Integrated design and structure analysis of robust iterative learning control system based on a two-dimensional model

In this paper, an iterative learning control (ILC) system is modeled as a two-dimensional (2D) Roesser system and the design of a robust ILC for a repetitive process with uncertain parameter perturbations and uncertain initial conditions is transformed to a robust stabilization problem of a 2D system. Based on the 2D robust control theory [Shi et al., J. Process Control 2005, 15, 907-924], a general design framework of robust ILC is formulated, which results in an ILC scheme consisting of two types of controls: a robust feedback control for ensuring the performances over time, and a P-type ILC for improving the tracking performance from cycle to cycle. The proposed design algorithms allow these two types of controls to be optimized, extended, and designed in an integrated fashion. To avoid the requirement of state feedback, an input-output-based ILC scheme is also developed