Frequency Domain Criteria for Absolute stability

Book excerpt: Frequency Domain Criteria for Absolute Stability presents some generalizations of the well-known Popov solution to the absolute stability problem proposed by Lur'e and Postnikov in 1944. This book is divided into nine chapters that focus on the application of Lyapunov's direct method to generate frequency domain criteria for stability. The first eight chapters explore the systems with a single nonlinear function or time-varying parameter. These chapters also discuss the development of stability criteria for these systems, the sufficiency theorems, and Lyapunov function. Some of the theorems applied to a damped version of the Mathieu equation and to a nonlinear equation derived from it are also covered. The concluding chapter deals with systems with multiple nonlinearities or time-varying gains. This chapter also outlines the basic definitions and tools, as well as the derivation of stability criteria. This work will serve as a reference for research courses concerning stability problems related to the absolute stability problem of Lur'e and Postnikov. Engineers and applied mathematicians will also find this book invaluable.