Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 96-97). Also available via the Internet.

This study investigates the application of adaptive time-suboptimal positional control to an electrical machine with a wide range of loading conditions. These unpredicatable load conditions included variable system parameters, such as inertia variations and nonlinear amplification gain in the servo driver, as well as external disturbances, including viscous frictional force, coulomb frictional force and static loading torque. The design objective was to provide an extremely fast positional movement to the desired target without overshoot and zero steady-state error over these loading conditions. The resultant microcontroller-based adaptive controller consists of an on-line parameter estimator and a robust time-(sub)optimal position controller. The system parameters are estimated by an recursive least squares (RLS) estimator during the acceleration phase. The sampling frequency used by the RLS algorithm is determined adaptively. During the crusing phase of the positional movement, the estimates are further improved by feeding intersample data (stored during the acceleration phase) through an off-line RLS estimator. The coulomb friction and the static loading torque are effectively compensated by a simple mechanism. Another novel mechanism which takes account of nonlinear amplifier gain has also been developed. The time-(sub)optimal position controller calculates the desired reference trajectory in real-time and directs the system state to the reference trajectory. The above adaptive control scheme was implemented on a microcontroller-based system and was applied to an experimental system consisting of a 500W DC permanent magnet motor fed by a pwm servo driver. Experimental results revealed that the proposed controller adapted well to changes in inertia, viscous friction, coulomb friction and amplifier nonlinearity, and the desired time-suboptimal respones were obtained in all these loading conditions.

High-speed electromagnetic moving-iron actuators are experimentally investigated and numerically simulated, using digitally-controlled instrumentation techniques, lumped-parameter( magnetic equivalent circuit)networks,and field (finite-element) models. Various actuator topologies, based on the moving-iron principle, that are capable of achieving very high operating speeds, are also investigated. An optically-based and digitally-controlled instrumentation technique is developed to assessth e actuatord ynamic performance.A dual voltage (microprocessor-controlled) strategy is also developed to improve actuator speed of response. A lumpedparameter model that accurately simulates, with minimum computation, the dynamic behaviour of the actuator is developed and experimentally verified. This model, whose magnetic parameters are derived from static field results, accounts for magnetic saturation, 3D effects due to width change between iron parts and transverse edge fluxes, and the dynamic coupling of the actuator system variables. A static lumped-parameterm odel is developed,i n parallel, to achieve insight into the underlying actuator design principle, and rapid predictions of the effects of parametric changes. Two-dimensional field models are developed, using a commercial finite-element package, to accurately predict the saturation levels, and to estimate the mmf/flux characteristics of each actuator component (iron and air part) and force characteristics for use in the dynamic lumped-parameter model. The 3D effects are taken into account by incorporating the results of 2D scalar potential models, in typical transverse planes, into the longitudinal (main path) solution using suitable compensation factors. Transient eddy current effects are also investigated. The study is extended by surveying various topologies of moving-iron devices, and analysing their relative performances. The objective of this investigation is to establish, quantify, and compare the factors limiting the performance, particularly the maximum accelerationr ate.

Orientador: Ernesto Ruppert Filho / Tese (doutorado)) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação / Made available in DSpace on 2018-08-23T16:55:43Z (GMT). No. of bitstreams: 1 LuqueCarcasi_DiodomiroBaldomero_D.pdf: 4622553 bytes, checksum: bb71dd897d06fd750e2849f700a8128e (MD5) Previous issue date: 2012 / Resumo: Este trabalho é uma contribuição ao estudo da determinação de parâmetros de geradores síncronos trifásicos de pólos salientes. A partir da literatura disponível sobre projeto de máquinas, inicia-se o desenvolvimento do dimensionamento do gerador síncrono trifásico de pólos salientes através de sucessivos cálculos realizados para as principais dimensões físicas da mesma. Com base nos dados iniciais de projeto e utilizando um software comercial de projeto de máquinas, foram realizados cálculos e detalhes do projeto obtendo-se os parâmetros operacionais do gerador síncrono trifásico de pólos salientes. A seguir, foram realizadas simulações dinâmicas do gerador utilizando métodos estandardizados com o intuito de determinar seus respectivos parâmetros operacionais, entre eles estão: o ensaio de curto circuito trifásico brusco, ensaio de rejeição de carga e ensaio de resposta em frequência, em todos os casos utilizou-se as técnicas de elementos finitos e um software comercial da Ansoft. Os dados obtidos nas simulações dos ensaios foram tratados matematicamente baseados nas normas IEEE Std 115 e IEC 34-4 para a obtenção dos valores dos parâmetros operacionais do gerador. Comparações entre os valores de projeto e os obtidos pelo método de elementos finitos foram realizadas mostrando que essa metodologia pode ser utilizada para complementar aos ensaios reais / Abstract: This work is a contribution to the study of the parameters determination of a salient-pole synchronous generator. From the available literature on machine design, it begins the project development of the three-phase synchronous generator through successive calculations performed for the main physical dimensions. Based on the initial data for design and using commercial software for machine design, we performed calculations and design details obtaining the operational parameters of the synchronous generator. Next, dynamic simulations for three-phase synchronous machine were performed using standard methods in order to determine their operating parameters as simulation of the three-phase sudden short-circuit tests, load rejection and standstill frequency response test, in all cases we used the finite elements techniques and ANSOFT commercial software for this. The data obtained in the simulations tests have been processed mathematically based on IEEE Std 115 and IEC 34-4 standards and the operating parameters values were obtained from the generator. Comparisons between the design values and those obtained by finite element method were performed showing that this methodology can be used to complement the actual test / Doutorado / Automação / Mestre em Engenharia Elétrica

In many instances of virtual machine deployments today, virtual machine instances are created to support a single application. Traditional operating systems provide an extensive framework for protecting one process from another. In such deployments, this protection layer becomes an additional source of overhead as isolation between services is provided at an operating system level and each instance of an operating system supports only one service. This makes the operating system the equivalent of a process from the traditional operating system perspective. Isolation between these operating systems and indirectly the services they support, is ensured by the virtual machine monitor in these deployments. In these scenarios the process protection provided by the operating system becomes redundant and a source of additional overhead. We propose a new model for these scenarios with operating systems that bypass this redundant protection offered by the traditional operating systems. We prototyped such an operating system by executing parts of the operating system in the same protection ring as user applications. This gives processes more power and access to kernel memory bypassing the need to copy data from user to kernel and vice versa as is required when the traditional ring protection layer is enforced. This allows us to save the system call trap overhead and allows application program mers to directly call kernel functions exposing the rich kernel library. This does not compromise security on the other virtual machines running on the same physical machine, as they are protected by the VMM. We illustrate the design and implementation of such a system with the Xen hypervisor and the XenoLinux kernel. / Science, Faculty of / Computer Science, Department of / Graduate

Les machines logiques prennent dans la vie moderne une place de plus en plus importante. Leur diversité s'étend du simple interrupteur aux calculateurs numériques en passant par l'ascenseur, la machine à laver...Longtemps ignorée l'algèbre de Boole est à l'origine de cette expension et demeure l'instrument de base pour aborder l'étude de ces machines. Après quelques rappels sur cette algèbre et les systèmes logiques qui, nous le verrons, peuvent se décrire par un ensemble de fonctions combinatoires, nous nous proposons dans ce qui suit de montrer comment les matrices booléennes peuvent être utilisées en vue de la réalisation de ces fonctions à partir d'un élément logique particulier que nous étudierons.

Une introduction nous permettra de préciser la notion de code et l'intérêt que présente le choix de ce code. Nous verrons ensuite une méthode de recherche d'un code répondant à certaines spécifications; un exemple d'application, traité en détail, nous fera mieux comprendre la marche à suivre. Quelques mots de la programmation sur calculatrice numérique effectuée pour cette méthode, suivront cet exemple. Dans le but de faire une comparaison entre les codes ainsi obtenus et ceux auxquels aboutit la méthode de Curtis, nous ferons quelques rappels sur cette dernière qui a été également programmée. En pages hors-texte, figurent les "listings" des deux programmes.

Une procédure systématique pour la conception „des servocommandes électrohydrauliques a toujours été la question fondamentale qui préoccupe certains chercheurs. On constate, dans l'étude linéaire des servocommandes, que les techniques de simulation peuvent être utilisées, sans recourir a des essaies sur un prototype, comme moyen de prédiction des caractéristiques d'un système hydraulique. Dans le but de contribuer à l'étude de ce problème, nous avons développé un modèle mathématique d'une servocommande hydraulique de vitesse, en conservant certaines non-linéarités lorsqu'il y a lieu. Le modèle est ensuite simulé sur l'ordinateur digital, et les résultats sont comparés avec les mesures expérimentales sur un système réel spécialement conçu à cette fin. Des pièces standards ont été choisies afin d'avoir une plus grande gamme d'application industrielle. Il a été constaté que le modèle simulé représente d'une manière satisfaisante le système physique. Utilisant les méthodes générales présentées dans ce texte et à partir des spécifications données par le manufacturier, on peut alors vérifier les caractéristiques du système futur à l'aide du programme de simulation proposé. Finalement, il n'y a aucun doute que cette méthode de conception est une des plus économiques au point de vue temps et coût.

Le contenu de ce mémoire rend compte de premiers travaux entrepris au département de génie mécanique dans le secteur des amplificateurs h fluides et éléments logiques pneumatiques, travaux partiellement financés par un octroi de recherche du Conseil national de la recherche h Ottawa. Le but assigné était, dans un premier temps, d'observer les écoulements h l'intérieur de circuits à éléments fluidiques. En effet, la connaissance de ces écoulements d'une grande complexité est imparfaite au point d'avoir recours h un certain empirisme dans l'élaboration pratique des circuits, A partir des informations recueillies, l'étude pourrait alors se développer sur différents plans tels que la recherche de modèles et l'amélioration des circuits.

Une première partie montre l'étude des "vibrations de flexion d'un arbre mécanique en rotation sur lequel est monté un disque, et qui n'est soumis qu'a des effets mécaniques linéaires, en régime permanent. Deux particularités ont été spécialement étudiées; - l'influence de l'effet gyroscopique du disque. - la résolution mathématique exacte du système en tenant compte de la masse répartie de l'arbre, La complexité du problème est due à la résolution d'une équation différentielle du quatrième ordre. Dans la deuxième partie, l'arbre précédent est soumis, en plus, à des effets mécaniques extérieurs non-linéaires (influence d'une force non-linéaire due à la présence d'un ressort à caractéristique du troisième degré). La particularité étudiée est l'influence de l'effet gyroscopique, juxtaposée à celle des forces non-linéaires. La complexité du problème est due aux résolutions d'équations différentielles non-linéaires; ces résolutions ne peuvent être qu'approchées et illustrent le phénomène dit de "saut".