Title: Robust gradient iterative learning control: time and frequency domain conditions

Authors: D.H. Owens, S. Daley

Addresses: Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK. ' Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK

Abstract: This paper considers the use of matrix models and the robustness of a gradient-based iterative learning control (ILC) algorithm using fixed learning gains to ensure monotonic convergence with respect to the mean square value (Euclidean norm) of the error time series. The paper provides a complete and rigorous analysis for the systematic use of matrix models in ILC. They provide necessary and sufficient conditions for robust monotonic convergence and permit the construction of sufficient frequency domain conditions for robust monotonic convergence on finite time intervals for both causal and non-causal controller dynamics.

Keywords: iterative learning control; ILC; robust control; parameter optimisation; positive-real systems; matrix models; robust monotonic convergence; finite time intervals; controller dynamics.

DOI: 10.1504/IJMIC.2008.021471

International Journal of Modelling, Identification and Control, 2008 Vol.4 No.4, pp.315 - 322

Published online: 28 Nov 2008 *

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