Resonance-based task space controller for multi-joint robot with adjustable equilibrium angle of elastic element

Abstract

This paper proposes a task space trajectory tracking controller based on resonance for multi-joint robots. This controller generates desired motions, which are specified in the task space, while adjusting stiffness of mechanical elastic elements installed in each joint of the robots. This controller also adjusts equilibrium angles of the elastic elements. These parameter adjustments minimize actuator torque. Advantages of the proposed controller are to work without using exact parameter values of the controlled systems nor huge numerical calculations. We mathematically discuss stability of the controlled systems. Simulation results demonstrate the effectiveness of the proposed controller.

Inertia Adaptive Control Based on Resonance for Energy Saving of Mechanical Systems

“…Therefore, the authors developed variable elasticity devices which can change elastic values mechanically [12]. Moreover, some adaptive controllers to tune elasticity were proposed [11]. In some of the proposed controllers, it is mathematically proven that the robot motion converges to a desired periodic motion and elastic values converge to desired values [9].…”