Resonance-based Control Method for Multi-Joint Robot with Variable Joint Stiffness

This study presents resonance-based control methods proposed by the authors for multi-joint robots. The proposed control methods adjust stiffness of mechanical elements installed in each joint of the robots to minimize actuator torque while generating desired periodic motions. Some of these control method adjust not only stiffness but also motion patterns to reduce further actuator torque. Advantages of proposed controllers are to work well without using exact parameter values nor huge numerical calculations. Some stability analyses, simulations and experiments have verified the effectiveness of the proposed control methods. The proposed controllers can be applied to walking/running robots, energy saving industrial manipulators, and walking support systems.