Active Disturbance Rejection Control of Electro Hydraulic Position Servo System Based on Noise Suppression

The limitation of measurement noise to the bandwidth of the extended state observer is a key problem that affects the performance of active disturbance rejection position controller of electro — hydraulic servo system. Therefore, an improved active disturbance rejection control method based on noise suppression extended state observer was proposed. The nonlinear model of the electro — hydraulic servo system was established, the chain integrator structure was constructed by coordinate transformation, and the "total disturbance" of the electro — hydraulic servo system was defined. A low-pass filter was introduced to suppress the high-frequency measurement noise, and the improved extended state observer was constructed by using the filtered position signal to compensate for the phase lag caused by the filter, separate the state feedback from the disturbance estimation, add new disturbance estimation adjustment parameters, and reconcile the contradiction between the high bandwidth and high estimation performance of the observer and the noise amplification. The controller was designed for a typical valve-controlled symmetrical cylinder electro — hydraulic servo system and the closed-loop system stability was analyzed by using Lyapunov stability theory. The control method required few tuning parameters which was easy for engineering practice. Simulation and test results showed that compared with traditional LADRC, the proposed control method had stronger disturbance suppression ability and higher position tracking accuracy under the disturbed state, which provided a reference for the engineering application of ADRC. © 2024 Chinese Society of Agricultural Machinery. All rights reserved.