New-ACE

Dept. of Electrical and Electronic Engineering
Imperial College London
London SW7 2AZ, United Kingdom
E-mail: a.astolfi@imperial.ac.uk

Alessandro Astolfi was born in Rome, Italy, in 1967. He graduated in electrical engineering from the University of Rome in 1991. In 1992 he joined ETH-Zurich where he obtained a M.Sc. in Information Theory in 1995 and the Ph.D. degree with Medal of Honour in 1995 with a thesis on discontinuous stabilization of nonholonomic systems. In 1996 he was awarded a Ph.D. from the University of Rome ``La Sapienza" for his work on nonlinear robust control. Since 1996 he is with the Electrical and Electronic Engineering Department of Imperial College, London (UK), where he is currently Professor in Non-linear Control Theory. From 1998 to 2003 he was also an Associate Professor at the Dept. of Electronics and Information of the Politecnico of Milano. Since 2005 he is also Professor at Dipartimento di Informatica, Sistemi e Produzione, University of Rome ``Tor Vergata''. He has been visiting lecturer in ``Nonlinear Control" in several universities, including ETH-Zurich (1995-1996); Terza University of Rome (1996); Rice University, Houston (1999); Kepler University, Linz (2000); SUPELEC, Paris (2001).

His research interests are focused on mathematical control theory and control applications, with special emphasis for the problems of discontinuous stabilization, robust stabilization, robust and adaptive control, and observer design. He is author of more than 70 journal papers, 20 book chapters and 190 papers in refereed conference proceedings. He is co-editor of three books, including the book ``Analysis and Design of Nonlinear Control Systems -- In Honor of Alberto Isidori'' (Springer Verlag), and author (with D. Karagiannis and R. Ortega) of the monograph ``Nonlinear and Adaptive Control with Applications" (Springer Verlag). He is Associate Editor of Systems and Control Letters, Automatica, IEEE Trans. Automatic Control, the International Journal of Control, the European Journal of Control, the Journal of the Franklin Institute, the IMA Journal of Mathematical Control and Information and he is subject Editor of the International Journal of Adaptive Control and Signal Processing. He has also served in the IPC of various international conferences.

A. Astolfi has been the recipient of the 2007 IEEE Control Systems Society Antonio Ruberti Young Researcher Prize. The Prize is given annually to ``recognize distinguished cutting-edge contributions by a young researcher to the theory or application of systems and control".

The problem of observer design for nonlinear, deterministic, finite-dimensional systems is discussed. We initially provide a survey of existing results for linear and nonlinear systems, pointing out open problems and directions of research. We then focus on the problem of global observer design for nonlinear systems, highlighting the role of normal forms, of input-state-output properties, of invariant manifolds and of an extended notion of homogeneity. The classical results in [5], [6] and Luenberger's ideas [9], [10], with their nonlinear enhancement proposed in [8] and further developed in [12], [1], are the point of departure for the construction of global observers.
We discuss in detail three global design methodologies. The design in [4], applicable to uniformly observable systems, exploits the notion of output-to-state-stability to construct a state norm estimator which is used to tune on-line  a high-gain observer. This design guarantees global convergence of the estimation error within the domain of definition of the trajectories. The design in [7], applicable to general nonlinear systems  exploits Luenberger's ideas (and their nonlinear counterpart) and the notion of invariant manifold to construct globally convergent (adaptive) state and parameter  estimators. The design in [2], applicable to systems in triangular forms, relies upon the newly developed notion of homogeneity in the bi-limit, and uses observer backstepping/ and dynamic scaling to recursively design globally convergent observers. The applicability of these global observer designs to the problem of global output feedback stabilization is also discussed [11], [2], [3].

[1] V. Andrieu and L. Praly. On the existence of Kazantzis-Kravaris/Luenberger observers. SIAM Journal of Control and Optimization, 45:432--456, 2006.
[2] V. Andrieu, L. Praly, and A. Astolfi. Homogeneous approximation, recursive observer design and output feedback. SIAM Journal of Control and Optimization, (to appear).
[3] A. Astolfi, D. Karagiannis, and R. Ortega. Nonlinear and Adaptive Control with Applications. Springer Verlag, London, 2008.
[4] A. Astolfi and L. Praly. Global complete observability and output-to-state stability imply the existence of a globally convergent observer. Mathematics of Control, Signals, and Systems, 18(1):32--65, 2006.
[5] J.-P. Gauthier and I. Kupka. Deterministic Observation Theory and Applications. Cambridge University Press, 2001.
[6] J.-P. Gauthier and I.A.K. Kupka. Observability and observers for nonlinear systems. SIAM J. Control and Optimization, 32(4):975--994, 1994.
[7] D. Karagiannis, D. Carnevale, and A. Astolfi. Invariant manifold based reduced-order observer design for nonlinear systems. IEEE Trans. Autom. Control, (to appear).
[8] N. Kazantzis and C. Kravaris. Nonlinear observer design using Lyapunov's auxiliary theorem. Systems and Control Letters, 34:241--247, 1998.
[9] D.G. Luenberger. Observing the state of a linear system. IEEE Trans. Military Electronics, 8:74--80, 1964.
[10] D.G. Luenberger. An introduction to observers. IEEE Trans. Autom. Control, 16(6):596--602, 1971.
[11] L. Praly and A. Astolfi. Global asymptotic stabilization by output feedback under a state norm detectability assumption. 44nd Conference on Decision and Control and 2005 European Control Conference, pages 2634--2639, 2005.
[12] M.Q. Xiao and A.J. Krener. Nonlinear observer design in the Siegel domain. SIAM Journal of Control and Optimization, 41:932--953, 2002.

Dept. of Electrical and Electronic Engineering
Imperial College London
London SW7 2AZ, United Kingdom
E-mail: d.limebeer@imperial.ac.uk

David J. N. Limebeer was born in Johannesburg South
Africa. He received the B.Sc.(Eng) degree in Electrical
Engineering from the University of the Witwatersrand in 1974,
and the M.Sc.(Eng) and Ph.D. degrees in 1977 and 1980,
respectively, from the University of Natal in South Africa. He
received the D.Sc. (Eng) degree from London University in
1992. From 1974 to 1976 he was an assistant engineer at the
Johannesburg City Council. He was a Research Assistant at the
University of Cambridge, England between 1980 and 1983. In
1984 he moved to the Department of Electrical Engineering,
Imperial College London as a lecturer. In 1989 he was promoted to Reader in Control
Engineering and to Professor of Control Engineering in 1993. He was head of the Control
Group in the Department of Electrical and Electronic Engineering between 1995 and 1999, and
the Head of the Department of Electrical and Electronic Engineering between 1999 and 2008.
He has held several summer visiting positions at the University of Southern California, the
Australian National University and Stanford University. He is a past editor of Automatica and
a past associate editor of Systems and Control Letters and the International Journal of Robust
and Nonlinear Control. He has served on the British Science and Engineering Research
Council's control and instrumentation sub-committee and is a current member of the
Engineering and Physical Science Research Council?s Control and Instrumentation College
and the CPDE committee. He was joint recipient of the AACC O. Hugo Schuck award for the
best paper presented at the 1983 American Control Conference. He was elected Fellow of the
American IEEE in 1992 and Fellow of the British IEE in 1994. He was also elected Fellow of
the Royal Academy of Engineering in 1997. His research interests include multivariable
system theory, the theory and application of robust control, dynamic system modelling and
identification, computer aided control system design, power system stability, the control of
tokomaks and the stability of two-wheeled road vehicles. He has published numerous papers
and a text book in these areas; three of his papers have been awarded prizes. He qualified as an
IAM advanced motorcycle instructor in 1998 and has passed the RoSPA advanced motorcycle
test at the gold grade.

The purpose of the presentation is to study the dynamic stability of
accelerating/braking two-wheeled road vehicles. It is shown that time-scale separation
can be used to study the oscillatory characteristics of the accelerating machine using
time-invariant models. These models are used to explain practically observed wobblemode
bursting oscillations, which are associated with down-hill riding in bicycles and
accelerating out of high-speed corners for motorcycles. If the vehicle is cornering
under constant acceleration at a fixed roll angle, it is shown that for low values of
acceleration (and braking), it follows closely a logarithmic spiral shaped trajectory.
The study to be presented is facilitated by a novel adaptive control scheme that
centres the machine?s trajectory on any arbitrary point in the ground plane. The
influences of longitudinally inclined and cambered road surfaces are also studied. The
bicycle model employed is based on that originally developed by Whipple, and
comprises two road wheels and two laterally-symmetric frame assemblies that are free
to rotate relative to each other along an inclined steering axis. For the most part the
front frame is treated as being flexible and the bicycle is fitted with force generating
road tyres, rather than classical nonholonomic rolling constraints. While the dynamics
of the bicycle is of interest in its own right, this research provides the theoretical
ground work required for studying bursting phenomena in high-performance
motorcycles, which are dynamically more complicated. Motorcycle steering
compensation results will be presented.

Dept. of Mechanical Engineering
Imperial College London
London SW7 2AZ, United Kingdom
E-mail: r.botas@imperial.ac.uk

Dr Martinez-Botas is a Reader in Turbomachinery in the Department of Mechanical Engineering at Imperial College with wide experience of both experimentation and numerical methods applied to a variety of turbo-machines.  Dr Martinez-Botas presently leads a group of 8 research students, assistants and technicians involved in various aspects of turbomachinery aero-thermal studies. The Thermofluids Division at Imperial College is internationally recognised as a key research centre responsible for new developments in the field of laser diagnostics and computational fluid dynamics, as applied to advanced petrol and diesel engines. He is a member of the Energy Technology for Sustainable Development Research Group.

The behaviour of the turbocharger turbine under pulsating exhaust flow environment has been the subject of interest for the past few decades. Variable geometry turbochargers (VGT) offer boosting solution which overcomes many of the conventional turbo charging problems such as turbolag and engine matching. Even the state of the art VGT are still based on steady state turbine assumption, with geometry control based dominantly on engine load and speed. But regardless of the engine load and speed the exhaust gas which is feeding the turbine is pulsating in nature, and the current VGT are not fully utilizing the energy available especially at the lower region of the pulse. An advanced turbo charging technique called Active Control Turbocharger (ACT) is proposed and demonstrated through experiment and simulation; where the turbine geometry will be operated actively to adapt to the pulsating exhaust flow in order to maximize the energy extraction without jeopardizing the overall turbine efficiency.

A mixed flow turbine with pivoting nozzle vanes was designed and tested at equivalent speed of 48000 rpm with inlet flow pulsation of 40 Hz and 60 Hz; these correspond to a four strokes diesel engine speed respectively of 1600 rpm and 2400 rpm, in order to compare with model?s results. The nozzle vane ring is capable of a pivoting range from 80° to 40° (with respect to radial direction), which corresponds to an area opening of 7% to 100% respectively. The turbine was tested in two modes: firstly with natural oscillation of nozzle vanes against the spring loading in the pulsating flow and secondly with forced oscillation.

A 1D engine model coupled with Active Control Turbocharger (ACT) was built using GT-POWER. The ACT was modeled based on a VGT with integrated control strategy that enables it to adapt to the incoming pressure pulses. This required appropriate sensor and actuator modeling in order for the turbine to be actively changing due to the incoming pressure pulses. The model emulates the first mode of the turbine operation in the experiment, which is with natural oscillation of nozzle vanes. Different performance maps of the turbine as acquired through experiments are used in the model as part of the whole diesel engine map matrix. The model enables the analysis of engine performance with ACT, and addresses possible improvements on the turbocharger. The operational strategy for the ACT has been developed to satisfy the whole engine working conditions. It aims at optimizing the ACT for better engine transient operation as well as improving turbine efficiency and power. The improvements will need to avoid the increase in the exhaust back pressure and compliment the EGR. The optimization of the ACT with experiments and validated model could find application in heavy duty diesel engine (low frequency-high pressure exhaust pulse).

University of Cambridge
Department of Engineering
Trumpington Street
Cambridge CB2 1PZ, United Kingdom

Malcolm Smith received the B.A. (M.A.) degree in mathematics, the M.Phil degree in control engineering and operational research and the Ph.D. degree in control engineering from Cambridge University, England. He was subsequently a Research Fellow at the German Aerospace Center, DLR, Oberpfaffenhofen, Germany, a Visiting Assistant Professor and Research Fellow with the Department of Electrical Engineering at McGill University, Montreal, Canada, and an Assistant Professor with the Department of Electrical Engineering at the Ohio State University, Columbus, USA. He is now a Fellow of Gonville and Caius College and a Professor in the Department of Engineering at the University of Cambridge.

The talk will discuss recent work on the synthesis of general passive mechanical impedances and its application to problems of mechanical control.  The need for a new modelling element (the inerter) will be explained and its mechanical construction discussed.  The recent deployment of the inerter in Formula One racing cars will be described.

Japan Patent Office
Tokyo, Japan
Email: h.ochiai@imperial.ac.uk

Hiroyuki OCHIAI studied Mechanical Engineering and Materials Science at Yokohama National University, Japan. He obtained a B.A. degree in mechanical engineering in 1997 and a M.A. degree in mechanical engineering in 1999. He conducted research on the interaction between the human body and external sources of vibration.

Since 1999 Hiroyuki OCHIAI has worked as a patent examiner in the Japan Patent Office (JPO), where he has examined patent applications relating to motorcycles, bicycle and all-terrain vehicles.

He is currently studying the stability of motorcycles as Academic Visitor at Imperial College London from July 2008 to June 2009.

This talk will introduce the basic knowledge of the patent  system for academic researchers.

Patents are not special but ordinary, not irrelevant but something to be concerned with and not dull but interesting! The presentation will explain what a patent is, why use patents, why patents should be obtained, how patents are obtained, how patents are searched, etc.

The presentation will attempt to provide introductory knowledge about patents to tempt you to be interested so that your research and achievements can be enhanced.

add2 Ltd
Hawkesyard Hall, Armitage Park, Armitage
Staffordshire WS15 1PU, United Kingdom

Christian Matthews received his M.Eng degree in Mechanical Systems & Design Engineering from the University of Liverpool, UK in 2003.  He subsequently joined the Powertrain Control Group for three years where his research interests were system identification and robust control methodologies applied to powertrain systems and transient dynamometers. He received his Ph.D in December 2007 for his thesis entitled 'Identification and Robust Control of Automotive Dynamometers'.

In November 2006, he joined add2 ltd where he is a Systems and Control Engineer specialising in HIL (Hardware-In-the-Loop) and RCP (Rapid Control Prototyping) techniques for development and validation of vehicle control systems. His other professional interests include vehicle dynamics, systems modelling and real-time simulation. He is actively involved in a joint research project between add2, The University of Warwick, QinetiQ and Jaguar/Land Rover entitled 'Evolutionary Validation of Complex Systems' (EVoCS).  He is also involved in collaboration with a number of University research group's in the UK.

While most controller synthesis techniques call for relatively compact frequency domain plant models, more detailed representations also have a role to play in the development cycle.  It is often important that the closed loop performance and robustness of a controller should be validated against a system model with sufficient detail to represent all of its important dynamics, nonlinearities and uncertainties prior to broader implementation, especially where safety critical functions are concerned.

This presentation will discuss the role which detailed simulation models can play throughout the control system development cycle, but will focus upon the validation stage. An example relating to vehicle control systems will be given in order to briefly illustrate different applications, including software-in-the-loop and hardware-in-the-loop methods.