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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.
1

Simulation and synchronization of distributed real-time systems / Simulering av distribuerade realtids system i Stateflow och TrueTime

Leuhusen, Joakim, Karlsson, Andreas January 2010 (has links)
<p>Today we are very much dependent on different kinds of real time systems. Usually,a real time system is a system which is interacting with a physical environmentwith sensors or activators. There are many advantages by replacing mechanicalcomponents with electrical ones. For instance, it is usually cheaper and possibleto add new functions to the device without replacing the electronic part, whichwould have been necessary with a mechanical one.The possibility of simulating a distributed system is used throughout the vehi-cle industry. With the simulation of connected sub systems, using modeled busesand real time kernels, one could increase the correctness of the behavior of the sys-tem and consequently decrease the amount of time spent later in the developingprocess.In this master thesis we used modeled CAN-buses and real time models tosimulate the connection and execution time of the systems. The simulation resultsare used to validate the functionality of the distributed system. Additionally, aworst-case response time analysis is made to set timing constraints on the systemto fulfill given deadlines.During the work, different settings of the network are tested to analyze thesystem frequency needed to sustain deadlines and correctness on the network.</p>
2

Simulation and synchronization of distributed real-time systems / Simulering av distribuerade realtids system i Stateflow och TrueTime

Leuhusen, Joakim, Karlsson, Andreas January 2010 (has links)
Today we are very much dependent on different kinds of real time systems. Usually,a real time system is a system which is interacting with a physical environmentwith sensors or activators. There are many advantages by replacing mechanicalcomponents with electrical ones. For instance, it is usually cheaper and possibleto add new functions to the device without replacing the electronic part, whichwould have been necessary with a mechanical one.The possibility of simulating a distributed system is used throughout the vehi-cle industry. With the simulation of connected sub systems, using modeled busesand real time kernels, one could increase the correctness of the behavior of the sys-tem and consequently decrease the amount of time spent later in the developingprocess.In this master thesis we used modeled CAN-buses and real time models tosimulate the connection and execution time of the systems. The simulation resultsare used to validate the functionality of the distributed system. Additionally, aworst-case response time analysis is made to set timing constraints on the systemto fulfill given deadlines.During the work, different settings of the network are tested to analyze thesystem frequency needed to sustain deadlines and correctness on the network.
3

Sistemas de controle distribuídos em redes de comunicação. / Networked control systems.

Takarabe, Erick Wakamoto 25 September 2009 (has links)
Sistemas de controle distribuídos cujas malhas são fechadas através de uma rede de comunicação são chamados de sistemas de controle distribuídos em redes de comunicação (NCS - Networked Control System). Este tipo de arquitetura permite a divisão do sistema de controle em módulos interconectados através da rede de comunicação, proporcionando a divisão do processamento, a redução de custo e de peso, além de facilitar o diagnóstico e manutenção do sistema e de aumentar a sua exibilidade e agilidade; e por isso seu emprego na indústria está se tornando comum (e.g., y-by-wire e drive-by-wire). Porém, a distribuição do processamento e a inserção de uma rede de comunicação aumenta a complexidade da análise e do projeto deste tipo de sistema. Um dos fatores que contribui para esse aumento da complexidade é a presença de atrasos aleatórios nos sinais de controle, causados pela dinâmica do sistema computacional (conjunto de hardware e software) que serve como plataforma para implementação do sistema de controle digital. Este trabalho faz um estudo sobre este tipo de sistema sob a perspectiva destes sinais com atrasos. Para isso, faz-se uso dos toolboxes para MATLAB: TrueTime e Jitterbug. Através destas ferramentas, mostra-se a existência de uma relação de compromisso entre o desempenho do controle e o desempenho do sistema computacional. Através deste estudo, é proposto uma solução de um sistema de controle do tipo NCS para um ROV (do inglês Remotely Operated Vehicle), modelado através de 6 equações diferenciais desacopladas não-lineares. Este tipo de veículo tem uma relevância econômica significativa para o Brasil, visto que é utilizado em operações de manutenção e instalação de plataformas de extração do petróleo que está depositado em profundidades que variam de mil a 2 mil metros. Para este NCS proposto, são utilizados controladores do tipo PI com estrutura feedback-feedfoward cujos parâmetros de projeto são obtidos em função dos atrasos inseridos pelo sistema computacional. / Distributed control systems wherein the control loops are closed through a communication network are called Networked Control Systems (NCSs). This type of architecture allows the control systems division into modules interconnected through the communication network, providing the processing division, reduction of cost and weight, and facilitates the systems diagnosis and maintenance, and increases their exibility and agility. Therefore its use in industry is becoming common (eg, y-by-wire and drive-by-wire). However, the processing distribution and the communication network insertion increase the system analysis and design complexity. One of the factors that contributes to this increased complexity is the presence of random time delays, caused by the dynamics of the computer system (set of hardware and software) used as a platform for digital control system implementation. This work deals with the networked control systems under these random time delays view. For this, it is used two MATLAB toolboxes: Jitterbug and TrueTime. With these tools, it is shown the existence of a relationship between the performance of control and performance of computer system. With this study, it proposed a solution of a NCS for a ROV (Vehicle Operated Remotely), modeled by 6 differential nonlinear decoupled equations. This type of vehicle has a significant economic relevance for Brazil, as it is used in maintenance and installation of platforms for oil extraction deposited at depths ranging from thousand to 2 thousand meters. For this proposed NCS are adopted PI controllers with feedfoward-feedback structure whose parameters design are given in terms of delay inserted by the computer system.
4

Sistemas de controle distribuídos em redes de comunicação. / Networked control systems.

Erick Wakamoto Takarabe 25 September 2009 (has links)
Sistemas de controle distribuídos cujas malhas são fechadas através de uma rede de comunicação são chamados de sistemas de controle distribuídos em redes de comunicação (NCS - Networked Control System). Este tipo de arquitetura permite a divisão do sistema de controle em módulos interconectados através da rede de comunicação, proporcionando a divisão do processamento, a redução de custo e de peso, além de facilitar o diagnóstico e manutenção do sistema e de aumentar a sua exibilidade e agilidade; e por isso seu emprego na indústria está se tornando comum (e.g., y-by-wire e drive-by-wire). Porém, a distribuição do processamento e a inserção de uma rede de comunicação aumenta a complexidade da análise e do projeto deste tipo de sistema. Um dos fatores que contribui para esse aumento da complexidade é a presença de atrasos aleatórios nos sinais de controle, causados pela dinâmica do sistema computacional (conjunto de hardware e software) que serve como plataforma para implementação do sistema de controle digital. Este trabalho faz um estudo sobre este tipo de sistema sob a perspectiva destes sinais com atrasos. Para isso, faz-se uso dos toolboxes para MATLAB: TrueTime e Jitterbug. Através destas ferramentas, mostra-se a existência de uma relação de compromisso entre o desempenho do controle e o desempenho do sistema computacional. Através deste estudo, é proposto uma solução de um sistema de controle do tipo NCS para um ROV (do inglês Remotely Operated Vehicle), modelado através de 6 equações diferenciais desacopladas não-lineares. Este tipo de veículo tem uma relevância econômica significativa para o Brasil, visto que é utilizado em operações de manutenção e instalação de plataformas de extração do petróleo que está depositado em profundidades que variam de mil a 2 mil metros. Para este NCS proposto, são utilizados controladores do tipo PI com estrutura feedback-feedfoward cujos parâmetros de projeto são obtidos em função dos atrasos inseridos pelo sistema computacional. / Distributed control systems wherein the control loops are closed through a communication network are called Networked Control Systems (NCSs). This type of architecture allows the control systems division into modules interconnected through the communication network, providing the processing division, reduction of cost and weight, and facilitates the systems diagnosis and maintenance, and increases their exibility and agility. Therefore its use in industry is becoming common (eg, y-by-wire and drive-by-wire). However, the processing distribution and the communication network insertion increase the system analysis and design complexity. One of the factors that contributes to this increased complexity is the presence of random time delays, caused by the dynamics of the computer system (set of hardware and software) used as a platform for digital control system implementation. This work deals with the networked control systems under these random time delays view. For this, it is used two MATLAB toolboxes: Jitterbug and TrueTime. With these tools, it is shown the existence of a relationship between the performance of control and performance of computer system. With this study, it proposed a solution of a NCS for a ROV (Vehicle Operated Remotely), modeled by 6 differential nonlinear decoupled equations. This type of vehicle has a significant economic relevance for Brazil, as it is used in maintenance and installation of platforms for oil extraction deposited at depths ranging from thousand to 2 thousand meters. For this proposed NCS are adopted PI controllers with feedfoward-feedback structure whose parameters design are given in terms of delay inserted by the computer system.
5

Sur la conception sûre des systèmes contrôlés en réseau. / On the safe design of networked control systems.

Naoui, Adel 19 December 2016 (has links)
De nos jours, les systèmes de contrôle-commande temps-réel distribués à travers un réseau de communication sont de plus en plus utilisés dans les secteurs de l’automobile, de l’avionique, de la robotique mobile, de la télécommunication et plus généralement de la conduite de procédés industriels. En comparaison avec les systèmes de contrôle point-à-point conventionnel, un système contrôlé en réseau (SCR) permet non seulement de réduire le câblage et les coûts d’installation, mais offre aussi plus de flexibilité pour faire évoluer une installation existante et favorise les actions de diagnostic et de maintenance. Comme le réseau est partagé par plusieurs boucles de contrôle et par d’autres applications, la conséquence est que le trafic de communication est difficilement maîtrisable, ce qui peut conduire à des pertes de messages et engendre des délais aléatoires. Par ailleurs, le diagnostic et la tolérance aux défauts sont des enjeux importants pour les SCR, particulièrement dans le cas ou le domaine d’utilisation exige une grande sécurité. Il est évident que la théorie et l’application des approches classiques de diagnostic et de tolérance aux défauts doivent être révisées lorsqu’il s’agit de SCR.L’étude des SCR, reposant sur des compétences en automatique, en informatique et en réseau propose naturellement des solutions propres à chaque domaine. La problématique du diagnostic des SCR consiste non seulement à détecter et localiser des défauts affectant l’ensemble du système mais aussi à distinguer, les perturbations et défaillances affectant le réseau de communication de celles du système contrôle. L’objectif de nos travaux de thèse est de proposer des modèles intégrés permettant de représenter le comportement des SCR et de contribuer à leurs diagnostics. / Real-time control systems distributed across communication networks are increasingly used in automotive, avionics, mobile robotics, and telecommunications and more generally in the conduct of industrial processes. Compared with point- to-point conventional control systems, a networked control system (NCS) can not only reduce wiring and installation costs, but also offer more flexibility to expand an existing facility and promote actions of diagnosis and maintenance. As the network is shared by multiple control loops and other applications, the result is that the communication traffic is difficult to control, which can lead to loss of messages and generate random delays.Diagnosis and fault tolerance are important issues for NCS, especially in the case where the area of application requires security. It’s obvious that the theory and application of conventional approaches to diagnosis and fault tolerance need to be revised when it comes to NCS.The study of the NCS, based on automatic skills, computer science and network competences naturally provides adequate solutions to each area. The problem of NCS diagnosis is the one hand to detect and locate faults affecting the whole system and on the other hand to distinguish, disturbances and malfunctions affecting the communication network of the control system.Our work aims is to propose integrated models to represent the behavior of NCS and contribute to its diagnosis.
6

Systém snímání dat a ovládání vodní elektrárny prostřednictvím internetové techniky / Data Acquisition and Control System of Hydroelectric Power Plant Using Internet Techniques

Sattouf, Mousa January 2015 (has links)
Vodní energie se nyní stala nejlepším zdrojem elektrické energie na zemi. Vyrábí se pomocí energie poskytované pohybem nebo pádem vody. Historie dokazuje, že náklady na tuto elektrickou energii zůstávají konstantní v průběhu celého roku. Vzhledem k mnoha výhodám, většina zemí nyní využívá vodní energie jako hlavní zdroj pro výrobu elektrické energie.Nejdůležitější výhodou je, že vodní energie je zelená energie, což znamená, že žádné vzdušné nebo vodní znečišťující látky nejsou vyráběny, také žádné skleníkové plyny jako oxid uhličitý nejsou vyráběny, což činí tento zdroj energie šetrný k životnímu prostředí. A tak brání nebezpečí globálního oteplování. Použití internetové techniky k ovladání několika vodních elektráren má velmi významné výhody, jako snížení provozních nákladů a flexibilitu uspokojení změny poptávky po energii na straně spotřeby. Také velmi efektivně čelí velkým narušením elektrické sítě, jako je například přidání nebo odebrání velké zátěže, a poruch. Na druhou stranu, systém získávání dat poskytuje velmi užitečné informace pro typické i vědecké analýzy, jako jsou ekonomické náklady, predikce poruchy systémů, predikce poptávky, plány údržby, systémů pro podporu rozhodování a mnoho dalších výhod. Tato práce popisuje všeobecný model, který může být použit k simulaci pro sběr dat a kontrolní systémy pro vodní elektrárny v prostředí Matlab / Simulink a TrueTime Simulink knihovnu. Uvažovaná elektrárna sestává z vodní turbíny připojené k synchronnímu generátoru s budicí soustavou, generátor je připojen k veřejné elektrické síti. Simulací vodní turbíny a synchronního generátoru lze provést pomocí různých simulačních nástrojů. V této práci je upřednostňován SIMULINK / MATLAB před jinými nástroji k modelování dynamik vodní turbíny a synchronního stroje. Program s prostředím MATLAB SIMULINK využívá k řešení schematický model vodní elektrárny sestavený ze základních funkčních bloků. Tento přístup je pedagogicky lepší než komplikované kódy jiných softwarových programů. Knihovna programu Simulink obsahuje funkční bloky, které mohou být spojovány, upravovány a modelovány. K vytvoření a simulování internetových a Real Time systémů je možné použít bud‘ knihovnu simulinku Real-Time nebo TRUETIME, v práci byla použita knihovna TRUETIME.

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