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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Dynamic torque clutch control for heavy duty vehicles using a backlash size and position observer

Eliasson Godonou, Samuel January 2017 (has links)
This master's thesis investigated the possibility to control the clutch torque in order to better traverse a Scania vehicles powertrain backlash. When traversing a backlash the torque difference between the two gears will at the time of contact excite oscillations in the powertrain, and by controlling the torque these oscillations can be minimized. The master's thesis solves this issue in three major steps. First a Simulink model was created to mimic the actual vehicles powertrain as closely as possible. It was created using mostly Simdriveline components and then validated by comparing simulations to measurements from real drives. After that backlash position and backlash size observers were created in order to estimate them. Using the developed Simulink model these observers could then be evaluated, and the backlash position observer proved to be very precise while the backlash size observer was not as precise but still usable. Finally a control strategy was devised, by using the estimates from the developed observers it was supposed to control the clutch torque in a better way than previously done. The controller was a switching controller that simply used the full engine torque while the backlash was in contact, and a P controller to control the clutch torque while performing a backlash traverse. The controller proved to perform well and was robust to errors in the backlash size. Future work to be done could be to develop a shaft torque observer for use in the already developed observers.
142

Iterative Observer-based Estimation Algorithms for Steady-State Elliptic Partial Differential Equation Systems

Majeed, Muhammad Usman 19 July 2017 (has links)
A recording of the defense presentation for this dissertation is available at: http://hdl.handle.net/10754/625197 / Steady-state elliptic partial differential equations (PDEs) are frequently used to model a diverse range of physical phenomena. The source and boundary data estimation problems for such PDE systems are of prime interest in various engineering disciplines including biomedical engineering, mechanics of materials and earth sciences. Almost all existing solution strategies for such problems can be broadly classified as optimization-based techniques, which are computationally heavy especially when the problems are formulated on higher dimensional space domains. However, in this dissertation, feedback based state estimation algorithms, known as state observers, are developed to solve such steady-state problems using one of the space variables as time-like. In this regard, first, an iterative observer algorithm is developed that sweeps over regular-shaped domains and solves boundary estimation problems for steady-state Laplace equation. It is well-known that source and boundary estimation problems for the elliptic PDEs are highly sensitive to noise in the data. For this, an optimal iterative observer algorithm, which is a robust counterpart of the iterative observer, is presented to tackle the ill-posedness due to noise. The iterative observer algorithm and the optimal iterative algorithm are then used to solve source localization and estimation problems for Poisson equation for noise-free and noisy data cases respectively. Next, a divide and conquer approach is developed for three-dimensional domains with two congruent parallel surfaces to solve the boundary and the source data estimation problems for the steady-state Laplace and Poisson kind of systems respectively. Theoretical results are shown using a functional analysis framework, and consistent numerical simulation results are presented for several test cases using finite difference discretization schemes.
143

Wilberforce and his milieux : the worlds of Anglican Evangelicalism, c.1780-1830

Atkins, Gareth January 2009 (has links)
Evangelical reformism has always been recognized as a massive influence on early nineteenth-century culture. Philanthropic pressure groups dominated public life. But while much attention has recently been devoted to the language and ideas which informed the Evangelical mindset, too many historians have accepted the heroic emphases of nineteenth-century memoirists, and have concentrated on Wilberforce and the crusade against slavery. This thesis contends that the real strength of the movement lay in business, the professions and burgeoning officialdom, and traces the clerical and business networks that connected this metropolitan nexus with provincial Britain. As is shown in chapters on the Church and Universities, patronage and politics, the City of London, the Navy and colonial affairs, this was a dynamic, highly-organized milieu in which patronage, place and influence were used to the full.
144

The Downfall of The Ryerson Press

Bradley-St-Cyr, Ruth January 2014 (has links)
For 141 years, The Ryerson Press was both a cultural engine for and a reflection of Canadian society. Founded in 1829 as the Methodist Book Room, it was Canada’s first English-language book publisher and became the largest textbook publisher in Canada. Its contributions to Canadian literature, particularly under long-time editor Lorne Pierce, were considerable. In 1970, however, the press was sold to American branch plant McGraw-Hill, causing a cultural and nationalist crisis in the publishing community. The purpose of this thesis is to explanation many of the factors causing the United Church to sell the House. The purchase of an expensive and outdated printing press in 1962 has been blamed for the sale, as has the general state of Canadian publishing at the time. However, the whole story is much more complex and includes publication choices, personnel shifts, management failures, financial ruin, organizational politics, inflation, and the massive cultural shift of the late 1960s. Specifically, the thesis looks at the succession crisis that followed Lorne Pierce’s retirement, the Woods, Gordon Management Report, the New Curriculum, The United Church Observer, the practice of hiring ministers as managers, the formation of the Division of Communication, the proposed merger of the United Church of Canada with the Anglican Church of Canada, and falling church membership.
145

Comparison of observer reliability of three-dimensional cephalometric landmark identification on subject images from Galileos and i-CAT CBCT.

Katkar, Rujuta Amol 01 January 2011 (has links)
No description available.
146

Optimalizace stavového regulátoru pro řízení DC motoru na FPGA / Optimization of the DC motor state space controller for FPGA

Maliszewski, Michal January 2017 (has links)
This thesis deals with the optimization of state space controller of DC motor on FPGA in LabVIEW environment on NI cRIO platform. In the first part, the state space model of the given DC motor is presented in Matlab/Simulink and then the position feedback controller with steady-state error elimination and with state observer with error compen-sation using LQR method is designed. The thesis continues with transforming the con-troller to LabVIEW environment where the code is edited for FPGA use. Next, the fo-cus on FPGA hardware resources consumption optimization leads to careful work with fixed-point data type. After successful code compilation on target hardware, the real given DC motor is connected and the series of tests are performed. The output of the thesis is working state space controller running on FPGA and the graphical user inter-face on real-time host cRIO, which enables the user to control the plant and save the data on the disk.
147

Code migration of reactive programming components, from JavaScript to C++ / Kodmigrering av reaktiva programmeringskomponenter, från JavaScript till C++

Rönbeck Lindahl, Sebastian January 2021 (has links)
The demands we put on the mobile applications we use continues to grow. They should be useful, elegantly designed, secure and effective. If an app does not meet those demands, it is likely that the user will replace it with another one. This thesis work was performed at Visiarc, which is a small company that is specialized at development of mobile- and web applications. They are looking for new ways of improving the performance of their apps. This study investigates whether a performance enhancement can be achieved through migrating the reactive programming components, which are being used to update the graphical user interface of their apps, from JavaScript where they currently are residing in Visiarc's system, to C++. The study explains how the new C++ system for managing reactive programming components was constructed. Two performance tests were created to compare the performance of the C++ system to the existing JavaScript system. The test results showed that further improvements to the native system are required in order to surpass the performance of the JavaScript system. What these improvements are and how to achieve them is briefly discussed.
148

An Interactive Exploration System for Physically-Observable Objective Vortices in Unsteady 2D Flow

Zhang, Xingdi 24 November 2021 (has links)
Vortex detection has been a long-standing and challenging topic in fluid analysis. Recent state-of-the-art extraction and visualization of vortices in unsteady fluid flow employ objective vortex criteria, which makes feature extraction independent of reference frames or observers. However, even objectivity can only guarantee that different observers reach the same conclusions, but not necessarily guarantee that these conclusions are the only physically meaningful or relevant ones. Moreover, a significant challenge is that a single observer is often not sufficient to accurately observe multiple vortices that follow different motions. This thesis presents a novel mathematical framework that represents physically realizable observers as the Lie algebra of the Killing fields on the underlying manifold, together with a software system that enables the exploration and use of an interactively chosen set of observers, resulting in relative velocity fields and objective vortex structures in real-time. Based on our mathematical framework, our system facilitates the objective detection and visualization of vortices relative to well-adapted reference frame motions, while at the same time guaranteeing that these observers are physically realizable. We show how our framework speeds up the exploration of objective vortices in unsteady 2D flow, on planar as well as on spherical domains.
149

Contrôle en couple et en vitesse du glissement d'un embrayage simple ou double dans une transmission automobile / Torque and speed control of a single or dual clutch in an automotive transmission

Losero, Rémi 21 January 2016 (has links)
Cette thèse de doctorat a été réalisée dans le cadre d’une convention CIFRE établie entre le laboratoire LAMIH UMR CNRS 8201 et l’équipementier automobile Valeo. Les problématiques de la thèse s’inscrivent dans un contexte proche de l’industrialisation à savoir l’estimation des couples embrayages lors des phases de changement de rapport dans une transmission à double embrayage et le contrôle de la vitesse de glissement de l’embrayage pour une transmission à simple ou à double embrayage. Afin de répondre à la problématique d’estimation de couple embrayage, un capteur virtuel de couple a été développé. Ce capteur virtuel est composé d’une estimation de la torsion des arbres de transmission basée sur une méthode d’ajout de dents virtuelles dans les capteurs incrémentaux d’une part, et d’un observateur Takagi-Sugeno discrétisé dans le domaine angulaire d’autre part. Ce procédé a permis l’estimation des couples embrayages d’une transmission à double embrayage sur une plateforme de simulation fournie par Valeo comportant un modèle complet de véhicule. Le procédé a également été testé sur des données réelles de débattement de double volant amortisseur, des estimations en ligne du couple moteur instantané acyclique et du couple embrayage ont alors été obtenues. Au cours de l’étude dédiée au glissement contrôlé de l’embrayage, une stratégie de contrôle robuste aux perturbations extérieurs induites par le conducteur et aux dispersions du système a été développée. Cette stratégie permet de répondre aux spécifications du cahier des charges en simulation. La stratégie de glissement contrôlé a également été validée sur véhicule lors d’essais sur piste et sur banc à rouleau. / This PhD has been done in an industrial framework with the so-called automotive equipment manufacturer Valeo and the laboratory of Automatic Control, Mechanics, Informatics and Human Sciences LAMIH UMR CNRS 8201 of Valenciennes, France. The issues of this PhD are closed to the industrialization context such as the clutch torque estimation during the gear shifting phases in a dual clutch transmission and the clutch slip speed control. In order to solve the inline clutch torque estimation issues, a virtual torque sensor has been developed. On one hand, this virtual sensor is composed of a shaft torsion angle estimation based on a method of virtual tooth adding into the encoder sensors. On another hand, discrete angular domain unknown input Takagi-Sugeno observer is used for the estimation of the dynamic part of transmitted torque. This methodology has permitted the estimation of the transmitted clutch torque of a dual clutch transmission in simulation. The simulation results have been obtained on a simulation platform provided by Valeo, including a complete vehicle model. The methodology has also been tested on real data of a dual mass flywheel angular deflection. Thus, online estimation of instantaneous acyclic engine torque and transmitted clutch torque has been obtained. Concerning the slip control, a robust control strategy against the external disturbances leaded to the driver and the system parameters incertitude has been developed. This strategy permits to ensure the required specifications in simulation. The strategy has been also validated on vehicle during track trials.
150

Synthèse d'observateurs et développement de capteurs intelligents pour la maintenance prédictive / Observer design and development of intelligent sensors for predictive maintenance

Cuny, Fabien 02 July 2019 (has links)
Cette thèse s’inscrit dans le cadre de la disposition CIFRE entre la société Robert Bosch et l’Université de Caen Normandie au sein du laboratoire GREYC puis LAC. Elle comprend deux volets, l'un étant à caractère fondamental et porte sur la synthèse d'observateurs. Quant à l'autre volet, il est à caractère plus appliqué et porte sur la mise en œuvre d’un réseau de capteurs et assurer l’acheminement des informations provenant de ces derniers. Ce dernier est effectué au moyen du réseau, qu’il soit câblé ou sans fil.Dans le premier volet de l'étude, on s'est intéressé à une classe assez générale de systèmes temps-variant et affines en l'état, dont la sortie est mesurée avec un retard et échantillonnée. La nouveauté dans cette classe de systèmes est double :(i) l'équation d'état est sujette à une injection du signal de sortie et se retrouve de ce fait dépendante des sorties futures qui sont indisponibles;(ii) les sorties futures interviennent, au niveau de l'équation d'état, non seulement sous la forme usuelle d'une fonction indépendante de l'état, mais aussi à travers la matrice d'état ellemême qui, de ce fait, apparaît comme une quantité inconnue du modèle.Ces deux nouveautés du modèle entrainent en fait la perte du caractère « affine en l'état » de ce dernier et font que l'on se retrouve confronté à un problème de synthèse d'observateurs jamais résolu antérieurement. La solution que nous proposons est un observateur de type « Filtre de Kalman » augmenté d'un prédicteur inter-échantillons et d'opérateurs de saturations. Nous analysons la stabilité exponentielle du système d'erreur d'estimation d'état en utilisant le théorème du petit gain et des outils de la stabilité de Lyapunov. L'analyse met en évidence l'existence d'intervalles d'admissibilité dans lesquels doivent se situer les valeurs admissibles du retard et de la période d'échantillonnage, afin de garantir la convergence exponentielle de l'observateur.Dans le deuxième volet, nous nous intéressons à la maintenance prédictive au travers d’applications pratiques via la mise en place d’un réseau de capteurs. Le but de ce réseau est d’effectuer de la maintenance prédictive sur les équipements sensibles. Ce dernier est un composant essentiel à la mise en œuvre d’applications IoT et Industrie 4.0.Des applications de l’IoT et de l’Industrie 4.0 sur le site Robert Bosch de Mondeville sont évoqués ainsi que le développement d’un simulateur de perturbations réseau afin de tester la robustesse de la communication d’un capteur vers un client. / This thesis is part of the CIFRE agreement between the company Robert Bosch and the University of Caen Normandy in the laboratory GREYC then LAC. It consists of two parts, one which is of a fundamental nature and concerns the synthesis of observers. For the other part, it is more applied and concerns the implementation of a sensors network and ensure the routing of information from them. This is done through the network, whether wired or wireless.In the first part of the study, we looked at a fairly general class of time-varying and affine systems as they are, whose output is measured with a delay and sampled. The novelty in this class of systems is twofold:(i) the state equation is subject to an output signal injection and is therefore dependent on future outputs that are unavailable;(ii) future outputs occur at the state equation not only in the usual form of a stateindependent function, but also through the state matrix itself, which fact, appears as an unknown quantity of the model.These two novelties of the model cause in fact the loss of the "affine in the state" character of this last one, and make that one is confronted with a synthesis problem of observers never resolved previously. The solution we propose is a "Kalman filter" type observer augmented by an inter-sample predictor and saturation operators. We analyze the exponential stability of the state estimation error system by using the small gain theorem and tools of Lyapunov stability. The analysis highlights the existence of eligibility intervals in which the allowable values of the delay and the sampling period must be located in order to ensure the exponential convergence of the observer.In the second part, we are interested in predictive maintenance through practical applications via the installation of a sensor network. The purpose of this network is to perform predictive maintenance on sensitive equipment. The latter is an essential component for the implementation of IoT and Industry 4.0 applications.The purpose of this sensor network is to perform predictive maintenance on sensitive equipment. The latter is an essential component for the implementation of IoT and Industry 4.0 applications. Moreover, an observer of sampled data for affine systems in the state with output injection was studied on the basis of observers.Applications of IoT and Industry 4.0 on the Robert Bosch site in Mondeville are discussed as well as the development of a network disturbance simulator to stress the robustness of the communication of a sensor to a client.

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