This work shows a contribution to the study of the Switched Reluctance Machine driven as a generator to connecting in the grid to inject active power. The main objective is show the Switched Reluctance Generator behavior under various operating conditions, as well as the development of an electronic converter to connect it to the low voltage grid. Thus, it presents a mathematical model for the Switching Reluctance Generator which includes the magnetic circuit saturation and a computational model for analyzing steady state and transient. Also it is presented a strategy of generated voltage control by the magnetization angle variation acting only in the top switch of the Asymmetrical Half Bridge converter. An intermediate stage was added in the switching control strategy to reduce the energy amount provided by the excitation source and get better utilization of electromechanical conversion. A detailed description of the control system equations of the DC-AC stage, PLL algorithm and design of injected current compensator are presented and discussed. Finally, it was constructed in laboratory a experimental platform for verification of the theoretical and simulation. / Este trabalho apresenta uma contribuição ao estudo da Máquina a Relutância Variável acionada como gerador para conexão com rede elétrica e injeção de potência ativa. O objetivo principal é apresentar o comportamento do Gerador a Relutância Variável sob diversas condições de operação, bem como o desenvolvimento de um conversor eletrônico para a sua conexão a rede elétrica de baixa tensão. Assim, é apresentado um modelo matemático para o Gerador a Relutância Variável que contempla a saturação do circuito magnético e um modelo computacional para análise em regime permanente e transitório. Também é apresentada uma estratégia de controle da tensão gerada através da variação do ângulo de magnetização atuando apenas nas chaves superiores do conversor assimétrico Half Bridge. Uma etapa intermediária no chaveamento foi acrescentada à estratégia de controle para diminuir a quantidade de energia fornecida pela fonte de excitação e obter melhor aproveitamento da conversão eletromecânica. Uma descrição detalhada do equacionamento do sistema de controle do estágio CC-CA, do algoritmo de PLL e projeto do compensador da corrente injetada são apresentados e discutidos. Por fim, construiu-se uma plataforma experimental em laboratório para a comprovação dos estudos teóricos e de simulação. / Doutor em Ciências

Made available in DSpace on 2016-08-17T14:52:43Z (GMT). No. of bitstreams: 1 Gilson Soares da Silva Junior.pdf: 3373997 bytes, checksum: f03b490d45ba68e7ae2eacd3f33b718a (MD5) Previous issue date: 2008-02-15 / In this work is analyzed the influence of a static var compensator (SVC) on the electromechanical stability of the electrical energy system of the industrial consumer ALUMAR that has a cogeneration. The main considerations on cogeneration systems, the FACTS Controllers and the systems involved in the analysis are described. Moreover, it is discussed the modeling of electrical system of ALUMAR highlighting the modeling updated and validated by the National Electric System Operator (ONS) and the modeling of cogenerators. / Análise da influência de um compensador estático de reativos (SVC) na estabilidade eletromecânica do sistema de energia elétrica do consumidor industrial ALUMAR o qual possui cogeração. Descrevem-se as principais particularidades sobre os sistemas de cogeração, os controladores FACTS e sobre os sistemas envolvidos na análise. Discute-se, ainda, a modelagem do sistema elétrico da ALUMAR, destacandose a modelagem atualizada e validada pelo Operador Nacional do Sistema (ONS) e a modelagem dos cogeradores.

Modern interconnected power systems are becoming highly complex and sophisticated, while increasing energy penetrations through congested inter-tie lines causing the operating point approaching stability margins. This as a result, exposes the overall system to potential low frequency power oscillation phenomena following disturbances. This in turn can lead to cascading events and blackouts. Recent approaches to counteract this phenomenon are based on utilization of wide area monitoring systems (WAMS) and power electronics based devices, such as flexible AC transmission systems (FACTS) and HVDC links for advanced power oscillation damping provision. The rise of hybrid AC-DC power systems is therefore sought as a viable solution in overcoming this challenge and securing wide-area stability. If multiple FACTS devices and HVDC links are integrated in a scheme with no supervising control actions considered amongst them, the overall system response might not be optimal. Each device might attempt to individually damp power oscillations ignoring the control status of the rest. This introduces an increasing chance of destabilizing interactions taking place between them, leading to under-utilized performance, increased costs and system wide-area stability deterioration. This research investigates the development of a novel supervisory control scheme that optimally coordinates a parallel operation of multiple FACTS devices and an HVDC link distributed across a power system. The control system is based on Linear Quadratic Gaussian (LQG) modern optimal control theory. The proposed new control scheme provides coordinating control signals to WAMS based FACTS devices and HVDC link, to optimally and coherently counteract inter-area modes of low frequency power oscillations inherent in the system. The thesis makes a thorough review of the existing and well-established improved stability practises a power system benefits from through the implementation of a single FACTS device or HVDC link, and compares the case –and hence raises the issue–when all active components are integrated simultaneously and uncoordinatedly. System identification approaches are also in the core of this research, serving as means of reaching a linear state space model representative of the non-linear power system, which is a pre-requisite for LQG control design methodology.

La thèse porte sur la sélection de poses optimales pour la calibration géométrique et élasto-statique de robots industriels utilisés pour l'usinage de pièces des grandes dimensions. Une attention particulière est accordée à l'amélioration de la précision de positionnement du robot après compensation des erreurs géométriques et élasto-statiques. Pour répondre aux exigences industrielles des opérations d’usinage, une nouvelle approche pour la définition d'essais pour la calibration de robots sériels et quasi-sériels est proposée. Cette approche est basée sur un nouveau critère de performance, orienté applications industrielles, qui évalue la qualité du plan d'essais pour la calibration via la précision de positionnement du manipulateur après compensation d'erreurs, et tient compte des spécificités de la tâche manufacturière à réaliser au moyen de configurations tests. Contrairement aux travaux précédents, l'approche développée requiert seulement une mesure des positions de points et non d’orientation de corps rigides à l’aide d’un système de mesure externe tel qu’un laser tracker. Cette méthode permet ainsi d'éviter les problèmes de non-homogénéité dans les équations d'identification. Par ailleurs, afin de prendre en compte l'impact du compensateur de gravité,qui induit une chaîne cinématique fermée, le modèle de raideur est étendu en y incluant certains paramètres élasto-statiques dont les valeurs dépendent de la configuration du robot. Une méthodologie pour la calibration des modèles de compensateurs de gravité est ainsi proposée. Les avantages des techniques développées pour la calibration de robots industriels dédiés à des opérations d’usinage sont validés et mis en évidence expérimentalement, à travers la calibration géométrique et élasto-statique du robot industriel KUKAKR-270. / The thesis deals with the optimal pose selection for geometric and elastostatic calibration for industrial robots employed in machining of large parts. Particular attention is paid to the improvement of robot positioning accuracy after compensation of the geometric and elastostatic errors. To meet the industrial requirements of machining operations, a new approach for calibration experiments design for serial and quasi-serial industrial robots is proposed. This approach is based on a new industry-oriented performance measure that evaluates the quality of calibration experiment plan via the manipulator positioning accuracy after error compensation, and takes into account the particularities of prescribed manufacturing task by introducing manipulator test-poses. Contrary to previous works, the developed approach employs an enhanced partial pose measurement method, which uses only direct position measurements from an external device and allows us to avoid the non-homogeneity of relevant identification equations. In order to consider the impact of gravity compensator that creates closed-loop chains, the conventional stiffness model is extended by including in it some configuration dependent elastostatic parameters, which are assumed to be constant for strictly serial robots. Corresponding methodology for calibration of the gravity compensator models is also proposed. The advantages of the developed calibration techniques are validated via experimental study, which deals with geometric and elastostatic calibration of a KUKA KR-270 industrial robot.

Le procédé de soudage par friction malaxage ou Friction Stir Welding (FSW), est un procédé récent utilisé pour le soudage de pièces métalliques avec différentes applications dans les industries aéronautique, automobile, spatiale et ferroviaire. Les robots industriels sériels peuvent être utilisés comme moyen de soudage FSW mais, à cause de leur rigidité, ils se déforment sous l’effet des forces générées par le procédé. Ceci entraîne une déviation de trajectoire de l’outil de soudage en position et en orientation qui induit des défauts dans le cordon de soudure. Dans ce travail, deux méthodes de correction de déviations ont été développées. La première méthode est basée sur l’estimation des déviations en position et en orientation dans l’espace cartésien à partir des modèles du robot et de déformation élasto-statique des corps et transmissions. Les déviations estimées permettent de développer une approche de programmation de trajectoires adaptées au soudage FSW robotisé. Contrairement aux méthodes d’interpolation linéaire généralement envisagées, cette approche utilise des approximations de trajectoires par des courbes de Bézier ou B-splines. Les validations expérimentales pour des trajectoires complexes, avec un robot Kuka KR500-2MT, ont permis d’obtenir une déviation résiduelle moyenne de l’ordre de 0,3 mm et des cordons de soudure sans défauts. Cette précision de trajectoire atteinte pour le FSW permet de considérer une exploitation industrielle de la solution développée. La deuxième méthode de correction des déviations utilise un asservissement de position en temps réel avec un capteur de profil laser 2D dans la boucle de retour. Deux synthèses de lois de commande ont été explorées pour cet asservissement. Malgré les perturbations externes liées aux contraintes du procédé, les résultats expérimentaux sur des trajectoires de soudage rectilignes et curvilignes montrent une bonne stabilité de l’asservissement et conduisent à une déviation résiduelle moyenne de l’ordre de 0,1 mm. Les intérêts et les difficultés de la mise en œuvre de cette deuxième méthode ont également été mis en exergue. / Friction Stir Welding (FSW) is a recent process used for welding metallic parts in aerospace, automotive, and railway industries. Serial industrial robots may be used as FSW welding machines, but because of their lack of stiffness, they undergo elastic deformation under the effect of stresses produced by the process. This causes a welding tool path deviation both in position and orientation, which induces defects in the weld seam. In this work, two path correction methods were developed. The first method is based on the prediction of the position and orientation deviations in the cartesian space from robot models and stiffness model of the links and the joints. The knowledge of tool deviations enabled the synthesis of a path programming approach adapted for robotic FSW. Unlike linear interpolation methods often used, this approach is based on approximations of the adapted path by Bézier or B-splines curves. Experimental validations on a Kuka KR500-2MT robot welding complex paths showed an average residual deviation of 0.3 mm and weld seams without defects. The path accuracy achieved makes it possible to consider an industrial exploitation of the developed solution. The second proposed correction method uses position feedback with a 2D laser profile sensor in the feedback loop for real-time measurement of deviations. Two controllers were designed to correct the deviations. In spite of the external disturbances related to the constraints of the process, experimental results obtained on straight and curvilinear welding paths showed the stability of the feedback loop and a mean residual deviation of 0.1 mm was achieved. The interests and difficulties of deploying this second method were also highlighted.

Orientador: Michael John Brennan / Abstract: The advances in microelectromechanical systems to power supply devices for monitoring the structural integrity, mainly for applications in remote areas or with difficult access, have made energy harvesting from ambient vibration a highly researched topic. Although several electromechanical mechanisms have been proposed for applications in a variety of fields, harvesting energy from railway track vibrations is relatively new, and only a small amount of research is ongoing in this topic. This thesis aims to determine the factors that govern the sleeper vertical vibration induced by a passing train, develop a methodology to emulate this vibration in a laboratory-based system and to derive a model of a load resistance attached to a linear electromagnetic transducer to determine the optimum energy harvested. The study shows the importance of knowing the vibration behaviour of the sleeper in order to tune the energy harvester to the correct excitation frequency. A comparison between piezoelectric and electromagnetic transducers is performed using a two-port network model to determine which transducer performs better for low frequency vibration. To emulate sleeper vibration due to a passing train using an electrodynamic shaker, a compensator filter is designed to remove the system dynamics. An analytical investigation into the energy dissipated by a load resistance attached to an electromagnetic transducer when subject to a time-limited base excitation, which may include the transie... (Complete abstract click electronic access below) / Resumo: Avanços em sistemas micro eletromecânico para fornecer energia à dispositivos para monitoramento de integridade estrutural, principalmente para aplicações em áreas remotas ou de difícil acesso, fez de extração de energia a partir de vibrações contidas no ambiente um tópico de pesquisa em destaque. Apesar de que diversos mecanismos eletromecânicos já foram propostos em uma variedade de aplicações, extração de energia à partir de vibrações em linhas férreas é, relativamente, novo e somente algumas pesquisas estão sendo realizadas sobre esse tópico. Esta Tese busca determinar os fatores que governam a vibração vertical do dormente induzida devido a passagem de um trem, desenvolver uma metodologia para emular esta vibração em um sistema em laboratório e derivar um modelo para um transdutor linear eletromagnético com uma carga resistiva acoplada. O estudo mostrou a importância de conhecer o comportamento vibracional do dormente de modo a sintonizar o extrator de energia com a frequência correta de excitação. Uma comparação entre transdutores piezoelétrico e eletromagnético é realizado utilizando um modelo quadripolo para determinar qual transdutor tem um melhor desempenho para vibrações em baixa frequência. Para emular a vibração do dormente devido a passagem de um trem em um agitador eletrodinâmico, um filtro compensador é projetado para remover a dinâmica do sistema. Uma investigação analítica da energia dissipada pela carga resistiva acoplada à um transdutor eletromagnético qua... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Trotz aller technischen Weiterentwicklungen in der Vergangenheit unterscheiden sich moderne elektronische Tachymeter in ihrer Grundkonstruktion nicht wesentlich von ihren analogen Vorgängern. Ihnen allen ist gemeinsam, dass eine Visur um den Nadir nicht möglich ist. Dies bedeutet, dass Punkte, welche sich in einem Zenitwinkelbereich zwischen ca. 170 und 230 gon befinden, nicht direkt gemessen werden können. Gegenstand der vorliegenden Arbeit war daher die Entwicklung eines Systems, mit welchem tachymetrische Messungen auch in einem Zenitwinkelbereich zwischen 170 und 230 gon möglich sind. Das Konzept basiert auf dem aus dem Markscheidewesen bekannten Hängetheodolit. Um Messungen im Bereich des Nadirs durchführen zu können, wird ein Tachymeter ähnlich einem Hängetheodolit in hängender Position montiert. In dieser Position ist der zur Horizontierung dienende interne elektronische Neigungskompensator jedoch nicht funktionsfähig. Die Horizontierung wird daher extern überwacht. Zu diesem Zweck wird das Tachymeter über eine geeignete Aufhängevorrichtung mit einem Neigungssensor verbunden. Die Kombination aus in hängender Position montiertem Tachymeter und externem Neigungssensor wird als Hängetachymeter bezeichnet. Bei der Kombination des Systems mit einem externen Neigungssensor kann eine geringe Abweichung zwischen der Stehachse des Tachymeters und der Lotachse des Neigungssensors fertigungsbedingt nicht vermieden werden. Zur Bestimmung dieser Abweichung wurden geeignete Verfahren entwickelt und auf ihre Genauigkeit untersucht. Die mit dem Tachymeter ermittelten Messwerte werden durch Instrumentenabweichungen beeinflusst und müssen um diese korrigiert werden. Auch sind die Messwerte um die mit dem externen Neigungssensor ermittelte Stehachsenneigung zu korrigieren. Die Achsenabweichungen des Tachymeters müssen in hängender Position bestimmt werden. Es kann nicht generell vorausgesetzt werden, dass diese mit den in aufrechter Position bestimmten Werten übereinstimmen. Zur Steuerung des Hängetachymeters wurde eine Software entwickelt, in welche die Kalibrierung der Sensoren, die Auswertung und Korrektur der Messwerte, deren Speicherung und Weiterverarbeitung sowie der Datenexport integriert wurden. Eine Kombination des Hängetachymeters mit einer Okularkamera ermöglicht die automatische Zielerkennung und -verfolgung nichtsignalisierter Punkte auch bei Messungen nahe dem Nadir. Zur Realisierung eines Autofokus wurde das Hängetachymeter mit einem Schrittmotor kombiniert, welcher über den Fokussierring des Tachymeters die Fokussierlinse bewegt. Eine Autofokusfunktion wurde auf Grundlage des Bildkontrastes entwickelt. Die Kalibrierung der Okularkamera basiert auf einer Modellierung des Abbildungsprozesses durch lineare Funktionen. Hierbei wurde die Abhängigkeit der Kalibrierwerte von der Position der Fokussierlinse (Position des Schrittmotors) aufgezeigt. Die zur optischen Zielerkennung eingesetzten Bildverarbeitungsalgorithmen gliedern sich in eine manuelle Punktanzielung im Bild, die Messung punktförmiger Muster durch Kantendetektion und Ellipsenanpassung und Bildzuordnungsverfahren nach der Methode der kleinsten Quadrate. Um die Leistungsfähigkeit des Hängetachymeters zu bestimmen, aber auch um die Güte der Kalibrierung zu testen, wurden mehrere Genauigkeitsuntersuchungen durchgeführt. Abschließend wurde das Hängetachymeter auch erfolgreich in der Industrievermessung eingesetzt und eine automatische Kalibrierroutine ohne Interaktion des Benutzers entwickelt. Die erreichten Genauigkeiten des Systems liegen im Bereich der Genauigkeiten des eingesetzten Tachymeters. / Despite all technical enhancements in the past modern electronic tacheometers do not differ significantly to their analogue predecessors. All have in common that aiming around the nadir is not possible. This means that points situated in the zenith angle region between ca. 170 to 230 gon cannot be measured directly. Therefore the subject of the present work was the development of a system that makes measurements in the zenith angle region between 170 and 230 gon possible. The concept is based upon the suspended theodolite which is known in mine-surveying. To carry out measurements in the region of the nadir a total station is mounted in a hanging position similar to a suspended theodolite. However the function of the tilt compensator which is used for levelling of the instrument is not supported in this position. Hence inclination is monitored externally. For this purpose the tacheometer is connected to a clinometer by an appropriate suspension arrangement. The combination of a tacheometer mounted in a suspended position and an external clinometer is called suspended tacheometer. Combining the system with an external clinometer a marginal variation occurs between the vertical axis of the tacheometer and the plummet axis of the clinometer due to production conditions. To quantify this variation an appropriate method was developed and its accuracy tested. Measurements conducted by the tacheometer are influenced by the variations of the instrument and must therefore be adjusted. Moreover these measurements must be adjusted by the inclination detected by the external clinometer. The axis variations of the tacheometer must be determined in suspended position. It cannot be generally presumed that these measurements comply with the ones determined in upright position. To actuate the suspended tacheometer a software was developed. This software also offers integrated functions for calibration of the sensors, analysis and adjustment of the measurements and their storage and processing as well as export of data. A combination of the suspended tacheometer with an ocular camera makes automatic target detection and tracking of non-cooperative signals possible also when measuring near the region of the nadir. To realize an autofocus the suspended tacheometer was combined with a stepper motor which moves the focus lens. Based on the image contrast an autofocus function was developed. The calibration of the ocular camera is based on modelling the mapping process by linear functions. Here the dependency of calibration values on the position of the focus lens (position of the stepping motor) was demonstrated. Image processing algorithms used for optical target detection can be divided into manual target detection in the image, measurement of point-shaped patterns by edge detection and ellipse adjustment and image allocation operations (Least squares matching). To determine the efficiency of the suspended tacheometer as well as to test the performance of the calibration several accuracy tests were performed. Also the suspended tacheometer was successfully deployed in industrial surveying. An automatic calibration routine without participation of a user was developed. The achieved accuracies of the system correspond with the accuracies of the inserted tacheometer.

La classe des systèmes non-linéaires dont la dynamique est définie par un champ de vecteurs polynomial est étudié. Des modèles polynomiaux peuvent représenter différents systèmes réels ou bien définir des approximations plus riches que des modèles linéaires pour des systèmes non-linéaires différentiables. Des techniques de programmation semi-définie développées récemment ont rendu possible l'étude de cette classe de systèmes avec des outils numériques. Le problème d'analyse en stabilité locale est résolu via des conditions basées sur la positivité de polynomes. Dans le cadre de la synthèse de lois de commande nous proposons un changement de variables linéaire pour traiter la synthèse de lois de commande non-linéaire qui garantissent la stabilité locale. Les ensembles définissant des estimations de la région d'attraction, définis par des courbes de niveau de la fonction de Lyapunov pour le système, sont également donnés par des fonctions polynomiales / We study the class of nonlinear dynamical systems which vector field is defined by polynomial functions. A large set of systems can be modeled using such class of functions. Tests for stability are formulated as semidefinite programming problems by considering positive polinomials to belong to the class of Sum of Squares polynomials. Polynomial control law gains are computed based on a linear change of coordinates and guarantee the local stability of the closed-loop system. Lyapunov theory is then applied in order to obtain estimates of the region of attraction for stable equilibrium points. Such estimates are given by level sets of polynomial positive functions

No description available.

<p>Real-time hybrid simulation (RTHS) has demonstrated certain advantages over conventional large-scale testing. In an RTHS, the system that is under study is partitioned into a numerical and a physical substructure, where the numerical part is comprised of those elements that are easier to model mathematically, while the physical part consists of those that present a complex behavior difficult to capture in a numerical model. The most complex part of this study is the isolation system, a technology used to protect structures against earthquakes by modifying how they respond to ground motions. Unbonded Fiber Reinforced Elastomeric Isolators (UFREIs) are devices that can accomplish this task and have gained attention in recent years because of their modest but valuable features that make them suitable for implementation in low-rise buildings and in developing countries because of their low cost. Our end goal for this work is to enable the testing of scaled versions of these elastomeric isolators to understand their behavior under shear tests and realistic loading. </p> <p>A testing instrument was designed and constructed to apply a uniaxial compressive force up to 22kN and a shear force of 8kN simultaneously to the specimens. A testing program was conducted where four primary sources of signal distortion were identified as caused by the servo-hydraulic system. From these results, a mechanics-based model was developed to understand better the dynamics that the sliding table can introduce to the measured signals accounting for inertial and dissipative forces. Two Bouc-Wen models were implemented to simulate the behavior of the UFREIs. The first only accounts for the hysteretic behavior of the isolator, and the second accounts for the additional nonlinearities found in the isolator’s behavior. These models were assembled in a virtual RTHS which is available to users interested in learning the applications of RTHS of a base-isolated structure with a nonlinear component.</p> <p>An RTHS experiment was conducted in the IISL where the control system comprised a delay compensator and a proportional-integral controller, which exhibited a good tracking performance with minimal delay and low RMSE. However, it can increase the distortion of the oil-column resonance in the measured signals. The simulation captures the behavior of the isolated structure for small displacements. However, it underestimates the displacement of the full-scale specimen for large displacements. The RTHS showed a better approximation of the displacement of the full-scale structure than the theoretical behavior approximated by the Bouc-Wen models.</p>