Time‐iteration‐domain integrated learning control for robust trajectory tracking and disturbance rejection: With application to a PMLSM

Abstract

Iterative learning control (ILC) has been widely used to improve motion performance when reference trajectories and external disturbances are strictly repetitive. However, the occurrence of non-repetitive trajectories and disturbances would significantly deteriorate the performance of traditional ILC methods. To solve this problem, a time-iteration-domain integrated learning control (TIDLC) scheme is proposed for enhancing robustness against non-repetitive trajectories and disturbances. The TIDLC scheme consists of an ILC term and a time-domain compensator (TC) term. While the ILC term that performs learning in the iteration-domain preserves excellent performance under repetitive tasks, the TC term that is updated in the time-domain can compensate for the variations of trajectories and disturbances. Stability and performance analyses are discussed in both the time-domain and iteration-domain. Experimental results on a permanent magnet linear synchronous motor (PMLSM) positioning system verify the validity of the proposed scheme.