Research on Active Disturbance Rejection Control Method for Electro-hydraulic Servo Loading System with Considering Clearance Disturbance

In the test of high-speed rail bearings, the electro- hydraulic servo-loading system is commonly used to simulate the actual alternating loading for the bearing. Due to the existence of the loading mechanism clearance and the transmission shaft system matching clearance, the loading system has a certain nonlinear displacement disturbance. Combined with the nonlinear characteristics of the electro-hydraulic servo system, the dynamic response characteristics and steady-state control accuracy of the force loading are seriously affected. To this end, the Active Disturbance Rejection control (ADRC) method is used to identify and compensate the gap disturbances using the feedback information of the extended state observer, and the tracking differentiator and feedback control rate are designed to improve the system response speed and suppress overshoot. The control method is applied to the control model of high-speed rail bearing electro-hydraulic servo-loading system. The simulation results show that the control method can achieve good control effect, and the anti-disturbance capability, response speed and steady-state performance of the system are significantly improved.