High-gain observers in nonlinear feedback control

High-gain observers play an important role in the design of feedback control for nonlinear systems. This talk overviews the essentials of this technique. It starts with motivating examples that illustrate the main features of high-gain observers, with emphasis on the peaking phenomenon and the role of control saturation in dealing with it. The use of the observer in feedback control is discussed and a nonlinear separation principle is presented. The use of an extended high-gain observer as a disturbance estimator is covered. The talk ends by presenting an experimental application of the extended high-gain observer to speed control of a Permanent Magnet Synchronous Motor (PMSM).

Prof. Hassan K. Khalil  

Department of Electrical & Computer Engineering  

Michigan State University 



Prof. Hassan K. Khalil received the B.S. and M.S. degrees from Cairo University, Egypt, in 1973 and 1975, respectively, and the Ph.D. degree from the University of Illinois, Urbana-Champaign, in 1978, all in electrical engineering. Since 1978, he has been with Michigan State University (MSU), where he has been the University Distinguished Professor of Electrical and Computer Engineering since 2003. He has consulted for General Motors and Delco Products and published several papers on singular-perturbation methods and nonlinear control. He is the author of High-Gain Observers in Nonlinear Feedback Contro (SIAM, 2017), Nonlinear Control (Pearson, 2015), Nonlinear Systems (Macmillan, 1992; Prentice Hall, 1996 and 2002) and coauthor of Singular Perturbation Methods in Control: Analysis and Design (Academic, 1986; SIAM, 1999). He was named IEEE Fellow in 1989 and International Federation of Automatic Control (IFAC) Fellow in 2007. He received the 1989 IEEE Control Systems Society (CSS) George S. Axelby Outstanding Paper Award, the 2000 American Automatic Control Council (AACC) Ragazzini Education Award, the 2002 IFAC Control Engineering Textbook Prize, the 2004 AACC O. Hugo Schuck Best Paper Award, the 2009 Alliances for Graduate Education and the Professoriate (AGEP) Faculty Mentor of the Year Award, and the 2015 IEEE CSS Bode Lecture Prize. At MSU he received the 1983 Teacher Scholar Award, the 1994 Withrow Distinguished Scholar Award, and the 1995 Distinguished Faculty Award. He was associate editor of IEEE Transactions on Automatic Control, Automatica, and Neural Networks and editor of nonlinear systems and control for Automatica. He was registration chair of the 1984 Conference on Decision and Control, finance chair of the 1987 American Control Conference (ACC), program chair of the 1988 ACC, and general chair of the 1994 ACC.