Individual Design Method for Bilateral Control System via Computer Network (Design of Controllers that Guarantee Stability Against Any Time-Varying Delay)

In order to communicate kinesthesic information, as well as visual and audio information, via computer network, we adopt the master-slave system that has been used in remote manipulation. The controller of the system via network should satisfy the following two requirements : a) the stability of the system can be guaranteed for any communication time delay, and b) the master controller can be designed independently of the slave controller. Several controllers have been proposed to meet the first condition, however, these controllers only guarantee smaller time delay than that estimated beforehand. This paper proposes a design method for a controller that satisfies both of the abovementioned requirements. Based on the small gain theorem, the stability criteria is derived such that each controller should be determined in order to make the gain of each complementary sensitivity function less than 1. The system designed by the proposed method can be stable for any time-varying communication delay and the controller of each manipulator can be designed even if we do not know the dynamics of the manipulator in a remote environment. The validity of the proposed method is confirmed by simulation.