Design and control of a multifunction myoelectric hand with new adaptive grasping and self-locking mechanisms

This paper presents a multifunction myoelectric hand that is designed with underactuated mechanisms. The finger design allows an adaptive grasp, including adaptation between fingers and phalanges with respect to the shape of an object. In addition, a self-lock is embedded in the metacarpophalangeal joint to prevent back driving when external forces act on the fingers. The thumb design also provides adaptation between phalanges and adds an intermittent rotary motion to the carpometacarpal joint. As a result, the hand can perform versatile grasping motions using only two motors, and is capable of natural and stable grasping without complex sensor and servo systems. Moreover, the adaptive grasping capabilities reduce the requirements of electromyogram pattern recognition, as analogous motions, such as cylindrical and tip grasps, can be classified as one motion.