Noise cancellation for electrotactile sensory feedback of myoelectric forearm prostheses

For achieving a closed-loop, bidirectional control over myoelectric prosthetic hands, adopting the electrical stimulation in the sensory feedback channel for providing electrotactile substitution is currently a big trend. However, the electrical pulses used for stimulation may spread to the EMG collection sites which significantly interferes the controlling stability. In this paper, a novel noise cancellation method is proposed to suppress the interference between the electrotactile feedback subsystem and the electromyographic collection subsystem. Based on the propagation model of the stimulation noise, this method integrates the optimization of the stimulation waveform, the special design of the stimulation electrode and the advanced technique of digital signal processing. Experiments on healthy subjects are conducted to verify the feasibility of the proposed method. Primary results show that, through the method, the signal to noise rate (SNR) of the EMG signals reaches to 43dB, without frequency or time multiplexing.