Design of Sliding Mode-Active Disturbance Rejection Controller Based on Exponential Reaching Law for Hydraulic Motor of Ship Washing Equipment Chassis

A sliding mode-active disturbance rejection compound control strategy based on exponential reaching law is proposed to solve the problem of speed fluctuation of valve-controlled hydraulic motor speed servo system due to nonlinear characteristics and external load torque disturbance. Firstly, a state-space model is established to describe the nonlinear system of valve-controlled hydraulic motor through mechanism analysis. Then, a second-order nonlinear active disturbance rejection controller is designed according to the system model, and the total disturbance is estimated and compensated in real time by using the nonlinear extended state observer. At the same time, sliding mode control is introduced and exponential reaching law is adopted to improve the nonlinear state error feedback control law of active disturbance rejection control, which improves the controller's response speed and reduces the controller's parameters to be adjusted while ensuring the ability of disturbance rejection. Based on this, a new nonlinear function is designed and adopted to replace the traditional nonlinear function in active disturbance rejection control to further improve the control performance. Finally, the effectiveness of the proposed control strategy is verified by Matlab/Simulink simulation.