Une nouvelle approche pour la détection en présence de paramètres inconnus

Nous considérons le problème de détection de défaillances dans les systèmes linéaires en présence de paramètres inconnus. Deux méthodes nouvelles basées sur des critères classiques d'optimisation en détection sont formulées. La position du problème est une transposition directe du problème du jeu à deux joueurs dans la théorie de la décision. De nouveaux critères d'évaluation des performances d'une décision en présence de nuisances déterministes sont élaborés. Ils conduisent à des solutions moins conservatives que les approches minmax classiques. Un exemple est étudié

Diagnosis and Fault-tolerant Control, 3rd Edition

Fault-tolerant control aims at a gradual shutdown response in automated systems when faults occur. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults, which bring about sudden shutdowns and loss of availability. The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical models of discrete-event systems represented by automata. The book is suitable for engineering students, engineers in industry and researchers who wish to get an overview of the variety of approaches to process diagnosis and fault-tolerant control. The authors have extensive teaching experience with graduate and PhD students, as well as with industrial experts. Parts of this book have been used in courses for this audience. The authors give a comprehensive introduction to the main ideas of diagnosis and fault-tolerant control and present some of their most recent research achievements obtained together with their research groups in a close cooperatio n with European research projects. The third edition resulted from a major re-structuring and re-writing of the former edition, which has been used for a decade by numerous research groups. New material includes distributed diagnosis of continuous and discrete-event systems, methods for reconfigurability analysis, and extensions of the structural methods towards fault-tolerant control. The bibliographical notes at the end of all chapters have been up-dated. The chapters end with exercises to be used in lectures

Fault recovery by nominal trajectory tracking

International audienceFault accommodation is meant to control the faulty system so as to preserve a given functionality. In model matching, the state dynamics is wished to be fault-invariant, leading to the family of pseudo-inverse and modified pseudo- inverse methods. In this paper, rather than the closeness between the faulty and the nominal system matrices, it is the closeness of their respective trajectories that is required. This problem setting allows to trade-off the quality of the accommodated trajectories and the energy of the accommodated control, and provides a clear definition of recoverable faults

Covers and partitions for observation based learning

International audienceA great number of complex industrial systems produce goods whose quality is very sensitive to the variations of some production parameters. It is often the case that no model exists, which relates the "quality variables" to the "production variables". However, the existence of such models would be very appreciable for process supervision. Knowledge based models can be constructed using the experience of the process operators, and used for diagnosis purposes. Another approach leads to use data analysis methods in order to construct statistical models, since the variables which define the product's quality and the operation parameters can often be evaluated. This is a learning situation, in which knowledge acquisition (model building) is made through the consideration of a set of examples (the data)

Analysis of dynamical systems based on information theory

International audienceKnowledge based control and supervision of unknown or uncertain systems needs the development of learning procedures which can be run on line together with the control, and which allow the identification of the actual rules governing the system evolution, in order to adapt its control, or to detect its deviations from nominal behaviour.The proposed paper is devoted to on line analysis of dynamical order, for systems whose description variables take on qualitative (or symbolic) values. The proposed approach uses information theory based indexes, which also provide a means to consider systems in which symbolic as well as numerical variables are used for the system description

Generalization in automatic learning using aggregation and prolongation

International audienceThis paper is concerned with Automatic Symbolic Learning. More precisely, our aim is to extract rules describing the Input/Output behaviour of a system, from observations which might be incoherent. The presented approach traduces an orientated learning situation, in which the knowledge acquisition (model building) is made through the consideration of a set of examples (the data)

Surveillance des systèmes non linéaires (application aux machines électriques)

Les algorithmes de surveillance (détection et localisation des pannes) reposent sur l'analyse d'un signal, appelé résidu, qui reflète la cohérence entre le comportement du modèle du système non défaillant et le comportement du système réel. Les résidus sont créés en utilisant essentiellement deux types d'approches : les observateurs et l'espace de parité. Dans ce mémoire, nous considérons des systèmes non-linéaires et comparons les résidus générés par les deux approches. Nous appliquons ensuite les résultats sur deux types de moteurs électriques. L'approche de type observateur nécessite en général deux étapes. Dans un premier temps, un sous-système découplé des perturbations et d'un sous-ensemble de pannes est extrait du modèle. Dans un second temps, un observateur est implanté sur ce sous système. Les résidus sont générés en comparant les grandeurs mesurées aux grandeurs estimées. Trois types d'observateurs sont étudiés dans ce mémoire : les observateurs de Luenberger, à grand gain et à mode glissant. L'approche de l'espace de parité consiste à extraire du système des relations d'entrée/sortie appelées Relation de Redondance Analytique (RRA). Les résidus sont générés en évaluant ces RRA avec les signaux mesurés. Les outils mis en œuvre pour obtenir des relations robustes vis-à-vis des entrées inconnues et des pannes sont plus simples que ceux utilisés pour extraire les sous-systèmes découplés dans l'approche observateur. Toutefois, un inconvénient majeur de cette approche est la nécessité de calculer des dérivées des signaux mesurés à des ordres parfois élevés. Pour les systèmes linéaires, il a été montré que les résidus issus de ces deux méthodes sont liés par un filtre linéaire. Dans un premier temps, nous étendons ce résultat aux systèmes non linéaires linéarisables.CERGY-ENSEA (951272302) / SudocLILLE1-BU (590092102) / SudocSudocFranceF

Reconfiguration analysis using generic component models

International audienceThis paper presents a formal approach to analyze system reconfigurability, based on a Generic Component Model (GCM), which describes the system from the services provided by its components, and their organization into Operating Modes, in order to achieve specific objectives. Following a bottom-up approach, services provided by elementary components are used as resources for services at a higher level. Several versions exist when the same service can be rendered by using distinct sets of resources. Reconfiguration results from the existence of multiple versions, since a faulty resource does not imply loosing the services that use it. A level regulation example shows the effectiveness of the proposed model and tools