Design of adaptive controller on task coordinate system for bilateral control system with communication delay

This paper proposes a controller for bilateral control system with communication delay. The bilateral control system consists of two master robots and two slave robots. A human operator handles two master robots, and two slave robots grasp and manipulate a task object cooperatively. The grasping force and manipulation force are fed back to the operator. The gain of master's controller is adaptively determined in terms of the stiffness of a contact object. Since conventional adaptive controllers are designed on robot coordinate system, the force and position information used for controller are based on robots, grasping force and manipulation force interfere with each other. The proposed adaptive controller is designed on task coordinate system, the force and position information used for controller are based on a task object, to reduce this interference. The validity of the proposed controller is verified via an experiment of a bilateral control using four liner motors.