The design of a prosthetic device for patients who have suffered loss of muscular control of the hand is described. The authors present some preliminary design considerations, with emphasis on the sensing and actuation systems. The prototype achieves several movements of the fingers of the hand. The design is closely based on the natural human hand to ensure effectiveness and comfort. The exoskeleton is worn as a tight glove, and the joints are flexed by cables and motors. Some preliminary test results are reported.

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This invention, referred to as an Energy-Efficient Running Aid, relates to passive (spring-actuated) running/walking aids for ortheses, prostheses, and robotsto allow faster running using less energy. The full invention is an leg ortheses or an energy-efficient running brace. It is a running brace which acts in parallel with a runner’s leg to support the runner during stance phase and to capture all foot-impact energy, preferably with the optimal constant-force curve, for use to thrust said runner back into the air during toe-off. Novel structural elements include a hyper-extending knee-lock, a variable-angle knee-lock, a kneeless adjustable-length brace, a self-guiding/constant force bow spring, a pulley-based/constant-force bow spring, a asymmetric brace foot, a load-tightening full harness, and a means to guarantee lock release at toe-off. The running brace eliminates impact injuries by absorbing the impact energy.

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The Rutgers Master II-ND glove is a haptic interface designed for dextrous interactions with virtual environments. The glove provides force feedback up to 16 N each to the thumb, index, middle, and ring fingertips. It uses custom pneumatic actuators arranged in a direct-drive configuration in the palm. Unlike commercial haptic gloves, the direct-drive actuators make unnecessary cables and pulleys, resulting in a more compact and lighter structure. The force-feedback structure also serves as position measuring exoskeleton, by integrating noncontact Hall-effect and infrared sensors. The glove is connected to a haptic-control interface that reads its sensors and servos its actuators. The interface has pneumatic servovalves, signal conditioning electronics, A/D/A boards, power supply and an imbedded Pentium PC. This distributed computing assures much faster control bandwidth than would otherwise be possible. Communication with the host PC is done over an RS232 line. Comparative data with the Cyber-Grasp commercial haptic glove is presented.

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Methods are provided for stabilizing a haptic interface of a computer-controlled one-port virtual-reality system or a two-port teleoperation system comprising a robot manipulator. «Stabilizing» means to reduce the sense of vibration in a haptic interface. A Passivity Observer is computed to measure the amount of ener gy produced at the haptic interface, and a Passivity Controller is calculated to damp or absorb excess energy which causes the sense of vibration. This inventi on also provides a «filter,» i.e. a threshold function which returns zero velocity if the computed estimated velocity is less than a small predetermined value, which may be applied to estimated velocities determined in impedance-based methods of this invention so as to remove noise in the velocity estimate. To improve speed of reaction of the systems, this invention also provides methods for resetting the Passivity Observer to zero when it has been too positive for too long a period of time. Systems implementing these methods are also provided.

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This paper analyzes the general requirements of Haptic Interfaces (HIs) for Virtual Prototyping operations. In particular two different paradigms of interaction with virtual objects are presented, respectively based on an anthropomorphic and a desktop Haptic Interface. The main aspects of mechanical and control system design of HIs and force rendering in Virtual Environments are discussed too. The experimental results of the simulations conducted with a force feedback arm exoskeleton are presented, pointing out the current limits of the existing devices and outlining the future developments.

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