Extraction and implementation of muscle synergies in hand-force control

The need of solving the problem of multi-degrees of-freedom in motor control is increasing as human-like robots become more popular these days. Muscle synergies hypothesis is a prominent suggestion for this problem. In this paper, we investigated the muscle synergies extracted from human subjects in a producing-force task to explore the mechanism of the human\´s skillful hand-movement at producing force while manipulating objects. We observed a high correlation estimation of the muscle synergies with the hand force, and derived a role division of muscle synergies in generating the hand force as well. These results give an optimal but simple way to control robots so as to make the robots\´ movement as skillful as human\´s. To verify this idea, we proposed "synergy based control" method using the characteristics of human\´s muscle synergies observed, and tested it on a pneumatic-driven arm robot whose structure assumes the human arm\´s. The program is in its first stage to control the robot.