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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.
41

Determinação das freqüências naturais e modos de vibrar de um veículo de dois eixos através de um programa computacional em Matlab-Simulink / Determination of the natural frequencies and ways to vibrate of a vehicle of two axles through a computational program in MatLab-Simulink

Ferreira, Hudson Tadeu 10 December 2003 (has links)
Este trabalho obtém as frequências naturais e seus respectivos modos de vibrar da massa suspensa e não suspensa de um veículo comercial através de um programa computacional desenvolvido em MatLab Simulink. As rodas do veículo são excitadas no modelo teórico com sinais harmônicos de frequência continuamente variável de 0 a 40 Hz e de 0 a 4 Hz, faixas que contém as frequências naturais da massa suspensa e não suspensa. As frequências naturais foram obtidas analisando-se a amplitude máxima das forças normais nos pneus, ângulo de arfagem e rolamento da massa suspensa e outras variáveis (respostas do veículo à excitação imposta na roda dianteira esquerda). A roda esquerda dianteira do veículo foi excitada em laboratório com movimento harmônico aleatório cujo power spectral density mostra uma faixa relativamente plana na faixa de 0 a 22 Hz. As frequências naturais foram obtidas analisando-se o PSD da resposta do veículo medida nos eixos e na massa suspensa. As frequências naturais da massa suspensa e não suspensa obtidas teoricamente foram comparadas com as obtidas no ensaio em laboratório. O conhecimento das frequências naturais da massa suspensa e não suspensa é o primeiro passo para a análise do ride do veículo. Os resultados práticos e teóricos mostraram-se próximos mostrando que o programa computacional desenvolvido em MatLab Simulink é uma opção para o projeto e otimização da suspensão de veículos comerciais. / This study has the natural frequencies and its respective ways of vibration the lifted mass and not lifted of a commercial vehicle through a computerized program developed at MatLab Simulink. The wheels of this vehicle are excited on the theoretic model with harmonic frequency signals continuously variable from 0 to 40 Hz and from 0 to 4 Hz, ranges that have the natural frequencies of the lifted mass and not lifted. These natural frequencies were obtained by analyses of the maximum amplitude of the normal strength on the tires, pitch angle, riding of the lifted mass and variables (reaction of the vehicle to the excitement stressed on the front left wheel). The front left wheel was excited in lab in harmonic random motion of which the power spectral density shows a range reasonable steady at the range of 0 to 22 Hz. The natural frequencies were obtained by the analyses of the PSD the reaction of the vehicle measured on the axels and the lifted mass. The natural frequencies of the lifted and not lifted mass theoretically obtained were compared with the ones obtained at the lab. The data on the natural frequencies of the lifted and not lifted mass is the first step to the analyses of the ride of the vehicle. The practical and theoretical results appear to close showing that the computerized program developed at the MatLab Simulink is an option for the project and suspension upgrades on commercial vehicles.
42

Determinação das freqüências naturais e modos de vibrar de um veículo de dois eixos através de um programa computacional em Matlab-Simulink / Determination of the natural frequencies and ways to vibrate of a vehicle of two axles through a computational program in MatLab-Simulink

Hudson Tadeu Ferreira 10 December 2003 (has links)
Este trabalho obtém as frequências naturais e seus respectivos modos de vibrar da massa suspensa e não suspensa de um veículo comercial através de um programa computacional desenvolvido em MatLab Simulink. As rodas do veículo são excitadas no modelo teórico com sinais harmônicos de frequência continuamente variável de 0 a 40 Hz e de 0 a 4 Hz, faixas que contém as frequências naturais da massa suspensa e não suspensa. As frequências naturais foram obtidas analisando-se a amplitude máxima das forças normais nos pneus, ângulo de arfagem e rolamento da massa suspensa e outras variáveis (respostas do veículo à excitação imposta na roda dianteira esquerda). A roda esquerda dianteira do veículo foi excitada em laboratório com movimento harmônico aleatório cujo power spectral density mostra uma faixa relativamente plana na faixa de 0 a 22 Hz. As frequências naturais foram obtidas analisando-se o PSD da resposta do veículo medida nos eixos e na massa suspensa. As frequências naturais da massa suspensa e não suspensa obtidas teoricamente foram comparadas com as obtidas no ensaio em laboratório. O conhecimento das frequências naturais da massa suspensa e não suspensa é o primeiro passo para a análise do ride do veículo. Os resultados práticos e teóricos mostraram-se próximos mostrando que o programa computacional desenvolvido em MatLab Simulink é uma opção para o projeto e otimização da suspensão de veículos comerciais. / This study has the natural frequencies and its respective ways of vibration the lifted mass and not lifted of a commercial vehicle through a computerized program developed at MatLab Simulink. The wheels of this vehicle are excited on the theoretic model with harmonic frequency signals continuously variable from 0 to 40 Hz and from 0 to 4 Hz, ranges that have the natural frequencies of the lifted mass and not lifted. These natural frequencies were obtained by analyses of the maximum amplitude of the normal strength on the tires, pitch angle, riding of the lifted mass and variables (reaction of the vehicle to the excitement stressed on the front left wheel). The front left wheel was excited in lab in harmonic random motion of which the power spectral density shows a range reasonable steady at the range of 0 to 22 Hz. The natural frequencies were obtained by the analyses of the PSD the reaction of the vehicle measured on the axels and the lifted mass. The natural frequencies of the lifted and not lifted mass theoretically obtained were compared with the ones obtained at the lab. The data on the natural frequencies of the lifted and not lifted mass is the first step to the analyses of the ride of the vehicle. The practical and theoretical results appear to close showing that the computerized program developed at the MatLab Simulink is an option for the project and suspension upgrades on commercial vehicles.
43

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.
44

Contribution à l’étude des non-linéarités au sein d’une association amplificateur-transducteur : atténuation des distorsions par un mode de contrôle en courant / Investigation on the non-linear behaviour of amplifier-transducer compounds : reducing distortion by way of current driving

Erza, Mehran 22 November 2013 (has links)
Ce travail réalisé au LAUM, concerne en premier lieu la caractérisation des distorsions, notamment non linéaires,observables sur des haut-parleurs en vue de les miniaturiser.En outre l’étude se rapporte au mode de contrôle de tels transducteurs au regard des avantages et des inconvénients présentés par l’électronique d’un pilotage en intensité.Après rappel des principales définitions permettant d’appréhender les mesures électroacoustiques, la structure et les propriétés des haut-parleurs font l’objet d’une première analyse, discutée dans le cadre des hypothèses de linéarité.Les exemples et les caractéristiques décrits en termes de fonctions de transfert sont présentés autour d’un transducteur générique de l’état de la technique. Les principes de la commande en courant sont ensuite présentés, compte tenu des caractéristiques globales des amplificateurs opérationnels de puissance disponibles actuellement. En maintenant l’intégrité de l’indice de contrôle en courant (Control Drive Index), la réjection du pic de résonance mécanique et des hautes fréquences sont discutés autour de structures de filtrages, soit incorporées à la boucle de feedback et adaptées au transducteur, soit disposées en feed forward. Au-delà de ces considérations de premier ordre les comportements non linéaires sont examinés. Après une analyse fondamentale se rapportant aux définitions et aux caractéristiques de non-linéarité, une évaluation analytique en régime mono fréquentiel est présentée, pour un transducteur commandé en courant. L’analyse est ensuite généralisée au moyen de modèles numériques originaux réalisés sous Simulink®, PSpice® et SLPS avec des sollicitations bitonales.Considérant divers dispositifs de l’état de la technique, des résultats conformes à ceux de la littérature récente et validés par l’expérience sont obtenus. Ainsi, les prototypes de micro haut-parleurs réalisés au laboratoire seront à court terme caractérisés avec plusieurs modes de conditionnement. / Undertaken with the LAUM, this work aims at first tocharacterize non linear distortions relative to electrodynamicloudspeakers with a view to miniaturizing units designed in thelaboratory. Furthermore, a special point about the advantages and drawbacks resulting from voltage or current driving has been investigated. After a brief review about the prominent definitions used in thefield of electro-acoustics, the main properties and specificitiesof transducers are discussed while considering at first linear devices. Considering a generic transducer of the state of theart, the main parameters are given in terms of transfer functions. Then, a current-driving policy is discussed whiletaking account of the actual power operational amplifier properties. Furthermore, the rejection of the mechanical resonance is investigated without any kind of alteration of theideal infinity of the Control Drive Index value. Specific filtering structures are calculated regarding a given transducer and considered either in feedforward or feedback arrangements within the circuitry. After such a first order analysis non linear behaviours areconsidered. At first a straightforward typology of non linearsystems is presented so as to highlight the most importantdefinitions. Then, a special analytical approach is given,allowing us to analyse the harmonic generation from a currentdriven loudspeaker with a mono frequency regime. Such anapproach is extended and generalized by way of original numerical models designed with Simulink®, PSpice® and SLPSsoftware, considering bi tonal stimuli signals. Then, such anapproach is considered with transducers and amplifiers of thestate of the art, allowing us to validate the whole relevantrationale. Thus, the micro speakers actually developed in thelaboratory should be investigated and optimized in the shortrun, considering their relevant electronic conditioning policy.
45

Requirement Recognition: Evaluierung von Ansätzen zur automatischen Generierung von Code aus Kundenanforderungen

Kraus, Patrice 12 September 2018 (has links)
Innerhalb der Automobilindustrie hat sich MATLAB/Simulink als Standardsoftware zur Entwicklung von Steuergerätsoftware durchgesetzt und besticht durch eine hohe technische Abstraktion sowie eine gute Lesbarkeit. Dabei bedient sich Simulink den Prinzipien der modellgetriebenen Softwareentwicklung, bei denen Software in einer domänenspezifischen Sprache entwickelt wird und anschließend auf eine technisch niedrigere Abstraktionsebene transformiert wird. Das in dieser Masterarbeit entwickelte Anforderungskonzept für eingebettete Systeme ermöglicht die teilautomatisierte Übertragung von Softwareanforderungen in ein Simulink-Modell und fügt dem Konzept der modellgetriebenen Softwareentwicklung eine zusätzliche Abstraktionsebene hinzu. Das Augenmerk liegt hierbei auf der Reduzierung von manuellen und redundanten Arbeitsschritten sowie einer hohen Übereinstimmung von Pflichtenheft und Modell. Das vorgestellte Konzept unterstützt eine vollautomatische Architekturgenerierung auf Basis des Pflichtenheft sowie Parameter und Signaldefinitionen. Ergänzend wird auch eine Notation zur teilautomatischen Generierung funktionaler Anforderungen vorgestellt aber auch informelle Anforderungsdefinitionen unterstützt und Softwaregestaltungsrichtlinien der ISO-26262 konzeptionell mitberücksichtigt. Abschließend wird eine prototypische Implementierung eines Transformators aufgezeigt und die Funktionalität anhand eines Fallbeispiels demonstriert. Hierbei hat sich gezeigt das auf Basis von wenigen Anforderungen ein hochspezifiziertes Simulink-Modell erstellt werden kann, welches dem Entwickler zahlreiche Routineaufgaben abnimmt und eine Konzentration auf die konzeptionell schwierigen Elemente der Softwareentwicklung erlaubt. / Within the automotive industry MATLAB/Simulink has established itself as standard software for the development of electronic control unit software and impresses with its high technical abstraction and good readability. Simulink uses the principles of model-driven software development, in which software is developed in a domainspecific language and then transformed to a technically lower abstraction level. The requirements concept for embedded systems developed in this master thesis enables the semi-automated transfer of software requirements into a Simulink model and adds an additional abstraction level to the concept of model-driven software development. The focus here is on the reduction of manual and redundant work steps as well as a high degree of conformity between the specifications and the model. The presented concept supports a fully automatic architecture generation based on the requirement specification as well as parameters and signal definitions. In addition, a notation for semi-automatic generation of functional requirements is presented, but informal requirement definitions are also supported and software design guidelines of ISO-26262 are conceptually taken into account. Finally, a prototype implementation of a transformer will be displayed and its functionality demonstrated by means of a case study. This has shown that a highly specified Simulink model can be created on the basis of a few requirements, which relieves the developer of numerous routine tasks and allows concentration on the conceptually difficult elements of software development.
46

Applying Formal Methods to Autonomous Vehicle Control / Application des méthodes formelles au contrôle du véhicule autonome

Duplouy, Yann 26 November 2018 (has links)
Cette thèse s'inscrit dans le cadre de la conception de véhicules autonomes, et plus spécifiquement de la vérification de contrôleurs de tels véhicules. Nos contributions à la résolution de ce problème sont les suivantes : (1) fournir une syntaxe et une sémantique pour un modèle de systèmes hybrides, (2) étendre les fonctionnalités du model checker statistique Cosmos à ce modèle et (3) valider empiriquement la pertinence de notre approche sur des cas d'étude typiques du véhicule autonome.Nous avons choisi de combiner le modèle des réseaux de Petri stochastiques de haut niveau (qui était le formalisme d'entrée de Cosmos) avec le formalisme d'entrée de Simulink afin d'atteindre un pouvoir d'expression suffisant. En effet Simulink est très largement utilisé dans le domaine automobile et de nombreux contrôleurs sont spécifiés avec cet outil. Or Simulink n'a pas de sémantique formellement définie. Ceci nous a conduit à concevoir une telle sémantique en deux temps : tout d'abord en introduisant une sémantique dite exacte mais qui n'est pas opérationnelle puis en la complétant par une sémantique approchée intégrant le facteur d'approximation recherché.Afin de combiner le modèle à événements discrets des réseaux de Petri et le modèle continu spécifié en Simulink, nous avons proposé au niveau syntaxique une interfacereposant sur de nouveaux types de transitions et au niveau sémantique une extension de la boucle de simulation. L'évaluation de ce nouveau formalisme a été entièrement implémentée dans Cosmos.Grace à ce nouveau formalisme, nous avons développé et étudié les deux cas d'étude suivants : d'une part une circulation dense sur une section d'autoroute et d'autre part l'insertion du véhicule dans une voie rapide. L'analyse des modélisations correspondantes a démontré la pertinence de notre approche. / This thesis takes place in the context of autonomous vehicle design, and concerns more specifically the verification of controllers of such vehicles. Our contributions are the following: (1) give a syntax and a semantics for a hybrid system model, (2) extend the capacities of the model-checker Cosmos to that kind of models, and (3) empirically confirm the relevance of our approach on typical case studies handling autonomous vehicles.We chose to combine high-level stochastic Petri nets (which is the input formalism of Cosmos) with the input formalism of Simulink, to obtain an adequate expressive power. Indeed, Simulink is largely used in the automotive industry and numerous controllers have been specified using this tool. However, there is no formal semantics for Simulink, which lead us to define such a semantics in two steps:first, we propose an exact (but not operational) semantics, then we complete it by an approximate semantics that includes the targeted approximation level.In order to combine the discrete event model of Petri nets and the continous model specified in Simulink, we define a syntactic interface that relies on new transition types; its semantics consists of an extension of the simulation loop. The evaluation of this new formalism has been entirely implemented into Cosmos.Using this new formalism, we have designed and studied the two following case studies: on one hand, a heavy traffic on a motorway segment, and on the other hand the insertion of a vehicle into a motorway. Our approach has been validated by the analysis of the corresponding models.
47

Simulation of a Complete Cardiovascular Loop: Development of a Simulink Based Pressure-Flow Model to Obtain the Origin of the Electrical Impedance Cardiogram

Trivedi, Dyuti Kishorbhai 09 June 2009 (has links)
No description available.
48

Dynamic Architectural Simulation Model of YellowCar in MATLAB/Simulink Using AUTOSAR System

Soltani, Saeed 28 September 2016 (has links)
The YellowCar at the professorship of computer engineering of TU Chemnitz is a demonstration vehicle. The car is equipped with multiple networked Electronic Control Unit (ECU)s. There are regular software and hardware updates. Before introduction of any new update, it is essential to test the behavior of the car. This can be done through simulation. Since the majority of the ECU in YellowCar are AUTOSAR based, several AUTOSAR simulation tools can be used to do so. However non-AUTOSAR ECU applications can still not be simulated in these tools. Moreover simulating with such tools need the whole application to be implemented and also very expensive. Simulink is one of the most powerful tools for the purpose of Model-in-the-Loop (MIL) testing which is a popular strategy in the embedded world. The scope of this Master thesis is analyzing the YellowCar and its architecture to develop a dynamic Simulink architectural model that can be modified and extended to facilitate future updates. The outcome of this thesis is an implementation of a model for the YellowCar which allows both AUTOSAR and non-AUTOSAR ECUs to be simulated as one system. Also the model supports extension by easy addition of new modules like ECU or sensor through a graphical user interface.
49

Dynamische Simulationskopplung von Simulink-Modellen durch einen Functional-Mock-up-Interface-Exportfilter

Lang, Jens, Rünger, Gudula, Stöcker, Paul January 2013 (has links)
Für den Austausch und zur Kopplung von Simulationsmodellen ist die Nutzung herstellerübergreifender Standards wie des Functional Mock-up-Interfaces (FMI) unerlässlich. In diesem Artikel wird eine Methode zum automatisierten Export von Simulationsmodellen aus Simulink in Module nach dem Standard FMI for Co-Simulation vorgestellt. Der automatisierte Export nutzt den Quelltextgenerator von Simulink und passt diesen über Templates für den Target Language Compiler so an, dass der erzeugte Quelltext das Functional Mock-up Interface implementiert. Der Artikel beschreibt die Methode zum Auslesen der Signaldefinitionen inkl. Bezeichner und Typen aus dem Simulink-Modell und die Methode zur Generierung des FMI-Quelltextes.
50

FPGAs: RE-INVENTING THE SIGNAL PROCESSOR

Dick, Chris 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / FPGAs are increasingly being employed for building real-time signal processing systems. They have been used extensively for implementing the PHY in software radio architectures. This paper provides a technology and market perspective on the use FPGAs for signal processing and demonstrates FPGA DSP using an adaptive channel equalizer case study.

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