Electro-hydraulic Position Control System Via Active Disturbance Rejection Controller Supplied with Oil by Variable-pressure Accumulators

Abstract

In some special hydraulic position control systems, the actuator is required to operate at a high speed in a short time. In order to reduce the installed power of the hydraulic pump station, the accumulator can be used as the auxiliary power source to provide sufficient flow for the actuator in a short time. However, due to factors such as accumulator oil supply pressure variation, hydraulic system nonlinearity, and disturbance of load and frictional resistance, position control of the system is more difficult. Aiming at this problem, this paper designs a nonlinear active disturbance rejection control (NLADRC) strategy based on the mathematical model of electro-hydraulic position control system with energy accumulator as power source, this controller estimates the system internal and external disturbances by nonlinear extended state observer (NLESO) in real time and the disturbance is compensated actively by nonlinear error feedback controller (NLSEF). Finally, the control method is verified through the joint simulation of MATLAB and AMESim. The simulation results show that compared with the PID controller, the NLADRC strategy effectively suppresses the internal and external disturbance of the system, reduces the adverse effect caused by the variable pressure oil supply of the accumulator, improves the position control accuracy of the system, improves the system static and dynamic control effect and verifies the effectiveness and superiority of the NLADRC strategy.