Orientador: Alberto Luiz Serpa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-25T12:10:51Z (GMT). No. of bitstreams: 1 CanahuireCabello_RuthVanessa_D.pdf: 5994310 bytes, checksum: 0f754dbcbe2bce27101f33806ca7f190 (MD5) Previous issue date: 2014 / Resumo: A síntese de controle H-infinito de estruturas flexíveis pode levar à obtenção de controladores de alta ordem. Estes controladores podem apresentar dificuldades para a implementação prática acarretando atrasos de resposta no sistema. Para evitar esse problema, este trabalho apresenta duas sínteses de controladores H-infinito de ordem reduzida por realimentação de saída. Para este propósito, são formulados dois problemas de otimização para a obtenção de controladores de ordem reduzida considerando que as matrizes de estado do controlador estão na forma canônica controlável e canônica modal. As duas sínteses propostas estão baseadas na minimização da norma H-infinito garantindo a estabilidade do sistema em malha fechada. Outro problema considerado neste trabalho são os efeitos de saturação dos atuadores sobre o sistema controlado. A saturação, quando presente no sistema, pode levar a uma perda de desempenho e as vezes à instabilidade da planta. Para tratar o problema de saturação é proposto um problema de otimização baseado no projeto de compensadores anti-windup. A abordagem proposta usa a síntese do problema H-infinito para minimizar diretamente os efeitos do sinal de saturação sobre o sinal de desempenho. Finalmente, as formulações são verificadas no controle ativo de vibração sobre um modelo teórico e em uma bancada experimental com uma viga de alumínio engastada-livre. Os métodos mostraram ter bom desempenho garantindo a estabilidade do sistema em malha fechada. Os problemas de otimização são resolvidos usando algoritmos genéticos e alguns aspectos numéricos são discutidos / Abstract: The H-infinity controller synthesis for flexible structures leads to full-order controllers. This can represent difficulties for practical controller implementation arising delay in the system response. To avoid this difficulty, this work presents two reduced order H-infinity controllers synthesis based on output feedback. For this goal, it is formulated two optimization problem to obtain a reduced order controller in its state-space controllable canonical form and state-space modal canonical form. The two proposed synthesis are based on the minimization of the H-infinity norm ensuring the stability of the closed loop system. Another problem considered in this work is related to the effects of saturation of the actuators on the controlled system. The saturation in the system can lead to a performance loss and occasionally to the instability of the plant. An optimization problem based on anti-windup compensator design is proposed to treat this problem. The proposed approach uses the H-infinity controller synthesis to minimize directly the saturation effects on the performance signal. Finally, the formulations are verified in the active control of vibration of a theoretical model and a cantilever aluminium beam is used on an experimental bench. The methods proposed presented good performance in terms of the stability of the closed loop system. The optimization problems are solved using genetic algorithms and some numerical aspects are discussed / Doutorado / Mecanica dos Sólidos e Projeto Mecanico / Doutora em Engenharia Mecânica

Orientador: Alberto Luiz Serpa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica. / Made available in DSpace on 2018-08-20T02:31:41Z (GMT). No. of bitstreams: 1 Mourao_KellenTazianiFernandes_M.pdf: 2493356 bytes, checksum: 4d9ad466fb48ec6e3f81311c9fd467b1 (MD5) Previous issue date: 2012 / Resumo: Neste trabalho foi utilizado o controle H'infinito' para atenuar vibrações em estruturas mecânicas. São utilizadas desigualdades matriciais lineares para encontrar o controlador ótimo. Sensores e atuadores são incorporados ao projeto e para determinar o melhor local onde devem ser fixados na estrutura são utilizadas duas metodologias: uma pela menor norma H'infinito' de malha fechada e a outra pela maior norma H''infinito' de malha aberta. Para modelar a estrutura a ser controlada é usado o método de elementos finitos. Após determinadas as posições ótimas para alocar sensores e atuadores, foram projetados controladores H''infinito' com filtros de ponderação escolhidos via algoritmos genéticos. Para projetar o controlador H'infinito' utilizou-se o modelo reduzido da planta, desconsiderando os modos residuais. São escolhidos filtros de ponderação via algoritmos genéticos para determinar as faixas de frequência de interesse com o intuito de projetar um controlador menos conservador e evitar o fenômeno de spillover, e consequentemente, que a malha fechada se torne instável. Os exemplos de aplicação foram realizados sobre uma estrutura flexível do tipo viga. Os resultados mostraram que os controladores projetados, após o posicionamento ótimo de sensores e atuadores e escolhidas das funções de ponderação via algoritmos genéticos, minimizaram a amplitude de vibração da estrutura garantindo a estabilidade do sistema / Abstract: In this work it was used the H'infinite' control to atenuate vibrations in mechanical structures. Linear matrix inequalities are used to find the optimal controller. Sensors and actuators are incorporated into the project. To determine the best place to allocate them in the structure two methods are used: the first is based on the highest closed-loop H'infinite' norm and the second is based on the lowest open-loop H'infinite' norm. The structure to be controlled was modeled through the finite element method. After determining the optimal placement to allocate sensors and actuators, the loop was closed and H'infinite' controllers were designed with weighting filters that were chosen via genetic algorithms for both cases of positioning. To design the H'infinite' controller, a reduced model of the plant was used, disregarding the residual modes. Weighting filters are found through genetic algorithms to determine the frequency bands of interest in order to design a controller with less conservatism and avoiding the phenomenon of spillover, and consequently, unstable closed loop. The application examples were based in a flexible beam structure. The results showed that the designed controllers, after the optimal placement of sensors and actuators and choosing the best parameters for the weighting functions, minimized the amplitude of vibration of the structure, ensuring system stability / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

This paper presents the whole process of building up a high precision, high dynamical MEMS acceleration sensor. The first samples have achieved a resolution of better than 500 micro g and a bandwidth of more than 200 Hz. The sensor fabrication technology is shortly covered in the paper. A theoretical model is built from the physical principles of the complete sensor system, consisting of the MEMS sensor, the charge amplifier and the PWM driver for the sensor element. The mathematical modeling also covers problems during startup. A reduced order model of the entire system is used to design a robust control with the Mixed-Sensitivity H-infinity Approach. Since the system has an unstable pole, imposed by the electrostatic field and time delay, caused by A/D-D/A conversation delay and DSP computing time, limitations for the control design are given. The theoretical model might be inaccurate or lacks of completeness, because the parameters for the theoretical model building vary from sample to sample or might be not known. A new identification scheme for open or closed-loop operation is deployed to obtain directly from the samples the parameters of the mechanical system and the voltage dependent gains. The focus of this paper is the complete system development and identification process including practical tests in a DSP TI-TMS320C3000 environment.

Made available in DSpace on 2015-03-04T18:50:44Z (GMT). No. of bitstreams: 1 Introducao.pdf: 140805 bytes, checksum: fc7ea84f193f6d764fa24f41af40d07f (MD5) Previous issue date: 2007-03-09 / Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Este trabalho trata do problema de controle H-infinito de uma classe de sistemas lineares com saltos Markovianos (MJLS) a tempo contínuo, onde a cadeia de Markov toma valores em um conjunto infinito enumerável. Um bounded real lemma (que chamamos JBRL) é desenvolvido, estabelecendo que a factibilidade de um conjunto infinito de desigualdades matriciais lineares (LMIs) interconectadas é necessária e suficiente para que um dado sistema seja estocasticamente estável (SS) e atenda a um desempenho H-infinito prescrito. O problema H-infinito estudado consiste na atenuação do efeito que perturbações estocásticas de energia finita causam na saída de um sistema, no pior caso. Neste problema, conhecido na literatura como "disturbance attenuation" (DA), assumimos ainda que o controlador somente tem acesso ao processo de saltos e a uma saída do sistema. Os controladores de interesse devem garantir que tanto a estabilidade (SS) quanto um desempenho H-infinito sejam observados no sistema em malha fechada - donde as condições impostas pelo JBRL são determinantes para a existência de soluções. Um importante aspecto dessa nova abordagem é que ferramentas tão fundamentais quanto o Complemento de Schur ou o Lema da Projeção, p.ex., não podem mais ser usados para manipular os conjuntos de LMIs infinitamente acopladas - tal dificuldade é contornada pela introdução de versões estendidas desses resultados, no início do trabalho. Um dos principais resultados deste trabalho caracteriza a existência de soluções através de dois problemas LMI complementares, um dos quais torna possível o design computacional de controladores. Por fim, são apresentados algoritmos para a construção prática de controladores, ótimos ou sub-ótimos, dando origem a um conjunto de ferramentas que, especialmente no caso em que a cadeia de Markov é finita, podem ser implementadas computacionalmente de maneira imediata. Mesmo no caso finito, os resultados da tese são mais fortes do que aqueles atualmente encontrados na literatura.

La conception des systèmes d'entrainement de bande est étudiée depuis de nombreuses années. Ces systèmes sont très répandus dans l'industrie puisque le conditionnement sous forme de bobines simplifie le traitement de nombreux matériaux tels que le papier, le carton, les polymères, ... Ces systèmes regroupent un grand nombre de difficultés : ils sont de grande dimension, un fort couplage existe entre les grandeurs et de nombreux paramètres varient au cours du temps. La méthode d’optimisation classique consiste à considérer chaque partie du système sans tenir compte des autres. De plus, au sein d'un même sous-ensemble, l’optimisation est réalisée discipline par discipline. Une nouvelle approche est proposée et appliquée à la synthèse de la commande : il s’agit de considérer le système global en prenant en compte la robustesse paramétrique. Ensuite, le choix optimal du tracteur maître et de la technologie d'asservissement de la tension de bane associée sont étudiées. / The design of roll-to-roll systems is studied for several years. This kind of system is very common in industry because the wound roll packaging simplify the treatment of material such as paper, cardboard, polymers, metal ... The studied systems have a high number of difficulties: they are large scale systems, a high coupling between physical values exists and several parameters are time dependent. The classical optimisation method consists in considering separately each subsystem without taking into account interactions. Moreover, the classical optimisation is made for each scientific field. A new approach is developed and applied to controller synthesis: the controllers are synthesized considering the global system with parametric uncertainties. The optimal choice of the master roller position and the technology used to control web tension are then studied.

Este trabalho trata do problema de controle H-infinito de uma classe de sistemas lineares com saltos Markovianos (MJLS) a tempo contínuo, onde a cadeia de Markov toma valores em um conjunto infinito enumerável. Um bounded real lemma (que chamamos JBRL) é desenvolvido, estabelecendo que a factibilidade de um conjunto infinito de desigualdades matriciais lineares (LMIs) interconectadas é necessária e suficiente para que um dado sistema seja estocasticamente estável (SS) e atenda a um desempenho H-infinito prescrito. O problema H-infinito estudado consiste na atenuação do efeito que perturbações estocásticas de energia finita causam na saída de um sistema, no pior caso. Neste problema, conhecido na literatura como "disturbance attenuation" (DA), assumimos ainda que o controlador somente tem acesso ao processo de saltos e a uma saída do sistema. Os controladores de interesse devem garantir que tanto a estabilidade (SS) quanto um desempenho H-infinito sejam observados no sistema em malha fechada - donde as condições impostas pelo JBRL são determinantes para a existência de soluções. Um importante aspecto dessa nova abordagem é que ferramentas tão fundamentais quanto o Complemento de Schur ou o Lema da Projeção, p.ex., não podem mais ser usados para manipular os conjuntos de LMIs infinitamente acopladas - tal dificuldade é contornada pela introdução de versões estendidas desses resultados, no início do trabalho. Um dos principais resultados deste trabalho caracteriza a existência de soluções através de dois problemas LMI complementares, um dos quais torna possível o design computacional de controladores. Por fim, são apresentados algoritmos para a construção prática de controladores, ótimos ou sub-ótimos, dando origem a um conjunto de ferramentas que, especialmente no caso em que a cadeia de Markov é finita, podem ser implementadas computacionalmente de maneira imediata. Mesmo no caso finito, os resultados da tese são mais fortes do que aqueles atualmente encontrados na literatura.

Ce travail de thèse est consacré à l'extension de l'Inversion Dynamique non-linéaire (NDI-Nonlinear Dynamic Inversion) pour un ensemble plus grand de systèmes non-linéaires, tout en garantissant des conditions de stabilité suffisantes. La NDI a été étudiée dans le cas de diverses applications, y compris en aéronautique et en aérospatiale. Elle permet de calculer des lois de contrôle capables de linéariser et de découpler un modèle non-linéaire à tout point de fonctionnement de son enveloppe d'état. Cependant cette méthode est intrinsèquement non-robuste aux erreurs de modélisation et aux saturations en entrée. En outre, dans un contexte non-linéaire, l'obtention d'une garantie quantifiable du domaine de stabilité atteint reste à l'heure actuelle complexe. Contrairement aux approches classiques de la NDI, notre méthodologie peut être considérée comme un cadre de compensation non-linéaire généralisé qui permet d'intégrer les incertitudes et les saturations en entrée dans le processus de conception. En utilisant des stratégies de contrôle antiwindup, la loi de pilotage peut être calculée grâce à un simple processus en deux phases. Dans ce cadre de travail généralisé des transformations linéaires fractionnaires (LFT - Linear Fractional Transformations) de la boucle fermée non-linéaire peuvent être facilement déduites pour l'analyse de la stabilité robuste en utilisant des outils standards pour de systèmes linéaires. La méthode proposée est testée pour le pilotage d'un véhicule de rentrée atmosphérique de type aile delta lors de ses phases hypersonique, transsonique et subsonique. Pour cette thèse, un simulateur du vol incluant divers facteurs externes ainsi que des erreurs de modélisation a été développé dans Simulink. / This thesis work is devoted to extending Nonlinear Dynamic Inversion (NDI) for a large scale of nonlinear systems while guaranteeing sufficient stability conditions. NDI has been studied in a wide range of applications, including aeronautics and aerospace. It allows to compute nonlinear control laws able to decouple and linearize a model at any operating point of its state envelope. However, this method is inherently non-robust to modelling errors and input saturations. Moreover, obtaining a quantifiable guarantee of the attained stability domain in a nonlinear control context is not a very straightforward task. Unlike standard NDI approaches, our methodology can be viewed as a generalized nonlinear compensation framework which allows to incorporate uncertainties and input saturations in the design process. Paralleling anti-windup strategies, the controller can be computed through a single multichannel optimization problem or through a simple two-step process. Within this framework, linear fractional transformations of the nonlinear closed-loop can be easily derived for robust stability analysis using standard tools for linear systems. The proposed method is tested for the flight control of a delta wing type reentry vehicle at hypersonic, transonic and subsonic phases of the atmospheric reentry. For this thesis work, a Flight Mechanics simulator including diverse external factors and modelling errors was developed in Simulink.

<div>Stoichiometric air-fuel ratio (AFR) and air/EGR flow control are essential control problems in today’s advanced spark-ignited (SI) engines to enable effective application of the three-way-catalyst (TWC) and generation of required torque. External exhaust gas recirculation (EGR) can be used in SI engines to help mitigate knock, reduce enrichment and improve efficiency[1 ]. However, the introduction of the EGR system increases the complexity of stoichiometric engine-out lambda and torque management, particularly for high BMEP commercial vehicle applications. This thesis develops advanced frameworks for sensing and control architecture designs to enable robust air handling system management, stoichiometric cylinder air-fuel ratio (AFR) control and three-way-catalyst emission control.</div><div><br></div><div><div>The first work in this thesis derives a physically-based, control-oriented model for turbocharged SI engines utilizing cooled EGR and flexible VVA systems. The model includes the impacts of modulation to any combination of 11 actuators, including the throttle valve, bypass valve, fuel injection rate, waste-gate, high-pressure (HP) EGR, low-pressure (LP) EGR, number of firing cylinders, intake and exhaust valve opening and closing timings. A new cylinder-out gas composition estimation method, based on the inputs’ information of cylinder charge flow, injected fuel amount, residual gas mass and intake gas compositions, is proposed in this model. This method can be implemented in the control-oriented model as a critical input for estimating the exhaust manifold gas compositions. A new flow-based turbine-out pressure modeling strategy is also proposed in this thesis as a necessary input to estimate the LP EGR flow rate. Incorporated with these two sub-models, the control-oriented model is capable to capture the dynamics of pressure, temperature and gas compositions in manifolds and the cylinder. Thirteen physical parameters, including intake, boost and exhaust manifolds’ pressures, temperatures, unburnt and burnt mass fractions as well as the turbocharger speed, are defined as state variables. The outputs such as flow rates and AFR are modeled as functions of selected states and inputs. The control-oriented model is validated with a high fidelity SI engine GT-Power model for different operating conditions. The novelty in this physical modeling work includes the development and incorporation of the cylinder-out gas composition estimation method and the turbine-out pressure model in the control-oriented model.</div></div><div><br></div><div><div>The second part of the work outlines a novel sensor selection and observer design algorithm for linear time-invariant systems with both process and measurement noise based on <i>H</i>2 optimization to optimize the tradeoff between the observer error and the number of required sensors. The optimization problem is relaxed to a sequence of convex optimization problems that minimize the cost function consisting of the <i>H</i>2 norm of the observer error and the weighted <i>l</i>1 norm of the observer gain. An LMI formulation allows for efficient solution via semi-definite programing. The approach is applied here, for the first time, to a turbo-charged spark-ignited (SI) engine using exhaust gas recirculation to determine the optimal sensor sets for real-time intake manifold burnt gas mass fraction estimation. Simulation with the candidate estimator embedded in a high fidelity engine GT-Power model demonstrates that the optimal sensor sets selected using this algorithm have the best <i>H</i>2 estimation performance. Sensor redundancy is also analyzed based on the algorithm results. This algorithm is applicable for any type of modern internal combustion engines to reduce system design time and experimental efforts typically required for selecting optimal sensor sets.</div></div><div><br></div><div><div>The third study develops a model-based sensor selection and controller design framework for robust control of air-fuel-ratio (AFR), air flow and EGR flow for turbocharged stoichiometric engines using low pressure EGR, waste-gate turbo-charging, intake throttling and variable valve timing. Model uncertainties, disturbances, transport delays, sensor and actuator characteristics are considered in this framework. Based on the required control performance and candidate sensor sets, the framework synthesizes an H1 feedback controller and evaluates the viability of the candidate sensor set through analysis of the structured</div><div>singular value μ of the closed-loop system in the frequency domain. The framework can also be used to understand if relaxing the controller performance requirements enables the use of a simpler (less costly) sensor set. The sensor selection and controller co-design approach is applied here, for the first time, to turbo-charged engines using exhaust gas circulation. High fidelity GT-Power simulations are used to validate the approach. The novelty of the work in this part can be summarized as follows: (1) A novel control strategy is proposed for the stoichiometric SI engines using low pressure EGR to simultaneously satisfy both the AFR and air/EGR-path control performance requirements; (2) A parametrical method to simultaneously select the sensors and design the controller is first proposed for the internal combustion engines.</div></div><div><br></div><div><div>In the fourth part of the work, a novel two-loop estimation and control strategy is proposed to reduce the emission of the three-way-catalyst (TWC). In the outer loop, an FOS estimator consisting of a TWC model and an extended Kalman-filter is used to estimate the current TWC fractional oxygen state (FOS) and a robust controller is used to control the TWC FOS by manipulating the desired engine λ. The outer loop estimator and controller are combined with an existing inner loop controller. The inner loop controller controls the engine λ based on the desired λ value and the control inaccuracies are considered and compensated by the outer loop robust controller. This control strategy achieves good emission reduction performance and has advantages over the constant λ control strategy and the conventional two-loop switch-type control strategy.</div></div>