H∞-based design approach to discrete-time learning control systems with iteration-varying disturbances

This paper is concerned with the iterative learning control (ILC) problem for discrete-time systems with iteration-varying disturbances. Using the so-called super-vector approach to ILC, the discrete domain bounded real lemma is employed to develop a sufficient condition ensuring both the stability and the desired H_∞ performance of the ILC process. It is shown that this sufficient condition can be presented in terms of linear matrix inequalities (LMIs), which can also determine the learning gain matrix. A numerical simulation example is included to validate the theoretical results.