La présente thèse concerne l’étude structurelle pour le recouvrement du défaut par l’approche du bond graph. L'objectif est d'exploiter les propriétés structurelles et causales de l'outil bond graph, afin d’effectuer à la fois le diagnostic et l’analyse de la commande du système physique en présence du défaut. En effet, l’outil bond graph permet de vérifier les conditions structurelles de recouvrement de défauts pas seulement du point de vue de l’analyse de commande, mais aussi en considérant les informations issues de l’étape de diagnostic. Par conséquent, l’ensemble des défauts tolérés est obtenu en mode hors-ligne avant d’effectuer une implémentation réelle. En outre, en estimant le défaut comme une puissance perturbatrice fournie au système, ce qui permet d’étendre les résultats d’analyse structurelle pour le recouvrement du défaut à une compensation locale adaptative, directement à partir du modèle bond graph. Enfin, les résultats obtenus sont validés dans une application d’un véhicule autonome intelligent redondant. / This work deals with structural fault recoverability analysis using the bond graph model. The objective is to exploit the structural and causal properties of the bond graph tool in order to perform both diagnosis and control analysis in the presence of faults. Indeed, the bond graph tool enables to verify the structural conditions of fault recoverability not only from a control perspective but also from a diagnosis one. In this way, the set of faults that can be recovered is obtained previous to industrial implementation. In addition, a novel way to estimate the fault by a disturbing power furnished to the system, enabled to extend the results of structural fault recoverability by performing a local adaptive compensation directly from the bond graph model. Finally, the obtained structural results are validated on a redundant intelligent autonomous vehicle.

La présente thèse concerne l’étude structurelle d’un système modélisé par Bond Graph du point de vue détection et isolation de défaut. En combinant la théorie du module avec les propriétés causales et structurelles de l’outil BG, de simples conditions graphiques permettant de conclure sur la détectabilité et l’isolabilité de défauts composant ont été proposées. Aussi,une procédure de placement de capteur optimal a été présentée pour le recouvrement de la surveillabilité du système en présence de défauts. Pour l’étape de diagnostic, une procédure systématique a été développée pour la génération des indicateurs de défauts sensibles aux défauts composants considérés. L’approche proposée dans ce travail a été validé par une application sur un quart de véhicule autonome intelligent. / This thesis is concerned with system structural analyses for fault detection and isolation. By using the module theory and the causal and structural properties of the Bond Graph tool, simple graphical conditions of structural detectability and isolability of plant faults are proposed. Also, a procedure for optimal sensor placement is performed in order to recover systems monitorability in the presence of plant faults. Moreover, for the diagnosis step, a procedure is proposed for a systematic generation of faults indicator which are only sensitive to the desired plant faults. The proposed approach in this work is validated by an application on a quarter of an autonomous intelligent vehicle.

Ce travail de thèse constitue une contribution à la modélisation et au diagnostic des systèmes multi-domaines à commutation (hybrides). Il est appliqué à la supervision des systèmes multi-sources d’énergie propre où l’hydrogène est utilisé comme moyen de stockage. Un tel système associe des composantes énergétiques de nature différente et fait l’objet de commutations produites par la connexion et déconnexion d’un ou plusieurs composants. Ces commutations génèrent différents modes de fonctionnement et sont liées à l’intermittence des sources primaires, aux capacités de stockage et à la disponibilité opérationnelle des ressources matérielles qui constituent le système. La présence de ces commutations engendre une dynamique variable qui est classiquement difficile à exprimer mathématiquement sans exploiter tous les modes. Ces difficultés de modélisation se propagent pour affecter toutes les tâches dépendantes du modèle comme le diagnostic et la gestion de modes de fonctionnement. Pour résoudre ces problématiques, un nouvel outil, Bond Graph Hybride piloté par événements, a été développé. Entièrement graphique, ce formalisme permet une modélisation interdisciplinaire globale du système. En séparant la dynamique continue gérée par le Bond Graph Hybride des états discrets modélisés par un automate intégré, l’approche proposée simplifie la gestion des modes de fonctionnement. Le modèle issu de cette méthodologie est également bien adapté au diagnostic robuste, réalisable sans recourir aux équations analytiques. Associée au diagnostic robuste, cette gestion des modes permet l’implémentation de stratégies de reconfiguration et de protection en présence de défaillances. / This research work constitutes a general contribution towards a simpler modelling and diagnosis of the multidisciplinary hybrid systems. Hybrid renewable energy systems where hydrogen is used to store the surplus of the power fits perfectly under this description. Such system gathers different energetic components that are needed to be connected or disconnected according to different operating conditions. These different switching configurations generate different operating modes and depend on the intermittency of the primary sources, the storage capacities and the operational availability of the different hardwares that constitute the system. The switching behaviour engenders a variable dynamic which is hard to be expressed mathematically without investigating all the operating modes. This modelling difficulty is transmitted to affect all the model-based tasks such as the diagnosis and the operating mode management. To solve this problematic, a new modelling tool, called event-driven hybrid bond graph, is developed. Entirely graphic, this formalism allows a multidisciplinary global modelling for all the operating modes at once. By separating the continuous dynamic driven by the bond graph, from the discrete states handled by an integrated automaton, this approach simplifies the management of the operating modes. The model issued using this methodology is also well-adapted to perform a robust diagnosis which is achievable without referring back to the analytical description of the model. The operating mode management, when associated with the on-line diagnosis, allows the implementation of reconfiguration strategies and protection protocols when faults are detected.

Ce travail de thèse présente différentes contributions pour la génération automatique de modèles représentant les Systèmes Dynamiques Hybrides (SDH) caractérisés par plusieurs modes de fonctionnement. Les composants du système (notamment les capteurs) peuvent être manuellement sélectionnée ou automatiquement exportés à partir des données de Conception Assistée par Ordinateur (CAO) ; ces éléments sont ensuite interconnectés pour reproduire le modèle complet du système industriel. Une fois le modèle créé, des schémas-blocs de simulation et de diagnostic, ainsi que la Matrice de Signature de Fautes (FSM) seront produits. Le logiciel est basé sur les Bonds Graph Hybrides ; la présence de commutations engendre des dynamiques variables (notamment des changements de causalité). Pour lever ces verrous, différents algorithmes sont proposés. En comparaison des logiciels existants, les algorithmes proposés sont valides pour les systèmes continus, discrets ou hybrides. Les théories et algorithmes développés sont appliqués sur un système ferroviaire de freinage électropneumatique. / This thesis work contributes to perform a automed model builder for Hybrid Dynamic Systems (HDS) with numerous modes. Technological components including sensors with an iconic format can be automatically export from a computer-aided design (CAD) scheme or manually drag from database and interconnected, so as to produce the overall HDS model, following industrial technological schemes. Once the model has been created, block diagram for simulation and diagnosis and a Fault Signature Matrix (FSM) could be generated.The theory and algorithm behind the software are based on Hybrid Bond Graphs (HBG). The switching behaviour engenders variables dynamics (particularly causal changes). To solve this problematic, news algorithm are performed. Compared with developed programs for automated modelling, the presented algorithm are valid for continuous, discrete and hybrid systems. The theory is illustrated by an industrial application which consists of the pneumo-electrical control of rolling stock.

Le travail de thèse concerne la conception intégrée d'un système de détection et localisation de fautes robuste aux incertitudes paramétriques pour les systèmes hybrides à base de modèle bond graph hybride(BGH) sous la forme LFT (Transformations linéaires fractionnelles). Sur la base de la littérature consultée, les systèmes hybrides sont principalement modélisés pour chaque mode de fonctionnement pour lequel sont générés des indicateurs de fautes déterministes. L'intérêt scientifique de la présente recherche peut être résumé comme suit : (1) l’utilisation d’un seul modèle BGH incertain basé sur les jonctions contrôlées et représentant l’ensemble des modes de fonctionnement, (2) exploitation des propriétés structurelles et causales du BGH LFT pour la génération systématique de Relations de Redondance Analytiques Globales (RRAG) et des seuils de détection robustes aux incertitudes paramétriques et, valides pour tous les modes de fonctionnement, et enfin (3) l’utilisation d’un seul outil : le modèle BGH de Diagnostic (BGHD), pour non seulement la modélisation mais aussi la surveillance en ligne. La démarche développée a été illustrée par un exemple pédagogique représentant un circuit électrique à commutation et par une application à un système hydraulique. / The present PH.D thesis deals with integrated design of robust Fault Detection and Isolation system (FDI) based on Hybrid Bond Graph (HBG) in Linear Fractional Transformation (LFT) form. Based on consulted literature about hybrid systems, each operating mode is mainly modelled by specific model for which are generated determinist fault indicators. The innovative interest of developed research can be summarized as follows: (1) use only one HBG uncertain model based on controlled junctions and representing all operating modes, (2) structural and causal properties of the LFT HBG are exploited for systematic generation of Global Analytical Redundancy Relations (GARRs), and detection thresholds, robust to parameter uncertainties, and (3) finally use of only one tool: the Diagnosis Hybrid Bond Graph (DHBG) for not only modelling but also for online surveillance. The developed approach is illustrated by electrical circuit pedagogical example and application to hydraulic system.

Vehicle suspensions have been a major focus of research and design since the introduction of the automobile. The two major characteristics that define the performance of a specific suspension design are the vehicle ride and handling. A simplified view of chassis development is that a desirable vehicle ride is provided by a "soft" suspension, and desirable vehicle handling is provided by "stiff" suspensions, it is impossible to simultaneously maximize both vehicle ride and handling in a passive suspension design. However, with the introduction of active components, such as actuators and semiactive dampers, coupled with dynamic control strategies, a more desirable compromise between the benefits of soft and stiff suspensions can be achieved. The purpose of this research is not to create a better suspension, but to investigate how active control can improve vehicle ride. As with any research area, a method for evaluating new ideas is required. Many computational methods exist for determining the ride performance of various suspension designs, however computational results alone can be hard to interpret and often deceiving. The following thesis outlines the design and validation of an experimental test rig for evaluating fully active or semi-active suspension algorithms. The test rig utilizes a fully active electromagnetic actuator which can simulate the performance characteristics of fully active as well as semi-active components which a suspension design may utilize. The demonstration rig couples visual inspection with computational analysis and provides the tools necessary for the designer to accurately interpret the ride performance of a new design and simultaneously compare it with a passive design. The goal is to provide a visual development platform in which new algorithms can be quickly and easily implemented and compared against existing algorithms to determine the performance characteristics of each on a physical system. The test rig demonstrated its ability to test both fully-active and semi-active skyhook control algorithms, and accurately simulated both fully-active and semi-active suspension components. The test rig provides a simple and cost effective way to evaluate new algorithms both computationally and visually on a physical system. / Master of Science

Notre étude se concentre sur les techniques qui offrent un support automatique pour l'adaptation et la révision des modèles dynamiques. <br />L'objectif est d'étudier comment l'outil bond graph peut aider à concevoir des systèmes innovants répondant à un cahier des charges exprimé en termes de comportement temporel ou fréquentiel.<br />Construire un modèle revient toujours à faire une abstraction du système initial. Faire une abstraction du système à modéliser signifie trouver les propriétés les plus pertinentes pour la tâche à résoudre. Pour un modélisateur peu expérimenté c'est une étape difficile, car s'il n'a pas fait les bons choix son modèle se montrera faux, étant trop grossier ou trop simple. <br />Avec notre approche, l'intention est d'indiquer une autre capacité de la méthodologie bond graph, celle d'un outil de reconstruction, qui pourrait suggérer des solutions dans le cas d'un dispositif inconsistant avec les spécifications. <br />Comme applications nous décrirons un instrument médical avec un problème fréquentiel observé après la phase de construction et un actionneur électro-hydrostatique dont on n'a pas modélisé un mécanisme physique qui influençait son comportement dynamique. On démontrera que l'outil de reconstruction présenté peut suggérer aux designers peu expérimentés des modifications à apporter aux modèles d'ordres insuffisants.<br />Nous désirons aussi que le système proposé dans cette étude puisse être utilisé comme outil dans la phase de conception des dispositifs technologiques soumis à un cahier des charges. En vue de la conception nous proposons un algorithme qui permet de retrouver les solutions proposées par les ingénieurs et si c'est possible des modèles alternatifs.<br />L'algorithme sera adapté au domaine des matériaux viscoélastiques pour obtenir, à partir des données expérimentales, tous les modèles qui correspondent à un matériau identifié.<br />Nous traiterons aussi le cas d'un nouveau concept pour un capteur de vitesse très sensible aux spécifications fréquentielles. Notre système est capable de proposer plusieurs architectures qui aideront l'ingénieur à choisir celle qui lui convient le mieux vis-à-vis de son cahier des charges.<br />Parce que les bond graphs permettent une représentation unifiée des systèmes physiques, à partir des modèles proposés, nous pouvons choisir des implémentations technologiques dans des domaine physiques différents.

Ce travail se concentre sur la modélisation et l'analyse d'un système de direction sur-motorisé d'un (véhicule) poids lourd omnidrive. Il fait partie d'un robot appelé RobuTAINeR, il est utilisé pour le transport conteneurs de 12 mètres à l'intérieur des espaces confinés à terminaux maritimes. Dans cette classe de robots, la direction et la roue jouent un rôle crucial pour la navigation autonome, par conséquent, il est une nécessité pour comprendre et modéliser les capacités de mouvement omnidirectionnel, la commutation des comportements dynamiques, et ses zones multi-domaines: électrique, mécanique, hydrodynamique, etc. La technique Bond Graph est une méthodologie unificatrice pour réaliser et analyser les systèmes physiques aussi bien que l'échange énergétique, ce qui fait possible l'exploiter non seulement pour la modélisation, mais aussi pour la détection de défauts et l'isolement. La validation du modèle a été réalisée avec la simulation en temps réel, établie à partir de données réelles obtenues dans le simulateur SCANeR Studio et par rapport à la simulation sur le logiciel 20sim. Cette technique est utilisée pour modéliser des systèmes complexes comme: le contrôle de la direction hydraulique; la partie électromécanique du système de traction; la dynamique longitudinale, latérale et de lacet dans le centre de gravité du robot; et les forces latérales et longitudinales présentées dans le pneu-sol. Le diagnostic est appliqué avec le modèle hybride qui est appelé Diagnostic Bond Graph. Ainsi, un autre objectif est de modéliser et d'améliorer la robustesse de la détection de défaut en présence d'incertitudes paramétriques afin de réduire les fausses alarmes. / This work focuses on the modeling and analysis of an over-actuated steering system of a mobile omnidrive heavy vehicle that is part of a wheeled robot called RobuTAINeR. This robot is used for transporting 12-meters containers inside confined spaces of maritime terminals. In this class of robots, the steering and wheel play a crucial role for the autonomous navigation; hence, there is a necessity to understand and model the omnidirectional motion capabilities, switching dynamic behaviors, and its multi-domain areas: electrical, mechanical, hydrodynamic, etc. The Bond Graph technique is a unifying methodology to perform and analyze physical systems, where there is energy exchange, not only suitable for modeling but also for Fault Detection and Isolation. The validation of this model has been done with real-time simulation, based on real data integrated into the professional simulator SCANeR Studio and compared with the simulation on 20Sim. This professional tool is used to model complex systems such as the control of the hydraulic steering; the electromechanical section of the traction system; the longitudinal, lateral, and yaw dynamics of the robot motion concerning its center of gravity; and the lateral and longitudinal forces presented in the tire-ground. The diagnosis is applied to the hybrid model which is called Diagnostic Bond Graph. Thus, another objective is to model and improve the robustness of fault detection in the presence of parametric uncertainties in order to reduce false alarms.

The electromagnetic machines like the dc, induction, synchronous motor/generator and the transformer have an energy flow framework that is similar. All these machines deal with electrical energy in the electrical domain that is interfaced with the magnetic domain. Except for the transformer, the other machines also have one more energy interface i.e. with the mechanical domain. In all these machines, the magnetic domain acts as the silent energy manager. The electrical and the mechanical domain energies will have to pass through the magnetic domain and appropriately get routed. In recognition of the commonality of this pattern of energy flow, this thesis proposes a generalised model of a multiphase electromagnetic device wherein the dc machine, induction machine, synchronous machine and the transformers are special cases of the proposed generalised model. This is derived using bond graphs that is based on the underlining principle of Energy Flow rooted in the concept of Conservation of Energy. A model is a set of mathematical equations representing a physical system. A model is as good as a modeller understanding of the physical system and the underlying approximation he makes while writing down the equations describing the models behaviour to the stimulus. A modelling language tool, which can cut down the approximations made by using the power of identified analogous characteristics across the physical domain, can help make a model more close to real life situation. Bond Graph is such a modelling language which is powerful enough to model the non-linear, multi-disciplinary, hybrid continuous-discrete phenomena encountered in a real life physical system. Bond graphs as a modelling tool was introduced by Professor H.Paynter at Massachusetts Institute of Technology in 1959. The Bond Graph methodology is based on consideration of energy flows between the ports of the components of an engineering system. Bond Graph methodology enables one to develop a graphical model that is consistent with the first principle of energy conservation without having the need to start with establishing and reformulating equations. The derivation of a mathematical model from the graphical description is automated by software tools. As a consequence, a modeller using this methodology can focus on modelling of the physical system. In the graphical representation of bond graph the vertices of a bond graph denote subsystems, system components or elements, while the edges, called power bonds, represent energy flows between them. The nodes of a bond graph have power ports where energy can enter or exit. Bond graph models are developed in a hierarchical top-down or bottom-up approach by using component models or elements from model libraries. An electromagnetic machine is a black box having an assemblage of windings in iron resulting in a combination of input/output ports on shaft and electrical terminals. Abstraction of an machine model by a modeller matching the vision of the observer above is an ideal goal. Bond graph methodology is an appropriate tool for trying to reach this goal as it is based on object oriented modelling techniques. There have been few attempts to model electric machine in bond graph earlier. A well established DC motor bond graph has been widely used in all bond graph literature. But AC rotating machine being a higher order nonlinear system poses a tougher challenge. Here too, there have been few attempts in modelling AC machines. It is observed that majority of AC machine bond graph models have been built up from their mathematical models. But as the bond graph modelling technique is based on the unifying theory of energy exchange, better insight into the system is achievable if the model is conceptualised from its physical structure. This thesis starts from the basic theory of energy port to conceptualise the generalised model from physical correspondence. In this thesis a Rotating Electrical Machine is studied as a physical system. The energy ports inside this physical system is identified. When a physical system receives the energy through its energy port in one energy cycle, it processes this energy in one of the three ways. The received energy is converted into useful work or it is dissipated or stored. The storage can further be classified into two ways, either as kinetic energy or as potential energy. For a rotating electric machine the input-output port for energy exchange are either in electrical or mechanical domain depending on the class of the machine. The magnetic domain across all class of electromagnetic device acts as the energy manager. In order to capture the features of the energy jumping across the air gap in a rotating electrical machine, wherein the magnetic fields from spatially distributed windings of the stator and rotor interplay, an Axis Rotator (AR) element -a mathematical commutator, is introduced in this thesis as a new bond graph element. In a multiphase device, the energy from the various phases and spatial axes are transferred through the axis rotator element. The Axis Rotator is a critical element which helps distinguish between the various classes of electromagnetic devices. The defining features of the Axis Rotator helps in deriving the various special electromagnetic devices (such as the dc machine, induction machine, synchronous machine and the transformer) from the generalised model. The Axis Rotator exists in the magnetic domain. It naturally inherits the characteristics of the magnetic domain. The Axis Rotator as a bond graph element is complex. In a specific case of 3φ Induction Motor an alternative bond graph model with all integral elements is developed. By one to one correspondence with the AR bond graph model, the inner component of ’AR’ can be identified. Another advantage of using this model is that saturable and non-saturable magnetic permeance can be separated out, a useful feature in the nonlinear model discussed next. One of the most distinguishing features of the magnetic domain is the existence of Magnetic Hysteresis. Magnetic Hysteresis is a well understood and studied subject. But this physical process is wilfully ignored by the modelling community at large. The main reason for this is the difficulty of modelling a nonlinear phenomena. The bond graph modelling naturally allows the inclusion of such non-idealities within its framework. This thesis proposes the generalised model along with the inclusion of magnetic non-linearities and non-idealities into the model of the system. This inherent strength of bond graph model flows from the fact that the models in bond graph are developed from the first principles of energy conversation and the mathematical equations are derived later from the evolved graph. The tools that are available for bond graph simulation are not adequate for power electronics systems. The existing tools do not address space vectors and frame transformations. As a consequence it is difficult to simulate the electromagnetic device models developed in this thesis. The need for a bond graph tool to address vectors and frame transformations, a common occurrence in electric machines dynamic model study was acutely felt. This necessitated a support for handling complex data class from the underlying mathematical engine of the software. MATLAB/Simulink is the commonly available mathematical tool which has a support for complex variables. Therefore during the course of this research work a new software tool box was developed which meets the need of electromagnetic machines in particular and other engineering domains in general. For developing the new bond graph simulation software, the language extender approach was chosen, as it combines the capabilities of existing popular mathematical engine with its tested graphical frontend and the flexibility of combining different modelling technique like bond graph, block diagram, equations etc. It also ensures portability as they are compiled by interpreted language compiler of the mathematical engine and are thus independent of the computer operating system. C-MEX S-function methodology was used to develop the software as it has access to lower level functions and methods of the underlying mathematical engine. This helps in speeding up the software execution time alongwith the flexibility in defining new complex elements like the Nonlinear Axis Rotator. In conclusion, this thesis makes the following contributions: (i) The Axis rotator concept to handle space vectors and frame transformations, (ii) generalised model of the electromagnetic device, (iii) introduction of the saturation and hysteresis non-linearity in the magnetic domain, (iv) development of the bond graph toolbox to handle vector and frame transformations.

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