Evaluation of the effectiveness of muscle assistive device using muscle fatigue analysis

There have been many kinds of wearable robots or wearable assistive devices to reduce the burden of workers in several industries. But there is no quantitative and objective method to evaluate the effectiveness of the device. In this study, a new method to evaluate the effectiveness of the muscle assistive device is suggested. 5 male subjects attended in the experiment to maintain posture of the overhead welding task with the tools. The surface electromyogram (sEMG) was recorded on 6 muscles with and without wearing the assistive device. The mean frequency (M F) and root mean square (RMS) were calculated and analyzed to evaluate the fatigue level of each muscle. The modified Borg RPE scale was scored in every minute for comparison through the experiment. By comparing the M F and RMS values when wearing assistive device and not wearing assistive device, we can specify the device can reduce the fatigue in some muscles. The slopes of regression line of M F and RMS plots may represent the fatigue level of each muscle, which can be used to evaluate the effect of the assistive device.