Made available in DSpace on 2016-12-12T17:38:37Z (GMT). No. of bitstreams: 1 Paulo Sergio Dainez - resumo.pdf: 31972 bytes, checksum: 94a24928564b90b196513e814cfe09a3 (MD5) Previous issue date: 2010-06-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the resonant linear compressor the piston is drive by a linear actuator and a resonant mechanical spring directly in the reciprocating motion, this is a mass spring resonant system, eliminating bearing and crank of the conventional reciprocating compressors, and the friction loss has a significant reduction. The maximum displacement of the piston is regulating by the equilibration between the power supply by the actuator and the power transfer to the gas compression process. This type of the compressor is design to work at the resonant frequency of the mass spring system, in this condition the efficiency is maximum. Then the control must drive the linear actuator in the maximum displacement of the piston and adjust the drive frequency at the system resonant frequency. For enable of this process is necessary that piston position is known with precision, however the installation of a sensor have same difficulty, since the refrigeration compressor is hermetic system, and it have high pressure and temperature, with wide range of variation. This work develop the implementation of a full order linear observer to estimate the displacement and the velocity of the piston of the resonant linear compressor, and a control system able to drive the compressor in the maximum piston displacement and in the resonant frequency, and only measured a current of the linear actuator, without sensor inside de compressor. For this a nonlinear model of the compressor and a linear model with variable coefficients for the observer are develop, also a simulator of the system is develop, where the compressor model is controlled by the displacement and the velocity signals calculate by observer, demonstrated the feasibility of the proposed technique in the present work. / Nos compressores lineares ressonantes o pistão é acionado por um atuador linear e molas diretamente no sentido do seu movimento alternativo, formando um sistema massa-mola ressonante, eliminando assim os mancais mecânicos e o sistema biela e manivela dos compressores convencionais, reduzindo de forma significativa as perdas por atrito. A amplitude do deslocamento do pistão é regulada pelo equilíbrio da potência fornecida pelo atuador e a potência transferida para o processo de compressão do gás. Estes compressores são projetados para funcionar na frequência de ressonância do sistema massa-mola, nesta condição a eficiência do sistema é máxima. Assim, o controle deve acionar o atuador linear na máxima amplitude de deslocamento do pistão e ajustar a frequência de acionamento na frequência de ressonância do sistema. Para viabilizar este processo é necessário que o curso do pistão seja conhecido com precisão, porém a instalação de um sensor apresenta dificuldades, pois os compressores de refrigeração são herméticos e estão sujeitos a pressões e temperaturas elevadas e com grande faixa de variação. Este trabalho propõe a implementação de um observador de estados de ordem plena, para estimar o deslocamento e a velocidade do pistão do compressor linear ressonante, e um sistema de controle capaz de acionar o compressor no deslocamento máximo e na frequência de ressonância, medindo somente a corrente no atuador linear, sem a necessidade de sensores instalados dentro do compressor. Para isto desenvolve-se um modelo não linear do compressor e um modelo linear equivalente de coeficientes variáveis para o projeto do observador, também é desenvolvido um simulador do sistema, onde o modelo do compressor é controlado pelos sinais de deslocamento e velocidade calculados pelo observador, demonstrando a viabilidade da técnica proposta no presente trabalho.

Made available in DSpace on 2014-12-17T14:55:21Z (GMT). No. of bitstreams: 1 MarceloRBGV_TESE.pdf: 4018928 bytes, checksum: 7940c018115fd94c74a5dbbd7d3f7fb6 (MD5) Previous issue date: 2014-06-27 / The industries are getting more and more rigorous, when security is in question, no matter is to avoid financial damages due to accidents and low productivity, or when it s related to the environment protection. It was thinking about great world accidents around the world involving aircrafts and industrial process (nuclear, petrochemical and so on) that we decided to invest in systems that could detect fault and diagnosis (FDD) them. The FDD systems can avoid eventual fault helping man on the maintenance and exchange of defective equipments. Nowadays, the issues that involve detection, isolation, diagnose and the controlling of tolerance fault are gathering strength in the academic and industrial environment. It is based on this fact, in this work, we discuss the importance of techniques that can assist in the development of systems for Fault Detection and Diagnosis (FDD) and propose a hybrid method for FDD in dynamic systems. We present a brief history to contextualize the techniques used in working environments. The detection of fault in the proposed system is based on state observers in conjunction with other statistical techniques. The principal idea is to use the observer himself, in addition to serving as an analytical redundancy, in allowing the creation of a residue. This residue is used in FDD. A signature database assists in the identification of system faults, which based on the signatures derived from trend analysis of the residue signal and its difference, performs the classification of the faults based purely on a decision tree. This FDD system is tested and validated in two plants: a simulated plant with coupled tanks and didactic plant with industrial instrumentation. All collected results of those tests will be discussed / As ind?strias est?o cada vez mais rigorosas quando o assunto ? seguran?a, tanto para evitar preju?zos financeiros com acidentes e baixa produtividade, quanto para preservar o meio ambiente. Diante dos grandes acidentes em todo o mundo envolvendo aeronaves e processos industriais (nucleares, petroqu?micos etc) procurou-se investir em sistemas que pudessem detectar e diagnosticar falhas (FDD-Fault Detection and Diagnosis). Os sistemas FDD podem evitar eventuais falhas auxiliando o homem na manuten??o e troca de equipamentos defeituosos. Nos dias de hoje os assuntos que envolvem detec??o, isolamento, identifica??o e diagn?stico de falhas est?o ganhando for?a no meio acad?mico e industrial. Diante deste impulso, neste trabalho ser? discutido a import?ncia do estudo de t?cnicas que possam auxiliar o desenvolvimento de sistemas de detec??o e diagn?stico de falhas e proposto um m?todo h?brido para a detec??o e diagn?stico de falhas em sistemas din?micos. Um breve hist?rico ? apresentado de forma a contextualizar as t?cnicas utilizadas no trabalho. A detec??o de falhas pelo sistema proposto ? baseada em observadores de estado juntamente com outras t?cnicas estat?sticas. A ideia principal ? utilizar o pr?prio observador, para al?m de servir como redund?ncia anal?tica, permitir a cria??o de um res?duo que ser? utilizado na detec??o da falha e tamb?m no seu diagn?stico. Um banco de assinaturas auxiliar? o sistema de identifica??o de falhas, que, baseado nas assinaturas oriundas das an?lises de tend?ncia do sinal do res?duo e sua derivada, ir? realizar a classifica??o das falhas baseada em uma ?rvore de decis?o. Este sistema FDD ser? submetido a alguns testes e valida??es em duas plantas: uma planta simulada de tanques acoplados e em uma planta did?tica com instrumenta??o industrial. Os resultados colhidos desses ensaios se mostraram satisfat?rios para um grupo de falhas testadas e ser?o discutidos no decorrer do trabalho

Essa dissertação apresenta um estudo analítico sobre a obra do arquiteto Louis I. Kahn, desde o ponto de vista da sua qualidade espacial, compreendida esta no modo como ocorre a interação entre espaço e usuário. Foram selecionados três edifícios como estudos de caso capazes de representar a síntese evolutiva da concepção de espaço ao longo da obra de Kahn, os quais foram submetidos a uma análise empírica baseada na experiência espacial do observador em movimento, lançando mão de um conjunto de ferramentas no assim denominado método do observador. Os edifícios estudados viabilizam o desenvolvimento de análises que abrangem desde as primeiras obras de Kahn, na década de 1930, até o seu falecimento, em 1974. A análise realizada registra o desempenho dos edifícios em termos de sua legibilidade e funcionalidade, compreendidas como qualidades inerentes ao espaço e ao modo como este condiciona a experiência do usuário, relacionandoas à concepção espacial do edifício. Procura-se ampliar a compreensão dos resultados obtidos à luz da evolução da obra teórica do autor, traçando relações de causa e efeito entre esta e os fenômenos registrados na realidade concreta dos edifícios. O trabalho busca ainda ampliar a compreensão da relação da obra de Kahn com o contexto da produção arquitetônica de sua época, investigando as influências que recebe e as contribuições que oferece, especialmente no que tange à continuidade da arquitetura moderna. / The present dissertation is as an analytical study about the work of architect Louis I. Kahn, focusing on its spatial quality, as funded in the interaction between space and people in motion. Three buildings were selected as case studies in order to capture the evolutionary synthesis of space conception happened during Kahn’s career. Each building was submitted to an empirical scrutiny based upon the spatial experience of a moving observer, using a set of tools named as the “method of the observer”. The buildings investigated are put in relation with other Kahn’s buildings, so allowing the development of an analytical discourse embracing since his first works, in the 1930’s, until his death, in 1974. The analysis registers the performance of the buildings in terms of their legibility and their functionality, both understood as qualities inherent to space and the way they shape the user’s experience, so relating them to the building’s spatial conception. The dissertation intends to enlarge the understanding of the findings by considering the evolution of Kahn’s theoretical work, so bringing cause-effect connections between theory and the registered phenomena in the concrete reality of buildings. Eventually, this study aims to enlarge the understanding of the link between Kahn’s work and the architectural environment of the time, so exploring the influences he received and contributions he gave, especially concerning the evolution of modern architecture.

Autotélico traz uma reflexão acerca das estruturas que constituem a linguagem poética com a qual trabalho. No decorrer dos anos percebi que as obras vêm se organizando através de regras próprias, relações estabelecidas no processo poético entre os conceitos de objeto, mitologia, construções narrativas cinemáticas e um espaço polissêmico manipulado pelo observador. Elementos heteróclitos que tendem a se interconectar e constituir um todo auto-organizado, através da regulação de um sistema unificador e coordenador dos elementos. Através da análise e reflexão sobre as principais obras em minha trajetória, permeada por questões teóricas e contrapontos com outras áreas, desenvolvo um pensamento sobre a obra como forma de instauração de realidades e apresento a idéia de uma estrutura poética como um processo contínuo de reconstrução, um sistema aberto em mutação, que tende a criar o ambiente material e teórico para novas reconfigurações ampliadas. Essa dissertação age, então, como uma ferramenta de mapeamento dos métodos de criação de sistemas para a instauração da obra artística, onde cada obra se apresenta una e múltipla, sinédoque de suas possibilidades, criando universos poéticos que se bifurcam e se transformam. / Autotélico (Autotelic) presents a reflection about the structures of the poetic language in the author‟s work. Over the years the artworks have been organizing themselves through relationships established during poetic process between object concepts, mythology, cinematic narrative constructions and a polysemic space manipulated by the observer. Eccentric elements tend to interconnect to create an organized whole through an adjuster system in itself. The most important works in the author‟s portfolio were analyzed with the related theory and other areas‟ counterpoints. The ideas of artworks as a reality establisher and a poetic structure as a continuous process of rebuild and mutation are developed. This dissertation brings a kind of mapping tool of the conception methods where each work is unique and multiple creating poetic universes that are in touch and in transformation.

Avgasmängden som bensindrivna fordon tillåts släppa ut minskas hela tiden. Ett sätt att möta framtida krav, är att förbättra katalysatorns effektivitet. För att göra detta kan luft-bränsle-förhållandet regleras med avseende på syrelagringen i katalysatorn, istället för som idag, reglera mot stökiometriskt blandningsförhållande. Eftersom syrelagringen inte går att mäta med en givare behövs en modell som beskriver katalysatorns dynamiska egenskaper. Tre sådana modeller har undersökts, utvärderats och jämförts. Två av modellerna har implementerats i Matlab/Simulink och anpassats till mätningar från en experimentuppställning. För att kunna observera syrelagringen online valdes slutligen en av modellerna ut, och implementerades i ett Extended Kalman filter. Ytterligare arbete behöver läggas ner på den mest lovande modellen, och detsamma gäller för Kalmanfiltret, men på sikt förväntas resultaten kunna bli bra. / The legal amount of emissions that vehicles with spark ignited engines are allowed to produce are steadily reduced over time. To meet future emission requirements it is desirable to make the catalytic converter work in a more efficient way. One way to do this is to control the air-fuel-ratio according to the oxygen storage level in the converter, instead of, as is done today, always trying to keep it close to stoichiometric. The oxygen storage level cannot be measured by a sensor. Hence, a model describing the dynamic behaviors of the converter is needed to observe this level. Three such models have been examined, validated, and compared. Two of these models have been implemented in Matlab/Simulink and adapted to measurements from an experimental setup. Finally, one of the models was chosen to be incorporated in an extended Kalman filter (EKF), in order to make it possible to observe the oxygen storage level online. The model that shows best potential needs further work, and the EKF is working with flaws, but overall the results are promising.

Ce travail vise à étudier les modes de présence du sujet et les degrés de la subjectivité dans les discours de voyage concernant la ville d’Istanbul. Nous nous proposons d’aborder la question de la présence dans les discours de voyage en analysant trois types de discours (les récits de voyage, les carnets de voyage et les guides touristiques) à l’aide de la sémiotique de l’énonciation, la sémiotique de la présence et la sémiotique visuelle. Le corps en tant que sujet énonçant peut être étudié dans la perspective de l’énonciation et en tant que sujet percevant peut être analysé dans la ligne de la perception. En partant de cette double fonction du corps, nous nous proposons d’étudier les marques de la subjectivité dans les discours de voyage à travers le sujet énonçant et le sujet percevant. Dans ce travail, nous observerons les styles énonciatifs qui précisent la place du sujet énonciateur, les différents rôles et les modes de saisies de l’énonciateur en tant qu’observateur. En outre, nous nous interrogerons sur les formes de présence de la « ville », autrement dit, sur la participation de la sensorialité (sujet) à la construction figurative de l’espace (objet). À part les stratégies énonciatives, le rapport texte-image, la contribution des différentes techniques de représentation (photo, dessin, carte) à l’instauration du sens seront étudiées dans le cadre de ce travail. Ces analyses concernant l’énonciation, la perception, la figurativité et la structure polysémiotique nous permettront de définir les caractéristiques sémiotiques de ces genres de discours. / This work aims to study the modes of presence of the subject and the degree of subjectivity in the discourses of travel concerning the city of Istanbul. We propose to address the issue of the presence in the discourse of travel by analyzing three types of discourse (the travel texts, travel notebooks and tourist guides) with the help of semiotics of the enunciation, the semiotics of presence and visual semiotics. The body as a enunciating subject can be studied in the perspective of enunciation and as a perceiving subject can be analyzed in the line of perception. Based on this dual function of the body, we propose to study the marks of subjectivity in the discourses of travel through the enunciating subject and the perceiving subject. In this work, we will observe the enunciation styles which specify the place of the enunciating subject, the different roles and input modes of the enunciator as an observer. In addition, we will examine the forms of presence of the "city", in other words, the participation of the sensoriality (subject) to the representational construction of space (object). Aside from enunciation strategies, the text-image relation, the contribution of different techniques of representation (photography, drawing, map) to the establishment of meaning will be considered in this work. These analysis concerning the enunciation, the perception, the figurativity and polysemiotic structure allow us to define the characteristics of these types of discourse.

Autotélico traz uma reflexão acerca das estruturas que constituem a linguagem poética com a qual trabalho. No decorrer dos anos percebi que as obras vêm se organizando através de regras próprias, relações estabelecidas no processo poético entre os conceitos de objeto, mitologia, construções narrativas cinemáticas e um espaço polissêmico manipulado pelo observador. Elementos heteróclitos que tendem a se interconectar e constituir um todo auto-organizado, através da regulação de um sistema unificador e coordenador dos elementos. Através da análise e reflexão sobre as principais obras em minha trajetória, permeada por questões teóricas e contrapontos com outras áreas, desenvolvo um pensamento sobre a obra como forma de instauração de realidades e apresento a idéia de uma estrutura poética como um processo contínuo de reconstrução, um sistema aberto em mutação, que tende a criar o ambiente material e teórico para novas reconfigurações ampliadas. Essa dissertação age, então, como uma ferramenta de mapeamento dos métodos de criação de sistemas para a instauração da obra artística, onde cada obra se apresenta una e múltipla, sinédoque de suas possibilidades, criando universos poéticos que se bifurcam e se transformam. / Autotélico (Autotelic) presents a reflection about the structures of the poetic language in the author‟s work. Over the years the artworks have been organizing themselves through relationships established during poetic process between object concepts, mythology, cinematic narrative constructions and a polysemic space manipulated by the observer. Eccentric elements tend to interconnect to create an organized whole through an adjuster system in itself. The most important works in the author‟s portfolio were analyzed with the related theory and other areas‟ counterpoints. The ideas of artworks as a reality establisher and a poetic structure as a continuous process of rebuild and mutation are developed. This dissertation brings a kind of mapping tool of the conception methods where each work is unique and multiple creating poetic universes that are in touch and in transformation.

A crescente demanda por produtos poliméricos com propriedades cada vez mais estritas tem forçado o desenvolvimento de técnicas de monitoramento em linha cada vez mais precisas e robustas. Infelizmente, grande parte das principais propriedades poliméricas não são quantificáveis em linha a partir das metodologias analíticas atualmente disponíveis e, portanto, na prática, as propriedades finais dos látices poliméricos são obtidas através da caracterização off line de amostras discretas coletadas do processo, resultando em um tempo de análise longo e indesejado para qualquer algoritmo de controle em tempo real. Por outro lado, como as reações de polimerização são altamente exotérmicas é possível quantificar continuamente a taxa de calor gerado pela reação a partir das medidas de temperatura e do balanço de energia que, por sua vez, pode ser usada para obter importantes informações acerca do estado do processo. Entretanto, esta técnica requer a atualização contínua do coeficiente global de troca térmica ao longo da reação, uma vez que este parâmetro está sujeito a variações temporais significativas. Portanto, o presente trabalho tem por objetivo analisar a viabilidade da aplicação conjunta dos conceitos da calorimetria e dos observadores não-lineares para a estimação dos estados de um processo químico. Para isso, serão analisadas duas reações químicas distintas: a) uma reação de hidrólise de anidrido acético, b) uma reação copolimerização em emulsão. Os resultados obtidos mostraram que essa metodologia é extremamente dependente dos parâmetros de sintonia do observador de estado, inviabilizando o seu uso para o monitoramento em linha de um processo químico. Por outro lado, a aplicação direta do balanço de energia para estimação do calor gerado pela reação, mostrou-se uma forma alternativa simples e viável para a estimação em tempo real dos estados de uma reação de polimerização. / The increasing demand for the production of polymers with more tight properties has placed great emphasis on the development of accurate and robust online monitoring techniques of polymerization reactions. Unfortunately, most of the main characteristics are not measurable online from analytical methodologies currently available and, therefore, in practice, the final properties of polymer latexes are obtained through off line characterization of discrete samples collected from the process, resulting in measurement delay which is undesirable for real-time control. On the other hand, since most of the polymerization reactions are highly exothermic, it is possible to quantify continuously the heat release rate based on temperature measurements and energy balance equations that, in turn, can be used to infer valuable information about the state of process. However, this approach requires up-dating the value of the global heat exchange coefficient through reaction, once this parameter is subject to significant time variations. Therefore, this work aims to examine the feasibility of joint implementation of the concepts of reaction calorimetry and nonlinear state observers for estimation of the states of a chemical process. In order to do that, two distinct chemical reactions will be considered: a) a hydrolysis of acetic anhydride reaction, b) an emulsion copolymerization reaction. The results showed that this approach shows a strong dependence of the tuning parameters, preventing its use for online monitoring of a chemical process. On the other hand, applying the heat balance it is possible to infer continuously the heat release rate and the states of polymerization reactions.

Le développement des systèmes intelligents pour contrôler la stabilité du véhicule et éviter les accidents routier est au cœur de la recherche automobile. L'expansion de ces systèmes intelligents à l'application réelle exige une estimation précise de la dynamique du véhicule dans des environnements diverses (dévers et pente). Cette exigence implique principalement trois problèmes : ⅰ), extraire des informations non mesurées à partir des capteurs faible coût; ⅱ), rester robuste et précis face aux les perturbations incertaines causées par les erreurs de mesure ou de la méconnaissance de l'environnement; ⅲ), estimer l'état du véhicule et prévoir le risque d'accident en temps réel. L’originalité de cette thèse par rapport à l’existant, consiste dans le développement des nouveaux algorithmes, basés sur des nouveaux modèles du véhicule et des différentes techniques d'observation d'état, pour estimer des variables ou des paramètres incertains de la dynamique du véhicule en temps réel. La première étape de notre étude est le développement de nouveaux modèles pour mieux décrire le comportement du véhicule dans des différentes situations. Pour minimiser les erreurs de modèle, un système d'estimation composé de quatre observateurs est proposé pour estimer les forces verticales, longitudinales et latérales par pneu, ainsi que l'angle de dérive. Trois techniques d'observation non linéaires (EKF, UKF et PF) sont appliquées pour tenir compte des non-linéarités du modèle. Pour valider la performance de nos observateurs, nous avons implémenté en C++ des modules temps-réel qui, embarqué sur le véhicule, estiment la dynamique du véhicule pendant le mouvement. / Enhancing road safety by developing active safety system is the general purpose of this thesis. A challenging task in the development of active safety system is to get accurate information about immeasurable vehicle dynamics states. More specifically, we need to estimate the vertical load, the lateral frictional force and longitudinal frictional force at each wheel, and also the sideslip angle at center of gravity. These states are the key parameters that could optimize the control of vehicle's stability. The estimation of vertical load at each tire enables the evaluation of the risk of rollover. Estimation of tire lateral forces could help the control system reduce the lateral slip and prevent the situation like spinning and drift out. Tire longitudinal forces can also greatly influence the performance of vehicle. The sideslip angle is one of the most important parameter to control the lateral dynamics of vehicle. However, in the current market, very few safety systems are based on tire forces, due to the lack of cost-effective method to get these information. For all the above reasons, we would like to develop a perception system to monitor these vehicle dynamics states by using only low-cost sensor. In order to achieve this objective, we propose to develop novel observers to estimate unmeasured states. However, construction of an observer which could provide satisfactory performance at all condition is never simple. It requires : 1, accurate and efficient models; 2, a robust estimation algorithm; 3, considering the parameter variation and sensor errors. As motivated by these requirements, this dissertation is organized to present our contribution in three aspects : vehicle dynamics modelization, observer design and adaptive estimation. In the aspect of modeling, we propose several new models to describe vehicle dynamics. The existent models are obtained by simplifying the vehicle motion as a planar motion. In the proposed models, we described the vehicle motion as a 3D motion and considered the effects of road inclination. Then for the vertical dynamics, we propose to incorporate the suspension deflection to calculate the transfer of vertical load. For the lateral dynamics, we propose the model of transfer of lateral forces to describe the interaction between left wheel and right wheel. With this new model, the lateral force at each tire can be calculated without sideslip angle. Similarly, for longitudinal dynamics, we also propose the model of transfer of longitudinal forces to calculate the longitudinal force at each tire. In the aspect of observer design, we propose a novel observation system, which is consisted of four individual observers connected in a cascaded way. The four observers are developed for the estimation of vertical tire force, lateral tire force and longitudinal tire force and sideslip angle respectively. For the linear system, the Kalman filter is employed. While for the nonlinear system, the EKF, UKF and PF are applied to minimize the estimation errors. In the aspect of adaptive estimation, we propose the algorithms to improve sensor measurement and estimate vehicle parameters in order to stay robust in presence of parameter variation and sensor errors. Furthermore, we also propose to incorporate the digital map to enhance the estimation accuracy. The utilization of digital map could also enable the prediction of vehicle dynamics states and prevent the road accidents. Finally, we implement our algorithm in the experimental vehicle to realize real-time estimation. Experimental data has validated the proposed algorithm.

Le problème étudié dans cette thèse est la commande en boucle fermée d'un système SCR (Réduction Sélective Catalytique) par l'urée tel qu'utilisé dans les systèmes de dépollution des gaz d'échappement des moteurs diesel automobiles. Une première contribution du manuscrit est en un modèle détaillé de la SCR, soulignant de la nature distribuée (1D) du système considéré, et plusieurs réductions successives de ce modèle de simulation conduisant à un modèle plus simple, utilisable à des fins de synthèse de contrôleur. Une seconde contribution consiste à prendre en compte la sensibilité au NH3 du capteur de NOx utilisé pour la rétroaction lors du développement d'algorithmes de commande (observateur d'état, boucle de rétroaction, séquencement de gain, interprétation du signal capteur). L'observateur-contrôleur présenté possède plusieurs points d'équilibre dues à la sensibilité du capteur de sortie. On montre que seul le point d'intérêt pratique est asymptotiquement stable, les autres étant instables naturellement, rendus instables par une implémentation spécifique ou aisémentdétectés comme indésirables. Ces deux contributions ont été testées expérimentalement et validées. En résumé, la méthode de contrôle proposée dans cette thèse permet, à partir d'un moteur conforme aux exigences Euro 5 et avec une procédure de pré-conditionnement du catalyseur, de satisfaire la norme Euro 6. / The problem studied in this thesis is the closed-loop control of a urea-SCR (urea Selective Catalytic Reduction) as used in aftertreatment systems of diesel vehicles. A first contribution of the thesis is a detailed model for the SCR, highlighting the distributed (1D) nature of the considered system, and several successive reductions of this simulation model leading to a simpler one, better-suited for control design purposes. A second contribution consists in considering the sensitivity to NH3 of the NOx sensor used in a feedback loop, in the development of the control algorithms (state observer, feedback, gain scheduling, measurement interpretation). The ambiguity of the output measurement could be detrimental to the closed loop response, as it generates multiple equilibrium points (artefacts), besides the point of practical interest. A study of the closed-loop dynamics is performed in the vicinity of each point, which shows that the closed loop system naturally converges to the point of interest not to the artefacts. Both contributions have been tested and validated experimentally. In summary, the method proposed in this thesis might allow an engine equipped with Euro 5 hardware to satisfy Euro 6 standard using a preconditioning procedure of the catalyst.