NTUEXO arm: SEMG-force based acquisition for a haptic system

Surface electromyogram (SEMG) signal driven exoskeleton system is now gaining more research interests due to the promise of offering a faster response haptic system than the traditional position or force driven exoskeleton system. However, the technology to control and drive the exoskeleton system using myosignal is still not well established. The major problem of implementing the SEMG signal into the system comes from its naturally random and inconsistence properties. This research work investigates the optimal use of SEMG signal acquisition to drive an exoskeleton system. Two major criteria are identified as the essential conditions for the acquired SEMG signal as being suitable for driving an exoskeleton system robustly. Firstly, the magnitudes of measured SEMG signals have to show significant positive changes with increasing of external load. Secondly, the patterns of SEMG signal are required to be consistent for a particular muscle action. The former part of this paper shows some essential procedures for satisfying the first criteria along with the different configurations of the experimental set-up that were performed. The results were compared so as to determine the best settings for the SEMG signal recording in order to obtain the consistent muscle activity measuring in Biceps Brachii and Brachioradialis muscles.