Robust Controller Design for Linear, Time-Varying Systems

• Published in: European journal of control Vol. 5; no. 2-4; pp. 222 - 241
• Main Authors: O’Brien, R.T., Iglesias, P.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1999
• Subjects: Controller design; H∞ control; Timevarying systems; H∞ control; Timevarying systems; Controller design
• ISSN: 0947-3580; 1435-5671
• DOI: 10.1016/S0947-3580(99)70157-3

This paper examines the design of controllers for linear, time-varying systems. A design procedure is presented that incorporates performance and robustness objectives into existing . H∞ optimal control methods for time-varying systems. Design guidelines are derived for several basic performance and robustness objectives using a description of the frequency domain behaviour of a time-varying system. The frequency response is dependent on time as well as frequency. These guidelines reflect the frequency domain intuition gained from the timeinvariant case as well as the time dependence of the frequency domain behaviour of a time-varying system. Performance specifications are incorporated through the selection of time-varying weighting filters. Time-varying realisations for the weighting filters are obtained by interpolating between timeinvariant realisations. Results on the localised-intime behaviour of these realisations are derived to permit localised-in-time performance specifications. This procedure is analogous to the loop-shaping design procedure of McFarlane and Glover for timeinvariant systems.