A multirate iterative learning control scheme

A novel control scheme has been developed in this work that combines the multirate technique and iterative learning control (ILC). The multirate technique produces a faster sampling rate by means of an estimator, which assists the ILC scheme to better perform in achieving perfect tracking along the iteration, axis. We first show the multirate and ILC design. Then the multirate estimator and ILC are unified both in a fixed sampling rate, in order to facilitate control system analysis. In the sequel the characteristics of multirate estimator, ILC and the synergy are analyzed respectively. Subsequently, the new scheme is applied to and verified by a ball-and-beam system.