Kinematic design of a linkage driven robotic hand for prosthetics capable of achieving ten grips

Developing low-cost upper-limb prosthetics for amputees in developing countries is an important problem. In this paper we have discussed the development of a robotic prosthetic hand capable of producing ten grip patterns. We have done a short qualitative survey of commercial prosthetic hands. The tradeoffs for selecting the number of motors providing maximum number of functional grips by the hand has been discussed. Position of the thumb for pinch grip has been determined. The position and orientation of other fingers have been determined based on anthropomorphic data. The fingers of the hand are driven by a linkage mechanism. Two phalanges of each finger are coupled by a four bar mechanism. The actuation mechanism and the placement of the motors have also been discussed.