Les systèmes de sécurité active du véhicule de distribution sont utilisés pour réduire la survenue de situations accidentogènes ou aider le conducteur dans de telles situations pour éviter l'accident. Dans cette étude, nous nous intéressons à la prévention des accidents liés à la perte de contrôle du véhicule par le conducteur. Une partie de ces accidents peut être prévenue par l'utilisation de systèmes de sécurité active de type ESP, qui résout les problèmes d'instabilité du véhicule de type "porteur" en lacet et en roulis. Nous étudions la possibilité d'améliorer les performances de tels systèmes en combinant les actions de freins aux actions d'autres actionneurs disponibles sur le véhicule de distribution, tels que les directions actives avant et arrière. Le véhicule de distribution considéré dans notre cas est sur-actionné car le nombre d'actionneur dépasse le nombre de degrés de liberté contrôlés par ces actionneurs. Nous appliquons deux types de commande adaptés au contrôle des systèmes sur-actionnés: le premier est basé sur la structure hiérarchisée (connu sous le nom de structure avec "allocation de contrôle") et le deuxième est basé sur la structure non-hiérarchisée par "commande prédictive à base de modèle". Dans ce travail, nous adaptons ces deux approches à la problématique du contrôle du véhicule poids lourd de type "porteur". Le développement de la commande passe par la modélisation de la dynamique du véhicule, la validation des modèles et l'analyse de sa stabilité. Les résultats de simulation de prestations ISO, reproduisant des situations réelles et déstabilisantes pour le véhicule, sur le modèle représentatif du comportement réel du véhicule poids lourd démontrent l'efficacité de la commande développée et permettent d'évaluer le gain d'utilisation des actions combinées des actionneurs du véhicule par rapport au schéma classique. Ils permettent en outre de porter un jugement sur les deux types de commandes mises en œuvre. / The active safety systems for the delivery heavy vehicle are used to reduce the hazardous situations and assist the driver in such situations to avoid accidents. This study is focused on the prevention of accidents associated with the loss of control by the driver. Some of these accidents can be prevented by the use of active safety systems such as ESP, which solves the problems of the roll and yaw instability of the single unit heavy vehicles. We study the possibility of improving the performances of such systems by combining the braking actions to actions of other actuators available on the vehicle, such as active front and rear steering systems. The heavy vehicle considered in this study is over-actuated, since the number of actuators exceeds the number of degrees of freedom controlled by these actuators. We apply two control strategies to the over-actuated vehicle control: the first one is the hierarchical control also known as control structure with control allocation, the second one is the model predictive control. In this work, we adapt these two approaches to the single unit heavy vehicle control. The control development passes through vehicle dynamics modeling, models validation and stability analysis. Simulation results of the ISO features, representing real hazardous situations, performed on the high-fidelity model, demonstrate the effectiveness of the developed control and allow evaluating the gain of using the combined actions of actuators in comparison with the classical scheme. The obtained results also allow to judge on two implemented control strategies.

Cette thèse concerne la modélisation des dynamiques de maladies foliaires de cultures pérennes tropicales à différentes échelles spatiales. Cette approche de modélisation est appliquée à la cercosporiose noire du bananier. Il s’agit d’explorer et de déterminer les paramètres environnementaux et de résistance de l’hôte ayant une influence significative sur la dynamique spatiotemporelle de la maladie et d’apporter des éléments associés au contrôle de la cercosporiose noire.Deux modèles ont été développés dans le cadre de cette thèse. La dynamique épidémiologique au niveau de la plante est décrite par un modèle mécaniste décomposé en un modèle de croissance de la plante et un module épidémiologique décrivant le cycle épidémique du pathogène. L’architecture du bananier est prise en compte par le biais de compartiments foliaires positionnés dans l’espace. Le modèle a été validé par un jeu de données indépendant. Les expérimentations numériques et l’analyse de sensibilité du modèle réalisées par les méthodes de Morris et de e-FAST ont permis de mieux comprendre le fonctionnement épidémique de cette maladie et d’identifier les paramètres influant le plus la dynamique épidémique en particulier la vitesse d’extension des lésions, la durée d’incubation et l’efficacité d’infection .L’approche bayésienne a permis de prendre en compte l’information a priori disponible pour ces trois paramètres sur lesquels a porté l’inférence statistique. L’analyse de sensibilité du modèle a également permis d’identifier l’influence de deux paramètres liés à la croissance de la plante : le nombre de feuilles sur une plante et le rythme d’émission foliaire Un modèle de dynamique spatio-temporelle de la cercosporiose noire a été développé à l’échelle d’un territoire à partir d’enquêtes effectuées enMartinique pendant la période d’invasion de cette maladie de septembre 2010 à mai 2012. Les données récoltées étant censurées, l’inférence des paramètres du modèle a été réalisée dans un cadre bayésien en utilisant un algorithme d’augmentation de données. Le modèle et l’inférence développés permettent de reconstruire la dynamique spatio-temporelle de l’invasion et de prédire la fin d’invasion sur le territoire.Les deux modèles de dynamiques spatio-temporelles développés à deux échelles spatiales différentes ont permis d’acquérir des informations importantes pour construire des outils de conception de méthode de contrôle de la cercosporiose noire des bananiers. / This thesis concerns the modeling of the dynamics of foliar diseases of tropical tree crops at different spatial scales. This modeling approach is applied to black Sigatoka of banana. It is to explore and determine the environmental parameters and host resistance has a significant influence on the spatiotemporal dynamics of the disease and to provide elements associated with the control of Sigatoka noire.Deux models were developed as part of this thesis. The epidemiological dynamics at the plant is described by a mechanistic model decomposed into a growth model of the plant and an epidemiological unit describing the pathogen epidemic cycle. The architecture of the banana is taken into account through foliar compartments positioned in space. The model was validated by an independent data set. Numerical experiments and model sensitivity analysis performed by the methods of Morris and e-FAST enabled to better understand the functioning of this epidemic disease and identify the parameters affecting the most dynamic epidemic especially speed extension of the lesions, the incubation period and efficiency of Bayesian .L'approche infection allowed to take into account prior information available for these three parameters that were the statistical inference. The model sensitivity analysis also identified the influence of two parameters related to plant growth: the number of leaves on a plant and rate of leaf emission A dynamic model of space-time Black Sigatoka has been developed at the scale of a territory from surveys enMartinique during the period of invasion of the disease from September 2010 to May 2012. The data collected being censored, inference of model parameters has was performed in a Bayesian framework, using a data augmentation algorithm. The model developed and inference possible to reconstruct the spatiotemporal dynamics of the invasion and predict the end of the invasion territoire.Les two spatio-temporal dynamics models developed at two different spatial scales has been gained important information for build tools design method of control of black Sigatoka of banana.

In this Thesis a Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulations of the converter switches , and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulations , this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic analysis of the converter states at steady-state is done for steady-state waveform acquisition , which increases the accuracy of the model especially for finding the control to inductor current frequency response. Finally the Discrete model is verified for the Half-Bridge DC/DC topology for its three main control schemes (Asymmetric , Symmetric , DCS). A GUI platform in MATLAB is presented as a wrapper that utilizes the models and analysis presented in this thesis.

Legged robots are well-suited for navigating unstructured terrain due to their ability to perform agile dynamic motions. Building on the efforts of Cal Poly's Legged Robotics Group, this project focuses on achieving stable forward hopping with a single legged robot. A comprehensive model of leg hopping is formulated, with leg dynamics during flight and stance phases derived using Euler-Lagrange equations. During the stance phase, a spring-mass system models the leg-ground interaction. The touchdown and lift-off conditions are formulated mathematically, and state mappings between phases are determined via momentum conservation. A two-phase hybrid controller is designed, incorporating trajectory planning during flight and ground-reaction force and impedance control during stance. Numerical simulations validate the design, followed by experimental testing on a Speedgoat real-time machine within a Simulink environment, showing good correlation with simulations. The impact of a control parameters on average velocity are experimentally analyzed. The results demonstrate the controller's effectiveness in achieving stable hops and provide a method for tuning hop speeds. This research also paves the way for future projects by thoroughly documenting the leg's physical parameters and addressing the challenge of implementing reliable impact and lift-off detection during experimental testing.

<p dir="ltr">Domestic refrigerator/freezers account for 6% of all energy consumption around the globe and mainly rely on vapor compression cycles to operate. Researchers have investigated advanced cycle architectures, such as dual-loop cycles and ejector-enhanced cycles to improve their efficiencies. However, the energy saving potential of these advanced cycles often do not justify the additional costs. To further improve efficiency and reduce energy consumption, this work presents and assesses a two-stage vapor-injected cycle for domestic refrigerator/freezer applications. The proposed cycle directs the refrigerant exiting the medium temperature evaporator directly into the injection port of a vapor-injection compressor. The cycle establishes two separate evaporation temperatures to better match the cabinet temperatures of fresh food and freezer compartments. The reduced difference between each cabinet temperature and its evaporation temperature can reduce heat transfer irreversibilities and improve overall system efficiency. A bypass circuit cycle triple-evaporator domestic refrigerator freezer was used as the baseline cycle to investigate the performance improvement of the proposed cycle. A previously validated dynamic model of the baseline cycle was modified to consider a two-stage vapor-injected cycle. The simulation predicted a 12.9% energy consumption reduction with the proposed cycle when utilizing the baseline compressor efficiency for the vapor-injected compressor.</p><p dir="ltr">To evaluate additional performance improvements, a detailed mechanistic compressor model of the baseline variable-speed compressor was developed and validated with experimental data. Next, a vapor-injection line was added to the compressor model as an additional flow path to the compression chamber. The injection line is modeled as a tube connected to an opening on the cylinder wall, which is uncovered during the compression stroke. The injection tube is controlled by a fast-acting solenoid valve to separate injection and suction flow for the compressor. Parametric studies were carried out to assess the effects of injection timing and injection port diameter on power consumption and overall isentropic efficiency with respect to the baseline compressor. It was found that vapor injection in the reciprocating compressor can reduce the specific work required by more than 10%. Based on parametric studies, opening time of the fast-acting solenoid valve directly impacts the compressor efficiency and mass flow rate. There exists an optimal cylinder pressure associated with the opening of the solenoid valve that leads to maximum compressor efficiency.</p><p dir="ltr">The mechanistic compressor model was integrated into the two-stage system model using a reduced-order model to obtain more realistic and higher fidelity results. The reduced-order model considers the injection thermodynamic state and timing as well as evaporating and condensing temperatures from the system operation. Further, a control scheme based on the two-stage vapor-injected cycle’s available control variables was developed. The vapor-injected reciprocating compressor’s injection timing was varied in a parametric study to study its effect on two-stage system’s performance. As a results, 29.7% energy consumption reduction compared to the baseline cycle was achieved at injection timing of 4.95 radians.</p><p><br></p><p dir="ltr">To confirm the design and realistic performance of the designed vapor-injected reciprocating compressor, a prototype was designed and tested. A fast-acting solenoid and in-line check valve are connected and mounted directly on the cylinder wall to reduce dead volume during compression. The solenoid valve is controlled using the crank angle measurement from a Hall-effect sensor detecting a series of specifically placed magnets on the crankshaft. The prototype compressor was tested using a hot-gas-bypass compressor test stand under different suction, discharge and injection pressures. The experimental results show the prototype compressor’s specific work was reduced by up to 25% during vapor-injected operation compared to its single-stage operation with no injection. The results also showed the specific work reduction increased with an increase of injection pressure when condensing and suction pressures were fixed. The experiments also confirmed the compressor is able to separate the suction and injection flow, confirming it’s ability to be used in the two-stage cycle.</p>

Os padrões espaciais das alterações da cobertura da terra podem ser analisados a partir de modelagens da sua dinâmica espacial. Essas modelagens são capazes de descrever possíveis fatores responsáveis pelas mudanças territoriais, bem como viabilizar a estimativa de impactos futuros sobre o ambiente simulado. Considerando as pressões do setor de infraestrutura portuária sobre as configurações da forma de uso e planejamento do espaço na região portuária da Baixada Santista, tais como o aporte por áreas de retroporto, o armazenamento e o transporte de cargas, este estudo buscou desenvolver modelos dinâmicos da paisagem e investigar a relação entre as alterações na cobertura da terra e a infraestrutura de transportes na região portuária da Baixada Santista. A partir de produtos de sensoriamento remoto e da metodologia de modelagem dinâmica espacial baseada em autômatos celulares, foram gerados mapas simulados e cenários de prognósticos, com e sem projetos de expansão portuária para o ano de 2024. Os mapas simulados do ano de 1995 e 2005 foram semelhantes aos mapeamentos temáticos de cobertura da terra reais e apresentaram boa avaliação. Importante ressaltar que, apenas o mapa simulado de 2013 não previu as novas instalações portuárias, mesmo com a simulação rodando com a variável de novos empreendimentos operacionais em curto intervalo de tempo. O modelo estacionário em 2024 mostrou a expansão de áreas construídas em substituição, sobretudo, às áreas de campo. Não houve expansão de novas manchas de áreas construídas e isso condiz com a tendência de expansão de áreas urbanas seguindo as áreas já consolidadas e com infraestrutura implantada. Com relação à geração de modelos com os projetos de expansão portuária, tem-se a implantação de diversos empreendimentos ocupando parte da margem esquerda do estuário e áreas de retroporto próximas do arco viário da Baixada Santista. / Spatial patterns of change in land cover can be analyzed with spatial dynamic models. This modeling can indicate the driving factors of territorial changes as well as assess future impacts over the simulated environment. Considering the pressures of the port infrastructure sector over the land use and physical planning in the region of Baixada Santista, such as the demand for backport areas as well as for loads storage and transport, this study aims to develop dynamic models of the landscape and investigate the relationship between land cover change and the transport infrastructure in the port area of Santos. With the aid of remote sensing products and cellular automata based models, simulated maps of past landscapes and maps of future landscape scenarios were generated, both considering and disregarding port expansion projects for the year 2024.The simulated landscape maps of 1995 and 2005 were similar to the real ones, and hence, presented high fitness indices. It is important to mention that only the simulated map of 2013, could not foresee the new port facilities, even when the runs took into account the variables associated with the new operational ventures in a short period of time. The stationary model showed an expansion of built-up areas, mainly replacing former field areas. There was no occurrence of new patches of built-up areas and this trend is consistent with the expansion of urban areas nearby the already consolidated and established areas disposing of infrastructure facilities. Regarding the generation of future simulated scenarios taking into account the port expansion projects, they could well reproduce the implementation of several projects along part of the left bank of the estuary and nearby areas of the road ring of Baixada Santista.

De nos jours, les exigences en productivité dans le monde industriel imposent aux robots un comportement optimal en termes de précision géométrique et dynamique, et en termes de temps de réponse. Ainsi, la présence des flexibilités dans les liaisons pivots des structures mécaniques légères se déplaçant à grande vitesse et sous charges importantes peut limiter dynamiquement la précision et le temps de stabilisation sur la pose finale du robot. La problématique traitée dans ces travaux concerne la maîtrise des vibrations des robots sériels à liaisons flexibles durant les opérations de prise et dépose (Pick and Place).Dans ces travaux, nous effectuons une modélisation et une identification expérimentale des paramètres géométriques et dynamique d’un robot à liaisons flexible. Ce modèle sera utilisé dans la synthèse d’une loi de commande basée modèle dédiée aux robots à flexibilité articulaire. Cette stratégie permet de réduire les vibrations lors des phases exigeantes dynamiquement. Des simulations sur un robot Scara sont alors conduites pour valider la pertinence de cette loi de commande qui intègre un modèle des flexibilités présentes dans les liaisons pivots dans le schéma de commande. Nous appliquons sur le même simulateur du robot à liaisons flexibles trois autres stratégies de commande afin de faire une comparaison (commande PD, commande dédiée aux robots rigides et commande ne considérant pas les amortissements). Le schéma de la loi de commande basée modèle permet de respecter la précision de pose finale avec une diminution du temps de stabilisation. Finalement, Le calcul de l’erreur d’asservissement nous a permis de constater l’influence des erreurs de modélisation de la flexibilité sur la précision de la tâche. Dans ce contexte, une analyse de sensibilité aux paramètres influents est établie. / Nowadays, the demand of productivity in the industrial world of robotics require robots to behave optimally in terms of geometric and dynamic accuracy and response time. Thus, the presence of flexibilities in rotational joints can dynamically limit the position control of manipulators having lighter arms, higher payload-to-weight ratio and doing tasks at high speed. The problem addressed in this work concerns the vibration control of serial robots with flexible joints performing Pick and Place tasks. In this work, we carry out modelling and experimental identification of the geometric and dynamic parameters of a robot with flexible joints. This model is then used in the synthesis of a model-based control law dedicated to manipulators with flexible joints. This strategy reduces vibrations resulting from joints sensitivity during dynamically demanding phases. Simulations on a Scara robot are then conducted to validate the relevance of the proposed control law which integrates joint flexibilities in the form of a feedback loop in the control diagram. To this end, three other control strategies (PD control, control dedicated to rigid structures and control not considering damping) are applied to the same simulator in order to make a comparative analysis. The diagram of the model-based control law allows to respect the set point with a reduction in the stabilization time.Finally, the calculation of the servo error allowed us to see the influence of flexibility modeling errors on the accuracy of the task. In this context, the sensitivity of this control law is evaluated through a sensitivity analysis.

Ces travaux de thèse ont été réalisés grâce à une collaboration entre Safran Helicopter Engines (anciennement Turbomeca) et le Laboratoire de Mécanique des Contacts et des Structures (LaMCoS) de l’INSA de Lyon (UMR CNRS 5259). Les boîtes de transmission par engrenages des moteurs d’hélicoptères convoient la puissance mécanique du turbomoteur aux accessoires (pompes, démarreur) et au rotor. Leur conception dépend des nécessités des équipements embarqués, en particulier l’allègement pour réduire la consommation en carburant. Les engrenages haute vitesse de la transmission sont allégés grâce à des enlèvements de matière dans les corps sous la denture, les voiles-minces. Un modèle dynamique d’engrenages a été développé pendant ce projet de recherche. Son approche modulaire permet l’inclusion conjointe des sollicitations dues aux vibrations de l’engrenage et de la nouvelle flexibilité des voiles-minces. Il dérive d’un modèle à paramètres concentrés, comprenant des arbres en poutre, des paliers et carters sous forme de raideurs additionnelles et un élément d’engrenage rigide inclus par son nœud central. Hypothèse est faite que tous les contacts sont situés sur les lignes de contact du plan d’action. Ces lignes sont discrétisées selon des tranches-minces dans les dents et la déviation normale des cellules est recalculée à chaque pas de temps selon la déflexion de la denture. Le nouveau modèle remplace l’engrenage rigide par une modélisation EF du pignon et/ou de la roue condensée sur les nœuds de jante. Une interface lie les raideurs du plan d’action discrétisé aux éléments finis du corps d’engrenage. L’élément prend donc en compte à la fois les sollicitations de l’engrenage et le comportement statique et modal des corps flexibles en dynamique. Des comparaisons sont faites avec des données numériques et expérimentales. Elles attestent de la capacité du nouveau modèle à prédire le comportement dynamique des engrenages flexibles à hauts régimes de rotation. Ces résultats intègrent entre autres des données locales et globales en dynamique. Finalement, le modèle est utilisé sur les deux cas académiques validés pour visualiser les effets des corps flexibles plus en détails. Un premier focus sera fait sur la déflexion statique due aux charges d’engrènement et sur l’optimisation sur le fonctionnement dynamique possible. Puis, les impacts des sollicitations de l’engrènement sur le voile en rotation seront étudiés. Enfin, le pignon et la roue seront affinés, afin de visualiser l’optimisation massique possible et son impact sur la dynamique de l’engrenage. / The research work presented in this manuscript was conducted in the Contact and Structural Mechanics Laboratory (LaMCoS) at INSA Lyon, in partnership with Safran Helicopter Engines (formerly-Turbomeca). In helicopters, the power from the turboshaft is transmitted to the rotor and the various accessories (pumps, starters etc…) via transmission gearboxes. In the context of high-speed, light-weight aeronautical applications, mechanical parts such as gears have to meet somehow contradictory design requirements in terms of reliability and mass reduction thus justifying precise dynamic simulations. The present work focuses on the definition of modular gear dynamic models, capable of integrating both the local phenomena associated with the instant contact conditions between the tooth flanks and the more global aspects related to shafts, bearings and particularly the contributions of light thin-rimmed /-webbed gear bodies. The proposed models rely on combinations of condensed sub-structures, lumped parameter and beam elements to simulate a pinion-gear pair, shafts, bearings and housing. Mesh elasticity is time-varying, possibly non-linear and is accounted for by Winkler foundations derived from a classic thin-slice model. The contact lines in the base plane are therefore discretised into elemental segments which are all attributed a mesh stiffness function and a normal deviation which are updated depending on the pinion and gear angular positions. The main originality in this PhD consists in inserting condensed finite elements models to simulate flexible gear bodies while keeping the simple and faster rigid-body approach for solid gears. To this end, a specific interface has been developed to connect the discretised tooth contact lines to the continuous finite element gear body models and avoid numerical spikes in the tooth load distributions for example. A number of comparisons with numerical and experimental results show that the proposed modelling is sound and can capture most of the quasi-static and dynamic behaviour of single stage reduction units with thin-webbed gears and/or pinions. The model is then applied to the analysis of academic and industrial gears with the objective of analysing the contributions of thin, flexible bodies. Results are presented which highlight the role of centrifugal effects and tooth shape modifications at high speeds. Finally, the possibility to further improve gear web design with regard to mass reduction is investigated and commented upon.

"A well-known challenge in estimating the distance of the antenna pair in time-of-arrival (ToA) based RF localization systems is the problem of obstruction of the direct path (DP) between transmitter and receiver. The absence of DP component in received channel profile creates undetected direct path (UDP) conditions. UDP condition, in turn, will cause occurrence of unexpected large ranging errors which pose serious challenge to precise indoor localization. Analysis of the behavior of the ranging error in such conditions is essential for the design of precise ToA-based indoor localization systems. This dissertation discusses two open problems in ToA-based indoor localization systems. The first contribution of this dissertation discusses the problem of modeling of dynamic behavior of ranging error. We propose a novel analytical framework for analysis of dynamic spatial variations of ranging error observed by a mobile user based on an application of Markov chain. The model relegates the behavior of ranging error into four main categories associated with four states of Markov process. Parameters of distributions of ranging error in each Markov state are extracted from empirical data collected from a measurement-calibrated ray tracing algorithm simulating a typical office environment. The analytical derivation of parameters of the Markov model employs the existing path-loss models for first detected path and total multipath received power in the same office environment. Results of simulated errors from the Markov model and actual errors from empirical data show close agreement. The second contribution of this dissertation discusses the problem of identification of UDP condition given an unknown channel profile. Existing of UDP condition in a channel profile poses serious degradation to ranging estimate process. Therefore, identification of occurrence of UDP condition is of our subsequent concern. After identification, the second step is to mitigate ranging errors in such conditions. In this dissertation we present two methodologies, based on binary hypothesis testing and an application of artificial neural network design, to identify UDP conditions and mitigate ranging error using statistics extracted from wideband frequency-domain indoor measurements conducted in typical office building. "

This thesis documents the studies conducted in deriving a mathematical model representing the dynamics of a maneuvering ship to be implemented as part of an interactive real-time simulation system, as well as the details and results of the implementation process itself. Different effects on the dynamics of ship motions are discussed separately, meaning that the effects are considered to be applied to the system one at a time and they are included in the model simply by the principle of superposition. The model is intended to include the hydrodynamic interactions between the ship hull and the ocean via added mass (added inertia), damping and restoring force concepts. In addition to these effects, which are derived considering no incident waves are present on the ocean, the environmental disturbances, such as wind, wave and ocean current are also taken into account for proposing a mathematical model governing the dynamics of the ship. Since the ultimate product of this thesis work is a running computer code that can be integrated into an available simulation software, the algorithm development and code implementation processes are also covered. Improvements made on the implementation to achieve &ldquo / better&rdquo / real-time performance are evaluated comparatively in reference to original runs conducted before the application of improvement under consideration. A new method to the computation of the wave model that allows faster calculation in real-time is presented. A modular programming approach is followed in the overall algorithm development process in order to make the integration of new program components into the software, such as a new hull or propulsion model or a different integrator type possible, easily and quickly.