Control and assessment of transhumeral prosthetic system

Abstract

Traditional upper extremity prostheses are comprised of an elbow joint and a terminal device (often either a split-hook or a hand) and have typically been limited to a single control input. In the case of a myoelectric prosthesis, a single pair of electromyograms (EMG) inputs from the biceps and triceps muscles, respectively, is typically used to control both the elbow and terminal device. Dependence on a single input forces the prosthesis to be controlled in a sequential manner, where either the hand or elbow is controlled at any given time. With fewer inputs to control more joints, new control strategies are required to provide a transhumeral amputee with control of a limb that feels intuitive and natural. The objective of this work is the development of highly functional and intuitive coordinated controller for an arm prosthesis that exhibits improved functionality relative to existing prostheses. This work leverages recent advances in MEMS in order develop a controller that enables the simultaneous movement of the anatomical shoulder joint and prosthetic elbow joint, and also enables switching between control of a hand and elbow, and is used in conjunction with EMG input to provide enhanced whole arm (hand and elbow) control, relative to the traditional conventional control approach. This work involves implementing the control methods on a prosthesis prototype and conducting studies on amputee subject to assess the effectiveness of the coordinated controller in performing different reaching tasks relative to traditional sequential control devices.