Robust Adaptive Iterative Learning Control for Discrete-Time Nonlinear Systems With Time-Iteration-Varying Parameters

In this paper, the robustness problem in adaptive iterative learning control for discrete-time nonlinear systems with time-iteration-varying parameters is investigated. The time-iteration-varying parameter can be expressed as the sum of an iteration-invariant time-varying part and a bounded iteration-drift term. Then a novel dead-zone method is applied in estimations of the iteration-invariant part and the drift bound simultaneously. The boundedness of tracking error is ensured by rigorous analysis. The efficacy of the proposed method is illustrated through simulation results.