Semi Plenary Lectures

Dariusz Uciński was born in Gliwice, Poland, in 1965. He studied electrical engineering at the Higher College of Engineering in Zielona Góra, Poland, from which he graduated in 1989.  He received Ph.D. (1992) and D.Sc. (2000) degrees in automatic control and robotics from the Technical University of Wrocław, Poland. In 2007 he was conferred the title of state professor, the highest scientific degree in Poland. He is currently a professor at the University of Zielona Góra, Poland.

He has authored and co-authored 40+ journal and 90+ conference papers. In 2005 his monograph entitled Optimal Measurement Methods for Distributed Parameter System Identification was published by CRC Press in Boca Raton, FL. He also co-authored two textbooks in Polish: Artificial Neural Networks– Foundations and Applications and Selected Numerical Methods of Solving Partial Differential Equations. For twenty years his major activities have been concentrated on measurement optimization for parameter estimation in distributed systems. Other areas of expertise include optimum experimental design, algorithmic optimal control, robotics and parallel computing. In his career, he has been both a leader and a member of several national and international research projects. Since 1992 he has served as the deputy editor the International Journal of Applied Mathematics and Computer Science. Since 2003 he has been the secretary of the IEEE Technical Committee on Distributed Parameter Systems Since 2008 he has been the Chair of the Control Systems Society Chapter of the IEEE Poland Section.

Since for distributed parameter systems it is impossible to observe their states over the entire spatial domain, the question arises of where to locate discrete sensors so as to estimate the unknown system parameters as accurately as possible. Both researchers and practitioners do not doubt that making use of sensors placed in an `intelligent’ manner may lead to dramatic gains in the achievable accuracy of the parameter estimates, so efficient sensor location strategies are highly desirable. In turn, the complexity of the sensor location problem implies that there are very few sensor placement methods which are readily applicable to practical situations. What is more, they are not well known among researchers. The aim of the talk is to give account of both classical and recent original work on optimal sensor placement strategies for parameter identification in dynamic distributed systems modeled by partial differential equations. The reported work constitutes an attempt to meet the needs created by practical applications, especially regarding environmental processes,  through the development of new techniques and algorithms or adopting methods which have been successful in akin fields of optimal control and optimum experimental design. While planning, real-valued functions of the Fisher information matrix of parameters are primarily employed as the performance indices to be minimized with respect to the positions of pointwise sensors. Particular emphasis is placed on determining the `best’ way to guide moving and scanning sensors, and making the solutions independent of the parameters to be identified. Extensive numerical results are included to show the efficiency of the proposed algorithms. A couple of case studies regarding the design of air quality monitoring networks and network design for groundwater pollution problems are adopted as an illustration aiming at showing the strength of the proposed approach in studying practical problems.

Professor Dariusz Uciński

Institute of Control and Computation Engineering
University of Zielona Góra
ul. Podgórna 50, 65-246 Zielona Góra, POLAND

Submission of draft papers:

May 15th, May 30th, 2010

Notification of acceptance:

July 1st, July 19th, 2010

Final version due:

September 1st, 2010

Prof. Christopher Edwards graduated from Warwick University in 1987 with a BSc honours in Mathematics.  In 1991, he moved to Leicester University as a postgraduate student in the Engineering Department funded by a British Gas Research Scholarship and was awarded a Ph.D. in 1995. He was appointed as a Lecturer in Control Engineering in the Department of Engineering at Leicester University in 1996, promoted to Senior Lecturer and Reader in 2004 and 2008 respectively, and awarded a personal chair in 2010. He is a member of the IEEE and a member of the IMA (which constitutes chartered mathematician status). He is the author of over 200 refereed papers and the co-author of a book ‘Sliding mode control: theory and applications’ (Taylor & Francis, 1998) and co-editor of the monograph ‘Advances in Variable Structure and Sliding Mode Control’ (Springer-Verlag, 2006). He is one of the editors of the recent book 'Fault Tolerant Flight Control' (Springer-Verlag, 2010) describing the results of the GARTEUR AG16 Action Group on fault tolerant control.

Sliding mode methods have been historically studied because of their strong robustness properties to a certain class of uncertainty. This is achieved by employing nonlinear control/injection signals to force the system trajectories to attain in finite time a motion along a surface in the state-space. The associated reduced order dynamics, whilst constrained to the surface is called the sliding motion, and possess strong robustness properties. This talk will consider how these ideas can be exploited for fault detection (specifically fault signal estimation) and subsequently fault tolerant control. The talk will also describe an application of these ideas to an aerospace system. It will describe piloted flight simulator results associated with the EL-AL 1862 Bijlmermeer scenario studied as part of the GARTEUR AG16 action group on fault tolerant control. The controller design was carried out without any knowledge of the types of faults/failures occurring on the aircraft, and employs sliding mode methods. The results demonstrate the successful real-time implementation of the proposed fault tolerant control scheme on a motion flight simulator configured to represent the EL-AL aircraft.

Professor Christopher Edwards

Control and Instrumentation Research Group, Department of Engineering
University of Leicester
University Road, Leicester, LE1 7RH, UNITED KINGDOM

Hans Henrik Niemann was born in Denmark in 1961. He received the MSc degree in mechanical engineering in 1986 and the PhD degree in 1988 from Technical University of Denmark.

From 1988 to 1994 he had a research position and from 1994 he has been Ass. Professor in control engineering at Technical University of Denmark. From 2009, he has been appointed as Director of the bachelor study program in electrical science.

His research interests are: Optimal and robust control, fault detection and isolation, active fault diagnosis, fault-tolerant control, controller architecture for controller switching and fault-tolerant control, system and performance monitoring, controller anti-windup.

He has authored and co-authored 25+ journal and 90+ conference papers in the area of optimal and robust control, controller architecture, fault diagnosis and fault-tolerant control.

The application of the primary Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization and the dual YJBK parameterization in connection with performance and fault tolerant control is the main focus in this presentation. A general controller architecture based on the YJBK parameterization will be described. This controller architecture can be based on simple controllers as e.g. P and PI controllers as well as more advanced controllers as e.g. observer-based feedback controllers.

Based on this controller architecture it is possible to analyze the closed-loop systems by using the dual YJBK transfer function. The analysis is derived with respect to closed-loop stability, fault diagnosis and system monitoring. Both passive and active on-line methods can be applied for fault diagnosis and system monitoring.

Controller designs involve redesign and controller reconfiguration of the nominal controllers. The redesign and controller reconfiguration is derived without affecting the nominal feedback controller by using the primary YJBK transfer function. The controller reconfiguration might also involve a change of the applied sets of sensors and actuators. Change of sensors and actuators is relevant in connection with optimizing the closed-loop performance and in connection with controller reconfiguration after detection of faults in the system.

Another important aspect in closed-loop systems is actuator saturation. The saturation problem can also be handled in the applied controller architecture. Anti-windup controllers can be designed by using the YJBK transfer function.

At last interconnection of dynamic subsystems in closed-loop will be considered. It will be shown that the YJBK parameterization can be applied in connection with both analysis and controller design for interconnected systems. Based on

the applied controller architecture, it is possible to estimate subsystems based on the dual YJBK transfer function.

Ass. Professor Henrik Niemann

Department of Electrical Engineering, Automation and Control, Build. 326

Technical University of Denmark

DK-2800 Kgs. Lyngby, DENMARK

Jin Jiang received his BESc. from Xi'an Jiaotong University, in Xi'an, China in 1982, and MESc. and Ph.D. degrees from the University of New Brunswick, in Fredericton, New Brunswick, Canada in 1984 and 1989, respectively. From 1991, He has been with the Department of Electrical & Computer Engineering, University of Western Ontario, London, Ontario, Canada, where he currently is a Senior Industrial Research Chair Professor in control, instrumentation, and electrical systems in nuclear power plants. He has a wide range of research interests, including fault-tolerant control of safety-critical systems, advanced control of electrical power plants and power systems, and advanced signal processing for diagnosis applications. He has published extensively, including co-authoring three books on the above subjects. He is also a member of IEC (International Electrotechnical Commission) 45A subcommittee to develop industrial standards on nuclear instrumentation and control for nuclear facilities. He also works closely with IAEA (International Atomic Energy Agency) on modern control and instrumentations for nuclear power plants.

The cost of design, implementation, and maintenance of a fault-tolerant control system are significantly higher than that of a traditional control system. Therefore, the only time that one can even think and justify of using a fault-tolerant control system is for safety-critical applications. How does a fault-tolerant control system increase the level of safety? This is the main subject of this talk.

In this talk, we will first look at the perception of safety in the eyes of public in terms of potential risks. In a safety-critical (in synonym: hazardous, dangerous, or risk-prone) system, the role of a fault-tolerant control system is extremely important.  One of its functions is to steer the process to a safe state whenever undesirable events (known as faults) occur. To fulfill this role reliably, the availability of the fault-tolerant control system has to be high. As we all know, in practice, things will break and designed functions will fail, it is just a matter of time. This also applies to fault-tolerant control system itself. Thus, to achieve a high degree of availability against random failures, one has to resort to redundancy.

Furthermore, to avoid common cause failures, there are special requirements on the redundancy, such as reliability, independence, separation, and diversity. The concept of defence in depth against various failure modes will also be introduced. Finally, as an example, we will take a brief look at how the concept of fault-tolerant control system is utilized in safety control systems within nuclear power plants.

So, why does one need fault-tolerant control systems anyway? The answer is to reduce potential and hidden risks in technological systems to a level that is deemed to be safe in the eyes of public.

Professor Jin Jiang

Electrical & Computer Engineering, Faculty of Engineering

The University of Western Ontario

London Ontario CANADA N6A 5B9