Fault Detection in Dynamic Systems: From State Estimation to Direct Input Reconstruction Methods FAULT DETECTION IN DYNAMIC SYSTEMS: FROM STATE ESTIMATION TO DIRECT INPUT RECONSTRUCTION METHODS

PREFACE Modern technology has increasingly created highly complex dynamical systems where the issues of systems' availability and operational safety have become one of the main problems: dependability and reliability became major concerns in the design of modern technical control systems. In engineering the term 'safety intensive' is used for denoting and characterizing these systems more closely. The scope of the theory and application of the technical and operational management of safety intensive systems is vast and increasing. This ranges from the most common issues of operational safety such as condition monitoring, fault detection and isolation, fault diagnosis, fault management and fault tolerance to some more general questions of the operation such as the effect of human factor, mentioning just a few. Indeed, faults may have a considerable impact on the achievement of the system's technical goal, on the security of human operators, on the integrity or on the profitability of the system itself, or on the integrity of the system's environment. Practically, for safety intensive applications, every kind of system is concerned: embedded systems (for civil or military applications), or huge complex installations , ranging from domestic systems to transportation, communication, industrial processes. Their design must take into account safety and dependability considerations, for economic, sociologic and human reasons. Incorporating safety issues into the design process is a rather contradictory problem, however. Introducing dependability considerations into the design and the exploitation of systems has a visible cost, while the production losses, quality losses, performance degradations or even accidents which they would help to avoid are obviously not so apparent. In other words, selling safety is not an easy problem in modern economy where the actors of the economy are mostly interested in maximizing their profits. In order to push decision makers of the economy towards the acceptance of safety regulations, and to encourage a volunteer approach to the consideration of those problems, it is necessary to develop techniques and application method-ologies which produce safe and secure systems at affordable prices, and in parallel, to develop analysis and evaluation tools in order to quantify, prove and certify the abovementioned systems performances, that is to say, to increase the confidence measures of the application of the new safety intensive technologies. Fault detection and isolation (FDI) issues, associated with fault tolerant control, have first been developed in the United States and in the former Soviet Union, mainly in the frame of defense and …