<p>This master’s thesis describes the development of a model of the catalystsystem aiming at control by an MPC. A well functioning model, which is suitable in control purpose, is important while emission legislation become more and more hard to fulfill for the car manufacturers. Much research has been done in the field of physical modeling of the system, but in this work a linear adaptive time discrete ARX-model is developed and validated.</p><p>The systems tendency to change its dynamic during usage implies that the model must be adaptive. The developed model proved to be well functioning and shows promising conditions for the MPC design. The system and the model are analyzed in the time- and frequency domains and the model is both implemented and validated in a Saab 9-5.</p><p>The work has been performed both at Saab Automobile Powertrain AB in Södertälje and in Vehicular Systems Dept. of Electrical Engineering at Linköpings University.</p>

Feedback control of Chest Acceleration or Chest Deflection is believed to be a good way of minimizing the risk of injury. In order to implement such a controller in a car, an observer estimating these responses is needed. The objective of the study was to develop a model of the dummy’s chest capable of estimating the Chest Acceleration and the Chest Deflection during frontal crashes in real time. The used sensor data come from car accelerometer and spindle rotation sensor of the belt, the data has been collected from dummies during crash tests. This study has accomplished the aims using a simple linear model of the chest using masses, springs and dampers. The parameters of the model have been estimated through system identification. Two types of black-box models have also been studied, one ARX model and one state-space model. The models have been tested and validated against data coming from different crash setups. The results show that all of the studied models can be used to estimate the dummy responses, the physical grey-box model and the black-box state-space model in particular. / Genom att använda återkoppling av storheterna bröstacceleration och bröstintryck antas man kunna minska risken för skador vid krockar i personbilar. För att kunna implementera detta behövs en observatör för dessa storheter. Målet med denna studie är att ta fram en modell för att kunna skatta accelerationen i bröstkorgen samt bröstintrycket i realtid i frontala krockar. Sensordata som använts kom från en accelerometer och en givare för att mäta rotationen i bältessnurran. Detta har gjorts genom att modellera bröstkorgen med linjära fjädrar och dämpare. Dess parametrar har skattats från data från krocktester från krockdockor. Två s.k. black-box-modeller har också tagits fram, en ARX-modell och en på tillståndsform. Modellerna har testats och validerats mha data från olika sorters krocktester. Resultaten visar att alla studerade modeller kan användas för att skatta de ovan nämnda storheterna, den fysikaliska modellen och black-box-modellen på tillståndsform fungerade bäst.

Αντικείμενο αυτής της διπλωματικής εργασίας ήταν ο έλεγχος ηλεκτροκινητήρων μέσω ηλεκτρονικού υπολογιστή. Προσεγγίσαμε το πρόβλημα με τρόπο που μπορεί να χρησιμοποιηθεί για οποιοδήποτε τύπο συστήματος αρχίζοντας από το μηδέν και πραγματοποιώντας συγκεκριμένα βήματα. Αρχικά ορίσαμε το πρόβλημά μας ορμώμενοι από πρακτικές εφαρμογές που έχουν ανάγκη την επίτευξη του συγκεκριμένου έλεγχου που αφορά τους DC ηλεκτροκινητήρες. Επιλέξαμε ένα σύστημα ηλεκτροκινητήρων το οποίο προσομοιώνει επαρκώς το πρόβλημά μας, δηλαδή τόσο τον υπό έλεγχο ηλεκτροκινητήρα όσο και την διάταξη προσομοίωσης συνθηκών φορτίου. Στη συνέχεια μελετήσαμε το θεωρητικό υπόβαθρο γύρω από τη λειτουργία των DC κινητήρων αναλύοντας τόσο τα δομικά τους στοιχεία όσο και τη συμπεριφορά τους. Κατόπιν, επικεντρωθήκαμε στην πειραματική διάταξη κάνοντας μια αναλυτική και εκτενή περιγραφή των παραμέτρων της, του τρόπου λειτουργίας των στοιχείων της και του επιτρεπτού τρόπου λειτουργίας. Σύμφωνα με αυτά επιλέξαμε κατάλληλη διάταξη επικοινωνίας με τον υπολογιστή συνοδευόμενη από λογισμικό που θα μας επιτρέψει τον προγραμματισμό του ελέγχου της διεργασίας. Η κάρτα που επιτελεί αυτή τη διεργασία επιλέχθηκε με βάση τον αριθμό και το είδος εισόδων / εξόδων, τον μέγιστο ρυθμό δειγματοληψίας και τα δυνατά όρια λειτουργίας DC τάσης. Ακολούθησε θεωρητική περιγραφή του συστήματος και μοντελοποίηση των παραμέτρων του στο πεδίο Laplace και πήραμε μια θεωρητική απόκριση βασισμένη στις τιμές των προδιαγραφών που ορίζει ο κατασκευαστής για να δούμε μια πρώτη εικόνα του τι είδους σύστημα θα αντιμετωπίσουμε. Στη συνέχεια αναλύσαμε τη θεωρία αναγνώρισης βασισμένη στο γραμμικό πολυωνυμικό μοντέλο, καθώς και την επιλογή του αλγορίθμου αναγνώρισης που θα χρησιμοποιήσουμε και ορίσαμε τη μορφή και τάξη του μοντέλου που περιγράφει το σύστημα επαρκώς σύμφωνα. Κατασκευάσαμε το πρόγραμμα που καταγράφει την απόκριση ανοικτού βρόχου του συστήματος και με διαδοχικές πειραματικές μετρήσεις αναλύσαμε γραφικά τη συμπεριφορά του συστήματος, κάναμε παραδοχές, απλοποιήσεις και ορίσαμε τα γραμμικά όρια λειτουργίας. Τα παραπάνω συνετέλεσαν στην ομαλή διεξαγωγή καταγραφής της απόκρισης της εξόδου σε τυχαία είσοδο ώστε ο αλγόριθμος ARX να υπολογίσει το βέλτιστο προσεγγιστικό μοντέλο το οποίο στη 94 συνέχεια απλοποιήσαμε σε τάξη και προσαρμόσαμε ώστε να έχει όσο το δυνατόν πιο όμοια συμπεριφορά με το πραγματικό σύστημα. Η γνώση της προσεγγιστικής συνάρτησης μεταφοράς του συστήματος μας βοήθησε στο να επιλέξουμε το είδος ελέγχου που θα επιβάλλουμε στο σύστημα. Υλοποιήσαμε λοιπόν τον PI ελεγκτή και αναλύσαμε τη συμπεριφορά του πειραματικά για ένα συγκεκριμένο χρόνο δειγματοληψίας που είναι συνήθης να χρησιμοποιείται. Αφού βρήκαμε τις καλύτερες δυνατές τιμές των παραμέτρων του καταφέραμε όσο το δυνατόν καλύτερα τον έλεγχο του συστήματος για δεδομένο ρυθμό δειγματοληψίας. Τέλος, εξαντλήσαμε τις δυνατότητες που προσφέρει ο υπολογιστής και παραθέσαμε τη βελτιωμένη λειτουργία του ελεγκτή με πολύ μεγαλύτερο ρυθμό δειγματοληψίας κατά την οποία ορίσαμε εκ νέου τις βέλτιστες τιμές των παραμέτρων του. Το αποτέλεσμα είναι εκπληκτική ακρίβεια και επιτυχία στην επιτέλεση της επιθυμητής διεργασίας (tracking) από το σύστημα. Σκέψεις για την περεταίρω συνέχιση της εργασίας είναι ο έλεγχος AC κινητήρων με παρόμοια μέθοδο καθώς και η επιβολή διαφορετικού τύπου ελέγχου στο συγκεκριμένο σύστημα (fuzzy control, robust control). Αυτό μπορεί να γίνει πολύ εύκολα εφόσον το σύστημα είναι πλήρως αναγνωρισμένο από τη συνολική διαδικασία του κεφαλαίου 3 απλά αντικαθιστώντας τον ελεγκτή PI από διαφορετικό μέσω στοιχειώδους προγραμματισμού στο Labview. Στην εργασία αυτή αναλύθηκε ένα είδος ελέγχου αντιπροσωπευτικά αφού το μεγαλύτερο βάρος ενός τέτοιου προβλήματος, πέραν της φυσικής περιγραφής του συστήματος, αφορά πρωτίστως την αναγνώρισή του και τον πλήρη ορισμό του ως μαθηματικό μοντέλο. / This project is about DC motor control throught PID control. The control unit is programmed on Labview 8.5 and thus implemented by a PC unit. This project also contains identification theory based on ARX algorithm.

MEMS (Micro-Electro-Mechanical Systems) é um microsistema invasivo, intermediador e interativo que se desenvolve de forma inteligente, versátil e eficiente. Entretanto, a interatividade, característica que o torna altamente atrativo e suas qualidades de leveza, invisibilidade, economia quanto a consumo de energia, robustez e alta confiabilidade são foco de investigação. Através da obtenção dos parâmetros característicos muitos desses aspectos podem ser otimizados. Conseqüentemente, este trabalho se propõe obter os parâmetros característicos necessários ao modelo matemático de atuadores MEMS, baseados em deformação elástica e dinâmica combdrive, de forma a descrever com precisão o comportamento linear destes em nível de sistema. Os parâmetros característicos de MEMS podem ser extraídos no próprio simulador, ou identificados através da manipulação dos dados dos sinais de entrada e saída obtidos na execução de testes modais sobre o protótipo. Quando a identificação é determinística, utiliza sinais de excitação que obedecem a uma boa relação sinal-ruído (SNR-Signal-Noise Rate). Quando a identificação é estocástica utiliza sinais de excitação misturados com ruído. Essas duas formas de identificação podem ser interpretadas como os dois extremos de identificação. A rigor, qualquer procedimento que não esteja em nenhum desses extremos pode ser denominado de identificação “caixa-cinza”. Dessa forma, a proposta deste trabalho investigativo consiste em utilizar a identificação “caixa cinza” para obter os parâmetros característicos dos atuadores eletromecânicos MEMS combinando as vantagens dos procedimentos determinísticos e estocásticos. Sob este propósito, foi feita revisão das propriedades da matéria, conceituação de atuadores, compreensão da visão bottom-up e, finalmente, estudo de modelos estocásticos com entradas exógenas ARX (Autoregressive with Exogenous Inputs) e uso de estimadores recursivos, Mínimos Quadrado e Variável Instrumental. A comparação dos resultados do modelo determinístico produzido através de FEM/BEM permite testar o desempenho entre dois modelos de índoles diferentes. Os resultados obtidos após a coleta de dados, a escolha da representação matemática, a determinação da estrutura do modelo, a estimação dos parâmetros e a validação do modelo das três tipologias de atuadores desenvolvidos: pontes simples, ponte dupla e dobradiça dupla permitem identificar os parâmetros característicos com erro quadrático médio menor a 1% e validar esses parâmetros num período não maior a 0,5s. Os resultados se mostram altamente satisfatórios, tornando este trabalho uma contribuição científica à síntese de MEMS em nível de sistemas. / MEMS (Micro Electro-Mechanical Systems) is an invasive, intermediator and interactive small size system that develops in an intelligent, versatile and efficient way. However, the interactivity, feature that makes the system highly attractive and its qualities of lightness, invisibility, economy with regard to power consumption, robustness and high reliability are the focus of research. By obtaining the characteristic parameters many of these aspects can be optimized. Therefore, this study proposes to obtain the characteristic parameters necessary for the mathematical model for MEMS actuators, based on elastic deformation and dynamic comb-drive in order to accurately describe the linear behavior in level system. The characteristic parameters of MEMS can be extracted in the own simulator or identified through the manipulation of input and output data signals obtained in the execution of modal tests on the prototype. When the identification is deterministic, it uses the excitation signals that follow a good signal noise rate (SNR). When the identification is stochastic it uses excitation signals mixed with noise. These two forms of identification can be interpreted as the two extremes of the identification. Strictly speaking, any procedure that is not in any of these extremes may be called the "gray-box" identification. Thus, the propose of this research work consists of using the “gray-box” identification to obtain the characteristic parameters of the MEMS electro-mechanical actuators combining the advantages of the deterministic and stochastic procedures. Under this purpose, it was made revision of the matter features, conceptualization of the actuators, comprehension of the bottom-up vision and, finally, study of the stochastic models with autoregressive exogenous inputs (ARX) and the use of recursive estimators, Least Square and Instrumental Variable. The comparison of results of the deterministic model generated by FEM / BEM, allows testing the performance between two models of different kinds. The results obtained after the data collection, the choice of mathematical representation, the determination of the structure of the model, the estimation of the parameters and validation of the model of three actuators topologies developed (simple bridges, double bridge and double hinge) that permit to identify the parameters with a average quadratic error minor than 1% and to validate these parameters in a period not more than 0.5s. The results show highly satisfactory, becoming this work a scientific contribution to MEMS synthesis at system levels.

MEMS (Micro-Electro-Mechanical Systems) é um microsistema invasivo, intermediador e interativo que se desenvolve de forma inteligente, versátil e eficiente. Entretanto, a interatividade, característica que o torna altamente atrativo e suas qualidades de leveza, invisibilidade, economia quanto a consumo de energia, robustez e alta confiabilidade são foco de investigação. Através da obtenção dos parâmetros característicos muitos desses aspectos podem ser otimizados. Conseqüentemente, este trabalho se propõe obter os parâmetros característicos necessários ao modelo matemático de atuadores MEMS, baseados em deformação elástica e dinâmica combdrive, de forma a descrever com precisão o comportamento linear destes em nível de sistema. Os parâmetros característicos de MEMS podem ser extraídos no próprio simulador, ou identificados através da manipulação dos dados dos sinais de entrada e saída obtidos na execução de testes modais sobre o protótipo. Quando a identificação é determinística, utiliza sinais de excitação que obedecem a uma boa relação sinal-ruído (SNR-Signal-Noise Rate). Quando a identificação é estocástica utiliza sinais de excitação misturados com ruído. Essas duas formas de identificação podem ser interpretadas como os dois extremos de identificação. A rigor, qualquer procedimento que não esteja em nenhum desses extremos pode ser denominado de identificação “caixa-cinza”. Dessa forma, a proposta deste trabalho investigativo consiste em utilizar a identificação “caixa cinza” para obter os parâmetros característicos dos atuadores eletromecânicos MEMS combinando as vantagens dos procedimentos determinísticos e estocásticos. Sob este propósito, foi feita revisão das propriedades da matéria, conceituação de atuadores, compreensão da visão bottom-up e, finalmente, estudo de modelos estocásticos com entradas exógenas ARX (Autoregressive with Exogenous Inputs) e uso de estimadores recursivos, Mínimos Quadrado e Variável Instrumental. A comparação dos resultados do modelo determinístico produzido através de FEM/BEM permite testar o desempenho entre dois modelos de índoles diferentes. Os resultados obtidos após a coleta de dados, a escolha da representação matemática, a determinação da estrutura do modelo, a estimação dos parâmetros e a validação do modelo das três tipologias de atuadores desenvolvidos: pontes simples, ponte dupla e dobradiça dupla permitem identificar os parâmetros característicos com erro quadrático médio menor a 1% e validar esses parâmetros num período não maior a 0,5s. Os resultados se mostram altamente satisfatórios, tornando este trabalho uma contribuição científica à síntese de MEMS em nível de sistemas. / MEMS (Micro Electro-Mechanical Systems) is an invasive, intermediator and interactive small size system that develops in an intelligent, versatile and efficient way. However, the interactivity, feature that makes the system highly attractive and its qualities of lightness, invisibility, economy with regard to power consumption, robustness and high reliability are the focus of research. By obtaining the characteristic parameters many of these aspects can be optimized. Therefore, this study proposes to obtain the characteristic parameters necessary for the mathematical model for MEMS actuators, based on elastic deformation and dynamic comb-drive in order to accurately describe the linear behavior in level system. The characteristic parameters of MEMS can be extracted in the own simulator or identified through the manipulation of input and output data signals obtained in the execution of modal tests on the prototype. When the identification is deterministic, it uses the excitation signals that follow a good signal noise rate (SNR). When the identification is stochastic it uses excitation signals mixed with noise. These two forms of identification can be interpreted as the two extremes of the identification. Strictly speaking, any procedure that is not in any of these extremes may be called the "gray-box" identification. Thus, the propose of this research work consists of using the “gray-box” identification to obtain the characteristic parameters of the MEMS electro-mechanical actuators combining the advantages of the deterministic and stochastic procedures. Under this purpose, it was made revision of the matter features, conceptualization of the actuators, comprehension of the bottom-up vision and, finally, study of the stochastic models with autoregressive exogenous inputs (ARX) and the use of recursive estimators, Least Square and Instrumental Variable. The comparison of results of the deterministic model generated by FEM / BEM, allows testing the performance between two models of different kinds. The results obtained after the data collection, the choice of mathematical representation, the determination of the structure of the model, the estimation of the parameters and validation of the model of three actuators topologies developed (simple bridges, double bridge and double hinge) that permit to identify the parameters with a average quadratic error minor than 1% and to validate these parameters in a period not more than 0.5s. The results show highly satisfactory, becoming this work a scientific contribution to MEMS synthesis at system levels.

MEMS (Micro-Electro-Mechanical Systems) é um microsistema invasivo, intermediador e interativo que se desenvolve de forma inteligente, versátil e eficiente. Entretanto, a interatividade, característica que o torna altamente atrativo e suas qualidades de leveza, invisibilidade, economia quanto a consumo de energia, robustez e alta confiabilidade são foco de investigação. Através da obtenção dos parâmetros característicos muitos desses aspectos podem ser otimizados. Conseqüentemente, este trabalho se propõe obter os parâmetros característicos necessários ao modelo matemático de atuadores MEMS, baseados em deformação elástica e dinâmica combdrive, de forma a descrever com precisão o comportamento linear destes em nível de sistema. Os parâmetros característicos de MEMS podem ser extraídos no próprio simulador, ou identificados através da manipulação dos dados dos sinais de entrada e saída obtidos na execução de testes modais sobre o protótipo. Quando a identificação é determinística, utiliza sinais de excitação que obedecem a uma boa relação sinal-ruído (SNR-Signal-Noise Rate). Quando a identificação é estocástica utiliza sinais de excitação misturados com ruído. Essas duas formas de identificação podem ser interpretadas como os dois extremos de identificação. A rigor, qualquer procedimento que não esteja em nenhum desses extremos pode ser denominado de identificação “caixa-cinza”. Dessa forma, a proposta deste trabalho investigativo consiste em utilizar a identificação “caixa cinza” para obter os parâmetros característicos dos atuadores eletromecânicos MEMS combinando as vantagens dos procedimentos determinísticos e estocásticos. Sob este propósito, foi feita revisão das propriedades da matéria, conceituação de atuadores, compreensão da visão bottom-up e, finalmente, estudo de modelos estocásticos com entradas exógenas ARX (Autoregressive with Exogenous Inputs) e uso de estimadores recursivos, Mínimos Quadrado e Variável Instrumental. A comparação dos resultados do modelo determinístico produzido através de FEM/BEM permite testar o desempenho entre dois modelos de índoles diferentes. Os resultados obtidos após a coleta de dados, a escolha da representação matemática, a determinação da estrutura do modelo, a estimação dos parâmetros e a validação do modelo das três tipologias de atuadores desenvolvidos: pontes simples, ponte dupla e dobradiça dupla permitem identificar os parâmetros característicos com erro quadrático médio menor a 1% e validar esses parâmetros num período não maior a 0,5s. Os resultados se mostram altamente satisfatórios, tornando este trabalho uma contribuição científica à síntese de MEMS em nível de sistemas. / MEMS (Micro Electro-Mechanical Systems) is an invasive, intermediator and interactive small size system that develops in an intelligent, versatile and efficient way. However, the interactivity, feature that makes the system highly attractive and its qualities of lightness, invisibility, economy with regard to power consumption, robustness and high reliability are the focus of research. By obtaining the characteristic parameters many of these aspects can be optimized. Therefore, this study proposes to obtain the characteristic parameters necessary for the mathematical model for MEMS actuators, based on elastic deformation and dynamic comb-drive in order to accurately describe the linear behavior in level system. The characteristic parameters of MEMS can be extracted in the own simulator or identified through the manipulation of input and output data signals obtained in the execution of modal tests on the prototype. When the identification is deterministic, it uses the excitation signals that follow a good signal noise rate (SNR). When the identification is stochastic it uses excitation signals mixed with noise. These two forms of identification can be interpreted as the two extremes of the identification. Strictly speaking, any procedure that is not in any of these extremes may be called the "gray-box" identification. Thus, the propose of this research work consists of using the “gray-box” identification to obtain the characteristic parameters of the MEMS electro-mechanical actuators combining the advantages of the deterministic and stochastic procedures. Under this purpose, it was made revision of the matter features, conceptualization of the actuators, comprehension of the bottom-up vision and, finally, study of the stochastic models with autoregressive exogenous inputs (ARX) and the use of recursive estimators, Least Square and Instrumental Variable. The comparison of results of the deterministic model generated by FEM / BEM, allows testing the performance between two models of different kinds. The results obtained after the data collection, the choice of mathematical representation, the determination of the structure of the model, the estimation of the parameters and validation of the model of three actuators topologies developed (simple bridges, double bridge and double hinge) that permit to identify the parameters with a average quadratic error minor than 1% and to validate these parameters in a period not more than 0.5s. The results show highly satisfactory, becoming this work a scientific contribution to MEMS synthesis at system levels.

Closed-loop system identification and validation are important components in dynamic system modelling. In this dissertation, a comprehensive literature survey is compiled on system identification with a specific focus on closed-loop system identification and issues of identification experiment design and model validation. This is followed by simulated experiments on known linear and non-linear systems and experiments on a pilot scale distillation column. The aim of these experiments is to study several sensitivities between identification experiment variables and the consequent accuracy of identified models and discrimination capacity of validation sets given open and closed-loop conditions. The identified model structure was limited to an ARX structure and the parameter estimation method to the prediction error method. The identification and validation experiments provided the following findings regarding the effects of different feedback conditions: <ul> <li>Models obtained from open-loop experiments produced the most accurate responses when approximating the linear system. When approximating the non-linear system, models obtained from closed-loop experiments were found to produce the most accurate responses.</li> <li>Validation sets obtained from open-loop experiments were found to be most effective in discriminating between models approximating the linear system while the same may be said of validation sets obtained from closed-loop experiments for the nonlinear system.</li> </ul> These finding were mostly attributed to the condition that open-loop experiments produce more informative data than closed-loop experiments given no constraints are imposed on system outputs. In the case that system output constraints are imposed, closed-loop experiments produce the more informative data of the two. In identifying the non-linear system and the distillation column it was established that defining a clear output range, and consequently a region of dynamics to be identified, is very important when identifying linear approximations of non-linear systems. Thus, since closed-loop experiments produce more informative data given output constraints, the closed-loop experiments were more effective on the non-liner systems. Assessment into other identification experiment variables revealed the following: <ul> <li>Pseudo-random binary signals were the most persistently exciting signals as they were most consistent in producing models with accurate responses.</li> <li>Dither signals with frequency characteristics based on the system’s dominant dynamics produced models with more accurate responses.</li> <li>Setpoint changes were found to be very important in maximising the generation of informative data for closed-loop experiments</li></ul> Studying the literature surveyed and the results obtained from the identification and validation experiments it is recommended that, when identifying linear models approximating a linear system and validating such models, open-loop experiments should be used to produce data for identification and cross-validation. When identifying linear approximations of a non-linear system, defining a clear output range and region of dynamics is essential and should be coupled with closed-loop experiments to generate data for identification and cross-validation. / Dissertation (MEng)--University of Pretoria, 2009. / Chemical Engineering / unrestricted

This thesis explores data anonymization techniques within the context of a Swedish municipality with a focus on safeguarding data privacy, enhancement of decision-making, and assessing re-identification risks. The investigation, grounded in a literature review and an experimental study, employed the ARX anonymization tool on a sample municipality employee database. Three distinct human resource management (HRM) datasets, analogous to the employee database, were created and anonymized using the ARX tool to ascertain the efficacy and re-identification risks of the employed techniques.  A key finding indicates an inverse relationship between dataset size and re-identification risk, enhancing data utility with larger datasets. This suggests that larger datasets are more conducive to anonymization, motivating organizations to engage in anonymization efforts for internal analytics and open data publishing.  The study contributes to Information Security discourse, emphasizing the criticality of data anonymization in preserving privacy and ensuring data utility in the era of big data. The research faced constraints due to privacy considerations, necessitating the use of similar, rather than actual, datasets, potentially affecting the results and limiting full representation for future techniques. The thesis primarily addresses HRM applications, indicating the scope for future research into other municipal or organizational governance areas. In conclusion, it underscores the necessity of data anonymization in the face of tightening regulations and sophisticated privacy breaches. This positions the organization strategically for compliance, minimizes data breach risks and upholds anonymization as a fundamental principle of Information Security.

Les fours de maintien à induction sous vide sont utilisés pour la fabrication d'aubes de turbine à l'aide du procédé de fonderie à cire perdue. La maîtrise de la thermique de ce dernier est primordiale afin d'assurer la qualité de la production. Ce travail est composé de 3 grandes parties : la modélisation détaillée du four, la modélisation réduite et l'expérience. Un four axisymétrique et sa charge ont été modélisés numériquement à l'aide des logiciels FlexPDE et COMSOL Multiphysics. Ces modèles utilisent en entrée la puissance consommée par les inducteurs et fournissent en sortie la température en tout point du module de chauffe et de la charge. Les modèles réduits étudiés sont des modèles physiques dit convolutifs (enthalpique (0D), analytique de dimension 1 (1D)) et paramétrique de type AutoRégressifs avec variables eXogènes (ARX). Les modèles ARX ont été comparés aux modèles convolutifs (procédures d'identification, puis de validation, de modèles). L'objectif est d'accéder à des températures en certains points du four sans présence d'un capteur physique local (capteur virtuel). Les modélisations détaillées et réduites ont été comparées à des expériences réalisées sur four de production. Cette dernière partie n'est pas décrite dans ce mémoire / Vacuum holding induction furnaces are used for the manufacturing of turbine blades by loss wax foundry process. Heat transfer control in a holding furnace is crucial to ensure the quality of manufacturing. This work has 3 major parts, which are the detailed modelling, reduced modelling and experiments. An axyisymmetric furnace and its load have been numerically modelled using FlexPDE and COMSOL Multiphysics, finite element codes. Modelling takes as inputs the electric power consumed by inductors and gives the temperature field in the heating module. The studied reduced models are phyisical convolutive models (enthalpic (0D), 1 dimension analytical (1D)) and parametric like AutoRegressive with eXogeneous inputs (ARX). ARX models have been compared to convolutive models (identification, validation). The goal is to get temperatures in the heating module without local presence of physical sensors (virtual sensor). Detailed and reduced models have been compared to experiments on the furnace. This last part is not described in this document

Made available in DSpace on 2016-08-17T14:53:03Z (GMT). No. of bitstreams: 1 Jorge Farid Amate.pdf: 1076998 bytes, checksum: 7c54d6bc2833288f1945368aa6976936 (MD5) Previous issue date: 2009-02-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / In industrial processes, where parameters estimation and standard recognition are desired, digital filters technology is used to do estimation. The digital filter is responsible for prediction and filtering process. Then, the filter behavior can be analyzed based on performance, gains and others variables linked to the specified model. However, to obtain trusty variables and data to estimate the process in question, a model that represents well the physics plant is needed. To do this, are applied techniques based on Systems Identification where we obtain the ARX, ARMAX, Output-Error and Box-Jenkins models of the electrolytic pot. Results, validation and their analysis, applied in standard recognition, using different structures are presented. / Em processos industriais, onde deseja-se a estimação de parâmetros e reconhecimento de padrões, utiliza-se da tecnologia de filtros digitais para tal fim. O filtro digital é responsável pelo processo de predição e filtragem. Assim, pode-se fazer uma análise do comportamento do filtro baseada no desempenho, ganhos e outras variáveis ligadas ao modelo especificado. Porém, para obtenção de variáveis e dados confiáveis para estimar-se o processo em questão, necessita-se de um modelo que represente bem a planta física. Para isto, são aplicadas técnicas baseadas em Identificação de Sistemas, onde são obtidos os modelos ARX, ARMAX, Output-Error e Box-Jenkins da cuba eletrolítica. São apresentados os resultados, validações dos modelos e análise dos mesmos, aplicados ao reconhecimento de padrões, utilizando-se diferentes estruturas.