慣性パラメータの根軌跡に基づいたダイレクト・ロボットの負荷感度低減化制御系の設計

抄録

Direct-drive robots have excellent features including no backlash, small friction, and high mechanical stiffness. However, dynamic coupling among joints as well as nonlinear effects become more prominent than traditional robots with reducers. Another critical issue is that the robot becomes more sensitive to the change of load. In this paper, we develop a design method of control system for reducing the influence of dynamic coupling and load sensitivity on the direct-drive robots. For the design of control system, we use a root locus that takes inertia as parameter. A positive current feedback scheme is proposed in the implementation. And a problem in application the method to the brushless DC motor is considered. Finally, the method is implemented on a 2 d. o. f. planar direct-drive robot with brushless DC motors as actuators. Then the validity of the method is demonstrated through experiments.