Design Of Human Surface EMG Signal Detector And Neuromuscular Electrical Stimulator

sEMG (Surface Electromyography) signal detecting and feature extraction has important physiological significance, which contributes to experts’better grasping the basic characteristics of muscle, and can display the muscle strength intuitively. Applying NMES (Neuromuscular Electrical Stimulation) combined with the sEMG signal to athlete’s muscle training can take a special training on the target muscle precisely, which will improve the training efficiency effectively. For this purpose, we design a new sEMG signal detecting and neuromuscular electrical stimulating system.The surface EMG signal detector requires a high input impedance, CMRR(common mode rejection ratio) and good noise filtering capabilities. It amplified the weak SEMG signal by preamplifier constituted by dual op amp in parallel form, resistive and capacitive coupling circuit and INA128, with which the preprocessor can get high input impedance and high CMRR; Shielding driver and right leg drive as well as floating power are introduced to further improve the CMRR and anti-interference ability; Then high-pass and low-pass filter, and50Hz notch filter are designed to filter out the noise of different bands. Through experimental tests, the preprocessor has a high anti-interference ability, and can effectively filter out the noise, suppress power frequency interference, and can meet the requirements of SEMG signal de-noising and amplification.A new type of NMES design alternative which can control the current more accurately is present. The cost of the hardware design is greatly reduced with using a MCU control the current. Numbers of security control measures are designed for the system to avoid safety problems.This paper elaborated the design process of slave computers from the system framework and technical norms to each module hardware design. Through experimental tests, the feasibility of the system is proved.