Discrete-Time Output-Feedback Robust Repetitive Control for a Class of Nonlinear Systems by Additive State Decomposition

摘要

The discrete-time robust repetitive control (RC, or repetitive controller,also designated RC) problem for nonlinear systems is both challenging andpractical. This paper proposes a discrete-time output-feedback RC design for aclass of systems subject to measurable nonlinearities to track referencerobustly with respect to the period variation. The design relies on additivestate decomposition, by which the output-feedback RC problem is decomposed intoan output-feedback RC problem for a linear time-invariant system and astate-feedback stabilization problem for a nonlinear system. Thanks to thedecomposition, existing controller design methods in both the frequency domainand time domain can be employed to make the robustness and discretization for anonlinear system tractable. To demonstrate the effectiveness, an illustrativeexample is given.