Force Control of Manipulators Based on H∞ Controller (Application of Joint Torque Feedback)
Guoguang Zhang*, Junji Furusho* and Akihito Sano**
*Department of Mechanical and Control Engineering, The University of Electro-Communications, 1-5-1, Chofugaoka, Chofu-shi, Tokyo, 182 Japan
**Department of Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi, 466 Japan
Force control using a hierarchical structure is discussed, which consists of upper force control and lower joint position control. The force controller calculators the joint position corrections necessary to control the force in the desired manner. These correction signals from the force controller are output to the lower controller and added to the nominal joint position command. In this paper, we apply mixed sensitivity design of H∞ control theory to a force control system. The nominal model is discussed, and the robustness against modeling error is analyzed. Owing to joint torque feedback control, the change of the controlled plant is reduced, so high gain force control can be achieved. Experimental results and eigenvalue analysis are also presented.