Low Order Suboptimal Robust Controller Design for Systems with Structured Uncertainty

Abstract

Abstract This paper considers the problem of designing robust controllers for linear plants affected by rank one real perturbations. The main objective of the paper is to use a convex parameterization of robustly stabilizing controllers for optimizing the stability margin over an assigned class of low complexity controllers. In fact, it is well known that if no constraints on the controller structure are imposed, the complexity of the resulting optimal controller is usually excessive. In this paper, a procedure is proposed which allows one to select a suboptimal controller within a fixed class, by solving a sequence of linear matrix inequalities feasibility problems. Several application examples are reported to discuss the performance of the proposed procedure.