Static output feedback stabilisation with H-infinity performance for a class of plants

In this paper, the problem of static output feedback control of a linear sy stem is considered. The existence of a static output feedback control law i s given in terms of the solvability of two coupled Lyapunov inequalities wh ich result in a non-linear optimisation problem. However, using state-coord inate and congruence transformations and by imposing a block-diagonal struc ture on the Lyapunov matrix, we will see that the determination of a static output feedback gain reduces, for a specific class of plants, to finding t he solution of a system of linear matrix inequalities. The class of plants considered is those which are minimum phase with a full row rank Markov par ameter. The method is extended to incorporate H-infinity performance object ives. This results in a sub-optimal static H-infinity control law found by non-iterative means. The simplicity of the method is demonstrated by a nume rical example. (C) 2001 Elsevier Science B.V. All rights reserved.