Research on Active Disturbance Rejection Control of Hydraulic Servo System in Complex Initial States

In this paper, an improved active disturbance rejection control (ADRC) with variable gain extended state observer (ESO) is designed to control the hydraulic servo system with complex initial states. A method arranging a smooth increase process for the gain of the extended state observer is used. The method using Lyapunov function proves that by setting the appropriate gain coefficient of the extended state observer, the asymptotic stability of the extended state observer can be ensured, and the sensitivity of the extended state observer to the initial observation error is reduced. The simulation results show that, compared with the fixed-gain expanded state observer, the variable-gain expanded state observer has a more stable control process and better convergence effect.