Reciprocal EMG controlled FES for pathological tremor suppression of forearm

A novel assistive system is designed to suppress pathological tremor of forearm via functional electrical stimulation (FES). It aims to attenuate the tremor with the minimum effect on the voluntary movement. Surface electromyograph (EMG) is adopted as the sensing feedback information to regulate FES. A two-stage filter is proposed to process the raw EMG signal. The first stage removes the artifacts in the raw EMG signal contaminated by FES. The second stage filter separates the high frequency tremulous EMG from the low frequency voluntary components. The extracted tremor EMG of biceps and triceps will then be used as control input in the FES controller to stimulate the two muscles reciprocally. This paper presents the design and implementation of the first stage of the two-stage filter. Experiments on healthy subjects have shown promising results.