POWERED WRIST ACTUATOR

Abstract

The human arm is certainly the most powerful tool a human being has. It is utilized in every task a human performs, from simple tasks like getting up or sitting on a chair to extreme sports like mountain climbing or squash and tennis. The absence of this tool due to any number of reasons can be very disturbing for the amputee and this disability can be mentally and physically torturing. So the modern science is doing its level best to create artificial limbs that can replace the natural arm. As the human arm consists of three separate joints, namely the wrist, elbow and shoulder joint, the amputation can also be of different types, like above elbow, below elbow or complete arm amputation from the shoulder joint. This requires that separate prosthetic joints should be available that can be easily attached either to the human user or can be attached to each other to form a complete prosthetic arm. The purpose of this thesis was to create a prosthetic wrist joint that can behave like a human wrist and can be easily carried by a human user. So a 2-DOF powered prosthetic wrist actuator has been proposed that can provide the Abduction/Adduction & Flexion/Extension movements of the human wrist. The basic structure of the actuator is a Ball & Socket joint and the force is transmitted from the DC geared servo motors to the joint through the Bowden cables. The proposed design is capable of providing the required degrees of rotation in both axes i.e. 85° & 90° in flexion extension axis. The size and weight of the actuator lies within the ranges of an average human being’s wrist.