Design of a Highly Compliant Underactuated Prosthetic Hand

This paper presents a highly compliant prosthetic hand based on a novel synergy mechanism. The prosthetic hand consists of a synergy mechanism, four fingers and one thumb. The synergy mechanism can transmit the power from two motors to four fingers. It can effectively reduce the number of motors. At the same time, it makes the prosthetic hand have excellent dexterity. The underactuated finger has three joints with two DOF. It has two main motion modes: coupled motion in free space and self-adaptive motion when contacting with the object, which can mimic the human finger as much as possible. The thumb uses one motor to drive the two flexion-extension joints and uses a manual switch to drive the abduction-adduction joint, which can reduce the number of motors and the cost efficiently. The performance evaluation is given to demonstrate the comprehensive performance in terms of the versatility, compliance, sensing, size, weight and cost of the proposed design.