Adaptive Tuning of Stiffness and Motion for Multi-Joint Robot*

This paper proposes a new controller that adaptively tunes joint stiffness and motions of multi-joint robots to reduce actuator torque while generating periodic motions. This controller is composed of delayed feedback control, a stiffness adaptation technique, and positive linear state feedback of angular velocity. Advantages of the proposed controller are to work without exact parameter values of the robots nor huge numerical calculations. We analyzed stability of the closed loop systems. Simulation results show that the proposed controller generate energy saving periodic motions. Additionally, we discuss energy saving effect of linear state feedback of the proposed controller.