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ABSTRACT: This paper presents the design of a gas-actuated anthropomorphic arm prosthesis with 21 degrees of freedom and nine independent actuators. The prosthesis utilizes the monopropellant hydrogen peroxide as a gas generator to power nine pneumatic type actuators. Of the nine independent actuators, one provides direct- drive actuation of the elbow, three provide direct-drive actuation for the wrist, and the remaining five actuate an underactuated 17 degree of freedom hand. This paper describes the design of the prosthesis, including the design of small-scale high-performance servovalves, which enable the implementation of the monopropellant concept in a transhumeral prosthesis. Experimental results are given characterizing both the servovalve performance and the force and/or motion control of various joints under closed-loop control.
IEEE Transactions on Robotics 03/2008; · 2.54 Impact Factor
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ABSTRACT: This paper presents progress towards the development of a gas-actuated anthropomorphic arm prosthesis with 21 degrees of freedom and nine independent actuators. The system is designed to utilize the monopropellant hydrogen peroxide as a gas generator in order to power the nine pneumatic-type actuators. The design incorporates four actuators to provide direct-drive actuation of the elbow joint and three wrist degrees-of-freedom, while the remaining five actuate an underactuated 17 degree-of-freedom hand. This paper describes the prosthesis design, including the design of small-scale high-performance servovalves that enable implementation of the monopropellant concept in a transhumeral prosthesis. Video frame sequences of the prosthesis under closed loop control demonstrate its functionality in performing tasks representative of activities of daily living.
Rehabilitation Robotics, 2007. ICORR 2007. IEEE 10th International Conference on; 07/2007
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ABSTRACT: This paper presents the design of an anthropomorphic 21 degree-of-freedom, 9 degree-of-actuation arm prosthesis for use by transhumeral amputees. The design leverages the power density of pneumatic actuation with the energy density of liquid propellants to obtain a self-powered dexterous prosthesis in which all of the requisite power, actuation, and sensing is packaged within the volumetric envelope of a normal human arm. Specifically, the arm utilizes a monopropellant as a gas generator to power nine pneumatic-type actuators that drive an elbow, three wrist degrees-of-freedom, and a 17 degree-of-freedom compliant hand. The design considerations discussed in this work include the design of compact, low-power servovalves; the choice of actuators based on energetic requirements of a normal arm; the design of compact elbow and wrist joints with integrated position and force sensing; and the components of the compliant hand design. The liquid-fueled prosthesis is expected to approach the dexterity of an anatomical arm and is projected to deliver half of the force and power output of an average human arm.
Robotics and Automation, 2007 IEEE International Conference on; 05/2007
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ABSTRACT: This paper describes the design of a 21 degree-of-freedom, nine degree-of-actuation, gas-actuated arm prosthesis for transhumeral amputees. The arm incorporates a direct-drive elbow and three degree-of-freedom wrist, in addition to a 17 degree-of-freedom underactuated hand effected by five actuators. The anthropomorphic device includes full position and force sensing capability for each actuated degree of freedom and integrates a monopropellant-powered gas generator to provide on-board power for untethered operation. Design considerations addressed in this paper include the sizing of pneumatic actuators based on the requisite output energy at each joint; the development of small low-power servovalves for use with hot/cold gases; the design of compact joints with integrated position sensing; and the packaging of the actuators, on-board power, and skeletal structure within the volumetric envelope of a normal human forearm and elbow. The resulting arm prototype approaches the dexterous manipulation capabilities of its anatomical counterpart while delivering approximately 50% of the force and power output of an average human arm
Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE; 10/2006
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ABSTRACT: This paper describes a direct-injection configuration of a monopropellant-powered actuator that is intended to provide high-energy-density actuation for a self-powered position- or force-controlled human-scale robot. The proposed actuator is pressurized by a pair of solenoid injection valves (each of which control the flow of a monopropellant through a catalyst pack and directly into the respective side of a pneumatic-type cylinder), and depressurized via a three-way hot-gas proportional exhaust valve. A controller is described that coordinates the control of the two solenoid propellant injection valves, together with the control of the proportional hot-gas exhaust valve, in order to provide actuator force tracking. Experimental results are presented that validate the effectiveness of the force-control approach. Finally, energetic performance of the proposed actuator is experimentally assessed and shown to provide an energetic figure of merit, an order of magnitude greater than that of a battery-powered servomotor approach
IEEE/ASME Transactions on Mechatronics 09/2006; · 2.87 Impact Factor
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ABSTRACT: This paper describes the design and energetic characterization of an actuator designed to provide enhanced system energy and power density for self-powered robots. The proposed actuator is similar to a typical compressible gas fluid-powered actuator, but pressurizes the respective cylinder chambers via a pair of proportional injector valves, which control the flow of a liquid monopropellant through a pair of catalyst packs and into the respective sides of the double-acting cylinder. This paper describes the design of the proportional injection valves and describes the structure of a force controller for the actuator. Finally, an energetic characterization of the actuator shows improvement relative to prior configurations and marked improvement relative to state-of-the-art batteries and motors.
IEEE/ASME Transactions on Mechatronics 05/2006; · 2.87 Impact Factor
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ABSTRACT: This paper presents and experimentally demonstrates a control methodology that provides transparency and stability robustness in bilateral telemanipulator systems. The approach is based upon a previously published method that structures the human-manipulators-environment system in a manner that enables the application of frequency-domain loop-shaping methods. This paper reformulates the human-manipulator interaction described in the previously published work, and experimentally demonstrates the approach on a single degree-of-freedom telemanipulation system. Experimental measurements indicate significant improvements offered by the method in both the stability robustness and transparency of the human-manipulators-environment system. Finally, experimental results are presented that demonstrate the robustness in the transparency to significant changes in the environment dynamics.
IEEE Transactions on Robotics and Automation 07/2004;
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ABSTRACT: This paper presents a method for providing stability and robust transparency in bilateral teleoperator loops that include a time delay in the communication channel. Specifically, the proposed approach incorporates an adaptive Smith predictor within a frequency domain loop shaping approach that addresses both stability and transparency of the teleoperator loop. Experimental results are presented that demonstrate the effectiveness of the approach.
Advanced Intelligent Mechatronics, 2003. AIM 2003. Proceedings. 2003 IEEE/ASME International Conference on; 08/2003
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ABSTRACT: This paper describes the modeling and control of a direct-injection monopropellant-powered actuator. The actuation system utilizes the catalytic decomposition of a monopropellant, the products of which are directly injected into opposing chambers of a pneumatic cylinder in order to obtain a controllable force source. The system incorporates a pair of proportional liquid fuel valves and a three-way rotary spool valve to control the pressurization and depressurization of each chamber of the actuator. A model of the catalytic decomposition of the monopropellant and the compressible gas dynamics is derived in order to control the output force of the hot gas actuator. Using a Lyapunov function, a model-based sliding mode controller is developed for the multi-input single-output nonlinear system. Experimental results of the actuator force tracking demonstrate the validity of the model of the monopropellant-based actuator and the performance of the nonlinear controller.
American Control Conference, 2004. Proceedings of the 2004;
