Iterative Learning Control of Discrete Systems with a Switching Reference Trajectory and Saturating Inputs

Iterative learning control has been developed for application to systems that repetitively execute the same finite duration task, where the objective is to follow a supplied reference trajectory. In many current designs, the reference trajectory is specified at the outset, but others, such as materials processing, may require one or more changes, or switching, of this trajectory. This paper develops a new design for the previously unconsidered case of discrete linear dynamics with a switching reference trajectory and saturation of the input signal. The design is established using the stability theory for nonlinear repetitive processes, a class of 2D systems, and uses vector Lyapunov functions. A numerical case study demonstrates the applicability of the new design.