On Robust Iterative Learning Control against Iteration-Varying Uncertain Plant Parameters

This paper considers the robust convergence problem of iterative learning control (ILC) for discrete-time systems in the presence of iteration-varying uncertain plant parameters. If the uncertain parameters all converge along the iteration axis, then the perfect tracking property of ILC can be achieved under certain conditions. Otherwise, the tracking objective of ILC can be achieved within a bound if some of the uncertain parameters are bounded, rather than convergent, along the iteration axis.