Adaptive Motion Control for Electro-hydraulic Servo Systems With Appointed-Time Performance

This article focuses on the asymptotic adaptive appointed-time performance control for electro-hydraulic servo systems subject to unknown inconstant linearizable parameters, nonlinear parameters, and disturbances. To overcome this issue, uniting the adaptive control with an appointed-time performance function, an adaptive appointed-time performance controller is developed for electro-hydraulic servo systems, in which unknown inconstant linearizable parameters, nonlinear parameters, and disturbances can be addressed simultaneously. This relieves the assumption that unknown parameters should be constant and linearizable in most of the existing adaptive control results. Moreover, an introduced appointed-time performance function can guarantee that the tracking error is restricted to a prescribed boundary and converges to a preset region within an appointed time without any initial performance restriction. Theoretical analysis reveals that both the asymptotic steady performance and the appointed-time performance of the tracking error could be achieved with this presented method. Comparative experimental results also reveal the merits of this method.