Sufficient conditions for the synthesis of H∞ fixed-order controllers

This brief note deals with the synthesis of H-infinity fixed-order controllers for linear systems. It is well known that this problem can be formulated as a bilinear matrix inequality optimization problem which is non convex and NP hard to solve. In this paper sufficient conditions are provided which allow to convert the controller design into a linear matrix inequality feasibility problem. A numerical example on a practical control problem shows the application of the proposed technique. Copyright (C) 2000 John Wiley & Sons, Ltd.