ROCOND06 - Program

B. R. Barmish	University of Wisconsin-Madison (USA)
Title:	On Robustness with Nonlinear Parameter Dependence: A New Framework
Abstract:	In this plenary, the focal point is robustness problems which involve nonlinear dependence on the uncertain parameters. Motivated by NP-hardness considerations and the limited number of results in the literature to date, a new line of research is described. To this end, we begin with the following simple formulation of a robustness problem: Determine if a given function f (x) is negative for all x in a given constraint set X . Then, letting Xbad denote the set over which this constraint is violated, we consider a “softening” of the problem. Namely, determine if the volumetric inequality Vol( Xbad ) < epsilon is satisfied with epsilon > 0 being associated with an “acceptable” level of performance violation. Within this framework, we present a number of results obtained to date. After introducing some ideas involving dilation integrals and conditioners, it is seen that many nonlinear robustness problems can be reduced to convex programming. Subsequently, we describe specific classes of robustness problems for which solutions are readily obtainable.
Biography:	B. Ross Barmish was born in Montreal, Quebec in 1949. He received the Bachelor’s degree in Electrical Engineering from McGill University, Montreal, Quebec in 1971. In 1972 and 1975 respectively, he received the M.S. and Ph.D. degrees, both in Electrical Engineering, from Cornell University, Ithaca, NY. From 1975 to 1978 he served as Assistant Professor of Engineering and Applied Science at Yale University, New Haven, CT. From 1978 to 1984, he was as an Associate Professor of Electrical Engineering at the University of Rochester, Rochester, NY. In August 1984, he joined the University of Wisconsin, Madison, WI where he is currently Professor of Electrical and Computer Engineering. From January 2001-December 2003, he was with the Department of Electrical Engineering and Computer Science at Case Western Reserve University, Cleveland OH, where he served as Department Chair and held the Eric Nord Endowed Chair in Computer Engineering. Professor Barmish is a Fellow of IEEE for contributions to robust control and has received the the Best Paper Award for Journal Publication on two consecutive occasions from the International Federation of Automatic Control: in Tallin, Estonia covering the period 1987-1989 and in Sydney Australia covering publication from 1990-1992. In 2004, he won the University of Wisconsin’s Byron Byrd Award for Excellence in Research Publication and was named by the university as being among the most highly cited faculty. Over the years, Professor Barmish has been involved in a number of professional society and consulting activities. For example, from 1982 to 1984, he served as an Associate Editor for the IEEE Transactions on Automatic Control and was Program Chairman for the 1992 American Control Conference. From 2002-2004, he served as member of the IEEE Control Systems Society Board of Governors and as chair of a number of IEEE prize paper committees. From 1990-1995, he was an Associate Editor for Mathematics of Control, Signals and Systems and he is currently an Associate Editor for the International Journal of Robust and Nonlinear Control. Over the last two decades, he has served as a consultant in the areas of fermentation control and automotive control for Centro Ricerche Fiat. Since the publication of his 1994 textbook, New Tools for Robustness of Linear Systems, Professor Barmish has working on robustness problems with nonlinear parameter dependence. More recently, he has been pursuing a new line of research on physics-motivated control problems.
A. Ben Tal	Technion (IL)
Title:	Robust Optimization and Uncertainty Affected Linear Dynamic Systems
Abstract:	We survey the main developments in the Robust Optimization (RO) methodology, which is aimed at solving optimization problems (static and dynamic) affected by uncertainty. We focus primarily on issues of computational tractability of the robust counterparts emerging from conic optimization problems (linear, conic quadratic and semidefinite) and derive probabilistic guarantees for their solutions. Finally we discuss the synthesis of uncertainty affected discrete-time linear control systems, and use a reparametrization scheme that converts these (otherwise nonconvex) control problems into tractable convex programming ones.
Biography:	Aharon Ben-Tal (Israel) is Professor of Operations Research and Head of the MINERVA Optimization Center at the Technion Israel Institute of Technology. He received his Ph.D. in Applied Mathematics from Northwestern University in 1973. He has been a Visiting Professor at the University of Michigan, University of Copenhagen , Delft University of Technology and MIT. His recent interests are in Continuous Optimization, particularly nonsmooth and large-scale problems, conic and robust optimization, as well as convex and nonsmooth analysis. In the last 10 years, he has devoted much effort to the engineering applications of optimization methodology and computational schemes. He has published more than 100 papers in professional journals and co-authored two books: Optimality in Nonlinear Programming: A Feasible Direction Approach (Wiley-Interscience, 1981) and Lectures on Modern Convex Optimization: Analysis, Algorithms and Engineering Applications (SIAM-MPS series on optimization, 2001). He was dean of the Faculty of Industrial Engineering and Management at the Technion (1989-1992). He served as a council member of the Mathematical Programming Society (1994-1997). He was Area Editor (Continuous Optimization) of Math. Of Operations Research (1993-1999), and member of the Editorial Board of SIAM J. Optimization ,Math Programming, J. Convex Analysis, OR Letters, Math. Modelling and Numerical Analysis.
A. S. Lewis	Cornell University (USA)
Title:	Nonsmooth Optimization and Robust Control
Abstract:	Many questions of robust control analysis and synthesis fundamentally involve nonsmooth sets and functions, and their variational properties. Central examples include distances to instability and uncontrollability, the H∞ norm, and pseudospectra. This talk surveys what current ideas from nonsmooth analysis have to say about the structure and conditioning of such functions and sets, and their numerical optimization. I will focus on notions of nonsmooth differentiation and “regularity” and on structural tools such as “partial smoothness” and semi-algebraic techniques, illustrating how each idea helps in algorithm design and analysis. Joint work with J.V. Burke, Univ. Washington, Seattle, USA and M.L. Overton, New York Univ., USA.
Biography:	Adrian S. Lewis was born in England in 1962. He is a Professor at Cornell University in the School of Operations Research and Industrial Engineering. Following his B.A., M.A., and Ph.D. degrees from Cambridge, and Research Fellowships at Queens’ College, Cambridge and Dalhousie University, Canada, he worked in Candada at the University of Waterloo (1989-2001) and Simon Fraser University (2001-2004). He is an Associate Editor of the SIAM Journal on Optimization, Mathematics of Operations Research, and the SIAM/MPS Book Series on Optimization, and is a Co-Editor for Mathematical Programming. He received the 1995 Aisenstadt Prize, from the Canadian Centre de Recherches Mathematiques, the 2003 Lagrange Prize for Continuous Optimization from SIAM and the Mathematical Programming Society, and an Outstanding Paper Award from SIAM in 2005. He co-authored ”Convex Analysis and Nonlinear Optimization” with J.M. Borwein. His research concerns variational analysis and nonsmooth optimization, with a particular interest in optimization problems involving eigenvalues.
P. Ménard	Airbus (FR)
Title:	Flight Controls: the robust design challenge
Abstract:	After a brief introduction to Flight Controls and typical systems architecture (HMI components, energy circuits, computers, actuation device...), we will focus on the control loops, and give an overview about aircraft dynamics, control laws design criteria, multi-disciplinary design constraints, and key drivers for aircraft users (pilots, maintenance, passengers...) Then the control loops design robustness challenge will be discussed: to achieve this robustness target. Most of the parameters the aircraft control system has to be robust against will be briefly presented, to help Automatic Control community to tighten the link between theory and actual design. Finally we will give practical examples of what could be achieved to cope with these robustness constraints. This may illustrate typical solutions developed either on commercially used aircraft, or in the research frame, and may help high skilled Automatic Control specialists to get in touch with typical design problems we may encounter in civil aeronautical transport field.
Biography:	Philippe Menard has been in charge of Airbus A340 Autopilot Control Laws design till its first certification in 1993. Then he gained Cat 3 certification experience in contributing to harmonize JAA (european) and FAA (american) certification rules and process for automatic landing function. In 1996 he drived a ”generic autopilot” research pro ject, to extract the best technical principles and solutions for minimizing design and upgrade effort while setting an autopilot on a new aircraft. During few years he led a research group to prepare the A380 control laws, by testing on a prototype new laws including flight envelope protections laws. In 2003, he became Research Methods & Tools Group leader for the Stability and Control Department, part of the Flight Control and Hydraulics Domain in Airbus-France.
I. Postlethwaite	University of Leiscester (UK)
Title:	Robust Control Applications
Abstract:	This plenary presentation will demonstrate the growing importance of robust control theory by describing its application to some non-trivial practical control problems. The talk will begin with a description of the design and flight test of a new batch of H-infinity controllers for the Bell 205 helicopter. At the heart of each controller is an H-infinity loop-shaping controller, augmented with a hand-tuned reference filter to improve tracking performance and to reduce a perceived phase lag which pilots had complained of previously. Flight testing revealed that, with such an architecture, it was relatively easy to get Level 1 handling qualities ratings in low aggression manoeuvres. Further fine tuning resulted in Level 1 qualities for high aggression manoeuvres and one controller performed to Level 1 standard in all manoeuvres tested. The second half of the talk will consider how robust control techniques can be used to design antiwindup compensators to counter problems associated with saturating actuators, such as pilot-induced oscillations in aircraft and stability/robust performance problems in state-of-the-art hard-disk drive servo systems. The paper is written in two parts: Part 1 considers helicopter control and Part 2 addresses saturation problems in high-performance head-positioning servo systems in high-density hard-disk drives.
Biography:	Ian Postlethwaite was born in Wigan, England in 1953. He received a First Class BSc (Eng) degree from Imperial College, London University in 1975 and the PhD degree from Cambridge University in 1978. From 1978 to 1981 he was a Research Fellow at Cambridge University and spent six months at General Electric Company, Schenectady, USA. In 1981, he was appointed to a Lectureship in Engineering Science at Oxford University. In 1988, he moved to a Chair of Engineering at the University of Leicester where he was Head of Department from 1995-2004 and is now a Pro-Vice-Chancellor. He has held visiting research positions at the Australian National University and the University of California at Berkeley. His research involves theoretical contributions to the field of robust multivariable control and the application of advanced control system design to engineering systems. He is a Fellow of the IEEE, the IEE and the InstMC. In 1991, he received the IEE FC Williams premium; in 2001, he was awarded the Sir Harold Hartley Medal of the InstMC; and in 2002, he received a best paper prize from the IFAC Journal of Control Engineering Practice. He is a co-author with Sigurd Skogestad of Multivariable Feedback Control (Wiley, 1996 and 2005).
M. Steinbuch	Eindhoven University of Techology (NL)
Title:	Advanced Motion Control
Abstract:	In motion systems, such as robotics, pick-and-place machines and disc drives, plant models are relatively easy to acquire with high accuracy, and feedforward is always used for servo tasks. The primary role of the feedback is to suppress disturbances, however, here the fundamental limitations with respect to controlled performance are felt, which are primarily due to causality. The Bode Sensitivity integral expresses the causality in the form of reduction of low-frequent disturbances, on the cost of the amplification of (typically) high frequent signals (Water bed effect), e.g. measurement noise. It is this fundamental limitation which is the driving force for a few lines of research: (i) further exploring feedforward, including iterative learning control, (ii) disturbance- and data- based control, i.e. using the internal model principle and also the principle of ’machine-in-the-loop’ for adjusting the controller parameters on the basis of on-line measurement, (iii) non-linear control of linear motion systems, and finally (iv) multivariable robust control of mechanical systems.
Biography:	Maarten Steinbuch is full professor in Systems and Control. He received the M.Sc. degree in Mechanical Engineering from Delft University of Technology, Delft, The Netherlands, in 1984. From 1984 until 1987 he was a research assistant at Delft University of Technology and KEMA (Power Industry Research Institute), Arnhem, The Netherlands. In 1989 he received the Ph.D. degree from Delft University of Technology on the sub ject of Modelling and Control of Wind Energy Conversion Systems. From 1987-1998 he was with Philips Research Labs., Eindhoven as a Member of the Scientific Staff, working on modelling and control of mechatronic applications. From 1998-1999 he was manager of the Dynamics and Control group at Philips Center for Manufacturing Technology. Since 1999 he is full professor of the Control Systems Technology group of the Mechanical Engineering Department of Eindhoven University of Technology. His research interests are modelling and control of motion systems. He was an associate editor of the IEEE Transactions on Control Systems Technology (1993-1997), of IFAC Control Engineering Practice (1994-1996), and of IEEE Control Systems Magazine (1999-2002). He is currently editor-at-large of the European Journal of Control. In 2003 and in 2005 he obtained the ’Best-Teacher award’ of the Department of Mechanical Engineering, TU/e.

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