Shifting Paradigms for Robust Control — Then and Now

January 17, 2014, Webb 1100

Michael Safonov

University of Southern California, Electrical Engineering


A revolution in control theory thought happened in the early 1970’s when the dominant focus of research shifted from optimality to robustness in response to unexpected failures of optimal control theory to produce feedback control designs capable of tolerating normal differences between design models and reality. The robustness concept has since become such an integral part of present day control theory that it is difficult to imagine that time long ago when the concept lacked a clear mathematical representation and the tools of multivariable robustness analysis were yet to be identified. We shall revisit that time to examine the events that facilitated, and necessitated, this remarkable paradigm shift. Next, looking to the future, we will consider how failures of robust control designs to cope with incorrect uncertainty estimates are beginning to spur control theorists to consider data-driven problem formulations for estimation and control that tacitly question the roles of basic concepts like ‘true model and uncertainty bounds’, stochastic noise models and even Bayesian probability. We will discuss how and why Karl Popper’s scientific logic of unfalsification seems to be emerging as a central concept in these data-driven problem formulations, and how the unfalsification concept might again shift the focus of mathematical research in the areas of estimation and control.

Speaker's Bio

Michael G. Safonov was born in Pasadena, CA, on November 1, 1948. He received the B.S., M.S., Engineer, and Ph.D. degrees in electrical engineering from the Massachusetts Institute of Technology, Cambridge, MA in 1971, 1971, 1976 and 1977, respectively. From 1972 to 1975 he served with the U.S. Navy as Electronics Division Officer aboard the aircraft carrier USS Franklin D. Roosevelt (CVA-42). Since 1977 he has been with the University of Southern California where he is presently a Professor of Electrical Engineering. He has been a consultant to The Analytic Sciences Corp., Honeywell Systems and Research Center, Systems Control, Systems Control Technology, Scientific Systems, United Technologies, TRW, Northrop Aircraft, Hughes Aircraft and others. His consulting and university research activities have involved him flight control system design studies in which modern robust multivariable control techniques were applied to a variety of aircraft including the CH-47 Chinook helicopter (Analytic Sciences Corp., 1976), the NASA HiMAT aircraft (Honeywell/USC, 1980) and the F/A-18 Hornet (Northrop, 1987-1991). During the academic year 1983-1984 he was a Senior Visiting Fellow with the Department of Engineering, Cambridge University, England, and in summer 1987 he held a similar appointment at Imperial College of Science and Technology, London, England and in 1990-1991 at Caltech, Pasadena, CA. He has authored or co-authored more than two hundred journal and conference papers and the books Stability and Robustness of Multivariable Feedback Systems (MIT Press, 1980) and Safe Adaptive Control: Data-driven Stability Analysis and Robust Synthesis (Springer-Verlag, 2011). Additionally, he is co-author of the MATLAB Robust Control Toolbox (Natick, MA: MathWorks). His research interests include robust control, adaptive control and nonlinear system theory, with applications to aerospace control design problems. He served as an Associate Editor of the IEEE Trans. on Automatic Control from 1985-1987 and is presently an editor of International Journal of Robust and Nonlinear Control and Systems and Control Letters. From 1993 to 1995, he was Chair of the AACC Awards Committee of the American Automatic Control Council. He is a Fellow of the IEEE and a Fellow of IFAC.