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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Modélisation dynamique basée sur l'approche bond graph d'une boucle fluide diphasique à pompage mécanique avec validation expérimentale / Bond graph based modeling and experimental validation of a two-phase fluid loop mechanically pumped

Kebdani, Mohamed 20 September 2016 (has links)
Cette thèse s’inscrit dans le cadre du projet FUI THERMOFLUIDE-RT impliquant des Grands Groupes (Zodiac DS, Safran Hispano, MBDA), des PME (Atmostat, ADR, ControlSys) et cinq laboratoires (CRIStAL, LML Arts et Métiers Paris Tech, LEGI Grenoble, LMT ENS Cachan, CEA-Liten Grenoble). Le but est d’étudier un nouveau système de refroidissement de l’électronique. La technologie retenue est celle d’une boucle fluide diphasique à pompage mécanique (BFDPM). La thèse traite la modélisation dynamique et la validation expérimentale des composants de la boucle. Ceci permet de prévoir l’efficacité du système à partir de ses paramètres d’entrée, d’analyser les problèmes de régimes transitoires, et de proposer un outil de dimensionnement. La méthodologie bond graph est retenue à cause du caractère multi-physique des composants. D’abord, la problématique de base et le contexte sont présentés. Ceci permet d’introduire la solution retenue, celle des BFDPM. Les objectifs de la thèse sont décrits. Ensuite, une description du banc expérimental développé au cours de cette thèse est proposée. Les trois chapitres suivant sont consacrés à l’étude théorique et expérimentale des équipements de la boucle. Chacun de ces chapitres commence par l’état de l’art sur les travaux de modélisation et les corrélations des coefficients d’échange et des pertes de charge. Une seconde partie décrit les phénomènes et les équations. Une troisième partie est réservée à la validation des modèles. Un dernier chapitre récapitule les travaux de couplage des modèles dynamiques validés séparément. En conclusion, un récapitulatif des contributions est effectué. Des perspectives à court et moyen terme sont proposées / This thesis is part of the collaborative project FUI THERMOFLUIDE-RT involving major groups (Zodiac DS, Safran Hispano, and MBDA), SMEs (Atmostat Alcen, ADR, AER, ControlSys) and five laboratories (CRIStAL Ecole Centrale de Lille, LML Arts et Métiers Paris Tech, LEGI Grenoble, LMT ENS Cachan, CEA-Liten Grenoble). The main purpose is to study a new electronic cooling system. The technology chosen consists of a two-phase fluid loop mechanically pumped (TPLMP). The thesis deals with the dynamic modeling and experimental validation of the cooling components. The developed dynamic model allows to predict the efficiency of the cooling loop, to conduct the study of transitional regimes, and provides an original tool dedicated to design the loop components. The bond graph methodology is adopted because of the multi physics character of the studied components. First, the basic issues and the industrial context are presented. This allows to introduce the chosen solution (TPLMP). The objectives of the thesis are described. Then, a description of the rig test is proposed. The following three chapters are devoted to a theoretical and experimental study of the loop equipment. Each chapter begins with a state of the art on modeling and correlations of the heat exchange coefficients and losses. A second part of the chapter describes phenomena and equations. A third part is dedicated to the experimental validation. A final chapter presents the coupling works of dynamic models validated separately. Finally, a summary of all contributions is made. Prospects for future developments in short and medium term are proposed.
122

Transducteurs ultra fins à base de polymères conducteurs : fabrication, caractérisation et modélisation / Ultrathin conducting polymer transducers : fabrication, characterization, and modeling

Nguyen, Ngoc Tan 21 September 2018 (has links)
Récemment, les actionneurs ioniques ultra-minces à base de poly (3,4-éthylènedioxythiophène) (PEDOT) ont surmonté certains obstacles initiaux pour augmenter le potentiel d'applications dans les dispositifs microfabriqués. Bien que la microfabrication d’actionneurs à trois couches, n’impliquant aucune manipulation manuelle, ait été démontrée, leurs performances mécaniques restent limitées pour des applications pratiques. Le but de cette thèse est d'optimiser les transducteurs dans la phase de fabrication des couches minces en utilisant des micro technologies, de caractériser complètement les propriétés électrochimiques des transducteurs ainsi obtenus, et de développer un modèle pour simuler leurs capacités électromécaniques bidirectionnelles (actionnement et détection). Tout d'abord, les actionneurs à trois couches ultra-minces à base de PEDOT sont fabriqués par polymérisation en phase vapeur de 3,4-éthylènedioxythiophène en réalisant un procédé de synthèse couche par couche. Le travail présenté constitue la première caractérisation complète de microactionneurs ioniques à base de PEDOT fonctionnant dans l’air d’une si faible épaisseur (17 μm) présentant une déformation en flexion et une génération de force de 1% et 12 μN respectivement. En effet, les propriétés électriques, électrochimiques et mécaniques des microactionneurs ont été minutieusement étudiées. La caractérisation non linéaire a été étendue à la dépendance de la capacité volumétrique sur une fenêtre de tension. Le coefficient d'amortissement a été caractérisé pour la première fois. Par ailleurs, un modèle multi-physique non linéaire a été proposé comme méthode de simulation des réponses en mode actionneur et capteur dans des couches multiples, représenté à l'aide d'un formalisme Bond Graph, et a été capable de mettre en œuvre tous les paramètres caractérisés. La concordance entre les simulations et les mesures a confirmé l'exactitude du modèle pour prédire le comportement dynamique non linéaire des actionneurs. En outre, les informations extraites du modèle ont également permis de mieux comprendre les paramètres critiques des actionneurs et leur incidence sur l'efficacité de l'actionneur et sur la distribution de l'énergie. Enfin, un nouveau modèle linéaire électromécanique bidirectionnel a été introduit pour simuler la capacité de détection du transducteur à trois couches et a été confirmé par des résultats expérimentaux dans les domaines fréquentiel et temporel d'un déplacement d'entrée sinusoïdal. Les actionneurs résultants et les modèles proposés sont prometteurs pour la conception, l'optimisation et le contrôle des futurs dispositifs de microsystèmes souples dans lesquels l'utilisation d'actionneurs en polymère devrait être essentielle. / Recently, ultrathin poly (3,4-ethylenedioxythiophene) (PEDOT) – based ionic actuators have overcome some initial obstacles to increase the potential for applications in microfabricateddevices. While microfabrication processing of trilayer actuators that involve no manual handling has been demonstrated, their mechanical performances remain limited for practical applications. The goal of this thesis is to optimize the transducers in thin films fabrication by micro technologies, fully characterize the electrochemomechanical properties of the resulting trilayers, and develop a model to simulate their bidirectional electromechanical ability (actuation and sensing). At first, ultrathin PEDOT-based trilayer actuators are fabricated via the vapor phase polymerization of 3,4-ethylenedioxythiophene combining with the layer by layer synthesis process. This constitutes the first full characterization of ionic PEDOT-based microactuators operating in air of such a small thickness (17 μm) having bending deformation and output force generation of 1% and 12 μN respectively. Secondly, electrical, electrochemical and mechanical properties of the resulting microactuators have been thoroughly studied. Non-linear characterization was extended to volumetric capacitance dependence on voltage window. Damping coefficient was characterized for the first time. Thirdly, a nonlinear multi-physics model was proposed as a method of simulating actuator and sensor responses in trilayers, represented using a Bond Graph formalism, and was able to implement all of the characterized parameters. The concordance between the simulations and the measurements confirmed the accuracy of the model in predicting the non-linear dynamic behavior of the actuators. In addition, the information extracted from the model also provided an insight into the critical parameters of the actuators and how they affect the actuator efficiency, as well as the energy distribution. Finally, a nouveau bidirectional electromechanical linear model was introduced to simulate the sensing ability of the trilayer transducer and was confirmed via experimental results in both frequency and time domains of a sinusoidal input displacement. The resulting actuators and the proposed models are promising for designing, optimizing, and controlling of the future soft microsystem devices where the use of polymer actuators should be essential.
123

Finite Element Modeling of the Mitral Valve and Mitral Valve Repair

Baxter, Iain A. 28 May 2012 (has links)
As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.
124

Input-shaped manual control of helicopters with suspended loads

Potter, James Jackson 13 January 2014 (has links)
A helicopter can be used to transport a load hanging from a suspension cable. This technique is frequently used in construction, firefighting, and disaster relief operations, among other applications. Unfortunately, the suspended load swings, which makes load positioning difficult and can degrade control of the helicopter. This dissertation investigates the use of input shaping (a command-filtering technique for reducing vibration) to mitigate the load swing problem. The investigation is conducted using two different, but complementary, approaches. One approach studies manual tracking tasks, where a human attempts to make a cursor follow an unpredictably moving target. The second approach studies horizontal repositioning maneuvers on small-scale helicopter systems, including a novel testbed that limits the helicopter and suspended load to move in a vertical plane. Both approaches are used to study how input shaping affects control of a flexible element (the suspended load) and a driven base (the helicopter). In manual tracking experiments, conventional input shapers somewhat degraded control of the driven base but greatly improved control of the flexible element. New input shapers were designed to improve load control without negatively affecting base control. A method for adjusting the vibration-limiting aggressiveness of any input shaper between unshaped and fully shaped was also developed. Next, horizontal repositioning maneuvers were performed on the helicopter testbed using a human-pilot-like feedback controller from the literature, with parameter values scaled to match the fast dynamics of the model helicopter. It was found that some input shapers reduced settling time and peak load swing when applied to Attitude Command or Translational Rate Command response types. When the load was used as a position reference instead of the helicopter, the system was unstable without input shaping, and adding input shaping to a Translational Rate Command was able to stabilize the load-positioning system. These results show the potential to improve the safety and efficiency of helicopter suspended load operations.
125

Finite Element Modeling of the Mitral Valve and Mitral Valve Repair

Baxter, Iain A. 28 May 2012 (has links)
As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.
126

Uma proposta de modelagem conceitual de sistemas dirigida por comportamento / A proposal of behavior-driven systems conceptual modeling

Bustos Reinoso, Guillermo January 1996 (has links)
A Modelagem Orientada a Objetos (MOO) é o processo de construção de modelos de sistemas através da identificação e definição de um conjunto de objetos relacionados, que comportam-se e colaboram entre si conforme os requisitos estabelecidos para o sistema. Esta definição inclui os três aspectos ortogonais, ou dimensões, deste tipo de modelagem: a dimensão estrutural dos objetos, a dimensão dinâmica do comportamento e a dimensão funcional dos requisitos. Conforme a importância relativa dada a cada uma destas dimensões, podem ser definidas três estratégias possíveis para conduzir a MOO. Estas estratégias são as dirigidas por dados, por comportamento e por processos. A estratégia dirigida por processos já esta superada. Atualmente, a estratégia dirigida por dados domina na maioria das técnicas de MOO. A estratégia dirigida por comportamento propõe que a estrutura dos objetos em um sistema pode ser determinada a partir do comportamento externo e interno que o sistema deve apresentar. Esta idéia é interessante, porque permite introduzir tardiamente o encapsulamento na MOO. Conforme é argumentado neste trabalho, as vantagens atribuídas a orientação a objetos são de implementação, isto é, a decisão de orientar ou não a objetos é, na realidade, uma decisão de design. Ao introduzir o encapsulamento na modelagem inicial do sistema, ganha-se o benefício da continuidade estrutural ao custo de colocar a MOO mais perto do design. Neste contexto, este trabalho apresenta um processo de modelagem conceitual de sistemas do ponto de vista comportamental que introduz tardiamente o encapsulamento da orientação a objetos como primeiro passo de design. Em outras palavras, é proposta uma técnica de modelagem sob uma estratégia dirigida por comportamento (privilegiando, assim, o aspecto dinâmico dos sistemas) com o suficiente poder de expressão para, ao mesmo tempo, permitir a modelagem de sistemas de informação no nível conceitual e derivar dos modelos dinâmicos obtidos uma representação estrutural orientada a objetos. 0 sistema, na concepção desta proposta, é composto por um conjunto de processos concorrentes, cada um dos quais recebe um estimulo do ambiente, realiza um tratamento especifico sobre ele e gera para o ambiente uma resposta. Os estímulos externos são decompostos em conjuntos de eventos concorrentes tratados no interior do processo. As ações realizadas no interior do mesmo são compostas nas respostas geradas para o exterior. Os processos são modelados comportamentalmente, utilizando o formalismo proposto High-Level Statecharts (HLS). HLS é uma extensão dos statecharts de Harel. As principais extensões propostas são a introdução de estados "parametrizados" usando variáveis e a representação genérica de conjuntos de estados concorrentes e exclusivos. 0 modelo de processos e desintegrado em unidades de comportamento que tratam das mesmas variáveis. Estas unidades são integradas em um modelo de ciclos de vida para estas variáveis. Finalmente, apos a aplicação da técnica de modelagem conceitual, e obtido um modelo estrutural orientado a objetos. Este modelo e derivado utilizando unicamente informações contidas nos modelos dinâmicos gerados no processo da técnica proposta. No modelo estrutural são identificadas classes, objetos, atributos, associações estáticas, hierarquias de herança e operações. Todo o processo e exemplificado utilizando o problema padrão de preparação de congressos da IFIP. / Object-Oriented Modeling (OOM) is the process of construction of systems models, through an identification and definition of a set of relating objects. These objects have a collaborative behavior according to the system requirements previously defined. This definition includes three modeling aspects or dimensions: object structural dimension, behavior dynamic dimension and requirements functional dimension. Depending on a relative importance of each dimension, three possible strategies to drive OOM are defined. The strategies are: data-driven, behavior-driven and process-driven. Process-driven strategy is obsolete. Nowadays, data-driven is the dominant strategy in the world of OOM techniques. Behavior-driven strategy suggests both internal and external system behaviors define its object structure. This idea is attractive because it allows a late encapsulation in the OOM. As explained in this work, the main advantage to use object-orientation is for implementation. So, to object-orient or not to object-orient is a design decision. If encapsulation is introduced in the very beginning of systems modeling, the structural continuity is achieved at the cost of pulling OOM closer to design. In this context, the work presents a process of systems conceptual modeling using a behavioral point of view. This process introduces object-oriented encapsulation lately as a first step in the design phase. In other words, this work is a proposal of a modeling technique under a behavior-driven strategy (focusing the dynamic aspect of the systems) with enough expression power to model information systems at conceptual level and, at the same time, to derive of an object-oriented structural representation from the dynamic models. As conceived in the proposal, a system is composed by a set of concurrent processes. Each process receives a stimuli from the environment, makes a specific treatment on it and generates a response to the environment. The external stimuli is decomposed into a set of concurrent events which are internally handled by the process. Actions internally performed by the process are composed into a response which is sent outside the process. Processes are behaviorally modeled using a proposed formalism called High-Level Statecharts (HLS). HLS is a extension of Harel's statecharts. The main extensions proposed are parameterized states using variables and generic representation of concurrent and exclusive sets of states. Process model is disintegrated into behavior units handling the same variables. The units are integrated into a life cycle model for these variables. Finally, after the modeling technique has been applied, an object-oriented structural model is obtained. This model is derived exclusively using information from the dynamic models constructed during the modeling process. Classes, objects, attributes, static associations, inheritance hierarchies and operations in the structural model are identified. Examples used in all the modeling process are taken from the standard problem of IFIP conference.
127

Modélisation de la stabilisation de la matière organique et des émissions gazeuses au cours du compostage d'effluents d'élevage. / Modeling organic matter stabilization and gaseous emissions during windrow composting of livestock effluents

Oudart, Didier 08 November 2013 (has links)
La variété des pratiques de compostage et les différences de nature des substrats modifient la vitesse de dégradation de la matière organique (MO), la qualité finale du compost produit et la part d'émissions sous forme de polluants gazeux. L'optimisation du procédé nécessite la prédiction de ces transformations ou la réalisation d'essais empiriques. Cette thèse analyse les interactions entre les processus biologiques, biochimiques, physico-chimiques et thermodynamiques majeurs à l'origine de la stabilisation de la MO et des émissions gazeuses de CO2, H2O, NH3, N2O. Elle se focalise sur le compostage par aération passive en andain d'effluents d'élevage. La méthode s'appuie sur la modélisation dynamique et des expérimentations. L'impact des interactions entre la biodégradabilité du carbone, la disponibilité de l'azote, l'humidité et la porosité, sur la cinétique et la stœchiométrie des émissions gazeuses est analysé à partir d’observations en conditions contrôlées et sur une plateforme de compostage. Les écarts de répétabilité faibles en conditions contrôlées deviennent élevés en conditions de reproductibilité sur le terrain. Un modèle dynamique de compostage a été développé simulant la stabilisation de la MO et les émissions de CO2, H2O, NH3, N2O. Il est composé de quatre modules simulant les cinétiques d'oxydation de la MO par une population microbienne, les échanges thermiques et l'aération passive, le transfert d'oxygène, les transformations de l'azote. Lors de la phase thermophile, le facteur limitant le plus rapidement l'organisation de la MO est la disponibilité de l'azote. L'abaissement de la porosité entraîne une diminution des pertes gazeuses par l'augmentation de l'organisation de la MO. Le fractionnement initial de la MO ainsi que la teneur initiale en biomasse microbienne sont les facteurs clés pour prédire les cinétiques d'organisation de la MO. La calibration des paramètres d’initialisation du modèle reste à améliorer / The variety of the practices and the differences in nature of the substrates modify the kinetics of degradation of organic matter (OM), the final quality of the produced compost and the fraction emitted as gaseous pollutants. To optimize the composting process, it is required to predict these transformations or to do some empirical test. This thesis analyzes the interactions between the main biological, biochemical, physicochemical and thermodynamic processes which explain the OM stabilization and the gaseous emissions of CO2, H2O, NH3, N2O. Focus is done on windrow composting with passive aeration. The method is based on dynamic semi-empirical modeling of the process and experimentations. The impact of the interactions between bioavailability of carbon and nitrogen, moisture and porosity, on the kinetics and the stoechiometry of the gaseous emissions is analyzed with data gathered in controlled conditions and on a commercial composting plant. The repeatability differences are small in controlled conditions but higher in field conditions. A dynamic model of composting was developed simulating the stabilization of OM as well as the emissions of CO2, H2O, NH3, N2O. This model is composed of four coupled modules which simulate the kinetics of oxidation of OM by a heterotrophic microbial population, the heat transfers leading to the passive aeration, the transfer of oxygen, the transformations of nitrogen. During the thermopilic phase, the first factor limiting the organization of OM is the availability of nitrogen. The decrease in porosity induces a reduction in the gas losses through the increase in the organization of OM. The initial OM fractionation and the initial microbial biomass are the key factors to predict the kinetics of organization of OM. The calibration of the specific parameters used for model initialization needs a further implementation
128

Uma proposta de modelagem conceitual de sistemas dirigida por comportamento / A proposal of behavior-driven systems conceptual modeling

Bustos Reinoso, Guillermo January 1996 (has links)
A Modelagem Orientada a Objetos (MOO) é o processo de construção de modelos de sistemas através da identificação e definição de um conjunto de objetos relacionados, que comportam-se e colaboram entre si conforme os requisitos estabelecidos para o sistema. Esta definição inclui os três aspectos ortogonais, ou dimensões, deste tipo de modelagem: a dimensão estrutural dos objetos, a dimensão dinâmica do comportamento e a dimensão funcional dos requisitos. Conforme a importância relativa dada a cada uma destas dimensões, podem ser definidas três estratégias possíveis para conduzir a MOO. Estas estratégias são as dirigidas por dados, por comportamento e por processos. A estratégia dirigida por processos já esta superada. Atualmente, a estratégia dirigida por dados domina na maioria das técnicas de MOO. A estratégia dirigida por comportamento propõe que a estrutura dos objetos em um sistema pode ser determinada a partir do comportamento externo e interno que o sistema deve apresentar. Esta idéia é interessante, porque permite introduzir tardiamente o encapsulamento na MOO. Conforme é argumentado neste trabalho, as vantagens atribuídas a orientação a objetos são de implementação, isto é, a decisão de orientar ou não a objetos é, na realidade, uma decisão de design. Ao introduzir o encapsulamento na modelagem inicial do sistema, ganha-se o benefício da continuidade estrutural ao custo de colocar a MOO mais perto do design. Neste contexto, este trabalho apresenta um processo de modelagem conceitual de sistemas do ponto de vista comportamental que introduz tardiamente o encapsulamento da orientação a objetos como primeiro passo de design. Em outras palavras, é proposta uma técnica de modelagem sob uma estratégia dirigida por comportamento (privilegiando, assim, o aspecto dinâmico dos sistemas) com o suficiente poder de expressão para, ao mesmo tempo, permitir a modelagem de sistemas de informação no nível conceitual e derivar dos modelos dinâmicos obtidos uma representação estrutural orientada a objetos. 0 sistema, na concepção desta proposta, é composto por um conjunto de processos concorrentes, cada um dos quais recebe um estimulo do ambiente, realiza um tratamento especifico sobre ele e gera para o ambiente uma resposta. Os estímulos externos são decompostos em conjuntos de eventos concorrentes tratados no interior do processo. As ações realizadas no interior do mesmo são compostas nas respostas geradas para o exterior. Os processos são modelados comportamentalmente, utilizando o formalismo proposto High-Level Statecharts (HLS). HLS é uma extensão dos statecharts de Harel. As principais extensões propostas são a introdução de estados "parametrizados" usando variáveis e a representação genérica de conjuntos de estados concorrentes e exclusivos. 0 modelo de processos e desintegrado em unidades de comportamento que tratam das mesmas variáveis. Estas unidades são integradas em um modelo de ciclos de vida para estas variáveis. Finalmente, apos a aplicação da técnica de modelagem conceitual, e obtido um modelo estrutural orientado a objetos. Este modelo e derivado utilizando unicamente informações contidas nos modelos dinâmicos gerados no processo da técnica proposta. No modelo estrutural são identificadas classes, objetos, atributos, associações estáticas, hierarquias de herança e operações. Todo o processo e exemplificado utilizando o problema padrão de preparação de congressos da IFIP. / Object-Oriented Modeling (OOM) is the process of construction of systems models, through an identification and definition of a set of relating objects. These objects have a collaborative behavior according to the system requirements previously defined. This definition includes three modeling aspects or dimensions: object structural dimension, behavior dynamic dimension and requirements functional dimension. Depending on a relative importance of each dimension, three possible strategies to drive OOM are defined. The strategies are: data-driven, behavior-driven and process-driven. Process-driven strategy is obsolete. Nowadays, data-driven is the dominant strategy in the world of OOM techniques. Behavior-driven strategy suggests both internal and external system behaviors define its object structure. This idea is attractive because it allows a late encapsulation in the OOM. As explained in this work, the main advantage to use object-orientation is for implementation. So, to object-orient or not to object-orient is a design decision. If encapsulation is introduced in the very beginning of systems modeling, the structural continuity is achieved at the cost of pulling OOM closer to design. In this context, the work presents a process of systems conceptual modeling using a behavioral point of view. This process introduces object-oriented encapsulation lately as a first step in the design phase. In other words, this work is a proposal of a modeling technique under a behavior-driven strategy (focusing the dynamic aspect of the systems) with enough expression power to model information systems at conceptual level and, at the same time, to derive of an object-oriented structural representation from the dynamic models. As conceived in the proposal, a system is composed by a set of concurrent processes. Each process receives a stimuli from the environment, makes a specific treatment on it and generates a response to the environment. The external stimuli is decomposed into a set of concurrent events which are internally handled by the process. Actions internally performed by the process are composed into a response which is sent outside the process. Processes are behaviorally modeled using a proposed formalism called High-Level Statecharts (HLS). HLS is a extension of Harel's statecharts. The main extensions proposed are parameterized states using variables and generic representation of concurrent and exclusive sets of states. Process model is disintegrated into behavior units handling the same variables. The units are integrated into a life cycle model for these variables. Finally, after the modeling technique has been applied, an object-oriented structural model is obtained. This model is derived exclusively using information from the dynamic models constructed during the modeling process. Classes, objects, attributes, static associations, inheritance hierarchies and operations in the structural model are identified. Examples used in all the modeling process are taken from the standard problem of IFIP conference.
129

Modelagem dinâmica e controle para navegação de um veículo aéreo não tripulado do tipo quadricóptero

Lima, Gabriela Vieira 14 August 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Technological advances in electromechanical sensor and actuators, energy storage, data processing and control methodology made possible the development of unmanned aerial vehicles (UAVs). The quadrotor has emerged as one of these research platforms due to its mechanical simplicity, high maneuverability, as well as its capability of hovering and perform vertical take-off and landing. However, such vehicle presents some challenging issues to control area, like: nonlinearity, time-varying behavior, in addition it belongs to the class of underactuated mechanical systems, and it is subject to aerodynamics disturbances and parametric uncertainties. Therefore, this dissertation has as main objective, contribute to development and control strategies implementation to solve the positioning and path tracking problems of unmanned aerial vehicles, focusing on an underactuated mechanical system. In order to obtain a dynamic model that represents the aerial vehicle properly and realistically, the motion equations were developed based on the physics laws that define the mechanical system. The model we obtained is decoupled, thus we consider the presence of two subsystems, the rotational and the translational ones. A cascade control strategy was implemented, so that, a model predictive control (MPC) was developed to the altitude and orientation control of the aerial vehicle. However, the positioning control along the xy axis was performed through a proportional integral derivative control (PID). Such strategies allowed a smooth path tracking, beyond the possibility of dealing with physical constraints of the system. In order to assess the robustness of the control structure shown, we performed flight simulations under the presence of aerodynamics disturbances and parametric uncertainties. / Avanços tecnológicos em sensores e atuadores microeletromecânicos, no armazenamento de energia, no processamento de informações e em metodologias de controle possibilitaram o desenvolvimento dos veículos aéreos não tripulados (VANT s). O quadricóptero tem emergido como uma destas plataformas de pesquisa devido a sua simplicidade mecânica, a alta manobrabilidade, bem como a capacidade de realizar pairagem e decolagens e pousos verticais. Contudo, tal veículo apresenta algumas características desafiadoras para a área de controle, como: não linearidades, comportamento variante no tempo, além de pertencer à classe dos sistemas mecânicos subatuados e estar sujeito a distúrbios aerodinâmicos e incertezas paramétricas. Desta forma, este trabalho possui como principal objetivo contribuir para o desenvolvimento e a implementação de estratégias de controle para solucionar os problemas de posicionamento e rastreamento de trajetória em veículos aéreos não tripulados, focando em um sistema mecânico subatuado. Com o intuito de obter um modelo dinâmico que represente de forma apropriada e realista o veículo aéreo, suas equações de movimento foram desenvolvidas baseando-se nas leis físicas que regem o sistema mecânico. O modelo obtido é desacoplado, portanto, consideramos a existência de dois subsistemas, o rotacional e o translacional. Uma estratégia de controle em cascata foi implementada, de modo que, um controle preditivo baseado em modelo (CPBM) foi desenvolvido para o controle da altitude e da orientação do veículo aéreo. Já o controle de posicionamento no eixo xy foi efetuado através de um controlador proporcional integral derivativo (PID). Tais estratégias permitiram um rastreamento de trajetória suave, além da possibilidade de lidar com as restrições físicas do sistema. Com o intuito de avaliar a robustez da estrutura de controle apresentada, foram realizadas simulações de voo na presença de distúrbios aerodinâmicos e incertezas paramétricas. / Mestre em Ciências
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Uma proposta de modelagem conceitual de sistemas dirigida por comportamento / A proposal of behavior-driven systems conceptual modeling

Bustos Reinoso, Guillermo January 1996 (has links)
A Modelagem Orientada a Objetos (MOO) é o processo de construção de modelos de sistemas através da identificação e definição de um conjunto de objetos relacionados, que comportam-se e colaboram entre si conforme os requisitos estabelecidos para o sistema. Esta definição inclui os três aspectos ortogonais, ou dimensões, deste tipo de modelagem: a dimensão estrutural dos objetos, a dimensão dinâmica do comportamento e a dimensão funcional dos requisitos. Conforme a importância relativa dada a cada uma destas dimensões, podem ser definidas três estratégias possíveis para conduzir a MOO. Estas estratégias são as dirigidas por dados, por comportamento e por processos. A estratégia dirigida por processos já esta superada. Atualmente, a estratégia dirigida por dados domina na maioria das técnicas de MOO. A estratégia dirigida por comportamento propõe que a estrutura dos objetos em um sistema pode ser determinada a partir do comportamento externo e interno que o sistema deve apresentar. Esta idéia é interessante, porque permite introduzir tardiamente o encapsulamento na MOO. Conforme é argumentado neste trabalho, as vantagens atribuídas a orientação a objetos são de implementação, isto é, a decisão de orientar ou não a objetos é, na realidade, uma decisão de design. Ao introduzir o encapsulamento na modelagem inicial do sistema, ganha-se o benefício da continuidade estrutural ao custo de colocar a MOO mais perto do design. Neste contexto, este trabalho apresenta um processo de modelagem conceitual de sistemas do ponto de vista comportamental que introduz tardiamente o encapsulamento da orientação a objetos como primeiro passo de design. Em outras palavras, é proposta uma técnica de modelagem sob uma estratégia dirigida por comportamento (privilegiando, assim, o aspecto dinâmico dos sistemas) com o suficiente poder de expressão para, ao mesmo tempo, permitir a modelagem de sistemas de informação no nível conceitual e derivar dos modelos dinâmicos obtidos uma representação estrutural orientada a objetos. 0 sistema, na concepção desta proposta, é composto por um conjunto de processos concorrentes, cada um dos quais recebe um estimulo do ambiente, realiza um tratamento especifico sobre ele e gera para o ambiente uma resposta. Os estímulos externos são decompostos em conjuntos de eventos concorrentes tratados no interior do processo. As ações realizadas no interior do mesmo são compostas nas respostas geradas para o exterior. Os processos são modelados comportamentalmente, utilizando o formalismo proposto High-Level Statecharts (HLS). HLS é uma extensão dos statecharts de Harel. As principais extensões propostas são a introdução de estados "parametrizados" usando variáveis e a representação genérica de conjuntos de estados concorrentes e exclusivos. 0 modelo de processos e desintegrado em unidades de comportamento que tratam das mesmas variáveis. Estas unidades são integradas em um modelo de ciclos de vida para estas variáveis. Finalmente, apos a aplicação da técnica de modelagem conceitual, e obtido um modelo estrutural orientado a objetos. Este modelo e derivado utilizando unicamente informações contidas nos modelos dinâmicos gerados no processo da técnica proposta. No modelo estrutural são identificadas classes, objetos, atributos, associações estáticas, hierarquias de herança e operações. Todo o processo e exemplificado utilizando o problema padrão de preparação de congressos da IFIP. / Object-Oriented Modeling (OOM) is the process of construction of systems models, through an identification and definition of a set of relating objects. These objects have a collaborative behavior according to the system requirements previously defined. This definition includes three modeling aspects or dimensions: object structural dimension, behavior dynamic dimension and requirements functional dimension. Depending on a relative importance of each dimension, three possible strategies to drive OOM are defined. The strategies are: data-driven, behavior-driven and process-driven. Process-driven strategy is obsolete. Nowadays, data-driven is the dominant strategy in the world of OOM techniques. Behavior-driven strategy suggests both internal and external system behaviors define its object structure. This idea is attractive because it allows a late encapsulation in the OOM. As explained in this work, the main advantage to use object-orientation is for implementation. So, to object-orient or not to object-orient is a design decision. If encapsulation is introduced in the very beginning of systems modeling, the structural continuity is achieved at the cost of pulling OOM closer to design. In this context, the work presents a process of systems conceptual modeling using a behavioral point of view. This process introduces object-oriented encapsulation lately as a first step in the design phase. In other words, this work is a proposal of a modeling technique under a behavior-driven strategy (focusing the dynamic aspect of the systems) with enough expression power to model information systems at conceptual level and, at the same time, to derive of an object-oriented structural representation from the dynamic models. As conceived in the proposal, a system is composed by a set of concurrent processes. Each process receives a stimuli from the environment, makes a specific treatment on it and generates a response to the environment. The external stimuli is decomposed into a set of concurrent events which are internally handled by the process. Actions internally performed by the process are composed into a response which is sent outside the process. Processes are behaviorally modeled using a proposed formalism called High-Level Statecharts (HLS). HLS is a extension of Harel's statecharts. The main extensions proposed are parameterized states using variables and generic representation of concurrent and exclusive sets of states. Process model is disintegrated into behavior units handling the same variables. The units are integrated into a life cycle model for these variables. Finally, after the modeling technique has been applied, an object-oriented structural model is obtained. This model is derived exclusively using information from the dynamic models constructed during the modeling process. Classes, objects, attributes, static associations, inheritance hierarchies and operations in the structural model are identified. Examples used in all the modeling process are taken from the standard problem of IFIP conference.

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