Parametric adaptive control of single-rod electrohydraulic system with block-strict-feedback model

To address the universal single-rod electrohydraulic system (EHS), a block-strict-feedback model is constructed for the position control loop design. Different from the previous strict-feedback controllers used in EHS, the proposed controller avoids the model order-reduction problem and relaxes the strict-feedback model assumption for the single-rod EHS encountered by the existing results. Hence, all the dynamic physical states of single-rod EHS are directly used in control design. Since the hydraulic parametric uncertainties and the external load would degrade the output tracking performance of EHS, an adaptive control is proposed to guarantee all system states globally and uniformly bounded with parameter adaptation. The constraint holding technique called prescribed performance constraint (PPC) is adopted to improve the output response and to achieve a desirable performance. The effectiveness of the proposed controller is demonstrated by a comparison with the strict-feedback controller via both simulation and experiments.