Weights for Stability and Performance Preservation

P.J. Goddard and K. Glover

Abstract

In this paper we investigate the design of reduced order controllers using an H infinity framework. Provided there exists a stabilising controller, K0, giving satisfactory closed loop performance we derive frequency weights such that if the infinity norm of W_2^{-1} (K-K0) W_1^{-1} is less than 1 then K is also a stabilising controller satisfying the same level of closed loop performance.

Keywords Controller order reduction, Frequency weighted model reduction, H-infinity.