josé RAGOT | Université de Lorraine (original) (raw)
José RAGOT received the "Diplome d'Ingénieur" (Engineer Degree) with specialization in control from the Ecole Centrale de Nantes (France) in 1969. Then, he joined the University of Nancy (France) where is received the "Diplôme d'Etudes Approfondies" (Master Degree) in 1970. In 1973 he obtained the "Diplôme de Doctorat" (Ph. D. degree), a position as assistant professor at University Henri Poincaré in Nancy, and in 1980 the "Diplôme de Doctorat-es-Sciences". José Ragot moved up to professor in 1985 at the Institut National Polytechnique de Lorraine (INPL, National Polytechnic Institute of Lorraine). He has successfully advised 70 Ph.D. and published about 500 refereed technical communications including 130 papers in international journals and 370 communications in international conferences, 4 books (Masson, Hermès, Lavoisier), 14 chapters in collective volumes. Applications have been in various fields such as mineral and metallurgical processing, chemical engineering, water treatment, aerospace, environmental processes. Since 1980, he was the conductor of about 60 industrial research projects (with EDF, ELF, SOCOMINE, HBL, ARCELOR MITAL, AIRLOR, ESPOL, PECHINEY, ALSTOM, SNECMA, LAFARGE, DELPHI, RHÔNE POULENC, PSA, AIRBUS, THALES …). He was a member of more that 220 Ph. D. committees (France, Spain, Germany, Belgium, Russia, Tunisia, Algeria, India). He regularly contributes to national and international activities as a member of TC4 and TC6 of IFAC, through conferences organization, international program committee of conferences, reviewer in international journals and conferences, national expert for research project of the French CNRS, national expert for laboratory activities evaluation for the French Ministary of Research. He was invited at several universities as a lecturer: EPFL (Lauzane, Suisse), UTC (Compiègnes, France), UTT (Troyes, France), ENIT (Tunis, Tunisie), ENIM (Monastir, Tunisie), Jijel University (Annaba, Algérie), ESISAR (Valence, France), LAAS (Toulouse, France), GIPSA_lab (Grenoble, France) … His major research fields include data validation and reconciliation, process diagnosis, fault detection and isolation. Another part of his activities is devoted to modelisation and state estimation, adapted to process diagnosis and mainly in the field of multi-models. Prof. Ragot is researcher in the "Centre de Recherche en Automatique de Nancy" (CRAN, CNRS UMR 7039) where he was the head of the group "process diagnosis" during 12 years. Presently he is a Emeritus Professor (with the degree "Classe Exceptionnelle") at the "Ecole Nationale Supérieure de Géologie" (french "Grande Ecole") where he has been in charge the formation in automatic control.
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Papers by josé RAGOT
IFAC Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives, SDEMPED'97, Sep 1, 1997
Abstract: All the methods of fault detection and isolation (FDI) are based, either explicitly or ... more Abstract: All the methods of fault detection and isolation (FDI) are based, either explicitly or implicitly, on the use of redundancy, ie relations among the measured variables. Since the founder work of Potter and Suman [22], the problem of generation of redundancy relations has been widely addressed. This paper presents the fundamental results obtained in this area. Keywords: redundancy relations, fault detection and isolation, model-based diagnosis.
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Recently, fault detection and process monitoring using principal component analysis (PCA) were st... more Recently, fault detection and process monitoring using principal component analysis (PCA) were studied intensively and largely applied to industrial process. PCA is the optimal linear transformation with respect to minimizing the mean squared prediction error. If the data have nonlinear dependencies, an important issue is to develop a technique which can take into account this kind of dependencies. Recognizing the shortcomings of PCA, a nonlinear extension of PCA is developed. This paper proposes an application for sensor failure detection and isolation (FDI) to an air quality monitoring network via nonlinear principal component analysis (NLPCA). The NLPCA model is obtained by using two cascade three layer RBF-Networks. For training these two networks separately,
the outputs of the first network are estimated using principal curve algorithm [7] and the problem is transformed as two nonlinear regression problems.
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This paper presents a method for state-estimation of Takagi-Sugeno descriptor systems (TSDS) affe... more This paper presents a method for state-estimation of Takagi-Sugeno descriptor systems (TSDS) affected by unknown inputs (UI). For ease of implementation's sake, the proposed observers are not in descriptor form but in usual form. Sufficient existence conditions of the unknown input observers are given and strict linear matrix inequalities (LMI) are solved to determine the gain of the observers. If the perfect unknown input decoupling is not possible, the UI observer is designed in order to minimise the L2-gain from the UI to the state estimation error. The two previous objectives can be mixed in order to decouple the estimation to a subset of the UI, while attenuating the L2 gain from the other UI to the estimation. The proposed UI observers are used for robust fault diagnosis. Fault diagnosis for TSDS is performed by designing a bank of observers. A simple decision logic and thresholds setting allow to determine the occurring fault. The results are established for both the continuous and the discrete time cases. The proposed method is illustrated by a numerical example.
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European Control Conference, ECC'2001, Porto, Portugal, September, 4-7, 2001., 2001
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Industrial & Engineering Chemistry Research, 2004
In this paper, a new formulation of the problem of mass and energy balance equilibration in the c... more In this paper, a new formulation of the problem of mass and energy balance equilibration in the case of unknown-but-bounded errors is proposed. The bounds of the errors are specified over both a measurement noise and the balance equations. Both bounds are mainly motivated by experimental considerations of the measurement precision; with a more general interpretation, they can be considered as parameters that the user has to adjust to make the reconciliation possible. The method is particularly suitable for linear models but has been extended to nonlinear ones as well. Simulations provide results that compare favorably with those of classical reconciliation methods involving maximum likelihood estimation based on statistical knowledge of the measurement errors.
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4th Workshop on Advanced Control and Diagnosis, Nancy, France, November 16-17, 2006., 2006
Multiple-model approach is an interesting alternative and a powerful tool for modelling complex p... more Multiple-model approach is an interesting alternative and a powerful tool for modelling complex processes. This paper deals with the off-line identification of non-linear systems employing the multiple-model approach. We use an uncoupled state multiple-model in opposition to the classically used coupled state multiple-model (Takagi-Sugeno). The use of this new mutiple-model structure reveals a new undesirable phenomenon, called
unhooking, that deteriorates the quality of the obtained approximation. An original solution is proposed to avoid this phenomenon.
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European Control Conference ECC'95, Roma, Italia, September 5-8, 1995, 1995
The quality of the state estimation of a system and, consequently, its dependability are strongly... more The quality of the state estimation of a system and, consequently, its dependability are strongly conditioned by the number and the location of the measurements. The availability of a system may be increased if this latter is able to function even in the presence of sensor breakdowns. So, the measurement planning (measurement system design) represent a very important stage. This communication presents a method for assessing the availability of the necessary information for the process control and defining the sensor locations such that the variables required for controlling the process remain always observable even if one or more sensors become defective. Underlying, the connections between several concepts such observability, redundancy, sensor location and reliability are emphasised.
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International Journal of Mineral Processing, 1998
A new technique of data reconciliation, applied to validation of measures collected on a system, ... more A new technique of data reconciliation, applied to validation of measures collected on a system, is suggested in this paper. This approach is based on the inequality constraints describing the hyper space in which the state of the considered system is probably located. We also use the model of the system in which the residuals must, in the same way, be constrained in an hyper space. Finally, the complete problem of reconciliation appears in the form of LMI (linear matrix inequality) and thus can be solved with the software tools that are appropriate to this technique. Some examples show that classical problems of balance equilibration can be solved: total flow balances, partial flow balances, balances with partial measures, consideration of biased measures.
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Journal of The Franklin Institute, 2009
This paper deals with the state estimation of nonlinear discrete systems described by a multiple ... more This paper deals with the state estimation of nonlinear discrete systems described by a multiple model with unknown inputs. The main goal concerns the simultaneous estimation of the system's state and the unknown inputs. This goal is achieved through the design of a multiple observer based on the elimination of the unknown inputs. It is shown that the observer gains are solutions of a set of linear matrix inequalities. After that, an unknown input estimation method is proposed. An academic example and an application dealing with message decoding illustrate the effectiveness of the proposed multiple observer.
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Dans cet article, nous proposons une nouvelle approche formelle pour l'évaluation des bornes... more Dans cet article, nous proposons une nouvelle approche formelle pour l'évaluation des bornes de l'état d'un système incertain. La méthode qui en résulte utilise une représentation par intervalles, et repose sur la construction d'un système dynamique augmenté, où le nouveau vecteur d'état est composé des bornes inférieure et supérieure de l'état du système incertain. Il est important de noter que nous considérons des incertitudes structurées, où seules les bornes de chaque coefficient des matrices du système sont supposées ...
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Automatique Productique Informatique Industrielle, 1986
Un des aspect important du contrôle industriel est l'obtention e... more Un des aspect important du contrôle industriel est l'obtention et la visualisation d'informations pertinentes qui donnent une image des conditions opératoires d'un procédé. De façon classique maintenant, la théorie de l'estimation d'état fournit des algorithmes bien adaptés à cet objectif. Cependant, ces algorithmes sont difficiles de mise en oeuvre en raison des dimensions importantes des procédés. Cette communication présente des techniques faisant appel à différentes décompositions: décomposition par l'observabilité ...
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L'estimation est l'un des concepts les plus utilis{\'e}s en automatique, ... more L'estimation est l'un des concepts les plus utilis{\'e}s en automatique, dans les domaines de l'identification, de l'observation, de la commande et du diagnostic. Le cas des syst{\`e}mes lin{\'e}aires {\`a} param{\`e}tres constants est bien r{\'e}solu ainsi que l'extension aux syst{\`e}mes {\`a} param{\`e}tres variables. Lorsque les syst{\`e}mes sont affect{\'e}s de perturbations non mesur{\'e}es, la probl{\'e}matique est plus d{\'e}licate et les approches {\`a}
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Dans cette communication, nous proposons une m{\'e}thode d&am... more Dans cette communication, nous proposons une m{\'e}thode d'estimation d'{\'e}tat d'un syst{\`e}me non lin{\'e}aire repr{\'e}sent{\'e} par un multi-mod{\`e}le de type Takagi--Sugeno dont les fonctions d'activation d{\'e}pendent de l'{\'e}tat. Pour cela, nous proposons la synth{\`e}se d'un multi-observateur de Luenberger et nous montrons comment d{\'e}terminer les gains du multi-observateur pour garantir la convergence globale asymptotique vers z{\'e}ro de l'erreur d'estimation d'{\'e}tat. Les conditions
Bookmarks Related papers MentionsView impact
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IFAC Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives, SDEMPED'97, Sep 1, 1997
Abstract: All the methods of fault detection and isolation (FDI) are based, either explicitly or ... more Abstract: All the methods of fault detection and isolation (FDI) are based, either explicitly or implicitly, on the use of redundancy, ie relations among the measured variables. Since the founder work of Potter and Suman [22], the problem of generation of redundancy relations has been widely addressed. This paper presents the fundamental results obtained in this area. Keywords: redundancy relations, fault detection and isolation, model-based diagnosis.
Bookmarks Related papers MentionsView impact
Recently, fault detection and process monitoring using principal component analysis (PCA) were st... more Recently, fault detection and process monitoring using principal component analysis (PCA) were studied intensively and largely applied to industrial process. PCA is the optimal linear transformation with respect to minimizing the mean squared prediction error. If the data have nonlinear dependencies, an important issue is to develop a technique which can take into account this kind of dependencies. Recognizing the shortcomings of PCA, a nonlinear extension of PCA is developed. This paper proposes an application for sensor failure detection and isolation (FDI) to an air quality monitoring network via nonlinear principal component analysis (NLPCA). The NLPCA model is obtained by using two cascade three layer RBF-Networks. For training these two networks separately,
the outputs of the first network are estimated using principal curve algorithm [7] and the problem is transformed as two nonlinear regression problems.
Bookmarks Related papers MentionsView impact
This paper presents a method for state-estimation of Takagi-Sugeno descriptor systems (TSDS) affe... more This paper presents a method for state-estimation of Takagi-Sugeno descriptor systems (TSDS) affected by unknown inputs (UI). For ease of implementation's sake, the proposed observers are not in descriptor form but in usual form. Sufficient existence conditions of the unknown input observers are given and strict linear matrix inequalities (LMI) are solved to determine the gain of the observers. If the perfect unknown input decoupling is not possible, the UI observer is designed in order to minimise the L2-gain from the UI to the state estimation error. The two previous objectives can be mixed in order to decouple the estimation to a subset of the UI, while attenuating the L2 gain from the other UI to the estimation. The proposed UI observers are used for robust fault diagnosis. Fault diagnosis for TSDS is performed by designing a bank of observers. A simple decision logic and thresholds setting allow to determine the occurring fault. The results are established for both the continuous and the discrete time cases. The proposed method is illustrated by a numerical example.
Bookmarks Related papers MentionsView impact
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Bookmarks Related papers MentionsView impact
European Control Conference, ECC'2001, Porto, Portugal, September, 4-7, 2001., 2001
Bookmarks Related papers MentionsView impact
Industrial & Engineering Chemistry Research, 2004
In this paper, a new formulation of the problem of mass and energy balance equilibration in the c... more In this paper, a new formulation of the problem of mass and energy balance equilibration in the case of unknown-but-bounded errors is proposed. The bounds of the errors are specified over both a measurement noise and the balance equations. Both bounds are mainly motivated by experimental considerations of the measurement precision; with a more general interpretation, they can be considered as parameters that the user has to adjust to make the reconciliation possible. The method is particularly suitable for linear models but has been extended to nonlinear ones as well. Simulations provide results that compare favorably with those of classical reconciliation methods involving maximum likelihood estimation based on statistical knowledge of the measurement errors.
Bookmarks Related papers MentionsView impact
4th Workshop on Advanced Control and Diagnosis, Nancy, France, November 16-17, 2006., 2006
Multiple-model approach is an interesting alternative and a powerful tool for modelling complex p... more Multiple-model approach is an interesting alternative and a powerful tool for modelling complex processes. This paper deals with the off-line identification of non-linear systems employing the multiple-model approach. We use an uncoupled state multiple-model in opposition to the classically used coupled state multiple-model (Takagi-Sugeno). The use of this new mutiple-model structure reveals a new undesirable phenomenon, called
unhooking, that deteriorates the quality of the obtained approximation. An original solution is proposed to avoid this phenomenon.
Bookmarks Related papers MentionsView impact
European Control Conference ECC'95, Roma, Italia, September 5-8, 1995, 1995
The quality of the state estimation of a system and, consequently, its dependability are strongly... more The quality of the state estimation of a system and, consequently, its dependability are strongly conditioned by the number and the location of the measurements. The availability of a system may be increased if this latter is able to function even in the presence of sensor breakdowns. So, the measurement planning (measurement system design) represent a very important stage. This communication presents a method for assessing the availability of the necessary information for the process control and defining the sensor locations such that the variables required for controlling the process remain always observable even if one or more sensors become defective. Underlying, the connections between several concepts such observability, redundancy, sensor location and reliability are emphasised.
Bookmarks Related papers MentionsView impact
International Journal of Mineral Processing, 1998
A new technique of data reconciliation, applied to validation of measures collected on a system, ... more A new technique of data reconciliation, applied to validation of measures collected on a system, is suggested in this paper. This approach is based on the inequality constraints describing the hyper space in which the state of the considered system is probably located. We also use the model of the system in which the residuals must, in the same way, be constrained in an hyper space. Finally, the complete problem of reconciliation appears in the form of LMI (linear matrix inequality) and thus can be solved with the software tools that are appropriate to this technique. Some examples show that classical problems of balance equilibration can be solved: total flow balances, partial flow balances, balances with partial measures, consideration of biased measures.
Bookmarks Related papers MentionsView impact
Journal of The Franklin Institute, 2009
This paper deals with the state estimation of nonlinear discrete systems described by a multiple ... more This paper deals with the state estimation of nonlinear discrete systems described by a multiple model with unknown inputs. The main goal concerns the simultaneous estimation of the system's state and the unknown inputs. This goal is achieved through the design of a multiple observer based on the elimination of the unknown inputs. It is shown that the observer gains are solutions of a set of linear matrix inequalities. After that, an unknown input estimation method is proposed. An academic example and an application dealing with message decoding illustrate the effectiveness of the proposed multiple observer.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Dans cet article, nous proposons une nouvelle approche formelle pour l'évaluation des bornes... more Dans cet article, nous proposons une nouvelle approche formelle pour l'évaluation des bornes de l'état d'un système incertain. La méthode qui en résulte utilise une représentation par intervalles, et repose sur la construction d'un système dynamique augmenté, où le nouveau vecteur d'état est composé des bornes inférieure et supérieure de l'état du système incertain. Il est important de noter que nous considérons des incertitudes structurées, où seules les bornes de chaque coefficient des matrices du système sont supposées ...
Bookmarks Related papers MentionsView impact
Automatique Productique Informatique Industrielle, 1986
Un des aspect important du contrôle industriel est l'obtention e... more Un des aspect important du contrôle industriel est l'obtention et la visualisation d'informations pertinentes qui donnent une image des conditions opératoires d'un procédé. De façon classique maintenant, la théorie de l'estimation d'état fournit des algorithmes bien adaptés à cet objectif. Cependant, ces algorithmes sont difficiles de mise en oeuvre en raison des dimensions importantes des procédés. Cette communication présente des techniques faisant appel à différentes décompositions: décomposition par l'observabilité ...
Bookmarks Related papers MentionsView impact
L'estimation est l'un des concepts les plus utilis{\'e}s en automatique, ... more L'estimation est l'un des concepts les plus utilis{\'e}s en automatique, dans les domaines de l'identification, de l'observation, de la commande et du diagnostic. Le cas des syst{\`e}mes lin{\'e}aires {\`a} param{\`e}tres constants est bien r{\'e}solu ainsi que l'extension aux syst{\`e}mes {\`a} param{\`e}tres variables. Lorsque les syst{\`e}mes sont affect{\'e}s de perturbations non mesur{\'e}es, la probl{\'e}matique est plus d{\'e}licate et les approches {\`a}
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
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Dans cette communication, nous proposons une m{\'e}thode d&am... more Dans cette communication, nous proposons une m{\'e}thode d'estimation d'{\'e}tat d'un syst{\`e}me non lin{\'e}aire repr{\'e}sent{\'e} par un multi-mod{\`e}le de type Takagi--Sugeno dont les fonctions d'activation d{\'e}pendent de l'{\'e}tat. Pour cela, nous proposons la synth{\`e}se d'un multi-observateur de Luenberger et nous montrons comment d{\'e}terminer les gains du multi-observateur pour garantir la convergence globale asymptotique vers z{\'e}ro de l'erreur d'estimation d'{\'e}tat. Les conditions
Bookmarks Related papers MentionsView impact
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