Design and control of an underactuated prosthetic hand

Abstract

The robotic hands can be divided into two major groups: fully-actuated and underactuated hands. In fully-actuated hands all the joints have separate motors, while in underactuated hands the number of motors is less than number of degrees of freedom. The underactuated hands can adapt to the object shape by use of their mechanical design while they have less functionality. A relationship between forces and displacement is found through virtual work method. Based on this relationship an analytical approach is used to optimize hand based on two criteria: isotopic force and maximum chance of stable grasping. A PD type of controller is designed for this class of hands and the functionality of designed hand is compared with fully actuated hand using virtual spring damper hypothesis.