Download An Introduction to Nonlinearity in Control Systems by Derek Atherton, The book is concerned with the effects of nonlinearity in feedback control systems and techniques which can be used to style feedback loops containing nonlinear elements. the material is of an introductory nature however hopefully provides an summary and provides a basic understanding of various topics, several developed in recent years, and several other of which have entire textbooks dedicated to them. Download the pdf from below to explore all topics and start learning.