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Bond graph model and computer simulation of a hydrostatic drive test standLeague, Richard B. January 1985 (has links)
A hydrostatic drive test stand was constructed to aid in the instruction of the characteristics of hydrostatic transmissions and to develop a time-varying load in a shaft to compare torque transducers. A mathematical model of the device was derived using the bond graph approach and was implemented using the Advanced Continuous Simulation Language (ACSL). The test stand was used to obtain experimental data to try to refine the model parameters. To facilitate the measurement of system flows, a microprocessor-based digital flow indicator was developed. Steady-state tests were performed at various constant pump swashplate angles; for the dynamic tests, the pump swashplate angle was cycled from zero degrees to 6.5 degrees. / Master of Science / incomplete_metadata
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Contributions à la modélisation et la commande des réseaux de trafic routier / Contributions to modeling and control of road traffic networksDimon, Catalin 24 February 2012 (has links)
Les principaux objectifs de la thèse sont de proposer des modèles dynamiques pour décrire la circulation routière en adaptant des modèles de la mécanique des fluides et à partir de ces modèles de concevoir et mettre en œuvre des algorithmes de contrôle. La circulation routière est considérée comme un système complexe organisé dans une structure décentralisée à trois niveaux: au plus haut niveau il y a le réseau routier, décomposé, au niveau suivant, en objets routiers (tronçons et intersections), aussi décomposés, au dernier niveau, en éléments (segments) routiers.La thèse est organisée en six chapitres. Le premier chapitre présente les problèmes spécifiques aux réseaux de circulation routière, ainsi que des modèles et des algorithmes de contrôle trouvés dans la littérature. Le deuxième chapitre présente les principaux outils nécessaires pour décrire un modèle de trafic macroscopique et des façons pour représenter le flux de véhicules. Dans le troisième chapitre, des modèles dynamiques sont proposés pour différents segments et tronçons routiers. Le quatrième chapitre est consacré à la conception d’algorithmes pour le contrôle du trafic et l’optimisation de la circulation, y compris une analyse de robustesse pour évaluer la tolérance du système aux non-linéarités du modèle. Le cinquième chapitre présente une stratégie de contrôle pour le réseau routier, en utilisant la représentation par des modèles à compartiments et le concept de dynamique positive. Dans le dernier chapitre de la thèse, les contributions de l’auteur sont mises en évidence et quelques perspectives pour le développement ultérieur de la recherche sont présentées / The main objectives of this thesis are to propose dynamic models in order to describe road traffic by adapting models of fluid mechanics and based on these models to design and implement control algorithms. Road traffic is seen as a complex system organized in a decentralized structure. At the highest level of complexity there is the traffic network, considered as a part of a city’s road infrastructure. At the next level, the network is decomposed into traffic objects represented by road sections (streets) and intersections. At the last level of complexity there are the road segments that are parts of a road section.The thesis is organized into six chapters. The first chapter presents specific problems of road traffic networks, as well as control models and algorithms found in literature. The second chapter presents the main tools needed to describe a macroscopic traffic model, and some ways of representing the flow of vehicles. In the third chapter, dynamic models are proposed for different road segments and sections. The fourth chapter is devoted to designing algorithms for traffic control and optimization, including a robustness analysis to evaluate the system’s tolerance to model nonlinearities. The fifth chapter presents a control strategy for the road network, using the representation with compartmental models and the concept of positive dynamic. In the last chapter of the thesis, the author’s contributions are highlighted and some perspectives for further development of the research are presented
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Génération de modèles de haut niveau enrichis pour les systèmes hétérogènes et multiphysiques / Generating high level enriched models for heterogeneous and muliphysics systemsBousquet, Laurent 29 January 2014 (has links)
Les systèmes sur puce sont de plus en plus complexes : ils intègrent des parties numériques, desparties analogiques et des capteurs ou actionneurs. SystemC et son extension SystemC AMSpermettent aujourd’hui de modéliser à haut niveau d’abstraction de tels systèmes. Ces outilsconstituent de véritables atouts dans une optique d’étude de faisabilité, d’exploration architecturale etde vérification du fonctionnement global des systèmes complexes hétérogènes et multiphysiques. Eneffet, les durées de simulation deviennent trop importantes pour envisager les simulations globales àbas niveau d’abstraction. De plus, les simulations basées sur l’utilisation conjointe de différents outilsprovoquent des problèmes de synchronisation. Les modèles de bas niveau, une fois crées par lesspécialistes des différents domaines peuvent toutefois être abstraits afin de générer des modèles dehaut niveau simulables sous SystemC/SystemC AMS en des temps de simulation réduits. Une analysedes modèles de calcul et des styles de modélisation possibles est d’abord présentée afin d’établir unlien avec les durées de simulation, ceci pour proposer un style de modélisation en fonction du niveaud’abstraction souhaité et de l’ampleur de la simulation à effectuer. Dans le cas des circuits analogiqueslinéaires, une méthode permettant de générer automatiquement des modèles de haut niveaud’abstraction à partir de modèles de bas niveau a été proposée. Afin d’évaluer très tôt dans le flot deconception la consommation d’un système, un moyen d’enrichir les modèles de haut niveaupréalablement générés est présenté. L’attention a ensuite été portée sur la modélisation à haut niveaudes systèmes multiphysiques. Deux méthodes y sont discutées : la méthode consistant à utiliser lecircuit équivalent électrique puis la méthode basée sur les bond graphs. En particulier, nous proposonsune méthode permettant de générer un modèle équivalent au bond graph à partir d’un modèle de basniveau. Enfin, la modélisation d’un système éolien est étudiée afin d’illustrer les différents conceptsprésentés dans cette thèse. / Systems on chip are more and more complex as they now embed not only digital and analog parts, butalso sensors and actuators. SystemC and its extension SystemC AMS allow the high level modeling ofsuch systems. These tools are efficient for feasibility study, architectural exploration and globalverification of heterogeneous and multiphysics systems. At low level of abstraction, the simulationdurations are too important. Moreover, synchronization problems appear when cosimulations areperformed. It is possible to abstract the low level models that are developed by the specialists of thedifferent domains to create high level models that can be simulated faster using SystemC/SystemCAMS. The models of computation and the modeling styles have been studied. A relation is shownbetween the modeling style, the model size and the simulation speed. A method that generatesautomatically the high level model of an analog linear circuit from its low level representation isproposed. Then, it is shown how to include in the high level model some information allowing thepower consumption estimation. After that, the multiphysics systems modeling is studied. Twomethods are discussed: firstly, the one that uses the electrical equivalent circuit, then the one based onthe bond graph approach. It is shown how to generate a bond graph equivalent model from a low levelrepresentation. Finally, the modeling of a wind turbine system is discussed in order to illustrate thedifferent concepts presented in this thesis.
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Modeling and Simulation of Physical Systems in a Mechatronic ContextSjöstedt, Carl-Johan January 2009 (has links)
This thesis gives different views on the modeling and simulation of physical systems, especially together with embedded systems, forming mechatronic systems. The main considered application domain is automotive. One motivation behind the work is to find suitable representations of physical systems to be used in an architectural description language for automotive embedded systems, EAST-ADL2, which is implemented as a UML2 profile, and uses concepts from both UML and SysML. As a part of the thesis, several languages and tools are investigated, including bond graphs, MATLAB/Simulink, Ptolemy II, Modelica, MATLAB/Simscape and SysML. For SysML, the modeling of continuous-time systems and how it relates to MATLAB/Simulink and Modelica is evaluated. A case study of an electric power assisted steering is modeled to show the differences, the similarities and the usage of the above mentioned languages and tools. To be able to classify the tools and languages, five realization levels were developed: Physical modeling models Constraint models Continuous causal models Discretized models Discretized models with solver and platform implementation By using these realization levels, models, tools and modeling languages can be classified, and transformations between them can be set up and analyzed. As a result, a method to describe the simulation behavior of a MATLAB/Simulink model has been developed using SysML activity diagrams as an approach to achieve integrated system models. Another result is an evaluation of the parametric diagrams of SysML for continuous-time modeling, which shows that they do not enable “physical modeling”, i.e. modeling the topology of the system and getting the underlying equations out of this topology. By including physical ports and physical connectors to SysML internal block diagrams, this could be solved. The comparison also shows many similarities between the languages. The results led to a more detailed investigation on conjugate variables, such as force and velocity, and electric current and voltage, and how these are treated in various languages. The thesis also includes two industrial case studies: one of a twin-screw compressor, and one of a simulation environment for automotive fuel-cell systems. Conclusions are drawn from these models, referring to the realization levels. / QC 20100810
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Contributions à la modélisation et la commande des réseaux de trafic routierDimon, Catalin 24 February 2012 (has links) (PDF)
Les principaux objectifs de la thèse sont de proposer des modèles dynamiques pour décrire la circulation routière en adaptant des modèles de la mécanique des fluides et à partir de ces modèles de concevoir et mettre en œuvre des algorithmes de contrôle. La circulation routière est considérée comme un système complexe organisé dans une structure décentralisée à trois niveaux: au plus haut niveau il y a le réseau routier, décomposé, au niveau suivant, en objets routiers (tronçons et intersections), aussi décomposés, au dernier niveau, en éléments (segments) routiers.La thèse est organisée en six chapitres. Le premier chapitre présente les problèmes spécifiques aux réseaux de circulation routière, ainsi que des modèles et des algorithmes de contrôle trouvés dans la littérature. Le deuxième chapitre présente les principaux outils nécessaires pour décrire un modèle de trafic macroscopique et des façons pour représenter le flux de véhicules. Dans le troisième chapitre, des modèles dynamiques sont proposés pour différents segments et tronçons routiers. Le quatrième chapitre est consacré à la conception d'algorithmes pour le contrôle du trafic et l'optimisation de la circulation, y compris une analyse de robustesse pour évaluer la tolérance du système aux non-linéarités du modèle. Le cinquième chapitre présente une stratégie de contrôle pour le réseau routier, en utilisant la représentation par des modèles à compartiments et le concept de dynamique positive. Dans le dernier chapitre de la thèse, les contributions de l'auteur sont mises en évidence et quelques perspectives pour le développement ultérieur de la recherche sont présentées
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[en] ORDER REDUCTION OF LINEAR MECHANICAL MODELS: A BOND GRAPH APPROACH / [pt] REDUÇÃO DE ORDEM DE MODELOS MECÂNICOS LINEARES: UMA ABORDAGEM VIA GRAFOS DE LIGAÇÃOMAURO SPERANZA NETO 08 May 2006 (has links)
[pt] Neste trabalho descreve-se um procedimento para o
desenvolvimento de modelos reduzidos de sistemas mecânicos
lineares baseado na técnica dos Grafos de Ligação. A
partir da análise da estrutura topológica dos principais
modelos mecânicos descritos por esta técnica estabeleceu-
se uma nova formulação que possibilita a obtenção de
variadas formas de representação matemática e definiu-se
um grafo genérico, formado por hipercampos armazenadores e
dissipadores de energia, onde se encontram as matrizes que
caracterizam a dinâmica do sistema.
Sobre o grafo genérico, com algumas restrições, foi
aplicada uma metodologia de normalização e desacoplamento
dos campos armazenadores, com base nos seus modos locais,
o que permitiu a criação de um grafo particionado,
acoplado através do campo dissipador. A análise dos
coeficientes do campo de acoplamento leva ao grafo de
Ligação Reduzido do sistema. Comprova-se a validade do
procedimento através de exemplos de fácil compreensão. / [en] It is described in this work a Bond Graph based procedure
to the development of linear mechanical systems reduced
order models. From the analysis of the topological
structure of the main mechanical models represented by
this technique it was established a new formulation that
permits to obtain several mathematical representation
forms and it was defined a generic graph, formed by energy
storage and dissipative hiperfields, where the matrices
that characterizes the system dynamics are included.
On the generic graph, with some constraints, it
was applied a methodology for the normalization and
decoupling of the energy storage fields, based on its
local modes, that permits to develop a partioned graph,
couplec through the dissipative field. The analysis of the
coupling field coefficients permits to define the system
Reduced Bond Graph. The procedure was comproved by easy
comprehensive examples.
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[pt] DESENVOLVIMENTO DE PLATAFORMA PARA TESTES E SIMULAÇÃO DE SISTEMAS MULTICÓPTEROS / [en] DEVELOPMENT OF A PLATFORM FOR TESTS AND SIMULATION OF MULTICOPTER SYSTEMSRENAN DE LIMA SIMOES MONDEGO VILELA 25 February 2021 (has links)
[pt] O crescente uso de veículos aéreos não tripulados (VANTs) em diversos setores
da sociedade é fruto de avanços da tecnologia. Por sua vez, a ampliação de
aplicações de VANTs traz consigo a necessidade de aumento de robustez destes
sistemas, especialmente em ambientes compartilhados com o ser humano. A
presente dissertação aborda o desenvolvimento de uma plataforma para testes
de veículos multicópteros, com o objetivo de contribuir para o processo de desenvolvimento
e implementação de drones, permitindo sua movimentação em
torno dos seus graus de liberdade de rotação e realizando medições de atitude
e força geradas pelo sistema, sem colocar o veículo ou seu operador em
risco. Todos os dados adquiridos pela plataforma são transmitidos para um
computador, onde foi desenvolvida uma interface virtual para sua visualização
em tempo real, além de permitir armazenamento para pós-processamento
e análises futuras. Também apresenta-se e discute-se o desenvolvimento do
simulador de trajetórias proposto, que mostra o deslocamento do veículo em
função da sequência de comandos fornecida, com base nos dados adquiridos
pela plataforma. No intuito de se propiciar um melhor entendimento do funcionamento
do sistema aqui desenvolvido, é apresentado um estudo detalhado
dos subsistemas que compõem um multicóptero, bem como do processo de
modelagem dinâmica de um veículo quadricóptero, por meio da técnica de
grafos de ligação. A modelagem do veículo é complementada com a identificação
de parâmetros fundamentais para a implementação do modelo, sendo
discutidos métodos para identificação de parâmetros inerciais do veículo e
parâmetros dinâmicos do sistema motopropulsor. / [en] The growing use of unmanned aerial vehicles (UAVs) in various sectors
of society is a result of advances in technology. In turn, the expansion of
UAV applications brings with it the need to increase the robustness of these
systems, especially in environments shared with humans. and comes together
with the need for increased robustness due to its use in shared environments
with humans. This dissertation approaches the development of a platform
for testing multicopter vehicles aiming at assisting the process of developing
and implementing drones, allowing movements around their rotational degrees
of freedom and making measurements of attitude and forces generated by
the system, without putting the vehicle or its operator at risk. All data
acquired by the platform is transmitted to a computer, where a virtual
interface was developed to provide real time visualization, in addition to
allowing data storage for post-processing and future analysis. The development
of the proposed trajectory simulator is also presented and discussed, that
shows the displacement of the vehicle as a function of the sequence of
commands provided, based on the acquired data. Aiming at allowing a better
understanding of the functioning of the developed system, a detailed study
of the subsystems that compose a multicopter is presented, as well as the
process of dynamic modeling of a quadcopter vehicle, by using bond graph
technique. The modeling of the vehicle is complemented with the identification
of fundamental parameters for the model implementation, such as methods for
the identification of inertial parameters of the vehicle and dynamics of the
powertrain system.
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Bond graph modeling of hydraulic circuits on a sweet sorghum harvesterRains, Glen Christopher 02 February 2007 (has links)
A whole-stalk harvester was developed as part of a sweet sorghum-for-ethanol production system. Gathering chains grasped the stalks as they were cut at the base with a disk-cutter. These stalks were flipped onto a cross conveyor and deposited into an accumulator. Periodically the machine stopped and the accumulator was dumped. All the components on the harvester are powered hydraulically. Five pumps on the harvester supply flow to seven actuator circuits. Power is delivered to the pumps from the tractor PTO via a universal joint driveline. Each of the six existing circuits and one proposed circuit were modeled with bond graphs and implemented for computer analysis using TUTSIM. Model validation was done by comparing simulated and measured driveline torque, line pressure, and return line flow rate in each of the six existing circuits.
Data collected on the gathering chains circuit was used to analyze the effect of driveline joint angles on transmitted torque and pump output. Torque measurements at three driveline angles showed a torsional vibration with a primary harmonic at driveline rpm and a secondary at twice driveline rpm. A combination of Cardan joint characteristics, mass unbalance, the secondary couple, and non-linear driveline and V-belt stiffness was used to model the driveline. Resulting simulated torque emulated the experimental very well. Measured pressure in the gathering chains circuit showed relatively low fluctuations at the highest amplitude torsional vibration (highest driveline joint angles). It was concluded that driveline vibration would not significantly affect the gathering chains circuit performance.
The cross-conveyor motor circuit simulation showed close agreement to experimental results. Mean predicted flow, pressure, and torque were within 8.9, 7.3, and 7.7 percent of mean measured values. A simulation with a stalk load on the conveyor showed that power requirement increased only 8.0 percent.
The accumulator dump circuit was analyzed to determine if the load on the motor would become over-running and cavitate the pump or motor as the stalks were being dumped. Simulation showed that a bundle up to 300 kg could be dumped without over-running the motor, and since this was a larger bundle than the bin could hold, a design modification was not necessary.
The disk-cutter circuit was designed based on simulation results for several combinations of motor, pump, and sheave ratio. A 7.3 cm³/rad motor, 2.53 cm³/rad pump , and 2:1 sheave ratio produced the correct disk-cutter speed, and low torsional vibration when cutting the stalks, consequently this combination was selected for the design. / Ph. D.
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[en] FLUID LINES MODELS FOR TRANSIENTS ANALYSIS AND SIMULATION USING THE POWER FLOW / [pt] MODELOS DE LINHAS FLUIDAS ATRAVÉS DO FLUXO DE POTÊNCIA PARA ANÁLISE E SIMULAÇÃO DE TRANSIENTESFELIPE AUGUSTO SILVA DE ANDRADE 28 September 2007 (has links)
[pt] O estudo de fenômenos transitórios em sistemas hidráulicos
está presente
em diversos ramos da engenharia, encontra-se na área de
hidrelétricas e na
indústria do petróleo. O presente trabalho apresenta uma
análise comparativa
deste fenômeno utilizando três abordagens de modelagem
distintas: o clássico
método das características, a técnica de grafos de ligação
e o tratamento através
do fluxo de potência. No caso do método das
características emprega-se o
procedimento proposto por Streeter. Na modelagem através
de grafo de ligação
adota-se a analogia generalizada entre os sistemas fluido,
mecânico e elétrico. Na
representação pelo fluxo de potência acopla-se módulos
previamente
desenvolvidos considerando as relações de causa e efeito
entre os componentes de
um sistema. Todos os métodos foram implementados em Matlab
e foram testados
e comparados a partir de simulações em dois sistemas
simples compostos de um
reservatório, linha fluida e válvula. Os resultados
obtidos através da metodologia
de fluxo de potência aproximam-se dos encontrados pelas
abordagens
tradicionais. / [en] The study of transitory phenomena in hydraulic systems is
present in several
branches of the engineering, in the hydroelectric power
stations area and in the
petroleum industry. The present work introduce a
comparative analysis of this
phenomenon using three approaches of distinct modeling:
the classic
characteristics method, the technique of bond graphs and
the treatment through
the power flow. In the case of characteristics method is
used the procedure
proposed by Streeter. In the modeling through bond graphs
is adopted the
generalized analogy among the fluid, mechanic and electric
systems. In the
representation by power flow modules previously developed
are coupled
considering the cause and effect relationships between
components of one system.
All methods were implemented in Matlab and were tested and
compared from
simulations in two simple systems composed of a reservoir,
fluid lines and valve.
The results obtained through the methodology of power flow
are near of the
discoveries by the traditional approaches.
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Bioaéroelasticité d’aéronefs à voilure tournante par bond graphs / Rotorcraft bioaeroelasticity using bond graphsTod, Georges 14 December 2015 (has links)
Dans certaines conditions de vol, les aéronefs à voilure tournante souffrent parfois de l’émergence d’oscillations indésirables, phénomènes potentiellement instables connus sous le nom de Couplages Pilote-Aéronef aéroélastiques (CPA). Ces phénomènes affectent de manière critique la sécurité et la performance des aéronefs. Par conséquent, il est important d’être capable de prédire l’émergence de tels phénomènes dynamiques, le plus tôt possible dans le processus de conception des hélicoptères. Une revue de la littérature révèle que ces phénomènes sont le résultat d’interactions entre les comportements biodynamique du pilote et aéroélastique des hélicoptères. Afin d’avoir une plus grande modularité et granularité dans le processus de modélisation de systèmes complexes, une approche par bond graphs est adoptée. Un modèle aéromécanique d’hélicoptère et un modèle neuro-musculo-squelettique d’un des membres supérieurs du pilote sont développés en bond graphs. Parmi les représentations proposées, trois sont originales, notamment afin de modéliser : des efforts aérodynamiques quasi-statiques, la liaison traînée-battement-pas entre pale et moyeu rotor, et les efforts musculaires à partir d’un modèle de Hill qui tient compte d’une boucle de rétroaction neuromusculaire. Des résultats encourageants sont obtenus lorsque l’on compare la transmissibilité, entre l’angle de manche de pas cyclique imposé par le pilote et des accélérations latérales de la cabine, calculée à partir du modèle biodynamique, et à partir des résultats expérimentaux tirés de la littérature. Un modèle du système bioaéroélastique homme-machine est linéarisé, au voisinage d’un vol stationnaire, et analysé en termes de stabilité. L’étude révèle, comme conjecturé dans la littérature, que le mode régressif de traînée peut être déstabilisé. De plus, il apparaît que le mode progressif de traînée peut également être déstabilisé lors d’un CPA sur l’axe latéral-roulis. Un critère d’analyse de la stabilité d’un équilibre d’un système dynamique à partir d’un modèle linéaire limite la possibilité de prendre en compte certains comportements non-linéaires et donc réduit l’espace de conception. Les premières pierres vers une méthode basée sur des fonctions de Chetaev sont posées, afin de déterminer si l’équilibre d’un système dynamique est instable, directement à partir d’un modèle mathématique non-linéaire de grande dimension, à un coût de calcul potentiellement intéressant. Afin d’illustrer la pertinence de la proposition, le cas de la résonance sol d’un hélicoptère est présentée. / Under certain flight conditions, rotorcrafts might suffer from the emergence of undesirable oscillations, potentially unstable phenomena, known as aeroelastic Rotorcraft-Pilot Couplings (RPCs). These phenomena critically affect the safety and performance of rotorcraft designs. Therefore, there is an important interest in being able to predict the emergence of such dynamic phenomena, as soon as possible during the design process of helicopters. A review of the state-of-the-art reveals that these phenomena are the result of interactions between pilots’ biodynamics and helicopters’ aeroelastic behaviors. In order to provide more modularity and granularity in the modeling of complex systems, a bond graph based approach is used. A helicopter aeromechanical model and a pilot upper limb neuromusculoskeletal model are developed using bond graphs. Three original bond graph representations are proposed, to model: quasi-steady aerodynamic forces, lag-flap-pitch joint at blades’ roots, and a Hill-type muscle force model that accounts for muscle reflexive feedback. Encouraging results are found when comparing the pilot biodynamic model transmissibility cyclic lever angle to lateral cockpit accelerations computations to literature experimental results. A linear model of the coupled human-machine bioaeroelastic system around hover is analyzed in terms of stability. It reveals not only the regressing lag mode, as conjectured in literature, but also the advancing lag mode can be destabilized during a lateral-roll aeroelastic RPC. Furthermore, a criterion to assess the stability of the equilibrium of a dynamic system from a linear model limits the possibility to take into account nonlinear physical behaviors, reducing the design space. The first blocks towards a method based on Chetaev functions is proposed, to determine if an equilibrium is unstable, directly from its large nonlinear mathematical model, at a potentially interesting computational cost. The helicopter ‘ground resonance’ case illustrates the soundness of the proposal.
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