Tracking control of two-flexible-link manipulators using distributed control strategy

This paper presents a distributed control strategy for two-flexible-link manipulator to track a desired trajectory in the joint space while canceling the link´s vibrations. The distributed control strategy decomposes the system into two subsystems. Each subsystem has a pair of one joint and one link. The strategy of control consists in controlling the last joint and stabilizing the last link by assuming that the first subsystem, i.e first joint and link, is stable. Then, going backward to the first subsystem, we control the first pair of joint-link using the same strategy. The control law of each subsystem is developed using sliding mode technique and the stability of the resulting tracking errors is proved using Lyapunov technique. This control strategy is simulated and results are compared with a PD controller. The simulation results show the effectiveness of this approach. A good tracking performance and capability to eliminate the vibrations are obtained.