On Dynamic Pinching Movements of Redundant Musculo-Skeletal Dual Finger Model

Abstract

The final goal of this research is to clarify and obtain the fundamental control strategy of human's pinching movements by using a redundant musculo-skeletal dual finger model. First, a mathematical model of a 3 D.O.F. musclo-skeletal dual finger in which each finger is actuated by six nonlinear redundant muscles is formulated. Next, the kinematics and dynamics considering geometrical constraints for the finger-object system are described, and a sensory-motor coordinated feedback control law is designed to realize stable pinching simultaneously with posture and position regulation. Then, some numerical simulations are performed and the results suggest that the co-contraction of the digitorum muscles makes it possible to realize human-like pinching movements. Also the convergence of the closed-loop dynamics is proved by using a concept of “Stability theory on a manifold.”