Research Of High Density Surface Electromyography Acquisition System

Surface electromyography(sEMG) is biological signal which is generated by human neuromuscular activity. It reveals important physiological and medical information of human body, which has been commonly used in applications. of diagnostic medical rehabilitation, muscle fatigue assessment and interaction. Contrast to early sEMG technologies, High Density surface EMG(HD-sEMG) can obtain richer topographical information and physiological information. HD-sEMG research requires high-spatial resolution, high-quality and high-precision sEMG. It also raises higher demand of convenience, responsiveness, endurance and other aspects of the sEMG acquisition system.Based on consideration of wearability, real-time and high-throughput, a detailed study of system architecture and transport network in the sEMG acquisition system is revealed in this paper. A real-time collection and transmission system is constructed, which is built on modular layered frame, wired USB with wireless WIFI transmission, asynchronous acquisition with synchronous collection, and high-precision synchronization mechanism based on double-buffers and slot switching. Detailed design and optimization are involved in hardware device, software platform and communication mechanism. This paper also proposes a method for making flexible array electrodes for surface EMG signal acquisition. After analysis of power line interference and baseline bias in sEMG data, several light real-time filtering algorithms are designed and tested for real data. To test its function and performance, an evaluation system is developed which has 128 sEMG channels with 1KHz sampling rate and 16bit data at each channel. As the results show, when 50ms is used as communication period, the inter-channel synchronization error is less than 320us, the refresh rate is up to 20Hz and the average delay at each channel is less than 80ms.