Continuous Estimation of Wrist Torque from Surface EMG Signals Using Path-dependent Model

Continuous estimation of wrist torque from surface electromyography （EMG） signals has been studied by some research institutes. Hysteresis effect is a phenomenon in EMG force relationship. In this work, a path-dependent model based on hysteresis effect was used for continuously estimating wrist torque from surface EMG signals. The surface EMG signals of the flexor carpi ulnaris （FCU） and extensor carpi radialis （ECR） were collected along with wrist torque of flexion/extension degree-of-freedom. EMG signal of FCU was used to estimate the torque of wrist flexion and EMG signal of ECR to estimate the torque of wrist extension. The existence of hysteresis effect has been proven either during wrist flexion or extension on all subjects. And the estimation performance of path-dependent model is much better than the overall model. Thus, the path-dependent model is suitable to improve the wrist torque＇s estimation accuracy.