This correspondence presents a prototype of a powered hand exoskeleton that is designed to fit over the gloved hand of an astronaut and offset the stiffness of the pressurized space suit. This will keep the productive time spent in extravehicular activity from being constrained by hand fatigue. The exoskeleton has a three-finger design, the third and fourth fingers being combined to lighten and simplify the assembly. The motions of the hand are monitored by an array of pressure sensors mounted between theexoskeleton and the hand. Controller commands are determined by a state-of-the-art programmable microcontroller using pressure sensor input. These commands are applied to a PWM driven DC motor array which provides the motive power to move theexoskeleton fingers. The resultant motion of the exoskeleton allows the astronaut to perform both precision grasping tasks with the thumb and forefinger, as well as a power grasp with the entire hand.

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This paper considers adding autonomy to robot hands used in teleoperation systems. Currently, the finger positions of robot hands in teleoperation systems are controlled via a robot master using a Dataglove or exoskeleton. There are several difficulties with this approach: accurate calibration is hard to achieve; robot hands have different capabilities from human hands; and complex force reflection is difficult. In this paper we propose a model of hand teleoperation in which the input device commands the motions of a grasped object rather than the joint displacements of the fingers. To achieve this goal, the hand requires greater autonomy and the capability to perform high-level functions with minimal external input. Therefore, a set of general, primitive manipulation functions that can be performed automatically is defined. These elementary functions control simple rotations and translations of the grasped objects. They are incorporated into a teleoperation system by using a simple input device as a control signal. Preliminary implementations with a Utah/MIT are discussed.

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The control of exploratory and manipulative procedures in teleoperation and virtual environments requires the availability of adequate advanced interfaces capable not only of recording the movements of the human hands and arms, but also of replicating sensations of contact and collisions. In this paper the problem of replicating external forces acting against the remote/virtual arm is addressed. The design of an arm exoskeleton system developed in the authors’ laboratory is presented. The exoskeletonconsists of a 7 DOF actuated and sensorized mechanical structure wrapping up completely the human arm and directly supported by the shoulders and the trunk of the human operator. Emphasis is given to the implemented control procedures and to the description of the transputer-based control architecture.

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An exoskeleton system is being developed to aid in the mobilization of walking-impaired patients. New approaches to personal robotic assists have solved many classic problems with weight, power, endurance, and cost. A versatile platform of development allows for many variations and applications including mobility assist for the paralyzed, amputee, and spastic patient (MAPAS). A variety of strap on supports and braces are used, depending on the magnitude of the forces required. The MAPAS system utilizes compressed gas to power the main force producing elements, or muscles. Pneumatic muscles are used to provide controllable joint torque with moderate levels of pressure. These muscles are mounted to the brace, providing pull-only torque to joints. The MAPAS control system features interpreted joint mapping. The function of each leg joint is primarily directed through the output of a finger joint sensor. A six to eight sensor hand goniometer provides the system with user input. Higher control features actuated by on-board intelligent devices enable finger joint inputs to be enhanced providing balance, gait anticipation, fault-recovery, and spasm signature compensation. Ambient pressure levels of on-board reservoirs can be changed to suit changing environments ranging from heavily loaded amputee walking up stairs to the slight correction of a mild spasm. The entire system is portable with on-board batteries, compressed air reservoirs, intelligent algorithms, and goniometric sensors.

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The development of haptic systems for VR and telepresence has been identified as a key feature in the progression from observation of the environment to interaction. Arm masters and exoskeletons have formed an important user interface for the provision of such facilities, with these devices requiring a subtle combination of complex mechanical, electrical and kinematic structures with user requirements of low mass, portability, comfort, flexibility and safety. The actuation system is often identified as a focus of this design blending process. This work considers the design, construction and testing of a light weight comfortable high power 7 degree of freedom force feedback exoskeleton. This is achieved through the use, modeling and control of pneumatic muscle actuators (pMA) that provide lightweight, low cost, flexible, portable, comfortable and inherently safe input/feedback/control operation. Models of operation in a virtual environment are developed and demonstrated, with experimental results to illustrate the effectiveness of the device in replicating contact forces and creating a sensation of virtual presence.

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