Development and verification of circular array electromyography system for the selective electromyography signal detection

Detecting selective electromyography (EMG) signals is important for minimizing errors in muscle information from crosstalk and delivering movement intension orders clearly. In this paper, we propose a circular-array EMG system for detecting the orientation of muscle fibers and recording maximal EMG amplitude. This system records six-channel bipolar EMG signals using a circular array grid consisting of twelve Au electrodes. We evaluate the performance of this system by hypothesizing that: (1) this system can detect the fiber orientation of forearm muscles (including flexor carpi radialis (FCR), extensor carpi radialis (ECR), pronator, and supinator) and record the maximal EMG amplitude; (2) it minimizes EMG amplitude error caused by twisting between the orientations of electrodes and muscles during complex movement from a body part with multi-degrees of freedom (DOF); the normalized root mean squares (Normalized RMS) were used to analyze the six-channel EMG signals to verify these three hypotheses. It was concluded that the circular array EMG system is superior to other systems in its acquisition of selective EMG signals. It could be a useful technique for improving the DOF in movement and obtaining accurate muscle information.