Chapter 2
Overview of the UnderlyingTheory2.1 Introduction
The material covered here is taken from a varietyof sources. The basic approach is
described by Doyle [1, 2], and further elaborated upon by Packard[3]. Summaries have
also appeared in workby Smith [4] and others.
Motivating background can be found in the early paper by Doyle and Stein [5]. An
overview of the robust controlapproach, particularly for process control systems, is
given by Morariand Zafiriou [6]. The reader can also find a description of the H∞/µ
synthesis robust controlapproach in [7].
There are a number of descriptionsof this approach to practical problems. In the last
few years a significant number of these have been described in the proceedings of the
American Control Conference (ACC)and the IEEEControl and Decision Conference
(CDC). Only some of the early illustrative examples are cited here.
Application of µsynthesis to a shuttle control subsystem is given by Doyle et al. [8].
Examples of flexible structure control are described by Balas and
coworkers [9, 10, 11, 12] and Smith, Fanson and Chu [13, 14]. There have also been
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