Robust Control Design

To a large extent, our lives on this earth depend on systems that operate auto­ matically. On a daily basis we come in contact with man made systems whose automatic operation ensures increa­ sed productivity, promotes economic development and improves the quality of life. Many systems can be found in nature; others are man-made. A primary component of such systems is a device or mechanism called the controller. In man-made systems, one must first design and then implement such a controller, either as a piece of hardware or as software code in a computer. The process of developing a controller can be dramatically improved if one can generate an appropriate dynamic model of the system under consideration. This study explains how to develop such controllers for system models with uncertainty. In many cases, dynamic models can be expressed in terms of linear, time-invariant equations, or transfer functions. The book presents methods for the robust design of system controllers, especially for systems with parameter uncertainty. The approach is based on the Nyquist Theorem, exploiting the properties of polynomials and polynomial value sets.