Design of a reference signal generator for an upper limb prosthesis myoelectric controller

Abstract

Since 1950s, the surface electromyographic signals are used by most of the electrically powered prostheses. These signals are collected from the skin surface and used indirectly as reference signals for the controller of the prostheses. Due to the nature of these signals it is impractical to feed these signals as inputs directly into the controller. The signals should be processed first, by segmentation, features extraction and features processing. Since only a limited number of muscles are used (usually two or three) a one-to-one correspondence between a muscle and a joint of the prosthesis cannot be established. Thus, the myoelectric control is unnatural, requires long periods for training and involves a great mental effort for the patient. We propose a reference signal generator (RSG), which is an interface module that receives the movement intentions of the patient and generates the position and speed reference signals for the controller. By means of the RSG the burden of the patient is reduced drastically and in the same time the safety in using the prosthesis is increased.