In this monograph, the author uses the functional representation of nonlinear systems developed by Professor Norbert Wiener and others to establish a theoretical basis for the quasi-linear approximate analysis of non-linear feedback systems with random inputs. He examines the validity of the usual assumption of Gaussian distribution of signals in such a system both theoretically and experimentally and develops tests that allow the accuracy of approximate analyses to be assessed. Further, the utility of several quasi-linear models that have been proposed in the control literature is evaluated, and the most suitable of these is applied to the analysis and synthesis of nonlinear systems in which both signals and noise are present. Various computation methods are also considered.
This book will interest the control theorist since in it a clear relation is established between the quasi-linear analysis of nonlinear systems and other more general methods. It also clarifies the mechanism underlying the breakdown of approximate methods under some circumstances. The book is also a useful and authoritative reference for the control engineer.
