Abstract:In order to solve the problem of internal and external disturbance, parameter uncertainties and variable control gains in the electro-hydrostatic actuators (EHAs) system, a reduced order linear active disturbance rejection position control method based on model information is proposed. Firstly, the control gain is selected based on the system model information. Secondly, the total disturbance in EHAs system are estimated by the reduced order linear extended state observe (ESO), and the total disturbance compensations are added in a controller to eliminate the influence of external disturbance and parameter uncertainties. By using singular perturbation theory, it is proved that the closed-loop system is semiglobally uniformly ultimately bounded, and the proposed controller can make the position track the desired trajectory with any desired accuracy as the bandwidth of ESO becomes sufficiently high. The simulation results show that the proposed method has fast response speed, high control precision, and strong robustness to external disturbances and parameter uncertainties.