Design A Prototype Of Underactuated Prosthetic Hand

Nowadays lots of human prosthetic hands are designed; they all followed the idea of the dexterous hands, which using high performance motors, sensors or other new technology to get more freedom or feeling. However the more motors are deployed, the more requirements to the bio-mechanical interface and the power will be higher. Because of the limitations of biological/mechanical interface technology, most of the prosthetic hands are low dexterousness and functionality, and with high weight, these kinds of hands are unaccepted by the market.In order to resolve the problem, a prototype of underactuated prosthetic hand is designed and developed. The hand has 15 revolute joints, actuated by 4 motors. The hand is more dexterous, more energy solving and smaller size. It can grasp different objects, like the mobile phones, the books, the bottles, the pingpong balls and etc, and has the good force distribution capability.This thesis introduces two main innovative structures first: One is underactuated finger; another is a miniature differential mechanism which is embedded inside the palm of the hand to control the differential motion of the two fingers. Then the kinematics and statics models of fingers are established and analyzed. Finally it gives the test outcome to validate the performance of this underacutated hand. Experimental results show that the hand has desirable performance in shape adaptive grasp. In addition, it is capable of imitating human grasp by using a human-machine interface.