Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 243-245). Also available via the Internet.

Thesis (M. Eng.)--Carleton University, 1996. / Also available in electronic format on the Internet.

Afin d’introduire de nouvelles fonctions dans les commandes de vol d’hélicoptère, il est nécessaire d’augmenter les bandes passantes de leurs actionneurs. La modélisation réaliste de l’ensemble du système d’actionnement, rendant compte de ses limitations de puissance et de sa consommation énergétique, ainsi que l’amélioration des technologies existantes des dispositifs d’étanchéité et de guidage sont les deux enjeux principaux permettant d’atteindre la durée de vie souhaitée à hautes fréquences. Pour supporter ce nouveau développement, ce travail s’organise en trois parties. Une première partie présente l’état de l’art des commandes de vol de l’hélicoptère. Une architecture générique d’actionneur est proposée ainsi que la terminologie associée. Une deuxième partie porte sur l’élaboration d’un modèle de connaissance détaillé à l’aide du formalisme Bond-graph pour le système d’actionnement. Un effort particulier est porté sur la standardisation des composants et de leurs interfaces dans une démarche orientée objet. La dernière partie traite concerne les dispositifs d’étanchéité et de guidage au niveau des vérins de commande de vol. Compte tenu de l’objectif d’utiliser des paliers fluides, les différentes manières de générer une force normale au sein d’un film fluide sont analysées. Puis, une étude plus approfondie des butées hydrostatiques et des paliers hybrides coniques est ensuite conduite en tenant compte des contraintes propres à l’aéronautique. L’ensemble des connaissances acquises sont appliquées à un cas concret de développement assisté par les modèles d’actionneur hautes fréquences pour le contrôle actif de rotor. / In order to introduce new functions in helicopter flight controls, it is necessary to increase the bandwidths of their actuators. A realistic modelling of the entire actuating system, taking into account its power limitations and its energy consumption, as well as the improvement of the existing sealing and guiding device technologies are the two main challenges to reach the desired high frequency without reducing dramatically the actuator lifespan. To support this new development, this work is organized in three parts. A first part presents the state of the art of the helicopter flight controls. A generic actuator architecture is proposed as well as the associated terminology. A second part deals with the development of a detailed knowledge-model using the Bond-graph formalism for the actuating system. A particular effort is made to standardize the components and their interfaces in an object-oriented approach. The last part deals with the sealing and guiding devices of flight control cylinders. Given the objective of using fluid bearings, the various ways of generating a normal force within a fluid film are analyzed. Then, a more detailed study of the hydrostatic thrust bearings and the conical hybrid bearings is then carried out taking into account the constraints specific to aeronautics. All the knowledge acquired is applied to a concrete case of development, aided by the models, of high frequency actuators for the active control of a rotor.

La conception des systèmes mécatroniques, vu leur complexité, nécessite d'entreprendre une approche systémique qui implique l'utilisation d'une méthodologie permettant, en premier lieu, de considérer le système avec toutes ces composantes (mécanique, électronique, informatique, etc.), de concevoir et de spécifier ce système par la définition de ces composants et des liens qui existent entre eux. D'autre part, elle doit aussi donner la possibilité de décrire ces composants avec les outils existants des différents domaines technologiques. Nous nous sommes tournés vers des technologies orientées-objet, en l'occurence l'ingénierie guidée par les modèles MDE, pour construire une méthodologie permettant d'entreprendre cette approche systématique supportant les activités d'ingénierie décrites dans le standard ISO/IEC/IEEE 15288. Dans cette thèse, nous proposons une méthodologie qui répond à ces besoins intitulés MISSyM. Dans MISSyM, les activités de conception sont réalisées sur des modèles SysML étendus par des profils supportant le standard IEEE 15288. De plus, MISSyM intègre le support d'éléments de modélisation spécifiques aux systèmes mécatroniques. Nous avons aussi intégrer dans MISSyM une extension à SysML supportant les Bonds Graphs et permettant d'entreprendre une analyse énergétique. Nous avons par la suite enrichi la méthodologie MISSyM par une méthode de vérification de la qualité de l'architecture qui repose sur un algorithme utilisant des métriques et un algorithme de partitionnement de la matrice de dépendances ou DSM. Nous avons en plus ajouté la génération de codes vers le langage de simulation Modelica. Finalement, nous avons décrit le processus global de la méthodologie basé sur l'architecture de modèles MDA et en concordance avec le standard IEEE 15288. Nous avons fourni un exemple d'application pour permettre aux ingénieurs système de mieux utiliser le langage SysML à travers cette méthodologie.

Des modules de supervision à base de modèle Bond Graph (BG) sont conçus pour les procédés énergétiques présents dans les industries à risques. Le BG comme outil multidisciplinaire est bien adapté à cause de la mise en jeu des énergies de nature diverse. Cet aspect de couplage (énergie, chimique...) rend les modèles dynamiques fortement non linéaires.<br />La génération systématique de modèles linéarisés des procédés complexes est considérée, le BG global d'une installation est directement obtenu à partir du Plan d'Instrumentation Détaillé (PID). Ces modèles sont valides car les processus thermofluides réels sont en général régulés autour d'un point de fonctionnement.<br />Les paramètres (coefficients hydrauliques, coefficients d'échange thermique...) n'étant pas toujours connus, la détermination directe des propriétés structurelles (commandabilité, observabilité, surveillabilité) des BGs sans<br />calcul préalable est utile pour la FDI (Fault Detection and Isolation).<br />Dans un premier temps, les modèles linéarisés sont exploités pour l'étude de la surveillance. Avant n'importe quelle implémentation industrielle (ou ajout de capteurs), la surveillabilité des composants, des actionneurs et des capteurs est considérée sans générer les Relations de Redondance Analytiques (RRA).<br />Dans un second temps, le modèle bond graph non linéaire est utilisé pour la conception des systèmes de<br />surveillance. En génie des procédés, il est possible d'identifier la catégorie des composants (actionneurs<br />hydrauliques, capteurs thermiques, etc..) à laquelle appartient l'élément défaillant. La surveillabilité de défauts simultanés d'actionneurs est considérée par une approche de platitude directe et générique.

<p>Important factors in manufacturing are quality and cost. Measuring machines play an important role for these fields. In order to meet higher demands on cost and accuracy, measuring machines can be constructed with weaker materials and increased mechanical flexibilities, and therefore there is a need to include the flexibilities in measuring machine models to obtain good performance. </p><p>The core theme in this thesis is modeling and idenfication of the physical parameters of drive mechanisms of a Brown&Sharpe Inc. Global A coordinate measuring machine. The approximation made is that the drive mechanisms can be described by a mass connected by springs, dampers and gear changes. It has been found that a one-spring model gives a reasonably good description of the studied CMM drive mechanism. The physical parameters of this model are identified using off-line algorithms. The algorithms are based on prediction error methods. For the off-line identification the MATLAB System Identification Toolbox and the bond graph representation is used. </p><p>The chosen model is then used for control. Traditional control and a Model-reference Adaptive System is derived and studied with the aim to increase the damping of CMM drive mechanisms. It is found that the adaptive system has very good disturbance rejection and can correct for drastic model errors. Another impact is that the damping of the studied drive mechanism can be increased with at least a factor of nine.</p>

Important factors in manufacturing are quality and cost. Measuring machines play an important role for these fields. In order to meet higher demands on cost and accuracy, measuring machines can be constructed with weaker materials and increased mechanical flexibilities, and therefore there is a need to include the flexibilities in measuring machine models to obtain good performance. The core theme in this thesis is modeling and idenfication of the physical parameters of drive mechanisms of a Brown&amp;Sharpe Inc. Global A coordinate measuring machine. The approximation made is that the drive mechanisms can be described by a mass connected by springs, dampers and gear changes. It has been found that a one-spring model gives a reasonably good description of the studied CMM drive mechanism. The physical parameters of this model are identified using off-line algorithms. The algorithms are based on prediction error methods. For the off-line identification the MATLAB System Identification Toolbox and the bond graph representation is used. The chosen model is then used for control. Traditional control and a Model-reference Adaptive System is derived and studied with the aim to increase the damping of CMM drive mechanisms. It is found that the adaptive system has very good disturbance rejection and can correct for drastic model errors. Another impact is that the damping of the studied drive mechanism can be increased with at least a factor of nine.

[pt] Este trabalho tem por objetivo a modelagem do comportamento dinâmico do motor de CC shunt, através da metodologia dos grafos de ligação. Primeiro será feito um levantamento de todos os parâmetros mecânicos, elétricos e magnéticos da máquina. O segundo passo será a obtenção de um grafo de ligação do motor e de suas respectivas equações de estado representativas. Através destas equações e dos parâmetros obtidos em laboratório será montado um modelo de simulação computacional pelo Matlab para verificação do comportamento da máquina desde a partida até o regime permanente, comprovando a veracidade do modelo. / [en] This work has the goal of modeling the dynamic behavior of a CC shunt motor, through the methodology of bond graphs. First all the mechanical, eletrical and magnetic parameters of the machine are measured. The second step will be the development of the motor bond graph and of its respective state equations. Using these equations and the measured parameters a Matlab simulation is set up to verify the transient behavior of yhe machine, checking the truthfulness of the model.

O problema de geração de estruturas de coalizão (CSG) envolve o particionamento do conjunto de agentes em todos os subconjuntos(ou, coalizões) possíveis. O que torna esse problema desafiador é o número de coalizões possíveis crescer exponencialmente a medida que novos agentes são inseridos, o número de coalizões é (2n − 1) onde n é o número de agentes. Entretanto, em muitas aplicações do mundo real, existem limitações inerentes nas coalizões possíveis: por exemplo, determinados agentes podem ser proibidos de estar na mesma coalizão, ou a estrutura de coalizão pode ser obrigada a conter coalizões do mesmo tamanho. Quando consideramos CSG restrito por grafos, onde a viabilidade de uma coalizão é restrita por um grafo de sinergia dos agentes, a complexidade computacional pode ser a mesma ou menor, dependendo do que se considera uma coalizão válida. Os grafos de sinergia são representações dos agentes como sendo os vértices e as suas relações são as arestas. Este trabalho é um estudo sobre a utilização de restrições envolvendo grafos como uma heurística sobre as coalizões para o problema enumeração de coalizão, de forma a considerar uma coalizão factível ou não de acordo com a densidade do subgrafo induzido pelos agentes. Os trabalhos atuais, que utilizam os grafos de restrição como heurística para reduzir a complexidade computacional, consideram uma coalizão válida somente se o subgrafo formado pelos agentes da coalizão é conexo. Verificou-se experimentalmente para grafos com a propriedade power law, comum em uma variedade de grafos reais, que restringir uma coalizão válida como sendo um subgrafo conexo pode não ser uma redução significativa. Entretanto a utilização de um subgrafo com restrições mais fortes, em particular uma clique garante uma redução exponencial do número de coalizões consideradas. Não existem teoremas que possam calcular qual a quantidade de subgrafos conexos ou mesmo o número de cliques em um grafo do tipo power law. No presente trabalho foi possível calcular experimentalmente para grafos power law com ate 17 vértices, sendo que também são apresentados resultados analíticos para grafos estrela (Kn−1,1 ). Os grafos estrela são uma aproximação aceitável, pois formam um hub, estrutura característica de grafos power law. Como trabalhos futuros podem ser citados: o mapeamento de domínios para os quais a restrição de clique seria adequada, além do desenvolvimento de um algoritmo que incorpore a restrição diretamente na contagem de coalizões validas. / The coalition structures generating problem (CSG) involves partitioning the set of agents in all possible subsets (or coalitions). What makes this problem challenging is the number of possible coalitions that grows exponentially as new agents are inserted. The number of coalitions is (2n − 1) where n is the number of agents. However, in many real-world applications, there are inherent limitations on possible coalitions: for example, some individuals may be prohibited from being in the same coalition or coalition structure may be required to contain coalitions of the same size. When we consider CSG restricted by graphs where the viability of a coalition is restricted by a synergy graph, the computational complexity can be maintained or eventually be smaller depending on what is considered a valid coalition. Synergy graphs are representations of the agents as being the vertices and their relationships are the edges. This work is a study on the use of restrictions involving graphs as a heuristic about coalitions for the problem coalition enumeration in order to consider a feasible coalition or not according to the density of the subgraph induced by the agents. Current works using the restriction graphs as heuristics to reduce the computational complexity, consider a coalition valid only if the subgraph formed by the agents of the coalition is connected. In this work it as experimentally verify for power law graphs, present in a variety of real graphs, that restricting availability coalition as a connected subgraph may in not prohibited a significant gain. However, they using a subgraphs with strong restrictions, in particular a clique, guarantees an exponential reduction in the number of considered coalition. There no are theorems calculate subgraphs or even the number of cliques on a type power law graph. In the present work it was possible to calculate values experimental for graphs of up to 17 vértices, being also presented analytics results for star graphs (Kn−1,1 ). Star graphs are an acceptable approximation, was they account for hubs, a characteristic structure of power law graphs. As future works can be cited the study of domains where the clique restriction is adequate as well as the development of an algorithm that incorporates the restriction for coalition counting.

[pt] Neste trabalho é desenvolvido um procedimento para a geração por inspeção das equações de estado e funções de transferência associadas a um grafo de ligação por meio de análises literal e numérica. O procedimento consiste na identificação de caminhos causais e a determinação de suas contribuições para as equações. É analisada a formulação matemática e discutida a implementação do procedimento em um código computacional. A aplicação do procedimento é ilustrada com exemplos, descreve-se detalhadamente as rotinas de entrada de dados, variáveis auxiliares, identificação dos caminhos e malhas causais, assim como a forma de apresentação dos resultados. / [en] In this work a procedure for the computer generation by inspection of the state equations and transfer functions, both in literal and numerical form, associated to a bond graph is discussed. The procedure consists of the identification of causal paths and the determination of its contributions for the equations. The mathematical background and the implementation of the procedure in a computational code are, also, presented. The application of the procedure is illustrated with examples; the routines for data entry, causal path and mesh identification and the used variables are described, as well as the form of presentation of the results.