Adaptive control with asymptotic tracking performance and its application to an electro-hydraulic servo system

This paper presents a discrete-time adaptive controller, which incorporates internal model principle for asymptotic tracking performance of systems with parametric uncertainties, unmodeled dynamics and disturbances. Global stability and tracking performance of the adaptive system are derived under conditions on the system's stabilizability and bounds of noise and unmodeled dynamics. It is shown that asymptotic tracking can be achieved while the unmodeled dynamics and disturbances exist. The adaptive algorithm is applied to an electrohydraulic servo system for periodic trajectory tracking and disturbance rejection. Experimental results based on an eighth-order adaptive system updated at 2560 Hz demonstrate the adaptive system's ability in high bandwidth tracking performance under effects of system variations and finite word length real-time computation.