Output feedback-based adaptive position control for hydraulic systems with preset performance

This article addresses the problem of output feedback-based adaptive specified-time performance control for hydraulic systems in the presence of unknown time-variant parameters and disturbances. To accomplish this study, a state observer driven by a position state, is first employed to gain the information of unmeasurable states in practice. By incorporating the command filter design with a specified-time performance function, an adaptive output feedback specified-time performance controller is devised to simultaneously dispose of unknown time-varying parameters and disturbances while circumventing complexity explosion. Furthermore, the employed specified-time performance function ensures that the tracking error remains confined within a predefined bound and converges to a preset region within a specified time. Theoretical analysis demonstrates that the proposed method enforces the specified-time convergence performance of the tracking error. Comparative experimental results further validate the advantages of the approach.