Comparison of contact interface factors for surface electromyography control wearable device

Abstract

Surface electromyography is commonly used as control signals for wearable devices. Compared to physical sensors, bioelectric signal are more sensitive to pressure and placement of interface. Discussion of these factors includes not only ergonomic issues but also control issues. Variations of the two factors in setup could lead to variability in output values. In this article, we mainly discussed the influence of the two factors, including contact pressure and placement, to estimate the elbow joint angles based on surface electromyography. To our knowledge, there has been no research about this problem. We first measured the surface electromyography signal with elbow flexion and extension motion, then estimated the angles of motion through the pattern recognition method, and finally assessed the distribution of contact pressure and the accuracy of regression. Our results indicated that the accuracy of angle recognition depends on the consistency of pressure distribution over the contact surface. The contact surface can be placed in the anterior of the upper arm at lower contact pressures. When high contact pressure is required, the placement of the strap should cover the muscle belly. The main contribution of this study is that our results can be used to guide the human-machine interface design of wearable devices.

Ergonomic Risk Assessment during an Informal Hand-Made Cookware Operation: Extending an Existing Model

“…Observational risk assessment was used to determine ergonomic risks, though this method is prone to significant measurement errors [ 42 ]. Improvements in ergonomic risk assessments include the introduction of an electrogoniometer and surface electromyography which measures postural levels [ 26 , 42 ]. These tools are able to accurately and reliably measure physical exposures in the workplace.…”

“…There are different types of risk assessment methodologies with varying levels of precision in accounting for occupational exposure variations; these broadly include self-reports, a subjective measure of workplace exposure based on the workers observations [ 25 ]. Direct measurement is a more precise measure of exposure and may provide real-time measures of exposure [ 26 ]. However, this method is more effective in controlled settings with predefined tasks and daily routines.…”