ECS-9703294 Freeman A basic purpose of feedback is to reduce the effect of uncertainty on the behavior of a system. When applied inappropriately, however, feedback can also increase the risk of instability and other undesirable phenomena. An obstacle to the successful design of feedback controllers has long been the presence of nonlinearity in models and in real systems. The goal of this project is to develop innovative methods for designing feedback controllers for uncertain nonlinear systems and to educate future engineers and researchers in their application. This project will build the foundation of an integrated program of research and education in nonlinear and robust control theory in the Robert R. McCormick School of Engineering and Applied Science at Northwestern University. The educational goals of this project are to revise existing undergraduate and graduate courses in systems and control and to develop new graduate courses on nonlinear control system analysis and design. Selected topics from the proposed research activities will be integrated into these courses. These activities will contribute substantially to the educational objectives of the Council on Dynamic Systems and Control, a new interdisciplinary program at Northwestern with participating faculty and students from five engineering departments. The research goals of this project are to further develop the nonlinear control design techniques pioneered by the PI and co-workers and to deepen the current understanding of fundamental issues in nonlinear control theory. During the course of this project, the PI will identify those flexibility's in new and existing nonlinear design methods which can be exploited to obtain good controllers for practical applications. For example, one task is to create new tools for incorporating nonlinear control constraints ubiquitous in real systems into the control design procedure, a departure from the traditional approach of ignoring such constraints during the design. Another task is to analyze the effects of measurement error on the behavior of nonlinear feedback loops and to develop design techniques for reducing such effects. In collaboration with Rockwell Science Center in Thousand Oaks, California, the new nonlinear design methods will be applied to problems in automotive control, aircraft control, and industrial automation control. This project will result in a significant contribution to the growing discipline of nonlinear control theory, particularly in the area of robust nonlinear control. Design guidelines developed during the course of this project will be invaluable to the control engineer who is trying to apply the state-of-the-art methods to real control problems. Furthermore, this project will make a substantial impact on the interdisciplinary graduate program in systems and control at Northwestern. Not only will students who take the proposed design courses be exposed to the latest breakthroughs in the field of nonlinear control, they will also develop an appreciation and basic understanding of the effects of nonlinearity in feedback loops created by nature or designed by engineers.
