Robotic Manipulator Control Based on Disturbance Observer: A High-Order Fully Actuated System Approach

Abstract

This paper focuses on the trajectory tracking control of a multi-degree-of-freedom manipulator system. Firstly, the actuator model is introduced into the manipulator system to generate a cascaded system, so as to avoid the negative impact of control for the actuator itself on the tracking accuracy of the system. Then, the trajectory tracking controller is designed based on the high-order fully actuated (HOFA) system approach to make the manipulator reach the desired position with high accuracy. Then, a universal nonlinear disturbance observer (UNDO) designed to compensate for the internal and external uncertainty in practical manipulator systems. Finally, a tracking differentiator (T-D) is employed to obtain the acceleration signal of the manipulator, avoiding the use of expensive acceleration sensors in the construction of the trajectory tracking controller and nonlinear disturbance observer. Simulation results reveal the effectiveness of the proposed method.