Robust Optimal Adaptive Sliding Mode Control with the Disturbance Observer for a Manipulator Robot System

In this paper, a robust optimal adaptive sliding mode control (OASMC) by using disturbance observer (DOB) is successfully proposed and applied in the manipulator robot system. The control gains are on-line adjusted by the DOB to compensate the unknown time-varying disturbances to optimize and stabilize the control system. The optimal control and sliding mode control are integrated based on the Lyapunov stability theory to obtain the optimal sliding mode control (OSMC). Then, the adaptation control gains are on-line adjusted by the DOB to compensate the unknown time-varying disturbances for the control system. The manipulator robot system is given as the control example to demonstrate the proposed OASMC. From the simulation results, the proposed OASMC successfully demonstrates the optimal, adaptive and robust control performances for the manipulator robot system. The novelty of this paper is that the DOB can correctly estimate the unknown time-varying disturbances to on-line adjust the control gain of OASMC to stabilize the manipulator robot system. The proposed OASMC simultaneously has optimal, adaptive and robust control characteristics.