A study about the posture and joint stiffness at stationary force control of human arm

The purpose of our research is to realize a simple and high performance control of robots using strategy of human arm operation. This time, we measure joint angle and joint stiffness of human arm during force control. When tip force is large, human being selects the posture using joint torque minimum index. When tip force is small, human being selects the posture so that manipulability becomes large. Moreover, the wrist stiffness becomes large so as to keep the posture. In order to adapt for perturbation, a regulator to avoid joint torque saturation is introduced. The effectiveness of this strategy is confirmed by a simulation result of human arm.