Extended‐state‐observer‐based correction adaptive preset performance control of electro‐hydraulic servo systems

Abstract When the parameters of electro‐hydraulic servo systems (EHSSs) change rapidly, direct adaptive control cannot estimate these parameters well, and prior knowledge of the parameter boundaries is often difficult to obtain directly in practical engineering applications. Therefore, an unconstrained adaptive law must be designed to track the time‐varying system parameters. This paper uses an extended state observer (ESO) to estimate the system velocity signal and external disturbance, and a preset performance function is combined with direct adaptive control to improve control accuracy. A PI correction law is proposed to correct the parameter adaptive law, which only requires the measurement information of the piston position and the observation information of the extended state observer. In the case of disturbance and rapid change of system parameters, the proposed method can estimate the system state and parameters well and ensure the tracking accuracy of the system. Finally, the superiority of the proposed method is verified by simulation and experiment.