ESO-Based Internal Mode Control-Sliding Mode Control for Servo System

In this paper, a synthesized controller strategy combining internal mode control (IMC), sliding mode control (SMC), and extended state observer (ESO) is proposed for the improvement of the control accuracy for a servo system. The IMC control is used to obtain the specified performance of tracking. The sliding mode characteristics of SMC are used to enhance the robustness of the control system against external noise interferences and parameter perturbation. ESO is used to estimation and compensation online, thus suppressing the total disturbances of the system. And a robust control scheme is used for the linear compensation part, so that the disturbance in the uncompensated part of the linear ESO can be better suppressed. The method can effectively suppress the disturbance effects to obtain higher tracking control accuracy, and the system stability is analyzed theoretically using the Lyapunov method. Finally, comparative simulation experiments are carried out in MATLAB/Simulink to prove the superiority of the method.