Composite control of flexible manipulators based on SMC-DO and LQR

This paper proposes a composite control method based on sliding-mode control with a disturbance observer (SMC-DO) and linear quadratic regulator (LQR) to realize the trajectory tracking and vibration suppression. Firstly, the system dynamics is decomposed into two sub-systems in two different time-scales based on singular perturbation (SP) theory. In slow time-scale, in view of the slow time-varying disturbance, an exponential disturbance observer is constructed and a slow controller based on SMC-DO is designed. In fast time-scale, a fast controller is designed based on LQR. Then, a composite controller is designed by combining the SMC-DO (slow) and LQR (fast) controllers. Finally, simulation results are given to show the effectiveness and feasibility of the proposed method and stability of the flexible manipulators is proved by SP theory.