Robust Control for Unstructured Perturbations — An Introduction

These lecture notes focus on the synthesis of robust con-
trollers for         feedback systems, in the presence of unstruc-
tured perturbations. It is      assumed, as a prerequisites, that
the reader is familiar with the basic      linear system and au-
tomatic control concepts. In part I interpolation      theory is
used to solve various single-input-single-output (SISO)               ro-
bust control problems. While the interpolation approach is
awkward   for multivariable systems, it provides a very natu-
ral and simple approach for SISO systems. In particular the
interpolation approach requires only      elementary knowledge
of complex variables, and provides a great deal of      physical
insight into various robust control problems. The                           required
interpolation theory is developed in some detail. Part II
is   devoted to multivariable systems. Two approaches are out-
lined: the            Hankle-norm approach and the two-Riccati-equa-
tion approach. In this part   only a limited number of results
are proven. However MATLAB software is      presented for nu-
merical solution. The book is addressed to                        researchers,
practicing engineers, and students who wish to get an               intro-
duction to robust control theory for unstructured                              plant
perturbations. The organization of the book as lecture notes
and   the presence of examples and of exercises at the end
of many chapters allow to use the book as an introductory
text in Robust Control courses.