To see the other types of publications on this topic, follow the link: Distribued control.
Dissertations / Theses on the topic 'Distribued control'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Distribued control.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Piardi, Artur Bohnen. "Proposta de uma estrutura híbrida de controle para sistemas de excitação de geradores síncronos distribuídos." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-19032018-075506/.
Full textAbstract:
Com o advento da geração distribuída foi permitido aos sistemas de distribuição a possibilidade de operação de forma ilhada dos sistemas interligados de grande porte. Apesar de suas vantagens, do ponto de vista técnico, ainda existe uma série de desafios que necessitam ser superados para a plena aplicação desse conceito. Um desses desafios é definido pela transição dos modos operativos dos geradores distribuídos durante o processo de ilhamento. Da forma em que é reportada na literatura, infere-se que tal transição é realizada de um modo inadequado, amplificando os transitórios observados nas grandezas do gerador distribuído - e por consequência, da rede em que o mesmo se conecta - durante o processo de ilhamento, o que não é desejável. No contexto apresentado, a principal contribuição desta pesquisa está em propor uma estrutura híbrida de controle a ser aplicada aos sistemas de excitação de geradores síncronos que operam em sistemas de distribuição que permitem a operação ilhada de determinadas porções de suas redes. A principal característica da estrutura proposta está em atenuar os transitórios das variáveis do gerador controlado durante o processo de ilhamento. Além disso, o arranjo da estrutura proposta estabelece um compromisso entre a potência reativa e a tensão terminal do gerador controlado, quando o mesmo opera em paralelo com os sistemas interligados de grande porte. Nessa condição, o sistema de controle mantém a potência reativa próxima da referência ajustada atendendo a uma faixa adequada de valores de tensão terminal.With the advent of distributed generation, the possibility of autonomous operation regarding the bulk power systems was allowed to the distribution systems. Despite its advantages, from the technical point of view, there are lots of challenges that need to be overcome for the full application of this concept. One of these challenges is the transition of distributed generators operating modes during the islanding process. Based in the literature survey, it is inferred that transition is performed in a wrong way, which amplifies the transients in controlled generator quantities and consequently, of the network connected to it during the islanding process, which is undesirable. In this context, the main contribution of this research is the proposal of a hybrid control structure to be applied to the excitation systems of synchronous generators that operate in distribution systems whose islanded operation of determined portions of its grids is permitted. The main characteristic of the proposed structure is the attenuation of transients of the controlled generator quantities during the islanding process. Furthermore, the design of this structure provides a compromise between the generator reactive power and terminal voltage when it operates in parallel with the bulk power systems. That way, the control system maintains the reactive power close to the adjusted reference attending an appropriate range of terminal voltage values.
2
Pham, Hoang Anh. "Coordination de systèmes sous-marins autonomes basée sur une méthodologie intégrée dans un environnement Open-source." Electronic Thesis or Diss., Toulon, 2021. http://www.theses.fr/2021TOUL0020.
Full textAbstract:
Cette thèse étudie la coordination de robots sous-marins autonomes dans le contexte d’exploration de fonds marins côtiers ou d’inspections d’installations. En recherche d’une méthodologie intégrée, nous avons créé un framework qui permet de concevoir et simuler des commandes de robots sous-marins low-cost avec différentes hypothèses de modèle de complexité croissante (linéaire, non-linéaire, et enfin non-linéaire avec des incertitudes). Sur la base de ce framework articulant plusieurs outils, nous avons étudié des algorithmes pour résoudre le problème de la mise en formation d’un essaim, puis celui de l’évitement de collisions entre robots et celui du contournement d’obstacle d’un groupe de robots sous-marins. Plus précisément, nous considérons d'abord les modèles de robot sous-marin comme des systèmes linéaires de type simple intégrateur, à partir duquel nous pouvons construire un contrôleur de mise en formation en utilisant des algorithmes de consensus et d’évitement. Nous élargissons ensuite ces algorithmes pour le modèle dynamique non linéaire d’un robot Bluerov dans un processus de conception itératif. Nous intégrons ensuite un réseau de neurones de type RBF (Radial Basis Function), déjà éprouvé en convergence et stabilité, avec le contrôleur algébrique pour pouvoir estimer et compenser des incertitudes du modèle du robot. Enfin, nous décrivons les tests de ces algorithmes sur un essaim de robots sous-marins réels BlueROV en environement Opensource de type ROS et programmés en mode autonome. Ce travail permet également de convertir un ROV téléopéré en un hybride ROV-AUV autonome. Nous présentons des résultats de simulation et des essais réels en bassin validant les concepts proposésThis thesis studies the coordination of autonomous underwater robots in the context of coastal seabed exploration or facility inspections. Investigating an integrated methodology, we have created a framework to design and simulate low-cost underwater robot controls with different model assumptions of increasing complexity (linear, non-linear, and finally non-linear with uncertainties). By using this framework, we have studied algorithms to solve the problem of formation control, collision avoidance between robots and obstacle avoidance of a group of underwater robots. More precisely, we first consider underwater robot models as linear systems of simple integrator type, from which we can build a formation controller using consensus and avoidance algorithms. We then extend these algorithms for the nonlinear dynamic model of a Bluerov robot in an iterative design process. Then we have integrated a Radial Basis Function neural network, already proven in convergence and stability, with the algebraic controller to estimate and compensate for uncertainties in the robot model. Finally, we have presented simulation results and real basin tests to validate the proposed concepts. This work also aims to convert a remotely operated ROV into an autonomous ROV-AUV hybrid
3
Nguyen, Thi Thanh Quynh. "A new approach for distributed programming in smart grids." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT079.
Full textAbstract:
Le principal défi du contrôle et de la gestion des réseaux électriques intelligents (Smartgrids) est la quantité de données à traiter. Les techniques classiques centralisées, même si elles offrent l’avantage de facilité de gestion par leur vision globale du réseau, ne supportent pas en pratique la croissance continue des volumes de données (bande passante limitée, goulot d’étranglement, quantité de calculs à assurer, etc.). Le passage à un contrôle et une gestion décentralisée (répartie), où le système est composé d’une multitude d’unités de calcul coopérantes, offre de très bonnes perspectives (robustesse, calcul au plus près des producteurs et consommateurs de données, exploitation de toutes les ressources disponibles), mais reste difficile à mettre en place. En effet, la programmation d’algorithmes distribués nécessite de prendre en compte les échanges de données et la synchronisation des unités participantes, cette complexité augmentant avec le nombre d’unités. Dans cette thèse, nous proposons une approche innovante de programmation de haut niveau d’abstraction masquant ces difficultés.Tout d’abord, nous proposons d’abstraire l’ensemble des unités de calcul du Smartgrid (compteur intelligent, capteurs, concentrateurs de données, etc.) sous forme d’une base de données distribuées. Chaque unité de calcul hébergeant une base de données locale et seules les données nécessaires à la poursuite du calcul sont échangées avec d’autres unités, ce qui diminue l’utilisation de la bande passante disponible. L’utilisation d’un langage de manipulation de données déclaratif simplifiera la programmation des applications de contrôle et de gestion. Nous proposons également SmartLog, un langage à base de règles (basé sur le langage Datalog et ses dérivés) dédié à ces applications. Il facilite la programmation distribuée des applications Smartgrid en réagissant immédiatement à tout changement dans les données.Même avec un langage tel que SmartLog, il est nécessaire de prendre en compte les échanges de données et la synchronisation des participants. C’est pourquoi nous proposons ensuite une approche simplifiant la programmation distribuée. Cette approche, nommée CPDE pour Centralized Programmation and Distributed Execution, consiste en deux étapes : (i) programmer l’application centralisée en SmartLog, car cela est plus facile, et (ii) traduire le programme centralisé en programme distribué en se basant sur la localisation réelle des données. Pour ce faire, nous proposons un algorithme de distribution semi-automatique des règles SmartLog.Afin de démontrer l’intérêt de CPDE, nous avons mené une expérimentation exhaustive en utilisant des applications et des algorithmes réellement utilisés dans les Smartgrids, telles que le contrôle secondaire dans les micro-réseaux isolés ou la régulation de tension équitable. L’expérimentation a été réalisée sur une plate-forme de simulation de réseau électrique temps réel, avec une machine de simulation OPAL-RT, et des un réseau Raspberry-Pi représentant les unités de calcul (leurs performances sont tout à fait comparables aux équipements réels). Cette expérimentation a permis de valider les comportements et les performances des programmes distribués conçus avec CPDE comparativement à leurs versions centralisées en SmartLog et à leurs versions de référence implantés en Java. Nous avons également étudié l’impact de différents paramètres, tels que le nombre d’unités de calcul ou les différentes alternatives de répartition des donnéesThe main challenge of smart grids control and management is the amount of data to be processed. Traditional, centralized techniques, even if they offer the advantage of the ease of management by their global grid vision, do not support in practice the continuous growth of data volumes (limited bandwidth, bottleneck, amount of calculations, etc.). The transition to decentralized(distributed)control and management, where the system is made up of a multitude of co-operating computing units, offers very good prospects (robustness, calculation close to the producers and consumers of data, exploitation of data in all available resources), but remains challenging to implement. In fact, the programming of distributed algorithms requires taking into account the data exchanges and the synchronization of the participating units; this complexity increases with the number of units. In this thesis, we propose an innovative approach of programming of a high level of abstraction masking these difficulties.First, we propose to abstract all Smartgrid computing units (smart meters, sensors, data concentrators, etc.) as a distributed database. Each computing unit hosts a local database and only the data needed to continue the calculation are exchanged with other units, which decreases the use of the available bandwidth. The use of a declarative data handling language will simplify the programming of control and management applications. Besides, we also propose SmartLog, a rule-based language (based on the Datalog language and its derivatives dedicated to these applications. It facilitates distributed programming of Smartgrid applications by immediately responding to any changes in the data.Even with a language such as SmartLog, it is necessary to take into account the data exchange and the synchronization of the participants. This is why we then propose an approach that simplifies distributed programming. This approach, named CPDE for Centralized Programming and Distributed Execution, consists of two steps: (i) programming the centralized application in SmartLog, as this is easier, and (ii) translating the centralized program into a distributed program based on the actual location of the data. To do this, we propose a semi-automatic Smartlog rule distribution algorithm.In order to demonstrate the interest of CPDE, we conducted a comprehensive experiment using applications and algorithms actually used in Smartgrids, such as secondary control in isolated micro-grids or fair voltage regulation. The experiment was carried out on a real-time electrical network simulation platform, with an OPAL-RT simulation machine, and a Raspberry-Pi network representing the computing units (their performances are quite comparable to the real equipment). This experiment allowed validating the behaviours and the performances of the distributed programs conceived with CPDE, and comparing to their centralized versions in SmartLog and their reference versions implanted in Java. The impact of different parameters, such as the number of calculation units or different data distribution alternatives, is studied as well
4
Dal, col Laura. "On distributed control analysis and design for Multi-Agent systems subject to limited information." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0034/document.
Full textAbstract:
Les systèmes multi-agents sont des systèmes dynamiques composés par plusieurs éléments qui interagissent entre eux. Ces éléments sont appelés agents. Un agent est un système dynamique caractérisé par deux propriétés. La première est que les agents sont autonomes— c’est-à-dire qu’ils ne sont pas dirigés par l’environnement extérieur et ils peuvent évoluer selon un comportement auto-organisé. La seconde est que les agents sont capables de communiquer entre eux pour accomplir des tâches complexes, telles que la coopération, la coordination et la résolution de conflits. L’un des problèmes courants concernant les systèmes multi-agents est la synchronisation. Les agents sont synchronisés lorsque leur évolution dans le temps converge vers une trajectoire commune. Plusieurs applications du monde réel peuvent être conceptualisés comme des problèmes de synchronisation des systèmes multi-agents : par exemple, l’alignement en vitesse ( flocking en anglais), et le contrôle de la formation du mouvement de groupes cohérents. La synchronisation des systèmes multi-agents peut être obtenue grâce à différentes techniques de contrôle. Dans cette thèse nous proposons des méthodes de contrôle centralisées et distribuées pour la synchronisation des systèmes multi-agents. Nous développons des conditions nécessaires et suffisantes pour la synchronisation des systèmes multi-agents, composés par des agents identiques et linéaires qui ne changent pas dans le temps, en utilisant une approche Lyapunov. Ces conditions sont utilisées pour la conception de lois de contrôles distribuées. ensuite, nous étendons les résultats aux systèmes multi-agents soumis à des perturbations externes, assurant un niveau de performance désiré grâce à une technique de contrôle de type 퐻 ∞ . enfin, nous étendons l’analyse aux systèmes multi-agents avec contraintes sur les actionneurs, en utilisant des techniques de contrôle anti-windup. Nous évaluons l’efficacité et les performances des stratégies de contrôle proposées dans plusieurs simulations, dont deux d’entre elles sont inspirées par des applications issues du monde réel. La première est le contrôle du vol en formation d’avions, et la seconde est l’analyse de la transmission de contenus vidéo comme un problème de synchronisation. Nous comparons aussi les résultats obtenus avec des techniques de contrôle alternativesMulti-agent systems are dynamical systems composed of multiple interacting elements known as agents . Each agent is a dynamical system with two characteristics. First, it is capable of autonomous action—that is, it is able to evolve according to a self-organised behavior, which is not influenced by the external environment. Second, it is able to exchange information with other agents in order to accomplish complex tasks, such as coordination, cooperation, and conflict resolution. One commonly studied problem in multi-agent systems is synchronization. The agents are synchronized when their time evolutions converge to a common trajectory. Many real-world applications, such as flocking and formation control, can be cast as synchronization problems. Agent synchronization can be achieved using different approaches. In this thesis, we propose distributed and centralized control paradigms for the synchronization of multi-agent systems. We develop necessary and sufficient conditions for the synchronization of multi-agent systems, composed by identical linear time-invariant agents, us- ing a Lyapunov-based approach. Then we use these conditions to design distributed synchronization controllers. Then, we extend this result to multi-agent systems subject to external disturbances enforcing disturbance rejection with 퐻 ∞ control techniques. Furthermore, we extend the analysis to multi-agent systems with actuator constraints using LMI-based anti-windup techniques. We test the proposed control design strategies in simulated examples among which two are inspired by real-world applications. In the first, we study airplane formation control as a synchronization problem. In the second, we analyze the delivery of video streams as a synchronization problem and we compare the results to existing controllers
5
Rossi, Luís Filipe Fragoso de Barros e. Silva. "Sistema para sensoriamento e controle para aplicações em biomecatrônica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-10052012-121527/.
Full textAbstract:
Diversos trabalhos relacionados ao desenvolvimento de dispositivos robóticos biomecatrônicos estão sendo realizados em vários laboratórios no mundo. Apesar desta crescente tendência, devido a uma falta de padronização nas tecnologias utilizadas, em especial no sistema de sensoriamento e controle, há uma grande divergência nos sistemas resultantes. De forma a se conseguir atender os requisitos dos projetos, muito tempo é despendido no desenvolvimento de sistemas de sensoriamento e controle dedicados. Dentro deste cenário, neste trabalho foi projetado e implementado um sistema de sensoriamento e controle modular específico para sistemas robóticos. Este foi desenvolvido de forma a poder ser utilizado em diversos projetos reduzindo o esforço para a sua implementação. O referido sistema foi dividido em três módulos: Processador Central, Nós e Rede de Comunicação. Foi dada uma especial atenção no aspecto relacionado à comunicação por ser um fator-chave para se conseguir manter compatibilidade entre diferentes sistemas. Uma rede de comunicação denominada R-Bone foi desenvolvida pelo fato de que os sistemas existentes não atendem aos requisitos propostos. Uma descrição conceitual do sistema projetado é apresentada e a sua implementação detalhada. Todos os aspectos técnicos relevantes foram descritos de forma a facilitar a sua replicação por outros grupos. Um driver para sistema operacional Linux foi desenvolvido em conjunto com uma camada de abstração para simplificar o seu uso. Os testes realizados demonstraram que o sistema desenvolvido atende os requisitos propostos, mantendo uma condição de estabilidade adequada em seu tempo de resposta, baixa latência e pouca defasagem entre os sinais coletados pelos sensores. De forma a contribuir para uma possível padronização dos sistemas utilizados na área, todos os arquivos e informações relevantes para a replicação do sistema proposto foram disponibilizados sob a licença GNU LGPL em um servidor SVN.Several works related to the development of biomechatronic robotic systems are being taken in several laboratories around the world. Despite this increasing trend, due to a lack of standardization in the used technologies, in special related to the control and sensing system, there is a wide divergence in the resulting system. In order to meet the project requirements, a lot of time is spent in the development of a custom control and sensing system. In this scenario, a modular sensing and control system specifically designed to be used in robotic systems, was designed and implemented. The last was developed in order to be used in several projects, thus reducing the effort spent on its implementation. This system was divided into three modules: Central Processor, Nodes and Communication Network. A special attention was given to the aspects related to the communication as it is the key-factor to keep compatibility among different systems. A communication network named R-Bone was developed, and its implementation was detailed. All the relevant technical aspects were described in order to facilitate its replication by other groups. A driver for the Linux operating system was developed in conjunction with an abstraction layer to simplify its use. The tests demonstrated that the system meets the proposed requirements, keeping a proper stability condition in the response time, low latency and little skew between the signals collected by the sensors. In order to contribute to a possible standardization of the systems used in the biomechatronics field, all the files with relevant information to make possible the replication of the proposed system were made available under the GNU LGPL license in a SVN server.
6
Gionfra, Nicolo. "Stratégies de commande distribuée pour l’optimisation de la production des fermes éoliennes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC017/document.
Full textAbstract:
Les travaux de thèse s’intéressent au réglage de la puissance active injectée dans le réseau, ce qui représente aujourd'hui l'une des problématiques principales du pilotage des parcs éoliens participant à la gestion du réseau. Dans le même temps, l'un des buts reste de maximiser la puissance extraite du vent en considérant les effets de couplage aérodynamique entre les éoliennes.La structure du contrôle-commande choisie est de type hiérarchisée et distribuée. Dans la première partie de la thèse, les travaux portent sur la commande de la turbine d'une éolienne autour des points de fonctionnement classiques mais également autour des points à puissance extraite réduite. En fait, cela relève d’une condition de fonctionnement nécessaire pour l'atteinte des objectifs imposés au pilotage d'un parc éolien.Dans la deuxième partie, le problème du contrôle à l'échelle d'un parc est posé sous la forme d'une optimisation distribuée parmi les turbines. Deux nouveaux algorithmes d'optimisation métaheuristique sont proposés et leur performance testée sur différents exemples de parcs éoliens. Les deux algorithmes s'appuient sur la méthode d'optimisation par essaim particulaire, qui est ici modifiée et adaptée pour les cas d'application aux systèmes multi agents. L'architecture de contrôlecommande globale est enfin évaluée en considérant les dynamiques des turbines contrôlées. Les simulations effectuées montrent des gains potentiels significatifs en puissance.Finalement, dans la troisième partie de la thèse, l'introduction d'une nouvelle étape de coopération au niveau des contrôleurs locaux des turbines, par l'utilisation de la technique de contrôle par consensus, permet d'améliorer les performances du système globalIn this PhD work we focus on the wind farm (WF) active power control since some of the new set grid requirements of interest can be expressed as specifications on its injection in the electric grid. Besides, one of our main objectives is related to the wind farm power maximization problem under the presence on non-negligible wake effect. The chosen WF control architecture has a two-layer hierarchical distributed structure. First of all, the wind turbine (WT) control is addressed. Here, a nonlinear controller lets a WT work in classic zones of functioning as well as track general deloaded power references. This last feature is a necessary condition to accomplish the WF control specifications. Secondly, the high level WF control problem is formulated as an optimization problem distributed among the WTs. Two novel distributed optimization algorithms are proposed, and their performance tested on different WF examples. Both are based on the well-known particle swarm optimization algorithm, which we modify and extend to be applicable in the multi-agent system framework. Finally, the overall WF control is evaluated by taking into account the WTs controlled dynamics. Simulations show potential significant power gains. Eventually, the introduction of a new control level in the hierarchical structure between the WF optimization and the WTs controllers is proposed. The idea is to let further cooperation among the WT local controllers, via a consensusbased technique, to enhance the overall system performance
7
Rawlings, Trevor. "Distributed control architecture." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/6077.
Full textAbstract:
This document describes the development and testing of a novel Distributed Control Architecture (DCA). The DCA developed during the study is an attempt to turn the components used to construct unmanned vehicles into a network of intelligent devices, connected using standard networking protocols. The architecture exists at both a hardware and software level and provides a communication channel between control modules, actuators and sensors. A single unified mechanism for connecting sensors and actuators to the control software will reduce the technical knowledge required by platform integrators and allow control systems to be rapidly constructed in a Plug and Play manner. DCA uses standard networking hardware to connect components, removing the need for custom communication channels between individual sensors and actuators. The use of a common architecture for the communication between components should make it easier for software to dynamically determine the vehicle s current capabilities and increase the range of processing platforms that can be utilised. Implementations of the architecture currently exist for Microsoft Windows, Windows Mobile 5, Linux and Microchip dsPIC30 microcontrollers. Conceptually, DCA exposes the functionality of each networked device as objects with interfaces and associated methods. Allowing each object to expose multiple interfaces allows for future upgrades without breaking existing code. In addition, the use of common interfaces should help facilitate component reuse, unit testing and make it easier to write generic reusable software.
8
Iyer, Ranjit. "Probabilistic distributed control." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1568128211&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Full text
9
Fabbiano, Ruggero. "Collaborative source-seeking control." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT038/document.
Full textAbstract:
Cette dissertation fait face au problème de la localisation de sources, un sujet qui a été largement étudié dans la littérature récente au vu de son grand nombre d'applications. En particulier, ce travail se concentre sur le pilotage de multiples capteurs, capables de prendre des mesures ponctuelles de la quantité émise, vers la source sans faire usage d'aucune information de position, qui se trouve être indisponible dans de nombreux cas pratiques (par exemple, sous l'eau ou dans l'exploration souterraine). En faisant quelques hypothèses sur le processus de diffusion, nous développons un modèle qui permet d'utiliser des outils mathématiques (l'intégrale de Poisson et ses dérivées) pour obtenir une simple approximation du gradient de la fonction décrivant le processus de diffusion, dont la source représente le maximum, ce qui permet d'utiliser l'algorithme du gradient et trouver l'emplacement de la source. Les contributions sont de trois ordres : d'abord, nous utilisons ces outils pour résoudre le problème de la recherche d'une source en deux dimensions à travers d'un contrôle centralisé, où un seul véhicule, équipé de multiples capteurs et sans information de position, se déplace dans un environnement planaire où se trouve une source. Ensuite, nous étendons cette recherche à un cadre en trois dimensions, en considérant un engin volant équipé de capteurs qui se déplace dans l'espace ; pour ce cas plus général, outre la validation par simulations, nous fournissons également une étude théorique des propriétes de convergence de la loi de commande proposée. Enfin, nous abordons le problème de la localisation de source de façon distribuée, compte tenu de plusieurs capteurs autonomes mobiles (en deux dimensions) ; outre le problème de mettre en oeuvre l'algorithme de localisation de source de manière distribuée, nous devons garantir un contrôle de la formation approprié pour assurer l'exactitude de l'estimation du gradient, et donc atteindre la source.}The dissertation faces the problem of source localisation, a topic which has been extensively studied in recent literature due to its large number of applications. In particular, it focuses on steering multiple sensors, able to take point-wise measurements of the emitted quantity, towards the source without making use of any position information, which happens to be unavailable in many practical cases (for example, underwater or underground exploration). By making some assumptions on the diffusion process, we develop a model which allows us to use some mathematical tools (the Poisson integral and its derivatives) for a simple approximation of the gradient of the function describing the diffusion process, whose source represents its maximum, making it possible to perform a gradient ascent to find the source location. The contributions are threefold: first, we use such tools to solve a 2-dimensional centralised source-seeking problem, where a single vehicle, equipped with multiple sensors and without position information, is moving in a planar environment where a source is supposed to emit. Then, we extend it to a 3-dimensional framework, considering a flying vehicle equipped with sensors moving in the space; for this more general case, in addition to simulation validation, we provide a theoretical study of the convergence properties of the proposed control law. Finally, we tackle the distributed source-localisation problem, considering several autonomous moving sensors (in two dimensions); in addition to the problem of implementing the source-localisation algorithm in a distributed manner, in this latter case we have also to guarantee a suitable formation control, to ensure the correctness of the gradient estimation and hence reach the source
10
Reis, Giann Braune. "Estratégia de controle fuzzy para um grupo motor gerador a diesel operando isolado ou conectado à rede de distribuição." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-23022015-133705/.
Full textAbstract:
Esta tese propõe uma estratégia de controle fuzzy para um grupo motor gerador a diesel como uma fonte de geração distribuída, cobrindo a parte mecânica do sistema que é composta por controle de velocidade e de potência ativa, a parte elétrica do sistema composta por controle de tensão e potência reativa, e também o controle de sincronismo com a rede de distribuição. A estratégia de controle foi baseada em lógica fuzzy que usou uma superfície de controle fixa para os controladores fuzzy. Foram investigados os distúrbios causados pelo efeito de conexão com a rede e da conexão de um motor de indução, um retificador não controlado e uma carga RLC. Resultados de simulação para fluxo de potência no modo conectado foram obtidos usando um alimentador padrão IEEE -1547. Os resultados de simulação obtidos para os modos isolado e conectado usando o controlador fuzzy foram superiores comparados aos resultados obtidos com um controlador comercial. Uma bancada experimental também foi usada para analisar a resposta do sistema no modo isolado com o controlador fuzzy proposto e com o controlador comercial para fins de comparação. Nesse contexto, espera-se com este trabalho contribuir para o desenvolvimento de pesquisas na área de controle e processamento de energia, uma vez que, soluções para a produção de energia utilizando a geração distribuída têm importância estratégica e têm sido foco de investimento e discussões por parte de governos, empresas e universidades.This thesis proposes a control strategy for a diesel generating set as a distributed generation source covering the mechanical part of the system which includes speed and active power control, the electrical part of the system which includes voltage and reactive power control, and also the synchronism control with the grid. The control strategy was based on a fuzzy logic which used a fixed controller surface for the fuzzy controllers. The effect of the disturbances caused by the grid connection and the disturbances caused by the activation of a induction motor, non controled rectifier and a RLC load types were investigated. Power flow simulation results for the grid-connected mode was obtained with a IEEE -1547 standard feeder. The simulations results for both stand-alone and gridconnected operations using fuzzy controllers were superior when compared to commercial methods. An experimental setup was also used to analyze the system responses under isolated mode with the proposed fuzzy controller and with the commercial controllers for comparison proposes. In this context, it is expected that this work contributes to the development of control and energy processing research area, since solutions for energy production using distributed generation have strategic importance and have been the focus of investment and discussions from governments, companies and universities.
11
Renzaglia, Alessandro. "Optimisation stochastique et adaptative pour surveillance coopérative par une équipe de micro-véhicules aériens." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00721748.
Full textAbstract:
L'utilisation d'équipes de robots a pris de l'ampleur ces dernières années. Cela est dû aux avantages que peut offrir une équipe de robot par rapport à un robot seul pour la réalisation d'une même tâche. Cela s'explique aussi par le fait que ce type de plates-formes deviennent de plus en plus abordables et fiables. Ainsi, l'utilisation d'une équipe de véhicules aériens devient une alternative viable. Cette thèse se concentre sur le problème du déploiement d'une équipe de Micro-Véhicules Aériens (MAV) pour effectuer des missions de surveillance sur un terrain inconnu de morphologie arbitraire. Puisque la morphologie du terrain est inconnue et peut être complexe et non-convexe, les algorithmes standards ne sont pas applicables au problème particulier traité dans cette thèse. Pour y remédier, une nouvelle approche basée sur un algorithme d'optimisation cognitive et adaptatif (CAO) est proposée et évaluée. Une propriété fondamentale de cette approche est qu'elle partage les mêmes caractéristiques de convergence que les algorithmes de descente de gradient avec contraintes qui exigent une connaissance parfaite de la morphologie du terrain pour optimiser la couverture. Il est également proposé une formulation différente du problème afin d'obtenir une solution distribuée, ce qui nous permet de surmonter les inconvénients d'une approche centralisée et d'envisager également des capacités de communication limitées. De rigoureux arguments mathématiques et des simulations étendues établissent que l'approche proposée fournit une méthodologie évolutive et efficace qui intègre toutes les contraintes physiques particulières et est capable de guider les robots vers un arrangement qui optimise localement la surveillance. Finalement, la méthode proposée est mise en œuvre sur une équipe de MAV réels pour réaliser la surveillance d'un environnement extérieur complexe.
12
Noubissie-Tchako, Jean-Félix. "Contribution à la conception d'un système de pilotage distribué pour les systèmes automatisés de production." Valenciennes, 1994. https://ged.uphf.fr/nuxeo/site/esupversions/b009a7c7-9c4b-406f-85e9-3c092db6d043.
Full textAbstract:
Les unités de production sont actuellement soumises à de fortes contraintes de productivité et de flexibilité. Les problèmes à résoudre sont relatifs au pilotage des installations avec prise en compte des perturbations, à la surveillance, au contrôle et à l'exploitation des équipements ainsi qu'au rôle des opérateurs. Il s'agit de rendre et de maintenir opérationnels les différents éléments de l'installation, de les synchroniser, de les coordonner et d'intégrer les ressources humaines et matérielles, dans une approche de gestion en flux tendus. Dans ce mémoire nous décrivons les principales fonctions des systèmes de pilotage des SAP et constatons que les structures de pilotage hiérarchisées classiques ne peuvent permettre d'atteindre pleinement les objectifs précédents. Nous montrons les avantages de la résolution distribuée de problèmes pour la spécification de systèmes de pilotage temps réel des SAP, et proposons un modèle d'organisation pour les systèmes distribués (concept de SIP) ainsi qu'un modèle de contrôle d'allocation dynamique de taches. Deux exemples d'applications nous permettent d'évaluer les modèles d'allocation dynamique de taches et de contrôle du système de pilotage distribué. Ces exemples démontrent la faisabilité et les potentialités des architectures distribuées pour le pilotage des SAP.
13
Schmidt, Ronald. "Distributed Access Control System." Universitätsbibliothek Chemnitz, 2001. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200100336.
Full text
14
Hamid, Tariq Parwaiz. "Control of distributed objects." Thesis, University of the West of Scotland, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260344.
Full text
15
Wang, Zongyao. "Distributed robot flocking control." Thesis, University of Essex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499765.
Full text
16
Huang, Qiang. "Distributed embedded control system." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400230.
Full text
17
OLIVEIRA, Érika Matos de. "Comparação dos Métodos de Paralelismo de Conversores para o Compartilhamento de Potência em Microrredes." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18269.
Full textAbstract:
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-01-27T17:17:31Z
No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
Dissertacao_Erika_1.pdf: 4090096 bytes, checksum: aad3d3481e2a810cc8765c9bade0883b (MD5)Made available in DSpace on 2017-01-27T17:17:31Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_Erika_1.pdf: 4090096 bytes, checksum: aad3d3481e2a810cc8765c9bade0883b (MD5) Previous issue date: 2016-07-29
FACEPE
Microrrede é um conjunto de geração distribuída e sistemas de armazenamento de energia que abastece a demanda de um grupo de consumidores. A existência de um controle local independente da rede elétrica define uma microrrede, a qual pode se conectar ao sistema tradicional de potência ou desconectar-se e funcionar de forma autônoma a depender das condições físicas e/ou econômicas. O presente trabalho apresenta dois métodos de controle para o paralelismo de inversores em microrredes, o controle por inclinação e o controle mestre-escravo, com o objetivo de realizar um estudo comparativo. Primeiramente, são mostrados os conceitos de geração distribuída, microrredes e paralelismo de inversores. Depois, são apresentados os fundamentos teóricos e as principais características dos controles por inclinação e mestre-escravo. Por fim, é feita uma comparação entre as duas técnicas de controle para que permita definir qual é a melhor. Esta comparação é feita por meio de simulações de uma microrrede, analisando o seu desempenho nas situações conectada à rede elétrica principal, em ilhamento e durante o transitório de desconexão. Também é observado o comportamento de grandezas como corrente, amplitude e frequência da tensão e ainda o compartilhamento de carga entre os inversores.
Microgrid is a set of distributed generation and energy storage systems that supplies the demand of a group of consumers . The existence of a local control, independently of the main grid, defines a microgrid, which can be connected to or disconnected from the traditional power system working autonomously depending on the physical or economic conditions. This work presents two control methods for paralleling inverters in microgrids, droop control and masterslave control, in order to conduct a comparative study between both control techniques. Firstly, the concepts of distributed generation, microgrid and paralleled inverters are shown. Then, it is presented the theoretical fundamentals and main features of droop control and master-slave control. Finally, a comparison is done between both control techniques to allow define the best control technique. This comparison is done by means of simulations of a microrrede, analyzing its performance in the situations connected to the main grid, in islanding and during the disconnection transient. Also, it is observed the quantities behavior such as the current, the voltage amplitude and frequency and also the power shared among the inverters.
18
Johansson, Olof, and Daniel Persson. "Workflows and Distributed Version Control." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3613.
Full textAbstract:
This bachelor thesis focuses on distributed version control systems and workflows used when working with such systems. The thesis will investigate benefits and disadvantages in using distributed version control in software development using a literature review of the available articles on the subject as well as a post-mortem analysis (with questionnaires and data collected from the build environment) of a student run software engineering project. We find that the migration costs are high, but that the advantages may outweigh its drawbacks for some. We conclude that many projects would benefit from migrating, but in particular, that new projects would not only benefit, but also not have high migration costs.En undersökning om hur man kan arbeta med moderna, distribuerade, versionshanteringssystem. Baserat på dels en literaturstudie, och dels en frågeundersökning bland studenter på BTH dras slutsatsen att det både finns för- och nackdelar, men att fördelarna verkar väga över i det generella fallet.
Jag (Olof Johansson) är nåbar främst per e-post, men även på telefonnummer +46739467135.
19
Dev, Kashinath. "Concurrency control in distributed caching." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-10112005-172329/.
Full textAbstract:
Replication and caching strategies are increasingly being used to improve performance and reduce delays in distributed environments. A query can be answered more quickly by accessing a cached copy than making a database round trip. Numerous techniques have been proposed to achieve caching and replication in various contexts. In our context of flat cluster-based networks, we have observed that none of the schemes prove to be optimal for all scenarios. In this thesis we look at concurrency control techniques for achieving consistency in distributed caching in flat cluster-based networks. We then come up with heuristics to choose some concurrency control mechanisms over others, depending on the parameters such as the number of data requests and the ratio of read to write requests.
20
Shucker, Brian. "Control of distributed robotic macrosensors." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239382.
Full text
21
Field-Richards, Hugh Sherwood. "A distributed control microprocessor system." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37693.
Full text
22
Zhao, Fang Ph D. Massachusetts Institute of Technology. "Distributed control of coded networks." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57776.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 97-101).
The introduction of network coding has the potential to revolutionize the way people operate networks. For the benefits of network coding to be realized, distributed solutions are needed for various network problems. In this work, we look at three aspects of distributed control of coded networks. The first one is distributed algorithms for establishing minimum-cost multicast connections in coded networks. The subgraph optimization problem can be viewed as an linear optimization problem, and we look at algorithms that solve this problem for both static and dynamic multicasts. For static multicast, we present decentralized dual subgradient algorithms to find the min-cost subgraph. Due to the special structure of the network coding problem, we can recover a feasible primal solution after each iteration, and also derive theoretical bounds on the convergence rate in both the dual and the primal spaces. In addition, we propose heuristics to further improve our algorithm, and demonstrate through simulations that the distributed algorithm converges to the optimal subgraph quickly and is robust against network topology changes. For dynamic multicast, we introduce two types of rearrangements, link rearrangement and code rearrangement, to characterize disturbances to users. We present algorithms to solve the online network coding problem, and demonstrate through simulations that the algorithms can adapt to changing demands of the multicast group while minimizing disturbances to existing users.
(cont.) The second part of our work focuses on analysis of COPE, a distributed opportunistic network coding system for wireless mesh networks. Experiments have shown that COPE can improve network throughput significantly, but current theoretical analysis fails to fully explain this performance. We argue that the key factor that shapes COPE's performance curve is the interaction between COPE and the MAC protocol. We also propose a simple modification to COPE that can further increase the network throughput. Finally, we study network coding for content distribution in peer-to-peer networks. Such systems can improve the speed of downloads and the robustness of the systems. However, they are very vulnerable to Byzantine attacks, and we need to have a signature scheme that allows nodes to check the validity of a packet without decoding. In this work, we propose such a signature scheme for network coding. Our scheme makes use of the linearity property of the packets in a coded system, and allows nodes to check the integrity of the packets received easily. We show that the proposed scheme is secure, and its overhead is negligible for large files.
by Fang Zhao.
Ph.D.
23
Burdis, Keith Robert. "Distributed authentication for resource control." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1006512.
Full textAbstract:
This thesis examines distributed authentication in the process of controlling computing resources. We investigate user sign-on and two of the main authentication technologies that can be used to control a resource through authentication and providing additional security services. The problems with the existing sign-on scenario are that users have too much credential information to manage and are prompted for this information too often. Single Sign-On (SSO) is a viable solution to this problem if physical procedures are introduced to minimise the risks associated with its use. The Generic Security Services API (GSS-API) provides security services in a manner in- dependent of the environment in which these security services are used, encapsulating security functionality and insulating users from changes in security technology. The un- derlying security functionality is provided by GSS-API mechanisms. We developed the Secure Remote Password GSS-API Mechanism (SRPGM) to provide a mechanism that has low infrastructure requirements, is password-based and does not require the use of long-term asymmetric keys. We provide implementations of the Java GSS-API bindings and the LIPKEY and SRPGM GSS-API mechanisms. The Secure Authentication and Security Layer (SASL) provides security to connection- based Internet protocols. After finding deficiencies in existing SASL mechanisms we de- veloped the Secure Remote Password SASL mechanism (SRP-SASL) that provides strong password-based authentication and countermeasures against known attacks, while still be- ing simple and easy to implement. We provide implementations of the Java SASL binding and several SASL mechanisms, including SRP-SASL.
24
Phadke, Swanand Shripad. "Distributed Control for Smart Lighting." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274899902.
Full text
25
Deshpande, Pranav. "Distributed Supervisory Control of Workflows." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000209.
Full text
26
Chauvet, Mathieu. "The management of distances in distributed-work : a Deleuzian approach to control." Thesis, Paris 9, 2012. http://www.theses.fr/2012PA090053.
Full textAbstract:
L’émergence du travail à distance a causé l’apparition de nombreux challenges pour les managers et leurs subordonnés. Par conséquent, maintenir une forme de surveillance s’avère plus que jamais nécessaire, notamment car le contrôle représente un moyen significatif pour réduire la problématique de la distance. Au regard du bouleversement conséquent amené par ce développement exponentiel des technologies, il convient de s’interroger sur la façon dont les processus de contrôle ont été remis en question dans le cadre de la rupture managériale introduite par le travail à distance. Notre réflexion théorique nous a finalement conduit à solliciter les travaux du philosophe Gilles Deleuze comme base conceptuelle. Les données issues de 49 entretiens et 7 journées d’observations nous permettent de démontrer le bouleversement significatif des pratiques de gestion lié à la reconsidération du contrôle dans le travail à distance. A la fois pour les managers qui voient leur rôle évoluer d'un statut de superviseur à facilitateur, et leurs subordonnés, dont l'activité sera majoritairement guidée par le management de leur visibilité, réactivité et modulation. Cette thèse de doctorat constitue finalement une illustration concrète en Management du concept Deleuzien des sociétés de contrôleDistributed- work has introduced challenges for both employees and managers alike. Maintaining a form of supervision and discipline remains then necessary as control is the ultimate means for the hierarchy to bridge the issue of distance. With regard to the unprecedented changes generated by the significant development of ICTs in organizations, we expressed the necessity to analyze how control is reconsidered within the managerial breakdown introduced by distributed-work. Our theoretical reasoning finally led us to use the works of French philosopher Gilles Deleuze as a basis for a more relevant conceptual framework. Data coming from 49 interviews and 7 days as non-participant observer enabled us to provide evidences for the disruption of management practices due to the reconsideration of control in distributed-work. Both for managers, evolving from a supervisory to a facilitator status, and distributed-workers themselves, whose activities will mainly be directed by the management of their visibility, responsiveness and modulation. Ultimately, this PhD dissertation provides concrete managerial manifestations for Deleuzian societies of control
27
Costello, Zachary Kohl. "Distributed computation in networked systems." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54924.
Full textAbstract:
The objective of this thesis is to develop a theoretical understanding of computation in networked dynamical systems and demonstrate practical applications supported by the theory. We are interested in understanding how networks of locally interacting agents can be controlled to compute arbitrary functions of the initial node states. In other words, can a dynamical networked system be made to behave like a computer? In this thesis, we take steps towards answering this question with a particular model class for distributed, networked systems which can be made to compute linear transformations.
28
Garonne, Vincent. "Etude, définition et modélisation d'un système distribué à grande échelle : DIRAC - Distributed infrastructure with remote agent control." Aix-Marseille 2, 2005. http://theses.univ-amu.fr.lama.univ-amu.fr/2005AIX22057.pdf.
Full text
29
Charrier, Rodolphe. "L'intelligence en essaim sous l'angle des systèmes complexes : étude d'un système multi-agent réactif à base d'itérations logistiques couplées." Phd thesis, Université Nancy II, 2009. http://tel.archives-ouvertes.fr/tel-00442841.
Full textAbstract:
L'intelligence en essaim constitue désormais un domaine à part entière de l'intelligence artificielle distribuée. Les problématiques qu'elle soulève touchent cependant à de nombreux autres domaines ou questions scientifiques. En particulier le concept d'essaim trouve pleinement sa place au sein de la science dites des ``systèmes complexes''. Cette thèse présente ainsi la conception, les caractéristiques et les applications d'un modèle original, le SMA logistique, pour le domaine de l'intelligence en essaim. Le SMA logistique trouve son origine en modélisation des systèmes complexes : il est en effet issu des réseaux d'itérations couplées dont nous avons adapté le modèle de calcul à l'architecture multi-agent. Ce modèle se fonde sur des principes communs à d'autres disciplines, comme la synchronisation et le contrôle paramétrique que nous plaçons au coeur des mécanismes d'auto-organisation et d'adaptation. Du point de vue mathématique, les applications logistiques sont à la base de la formalisation du comportement interne des agents constituant le SMA logistique, tout en prenant place dans un schéma ``influence-réaction''. L'environnement à base de champs est l'autre aspect fondamental du SMA logistique, en permettant la réalisation des interactions indirectes des agents et en jouant le rôle d'une structure de données pour le système. Les travaux décrits dans cette thèse donnent lieu à des applications principalement en simulation et en optimisation, comme c'est le cas pour la plupart des algorithmes du domaine de l'intelligence en essaim. L'intérêt et l'originalité du SMA logistique pour l'intelligence en essaim résident dans l'aspect générique de son schéma théorique qui permet de traiter avec un même modèle des phénomènes considérés a priori comme distincts dans la littérature : phénomènes de ``flocking'' et phénomènes stigmergiques ``fourmis'' à base de phéromones. Ce modèle répond ainsi à un besoin d'explication des mécanismes mis en jeu autant qu'au besoin d'en synthétiser les algorithmes générateurs.
30
Iutzeler, Franck. "Estimation et Optimisation Distribuée pour les Réseaux Asynchrones." Phd thesis, Telecom ParisTech, 2013. http://tel.archives-ouvertes.fr/tel-00927646.
Full textAbstract:
Cette thèse s'intéresse au problème d'estimation et d'optimisation distribuée dans les réseaux asynchrones, c'est à dire en n'utilisant que des communications locales et asynchrones. A partir de multiples applications allant de l'apprentissage automatique aux réseaux de capteurs sans-fils, nous concevons et analysons théoriquement de nouveaux algorithmes résolvant trois problèmes de nature très différentes : la propagation de la plus grande des valeurs initiales, l'estimation de leur moyenne et enfin l'optimisation distribuée.
31
Lundin, Mats. "Building Distributed Control Systems Using Distributed Active Real-Time Databases." Thesis, University of Skövde, Department of Computer Science, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-234.
Full textAbstract:
From the field of control theory, we can see that varying communication delays in a control system may be hard or even impossible to handle. From this point of view it is preferable to have these delays bounded and as small and as possible in order to adapt the control process to them. On the other hand, in some cases delays are inevitable and must be handled by the control system.
A control system may for different reasons be distributed, e.g., because of a distributed environment or severe environment demands such as heat or dust at some locations. Information in such a system will suffer from delays due to transportation from one place to another. These delays often show up in a random fashion, especially if a general network is used for transportation. Another source of delays is the system environment itself. For predictability reasons a real-time database is preferable if the delays are to be controlled.
A straightforward way of handling delays in a control system is to build the system such that delays are constant, i.e., to build a time invariant system. The time from sensor reading to actuation is made constant either by adding a suitable delay to achieve a total constant delay or by using time-triggered reading and actuation. These are simple ways of controlling the delays, but may be very inefficient because worst-case execution time must always be used. Other ways of handling varying delays are by using more tolerant control algorithms. There are two suitable control models proposed by Nilsson (1998) for this purpose. The tolerant algorithm approach is assumed in this work.
This thesis uses a distributed active real-time database system as a basis for building control systems. One of the main objectives is to determine how active functionality can be used to express the control system, i.e., how rules in the database can be used to express the control algorithm and for handling propagation of information. Another objective is to look at how the choice of consistency level in the database affects the result of the control system, i.e. how different consistency level affects the delays. Of interest is also to characterize what type of applications each level is suited for.
32
Abeysekera, Don Cecil Rohantha. "Performance of thread based distributed systems." Thesis, University of Kent, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334084.
Full text
33
Wen, Guoguang. "Distributed cooperative control for multi-agent systems." Phd thesis, Ecole Centrale de Lille, 2012. http://tel.archives-ouvertes.fr/tel-00818774.
Full textAbstract:
Cette thèse considère principalement trois problèmes dans le domaine du contrôle distribué coopératif des systèmes multi-agents(SMA): le consensus, la navigation en formation et le maintien en formation d'un groupe d'agents lorsqu'un agent disparait. Nous proposons 3 algorithmes pour résoudre le problème du calcul distribué d'un consensus à partir de l'approche leadeur-suiveur dans le contexte SMA à dynamique non-linéaire. La référence est définie comme un leader virtuel dont on n'obtient, localement, que les données de position et de vitesse. Pour résoudre le problème du suivi par consensus pour les SMA à dynamique non-linéaire, nous considérons le suivi par consensus pour SMA de premier ordre. On propose des résultats permettant aux suiveurs de suivre le leadeur virtuel en temps fini en ne considérant que les positions des agents. Ensuite, nous considérons le suivi par consensus de SMA de second. Dans le cas de la planification de trajectoire et la commande du mouvement de la formation multi-agents. L'idée est d'amener la formation, dont la dynamique est supposée être en 3D, d'une configuration initiale vers une configuration finale (trouver un chemin faisable en position et orientation) en maintenant sa forme tout le long du chemin en évitant les obstacles. La stratégie proposée se décompose en 3 étapes. Le problème du Closing-Rank se traduit par la réparation d'une formation rigide multi-agents "endommagée" par la perte de l'un de ses agents. Nous proposons 2 algorithmes d'autoréparation systématique pour récupérer la rigidité en cas de perte d'un agent. Ces réparations s'effectuent de manière décentralisée et distribuée n'utilisant que des informations de voisinage.
34
Zarate, Florez Jennifer. "Etudes de commande par décomposition-coordination pour l'optimisation de la conduite de vallées hydroélectriques." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT018/document.
Full textAbstract:
Une vallée hydroélectrique est constituée d'un nombre important de centrales interconnectées du fait de l'utilisation de la même ressource en eau. Pour pouvoir optimiser en temps réel sa production, il a été proposé dans cette thèse d'utiliser les méthodes associées aux systèmes à grande échelle pour développer les outils nécessaires. Cette étude de la commande globale du système a été orientée vers l'utilisation des méthodes de décomposition-coordination. Ces méthodes ont été examinées et appliquées à un cas d'étude simplifié (une partie de la vallée hydraulique) mis à disposition par EDF. Plus particulièrement, les méthodes de décomposition-coordination par les prix, ou encore par les prédictions des interactions, s'appuyant sur des commandes MPC, ont été considérées et comparées avec une commande centralisée. En vue d'une implémentation temps-réel, nous nous sommes intéressés à exprimer les problèmes d'optimisation comme des problèmes QP, pour ensuite obtenir des solutions explicites en utilisant une méthodologie de caractérisation géométrique. Nous avons proposé des formulations complètement explicites (niveau coordinateur et sous-systèmes) pour les deux méthodes. Des résultats de simulation avec des données réelles mises à disposition par EDF sont présentés. Afin de valider les méthodes conçues, une première phase d'implantation sur la plate-forme Supervision NG d'EDF permettant la communication avec un modèle de la vallée hydroélectrique (basé sur les équations de Saint Venant et la bathymétrie de la rivière), est enfin incluse dans ce mémoireThis study is mainly about the hydroelectric production problem. What we aim to do, is to develop optimization tools for a chain of hydroelectric plants, using appropriate control methodologies. A hydroelectric valley is a large scale system, made up of interconnected plants. The study of the global control system has been focused to the use of decomposition-coordination methods. Those methods have been examined and applied to a simplified case study (a part of a hydroelectric valley) given by EDF. To be more specific, the price decomposition - coordination method and the interactions prediction method, based on MPC controls, have been considered and compared to a centralized control. Because of the need of implementation in real time, we have expressed the optimization problems as QP problems, so as to obtain explicit solutions using the geometric characterization methodology. We have proposed a completely explicit formulation (both at the coordinator level and at the subsystems level) for both methods. Simulation results with real data information given by EDF are also presented. To verify and validate the designed methods, a first step of implementation on the supervision platform NG by EDF, that allows the communication with a model of the hydroelectric valley (based on the equations of Saint Venant and on the river bathymetry) is finally also included in this thesis
35
Shigueoka, Augusto Hirao. "Otimização de filtros modais espaciais usando redes de sensores aplicados ao controle de vibrações de estruturas do tipo viga e placa." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-25012017-163244/.
Full textAbstract:
Ao empregar a teoria de controle para a dinâmica de uma estrutura, é possível projetar um observador potencialmente complexo que a partir da leitura de apenas um sensor estime o estado do sistema e determine os modos de vibração presentes. Este trabalho, no entanto, estuda o uso de filtros modais em controle de vibrações, com a motivação de que essa estratégia dependa de menos componentes eletrônicos. O objetivo é encontrar um filtro modal que possua alto desempenho em malha fechada mesmo com um número reduzido de sensores. Primeiramente foi desenvolvido o modelo dinâmico do sistema em malha aberta, com posterior otimização do filtro modal por meio do método do ponto interior. Depois, foi desenvolvido o modelo dinâmico do sistema em malha fechada. A seguir, um algoritmo genético otimizou o sistema de controle de vibrações seguindo duas metodologias. A primeira considera apenas as posições dos sensores como variáveis de otimização, enquanto a segunda leva em consideração não só as posições dos sensores como também os ganhos do filtro modal e o ganho de retroalimentação de velocidade. Os resultados do estudo do sistema em malha aberta mostram que se trata se um problema de otimização não-convexa, mas todas as tentativas levaram a crer que o mínimo global tenha sido encontrado para a função objetivo proposta, baseada no desvio quadrático da função de resposta em frequência do filtro modal com relação a uma referência pré-estabelecida. Os resultados do estudo do sistema em malha fechada mostram que considerar as posições e os ganhos como variáveis de otimização levam a um filtro modal mais conveniente do que o que é obtido levando-se em consideração apenas as posições. Finalmente, a partir da interpretação dos resultados, conclui-se que mesmo com um filtro modal composto por 5 sensores é possível ainda desenvolver um sistema de controle de vibrações que seja de fase mínima. Apesar de existir spillover de observação do ponto de vista de um filtro modal, nota-se que todos os modos estão em fase, o que acaba por ser até benéfico para o sistema de controle de vibrações.The control systems theory may be applied to structural dynamics in order to design a potentially complex observer which is able to estimate the system\'s state from the readings of a sole sensor. This work, though, focused on the application of modal filters in vibration control based on the premise that this strategy will require a simpler hardware. The main target consists of finding a modal filter which can deliver high performance in vibration control despite being composed of a reduced number of sensors. In the first step, a dynamic model of a modal filter on a cantilever beam was developed, followed by an optimization carried on with the interior-point method. Then, the dynamic model of the closed-loop cantilever beam was developed aftwerwards. However, this time a genetic algorithm was used as the optimization method instead, with two methodologies being employed. While the first one considered only the placement of the sensors, the second one also takes into consideration the modal filter gains and the negative velocity feedback gain. The results yielded by the open-loop cantilever beam analysis showed that it is a non-convex optimization problem. However, all of the attempts support the belief that the global minimum has been found in the sense of the proposed objective function, which was based on the quadratic error between the frequency response function (FRF) of the modal filter and an idealized FRF used as reference. The results yielded by the closed-loop system optimization showed that it is more convenient to consider as optimization variables not only the placement of the sensors, but also their gains and the negative velocity feedback gain. Finally, after pondering over the obtained results, it has been concluded that the observation spillover resulting from a modal filter composed of a reduced number of sensors may be turned to the vibration control system\'s favour by means of optimization. The minimal-phase modal filter composed of 5 sensors found in this work stands out as the most notable example in this work, being able to guarantee stability for the first 12 modes since all of them are in-phase.
36
Quinton, Sophie. "Design, vérification et implémentation de systèmes à composants." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00685854.
Full textAbstract:
Nous avons étudié dans le cadre de cette thèse le design, la vérification et l'implémentation des systèmes à composants. Nous nous sommes intéressés en particulier aux formalismes exprimant des interactions complexes, dans lesquels les connecteurs servent non seulement au transfert de données mais également à la synchronisation entre composants. 1. DESIGN ET VÉRIFICATION Le design par contrat est une approche largement répandue pour développer des systèmes lorsque plusieurs équipes travaillent en parallèle. Les contrats représentent des contraintes sur les implémentations qui sont préservées tout au long du développement et du cycle de vie d'un système. Ils peuvent donc servir également à la phase de vérification d'un tel système. Notre but n'est pas de proposer un nouveau formalisme de spécification, mais plutôt de définir un ensemble minimal de propriétés qu'une théorie basée sur les contrats doit satisfaire pour permettre certains raisonnements. En cela, nous cherchons à séparer explicitement les propriétés spécifiques à chaque formalisme de spécification et les règles de preuves génériques. Nous nous sommes attachés à fournir des définitions suffisamment générales pour exprimer un large panel de langages de spécification, et plus particulièrement ceux dans lesquels les interactions sont complexes, tels que Reo ou BIP. Pour ces derniers, raisonner sur la structure du système est essentiel et c'est pour cette raison que nos contrats ont une partie structurelle. Nous montrons comment découle de la propriété nommée raisonnement circulaire une règle pour prouver la dominance sans composer les contrats, et comment cette propriété peut être affaiblie en utilisant plusieurs relations de raffinement. Notre travail a été motivé par les langages de composants HRC L0 et L1 définis dans le projet SPEEDS. 2. IMPLÉMENTATION Synthétiser un contrôleur distribué imposant une contrainte globale sur un système est dans le cas général un problème indécidable. On peut obtenir la décidabilité en réduisant la concurrence: nous proposons une méthode qui synchronise les processus de façon temporaire. Dans les travaux de Basu et al., le contrôle distribué est obtenu en pré-calculant par model checking la connaissance de chaque processus, qui reflète dans un état local donné toutes les configurations possibles des autres processus. Ensuite, à l'exécution, le contrôleur local d'un processus décide si une action peut être exécutée sans violer la contrainte globale. Nous utilisons de même des techniques de model checking pour pré-calculer un ensemble minimal de points de synchronisation au niveau desquels plusieurs processus partagent leur connaissance au court de brèves périodes de coordination. Après chaque synchronisation, les processus impliqués peuvent de nouveau progresser indépendamment les uns des autres jusqu'à ce qu'une autre synchronisation ait lieu. Une des motivations pour ce travail est l'implémentation distribuée de systèmes BIP.
37
Asadi, Fatemeh. "Self-organized distributed model predictive control." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720820.
Full text
38
Reinschke, Johannes Ullrich. "H∞-control of spatially distributed systems." Thesis, University of Cambridge, 1999. https://www.repository.cam.ac.uk/handle/1810/251474.
Full text
39
Segbefia, Frederick. "Optimal control of distributed energy storage." Thesis, Wichita State University, 2007. http://hdl.handle.net/10057/1554.
Full textAbstract:
It is shown in this research paper that, with the appropriate control system, a storage energy unit connected to a distribution system near the primary load, can completely level the load on a distribution feeder for any primary load profile. By doing simulations using an Excel spreadsheet, graphs were generated that show how the control system is able to achieve this objective in addition to quantifying the storage energy system to the primary load profile. Steps needed for future research projects to make the energy storage system economically viable are suggested.Thesis (M.S)-- Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering
"December 2007."
40
Khalil, Ashraf F. "Networked control of distributed energy systems." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3380/.
Full textAbstract:
This thesis reports a new method for stability analysis and maximum time delay estimation in networked control systems with applications to distributed energy systems. The proposed new method is based on using finite difference approximation for the delay term and then the Lyapunov system stability theorem is applied to derive the time delay boundary allowed to the system. The proposed method has been applied to networked control systems with state feedback controllers, with dynamic controllers, and to multi-units interconnected networked control systems. The proposed method is then extended to a class of networked control system with bounded nonlinearity and uncertainties. It is found that increasing the nonlinearity in the system will result in decreasing the maximum allowable time delay. Compared with most of the methods reported in the published literature, the new method is simple to use while the results are comparable. When the time delay is modelled using Markov Chain the stability of the networked control system is formulated as finding the solutions for Bilinear Matrix Inequalities. An improved V-K iteration algorithm is used to solve the Bilinear Matrix Inequalities in order to derive a controller to stabilize the systems.
41
Jones, Nathaniel Matthew. "Practical algorithms for distributed network control." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85760.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 135-138).
Optimal routing and scheduling algorithms have been studied for decades, however several practical issues prevent the adoption of these network control policies on the Internet. This thesis considers two distinct topics in distributed network control: (i) maximizing throughput in wireless networks using network coding, and (ii) deploying controllable nodes in legacy networks. Network coding is a relatively new technique that allows for an increase in throughput under certain topological and routing conditions. The first part of this thesis considers jointly optimal routing, scheduling, and network coding strategies to maximize throughput in wireless networks. We introduce a simple network coding strategy and fully characterize the region of arrival rates supported. We propose a centralized dynamic control policy for routing, scheduling, and our network coding strategy, and prove this policy to be throughput optimal subject to our coding constraint. We further propose a distributed control policy based on random access that optimizes for routing, scheduling, and pairwise coding, where pairwise coding captures most of the coding opportunities on random topologies. We prove this second policy to also be throughput optimal subject to the coding constraint. Finally, we reduce the gap between theory and practice by identifying and solving several problems that may occur in system implementations of these policies. Throughput optimal policies typically require every device in the network to make dynamic routing decisions. In the second part of this thesis, we propose an overlay routing architecture such that only a subset of devices (overlay nodes) need to make dynamic routing decisions, and yet maximum throughput can still be achieved. We begin by formulating an optimization problem that searches for the minimum overlay node placement that achieves maximum throughput. We devise an efficient placement algorithm which solves this problem optimally for networks not subject to interference constraints. Then we propose a heuristic control policy for use at overlay nodes, and show by simulation that this policy performs optimally in all studied scenarios.
by Nathaniel Matthew Jones.
Ph. D.
42
Tsai, Frank J. (Frank Jin-Fong) 1976. "Distributed active control for tension structures." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/81544.
Full text
43
Cosway, Paul Richard. "Replication control in distributed B-trees." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36957.
Full textAbstract:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 140-142).
by Paul Richard Cosway.
M.S.
44
Kadengal, R. "Distributed control architecture for multiservice networks." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1336884/.
Full textAbstract:
The research focuses in devising decentralised and distributed control system architecture for the management of internetworking systems to provide improved service delivery and network control. The theoretical basis, results of simulation and implementation in a real-network are presented. It is demonstrated that better performance, utilisation and fairness can be achieved for network customers as well as network/service operators with a value based control system. A decentralised control system framework for analysing networked and shared resources is developed and demonstrated. This fits in with the fundamental principles of the Internet. It is demonstrated that distributed, multiple control loops can be run on shared resources and achieve proportional fairness in their allocation, without a central control. Some of the specific characteristic behaviours of the service and network layers are identified. The network and service layers are isolated such that each layer can evolve independently to fulfil their functions better. A common architecture pattern is devised to serve the different layers independently. The decision processes require no co-ordination between peers and hence improves scalability of the solution. The proposed architecture can readily fit into a clearinghouse mechanism for integration with business logic. This architecture can provide improved QoS and better revenue from both reservation-less and reservation-based networks. The limits on resource usage for different types of flows are analysed. A method that can sense and modify user utilities and support dynamic price offers is devised. An optimal control system (within the given conditions), automated provisioning, a packet scheduler to enforce the control and a measurement system etc are developed. The model can be extended to enhance the autonomicity of the computer communication networks in both client-server and P2P networks and can be introduced on the Internet in an incremental fashion. The ideas presented in the model built with the model-view-controller and electronic enterprise architecture frameworks are now independently developed elsewhere into common service delivery platforms for converged networks. Four US/EU patents were granted based on the work carried out for this thesis, for the cross-layer architecture, multi-layer scheme, measurement system and scheduler. Four conference papers were published and presented.
45
Babazadeh, Davood. "Distributed Control of HVDC Transmission Grids." Doctoral thesis, KTH, Elkraftteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202753.
Full textAbstract:
Recent issues such as priority access of renewable resources recommended by European energy directives and increase the electricity trading among countries lead to new requirements on the operation and expansion of transmission grids. Since AC grid expansions are limited by legislative issues and long distance transmission capacity, there is a considerable attention drawn to application of HVDC transmission grids on top of, or in complement to, existing AC power systems. The secure operation of HVDC grids requires a hierarchical control system. In HVDC grids, the primary control action to deal with power or DC voltage deviations is communication-free and local. In addition to primary control, the higher supervisory control actions are needed to guarantee the optimal operation of HVDC grids. However, the implementation of supervisory control functions is linked to the arrangement of system operators; i.e. an individual HVDC operator (central structure) or sharing tasks among AC system operators (distributed structure). This thesis presents distributed control of an HVDC grid. To this end, three possible supervisory functions are investigated; coordination of power injection set-points, DC slack bus selection and network topology identification. In this thesis, all three functions are first studied for the central structure. For the distributed solution, two algorithms based on Alternating Direction Method of Multipliers (ADMM) and Auxiliary Problem Principle (APP) are adopted to solve the coordination of power injection. For distributed selection of DC slack bus, the choice of parameters for quantitative ranking of converters is important. These parameters should be calculated based on local measurements if distributed decision is desired. To this end, the short circuit capacity of connected AC grid and power margin of converters are considered. To estimate the short circuit capacity as one of the required selection parameters, the result shows that the recursive least square algorithm can be very efficiently used. Besides, it is possible to intelligently use a naturally occurring droop response in HVDC grids as a local measurement for this estimation algorithm. Regarding the network topology, a two-stage distributed algorithm is introduced to use the abstract information about the neighbouring substation topology to determine the grid connectivity.QC 20170306
46
Akhtar, Zohaib. "Distributed voltage control and demand response." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/61346.
Full textAbstract:
Future power systems will have low inertia which will lead to larger deviations and rates of change of grid frequency. Large loss of infeed (e.g. due to a fault in the DC grid) higher than the spinning reserve can be more frequent. Also, voltage constraints will result in curtailment of renewable energy in the distribution systems. This thesis investigates the characteristics and effectiveness of the use of power electronic compensators in the control of both grid voltage and frequency through aggregated demand response in an autonomous fashion without any need for communication. Not relying on communication is essential to have a plug-and-play functionality for these compensators, so no central controller is critical for the system operation. Concept of Electric Spring (ES) has been proposed recently, which is a series compensator used to decouple the non-critical load from the mains to form a Smart Load (SL). The voltage and hence the active and/or reactive power of the SL can be controlled to regulate the mains frequency and/or voltage. The classification of SLs is provided and the characteristics and capabilities of each type are demonstrated through modelling, control design and simulations. The effectiveness of SLs working in unison for voltage control is demonstrated through case studies on realistic power system models. The limitations of smart load with reactive compensation only are highlighted. To overcome these limitations, an additional shunt converter in back-to-back configuration is proposed, which increases the flexibility of the smart load without requiring any energy storage. The contribution of different types of SLs in primary frequency control is also investigated. Sensitivity analysis are included to show the effectiveness and limitations of SLs for varying load power factors, proportion of SLs, and system strengths. Due to the limitations associated with input voltage control technique used in SLs (such as load voltage tolerance and availability of non-critical loads), use of power electronic compensators in output voltage control like mid-feeder compensation (MFC) and point-of-load compensation (PoLC) are also analysed. A comparison between the MFC and PoLC option is presented in terms of their voltage control capability, required compensator capacity, network losses and PV throughput. Alongside voltage control, effectiveness of the PoLC option for exercising voltage controlled demand response is also demonstrated and compared against the MFC option.
47
de, Paola Antonio. "Distributed control in the smart grid." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/43846.
Full textAbstract:
This thesis addresses some of the challenges that arise when the new smart grid paradigm is applied to power systems. In particular, novel control strategies are designed to deal in a decentralized matter with the increasing complexity of the network. Two main areas are investigated: participation to frequency control of variable-speed wind turbines and management of large populations of competing agents (e.g. micro-storage devices and "smart appliances") that exchange energy with the system. The first part of this work presents two different techniques that allow wind turbines to provide frequency response: following the trip of a large power plant, the turbines population increases its aggregate generated power, reducing the resulting drop in frequency. A first method models the wind turbines as stochastic hybrid systems: the generators switch randomly between two operative modes characterized by different efficiency and generated power at equilibrium. Transitions are driven by frequency-dependent switching functions: single generators behave randomly while large populations perform deterministically, changing the total power in response to frequency variations. The second proposed control strategy allows a prescribed increase in generation, distributing the control effort among the individual turbines in order to maximize the duration of frequency support or minimize the resulting kinetic energy losses. The second part of the thesis deals with large populations of agents which determine their operation strategy in response to a broadcast price signal. Micro-storage devices performing energy arbitrage are initially considered: each agent charges/discharges during the day in order to maximize its profit. By approximating the number of devices as infinite, modelling the population as a continuum and describing the problem through a differential game with infinite players (mean field game), it is possible to avoid synchronicity phenomena and determine an equilibrium for the market. Finally, the similar case of flexible demand is analyzed, with price-responsive appliances that schedule their power consumption in order to minimize their energy cost. Necessary and sufficient conditions for the existence of a Nash equilibrium are provided, extending the results by introducing time-varying constraints on the power rate and considering partial flexibility of the devices.
48
Wadoo, Sabiha Amin. "Evacuation Distributed Feedback Control and Abstraction." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27439.
Full textAbstract:
In this dissertation, we develop feedback control strategies that can be used for evacuating people. Pedestrian models are based on macroscopic or microscopic behavior. We use the macroscopic modeling approach, where pedestrians are treated in an aggregate way and detailed interactions are overlooked. The models representing evacuation dynamics are based on the laws of conservation of mass and momentum and are described by nonlinear hyperbolic partial differential equations. As such the system is distributed in nature.
We address the design of feedback control for these models in a distributed setting where the problem of control and stability is formulated directly in the framework of partial differential equations. The control goal is to design feedback controllers to control the movement of people during evacuation and avoid jams and shocks. We design the feedback controllers for both diffusion and advection where the density of people diffuses as well as moves in a specified direction with time. In order to achieve this goal we are assuming that the control variables have no bounds. However, it is practically impossible to have unbounded controls so we modify the controllers in order to take the effect of control saturation into account. We also discuss the feedback control for these models in presence of uncertainties where the goal is to design controllers to minimize the effect of uncertainties on the movement of people during evacuation. The control design technique adopted in all these cases is feedback linearization which includes backstepping for higher order two-equation models, Lyapunov redesign for uncertain models and robust backstepping for two-equation uncertain models.
The work also focuses on abstraction of evacuation system which focuses on obtaining models with lesser number of partial differential equations than the original one. The feedback control design of a higher level two-equation model is more difficult than the lower order one-equation model. Therefore, it is desirable to perform control design for a simpler abstracted model and then transform control design back to the original model.Ph. D.
49
Rubio, Diana. "Distributed Parameter Control of Thermal Fluids." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30330.
Full textAbstract:
We consider the problem of controlling a thermal convection flow by feedback. The system is governed by the Boussinesq approximation of the coupled set of Navier-Stokes and heat equations. The control is applied through Dirichlet boundary conditions.
We concentrate on a two-dimensional mode and use a semidiscrete Galerkin scheme for numerical computations. We construct both a linear control and a non-linear quadratic control and apply them to the full non-linear model. First, we test these controllers on a one-mode approximation. The convergence of the numerical scheme is analyzed. We also consider LQR control for a two-dimensional heat equation.Ph. D.
50
Benahmed, Sif Eddine. "Distributed Cooperative Control for DC Microgrids." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0056.
Full textAbstract:
Au cours des dernières années, le réseau électrique connait une transformation rapide avec la pénétration massive des unités de production renouvelables et distribuées. Le concept de microgrids (micro-réseau électrique) est un élément clés de cette transition énergétique. Ces micro-réseaux sont constitués par un ensemble de plusieurs unités de production distribuées (DGUs), d'unités de stockage (SUs) et de charges interconnectées par des lignes électriques. Un microgrid peut être installé dans plusieurs endroits, par exemple dans des maisons, des hôpitaux, des quartiers, etc. et fonctionne soit en mode connecté au réseau principale, soit en mode isolé (autonome). Les microgrids sont confrontés à plusieurs défis liés à la garantie de la stabilité, la cybersécurité, l'optimisation des coûts énergétiques, la gestion de l'énergie, la qualité de l'énergie, etc. Dans ce travail, nous concentrons notre attention sur le contrôle des microgrids à courant continu en mode de fonctionnement autonome. La principale contribution de cette thèse est l’établissement de lois de commande par retour d’état distribuées assurant un partage de courant proportionnel entre les unités de production, une régulation de la tension moyenne des lignes et un équilibrage simultané des états de charge des éléments de stockage. En partant de l'hypothèse que les agents (DGU ou SU) ont les mêmes paramètres physiques, la preuve de la convergence exponentielle et globale est donnée en l’absence d’une connaissance de la charge présente sur le réseau. La thèse est divisée en trois parties. La première partie présente le concept des microgrids, un état de l’art sur leurs stratégies de contrôle et les préliminaires mathématiques nécessaires tout au long du manuscrit. La deuxième partie constitue la contribution théorique de cette thèse et aborde la synthèse de lois de contrôle distribuées, garantissant les objectifs envisagés en l’absence d’une connaissance de la charge variable sur le réseau et même en cas de perturbation constantes au niveau de l’entrée de commande. Cette garantie est apportée en considérant trois actions intégrales distribuées de type consensus. Dans la troisième partie, les contrôleurs proposés sont évalués dans différents scénarios par le biais de simulation Matlab/Simulink et de tests Hardware-in-the-Loop (HIL) en temps réel. Les résultats montrent que les objectifs de contrôle sont atteints avec succès, ce qui illustre l'efficacité de la méthodologie de contrôle proposéeIn recent years, the power grid has undergone a rapid transformation with the massive penetration of renewable and distributed generation units. The concept of microgrids is a key element of this energy transition. Microgrids are made up of a set of several distributed generation units (DGUs), storage units (SUs) and loads interconnected by power lines. A microgrid can be installed in several locations, for example in houses, hospitals, a neighborhood or village, etc., and operates either in connected mode to the main grid or in isolated (autonomous) mode. Microgrids are facing several challenges related to stability assurance, cyber-security, energy cost optimization, energy management, power quality, etc. In this work, we focus our attention on the control of islanded direct current microgrids. The main contribution is the design of a new distributed control approach to provably achieve current sharing, average voltage regulation and state-of-charge balancing simultaneously with global exponential convergence. The main tools are consensus in multi-agent systems, passivity, Lyapunov stability, linear matrix inequalities, etc. The thesis is divided into three parts. The First part presents the concept of microgrids, a literature review of their control strategies and the mathematical preliminaries required throughout the manuscript. The second part deals with the design of the proposed distributed control approach to achieve the considered objectives. The system is augmented with three distributed consensus-like integral actions, and a distributed-based static state feedback control architecture is proposed. Starting from the assumption that the agents (DGUs or SUs) have the same physical parameters, we provide proof of global exponential convergence. Moreover, the proposed control approach is distributed, i.e., each agent exchange relative information with only its neighbors through sparse communication networks. The proposed controllers do not need any information about the parameters of the power lines neither the topology of the microgrid. The control objectives are reached despite the unknown load variation and constant disturbances. In the third part, the proposed distributed controllers are assessed in different scenarios through Matlab/Simulink simulation and real-time Hardware-in-the-Loop experiment. The results show that the control objectives are successfully achieved, illustrating the effectiveness of the proposed control methodology