ABSTRACT:

This study proposes a real-time joint angle estimation method of human elbow by processing a biomedical signal of surface synergistic EMG (electromyogram) measured between biceps brachii and triceps brachii simultaneously. Actually, the EMG is known as a non-stationary signal, but the authors assume that it is quasi-stationary because a physical or physiological system has limitations in the rate at which it can change its characteristics. Based on the assumption, a pre-processing method to obtain pre-angle values from the raw synergistic EMG signal is firstly suggested, and then a method to estimate the joint angle through normalisation when there are external loads is discussed. In addition, an optimisation method to minimise the error between the normalised angle and real joint angle is proposed. Finally, the authors show the effectiveness of the suggested algorithm through experimental results.