Reduced-order compensation - LQG reduction versus optimal projection

Abstract

Six methods for design of reduced-order com~erlsation are compared using an example problem given by Enns. The methods considered comprise five LQG reduction techniques, reviewed in a recent paper by Liu and Anderson, and the Optimal Projection theory as k.plemented via a simple homotopy solution algorithm. Design results obtained by the different methods for forty-two different design cases are compared with respect to closed-loop stability and transient response characteristics. Of the LQGreduction procedures two are found to offer distinctly superior performance. However, only the Optimal Projection method provided stable designs in cases. Further details are given on the performance o f the numerical algorithm for solving the optimal projection equations and the corresponding design results.