sensitive to humidity and degrades with time. Thus, in this paper, a durable EAPap is studied. The fabrication of EAPap is explained and the actuation performance is shown with applied electric field, frequency, humidity level and time. The fabrication process includes dissolving cellulose fibers, eliminating solvent and Li ions with a mixture of deionized water and isopropyl alcohol, washing with water, drying and coating with gold. The morphology of the fabricated EAPap is analyzed by taking scanning electron microscope images and x-ray diffractograms. The actuation performance is tested in terms of bending displacement with frequency, time and humidity level

  19. Conducting IPN actuator/sensor for biomimetic vibrissa system

    NASA Astrophysics Data System (ADS)

    Festin, N.; Plesse, C.; Pirim, P.; Chevrot, C.; Vidal, F.

    2014-03-01

    Electroactive polymers, or EAPs, are polymers that exhibit a change in size or shape when stimulated by an electric field. The most common applications of this type of material are in actuators and sensors. One promising technology is the elaboration of electronic conducting polymers based actuators with Interpenetrating Polymer Networks (IPNs) architecture. Their many advantageous properties as low working voltage, light weight and high lifetime make them very attractive for various applications including robotics. Conducting IPNs were fabricated by oxidative polymerization of 3,4-ethylenedioxythiophene within a flexible Solid Polymer Electrolytes (SPE) combining poly(ethylene oxide) and Nitrile Butadiene Rubber. SPE mechanical properties and ionic conductivities in the presence of 1-ethyl-3- methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMITFSI) have been characterized. The presence of the elastomer within the SPE greatly improves the actuator performances. The free strain as well as the blocking force was characterized as a function of the actuator length. The sensing properties of those conducting IPNs allow their integration into a biomimetic perception prototype: a system mimicking the tactile perception of rat vibrissae.

  20. IPMC actuator array as a 3D haptic display

    NASA Astrophysics Data System (ADS)

    Nakano, Masanori; Mazzone, Andrea; Piffaretti, Filippo; Gassert, Roger; Nakao, Masayuki; Bleuler, Hannes

    2005-05-01

    Based on the concept of Mazzone et al., we have designed a novel system to be used simultaneously as an input and output device for designing, presenting, or recognizing objects in three-dimensional space. Unlike state of the art stereoscopic display technologies that generate a virtual image of a three-dimensional object, the proposed system, a "digital clay" like device, physically imitates the desired object. The object can not only be touched and explored intuitively but also deform itself physically. In order to succeed in developing such a deformable structure, self-actuating ionic polymer-metal composite (IPMC) materials are proposed. IPMC is a type of electro active polymer (EAP) and has recently been drawing much attention. It has high force to weight ratio and shape flexibility, making it ideal for robotic applications. This paper introduces the first steps and results in the attempt of developing such a structure. A strip consisting of four actuators arranged in line was fabricated and evaluated, showing promising capabilities in deforming two-dimensionally. A simple model to simulate the deformation of an IPMC actuator using finite element methods (FEM) is also proposed and compared with the experimental results. The model can easily be implemented into computer aided engineering (CAE) software. This will expand the application possibilities of IPMCs. Furthermore, a novel method for creating multiple actuators on one membrane with a laser machining tool is introduced.