Feasibility of using ipsilateral electromyographic signals to control an air-muscle-actuated grasping orthosis

In this work, we investigate the potential of using an air-muscle actuated orthosis controlled by an electromyographic (EMG) signal to reliably augment the grasping force of the hand, allowing allowing the user to reduce the muscle activation required for a power-grasping task . In particular, we tested the hypotheses that subjects could stably handle objects and learn to reduce both their grip force and muscle activation levels with force supplementation. In this study, a surface-mounted EMG sensor on the flexor digitorum provides the input to a proportional-integral-derivative controller governing the force generated by the orthosis. Nine subjects performed a sequence of unassisted and assisted lifts of a weighted and instrumented cylinder. When using the orthotic system to lift the cylinder. The grip force applied to the cylinder dropped for seven of the nine subjects (p <0.01) and the% MVC dropped for eight of the nine subjects (p <0.01). None of the subjects exhibited any instability or reported any difficulties when using the orthosis. On average, the subjects reduced their% MVC and grasp force by 31% and 56% respectively, so using an air-muscle-powered orthosis controlled by an ipsilateral EMG signal appears to be a feasible concept.