Research On Position Control Of Electro-hydraulic Servo System With Large Inertia Based On Extended State Observer

Electro-hydraulic position servo system is widely used in industrial,military and other occasions requiring heavy loads due to its fast response speed,strong anti-interference ability,and large output force or torque.The research object of this paper is an electro-hydraulic position servo system with a load of 100 tons.The system has model parameters uncertainty and unmodeled disturbance factors.In addition,under the influence of the large inertia of the load,the rapid response of the system is easy to cause overshoot and continuous oscillations.The existence of these factors brings great challenges to the fast and high-precision control of the electro-hydraulic position servo system with large inertia.In view of these characteristics,the main work of this paper is as follows:(1)To solve the problem of unknown parameters and strong disturbance in electro-hydraulic position servo system with large inertia,a switching active disturbance rejection control algorithm based on enhanced high-order extended state observer is proposed.To solve the problem of insufficient disturbance compensation under input constraints,an enhanced high-order extended state observer is constructed to improve the transient response performance of the system.Then,the switching control mechanism is used to integrate the advantages of high-order extended state observer and enhanced high-order extended state observer.The simulation results show that the designed algorithm can eliminate the system oscillations and realize the high-precision control of the electro-hydraulic position servo system with large inertia.(2)Aiming at the problem that the rapid response of the system is easy to lead to large overshoot under the influence of large load inertia,backstepping is introduced into the design of control algorithm,and an adaptive nonlinear backstepping algorithm based on corrected extended state observer is proposed.The corrected extended state observer is used to accurately estimate the unmeasurable states and disturbance of the system.The nonlinear error feedback mechanism introduced in backstepping can reduce overshoot while ensuring the fast response of the system.In addition,the adaptive error compensation function is constructed to solve the differential explosion problem in the backstepping design process.Finally,the stability of the closed-loop system is proved by Lyapunov theory.The simulation results show that the designed algorithm can greatly reduce the overshoot,eliminate the oscillations,and realize the fast and high-precision control of the electro-hydraulic position servo system with large inertia.