A Trans-Humeral Ortho-Prosthesis: Towards Power Assistive Prostheses

An ortho-prosthesis is a combination of a prosthesis and an orthosis capable of reproducing the functionality of a missing body part while providing power-assistance to the remaining body part. In this paper, a nine degrees of freedom (DOF) trans-humeral ortho-prosthesis is proposed. The prosthesis unit has five DOF; whereas orthosis unit has four DOF. The prosthesis unit is capable of performing elbow flexion/extension, forearm supination/pronation, ulnar/radial deviation, wrist flex-ion/extension and compound motion of thumb and index finger. The orthosis unit can achieve shoulder movements such as abduction/adduction, vertical flexion/extension, horizontal flexion/extension, and internal/external rotation. The prosthesis unit is serially mounted on the orthosis unit and overall weight of the system is directly transferred on to the back of the human. Simulation results have verified the effectiveness of the proposed design to carry out activities of daily living.