Asymptotic Adaptive Motion Control of Hydraulic Systems

Considering parametric uncertainties and unmodeled disturbances in hydraulic systems, this paper presents an asymptotic adaptive motion control scheme by adopting full state feedback. To accomplish this study, a novel parameter adaptive law based on both parametric estimation errors and tracking errors is developed to deal with parametric uncertainties of hydraulic systems, which can attenuate the major of parametric uncertainties and enhance the tracking performance. Then a composite robust integral of the sign of the error (RISE) feedback controller is employed to restrain the rest of parametric uncertainties and unmodeled disturbances. The developed continuous RISE-based controller is free of chattering, which is beneficial to practical implementation. Stability analysis indicates that the proposed method guarantees an excellent asymptotic tracking performance even in facing with time-variant disturbances and parametric uncertainties. Comparative simulation results are obtained to verify the high-performance nature of the proposed control strategy as well.