Design Of Wireless Wearable Surface EMG Signal Acquisition System

Surface electromyography(sEMG)is a comprehensive bioelectrical phenomenon produced by the conduction of electrical signals through the tissue fluid in the human epidermis.It has the advantages of not causing harm to the human body,painless,easy operation,etc.It has broad application prospects and considerable economic value in human-computer interaction,rehabilitation and other fields.This manuscript focuses on the interaction mode with gesture as input,studies the gesture perception based on electromyography information,realizes high-precision,portable and natural interaction means,and completes the design of the wearable myoelectric-collection experimental device with Bluetooth transmission.The device comprises three parts:a collecting board,a core board and a receiving end of the upper computer.The acquisition board completes the collection and pretreatment of the sEMG signals.The core board completes the analog-to-digital conversion of the sEMG signals,the aggregation and transmission of the sEMG data.The host computer completes the denoising processing of the data,thereby improving the gesture recognition rate.The noise analysis is performed on the first-stage differential amplifying circuit which is easy to introduce noise interference.After calculation,the effective value of noise of the designed circuit referred to input is 0.946μV,which is not higher than the limit of the sEMG signal acquisition system 1μV.The channel number,sampling frequency and transmission rate are analyzed.The MCU software program and Bluetooth development program are designed.The experimental results show that the entire data link can reach the transmission rate requirement of 24KB/s.Multi-resolution analysis theory is used to perform wavelet threshold denoising on sEMG signals,and a digital filter based on wavelet transform is designed.Experiments show that this method improves the signal-to-noise ratio of the signal and achieves good denoising effect.After actual testing,the device can complete high-speed real-time acquisition of 6-12 channels and 1 kHz sampling rate of sEMG signals,both denoising in hardware and software,providing a relatively clean sEMG signal for subsequent gesture recognition.