The object of this monograph is to present some optimal design methods
in a certain sense for obtaining linear multivariable feedback systems
such that they become insensitive or robust properties. The treatment is
mainly confined to linear time- invariant discrete systems with the
exception of the sections 3.1 and 3.3 in which it was used linear
time-invariant conti- nuous systems. Sensitivity and robust methods for
multivariable feedback systems have been extensively studied about the
last decade and the successful development has led to a much better
under- standing of the performance of insensitive and robust proce-
dures. The contribution of this monograph is an improved beha- viour of
the feedback systems under the influence of distur- bance, parameter
variations and/or nonlinear effects with new design methods.
Furthermore, in chapter 3 the reader finds improved necessary and
sufficient conditions for robust stabi- lity of the closed-loop system.
The authors would like to express their thanks to Mrs. Regina Hade, who
typed with great patience our manuscript and Mrs. Monika Thieke who drew
the figures and symbols very careful.