Cette thèse présente une contribution sur les problèmes de contrôle de réseaux d'irrigations en tenant compte des contraintes de communication grâce à une approche multicouches d’intelligence distribuée. Les analyses détaillées de chaque couche avec les résultats analytiques et les simulations seront décrites dans les différents chapitres. Ils mettent l'accent sur l'intérêt de l'approche multicouches, plus précisément sur son efficacité et sa fiabilité pour la supervision, l'optimisation multi-objectifs et le contrôle coopératif distribué sur des systèmes complexes de transport d'eau.La première couche analysé est le réseau hydraulique composé de canaux d’écoulements à surface libre, de sous-réseaux maillés de tuyaux sous pression et des structures hydrauliques (pompes vannes, ..). En intégrant les équations de Saint-Venant pour décrire l’écoulement physique des fluides en surface libre et la méthode Lattice Boltzmann pour la simulation du fluide, nous obtenons un modèle non linéaire discret pour les canaux à surface libre. Les structures hydrauliques sont généralement traitées comme des limites internes des biefs (tronçons) et modélisées par des relations entre les variables de flux et de pression.Permettant l'échange d'informations entre les éléments du système de contrôle, le réseau de communication sera considéré comme la deuxième couche. La résolution des problèmes d’hétérogénéités des systèmes et des communications (par exemple les retards de diffusion dans le réseau, la perte de paquets, la consommation d'énergie) sera étudié en introduisant une architecture de réseau hybride avec un routage dynamique basé sur les exigences de Qualité de Service (QoS) des applications de contrôle. Pour le routage dynamique dans le réseau, une composition pondérée de certaines métriques standards est proposée afin que le protocole de routage utilisant cette métrique composite converge sans boucle avec une « route » optimum. Grâce à différents scénarios de simulation, plusieurs critères de performance du réseau ont été évalués. La comparaison des résultats de simulation permet de valider l'intérêt de cette approche de composition pour le routage dynamique.Une troisième couche propose un système de contrôle réactif optimal développé pour la régulation du réseau d'irrigation dans un modèle étendue à grande échelle : Distributed Cooperative Model Predictive Control (DCMPC). Cette partie aborde la mise en œuvre de différentes stratégies de contrôle (centralisées, décentralisées et distribuées) et intègre la communication coopérative entre les contrôleurs MPC locaux afin d’améliorer les performances global es du système. La gestion de la divergence dans l'échange d'informations entre les contrôleurs est considérée comme un problème de consensus et résolue en utilisant un protocole de consensus asynchrone. Cette approche du contrôle distribué basée sur le paradigme des systèmes multi-agents, fournit une solution garantissant que tous les contrôleurs aient une vue cohérente de certaines valeurs des données nécessaires pour le calcul de décision. Un cas d’application sur un canal d'irrigation est étudié dans les simulations. La comparaison des résultats de simulations valide les avantages de l'approche du contrôle distribué coopératif par rapport aux autres stratégies de contrôle. / This thesis presents control problems of irrigation network with communication constraints and a multi-layer approach to solve these problems in a distributed manner. Detailed discussions of each layer with analytical and simulation results are described throughout several chapters. They emphasize the potential interest of the multi-layer approach, more precisely its efficiency and reliability for supervision, multi-objective optimization and distributed cooperative control of complex water transport systems. Conventionally, the first layer to be considered is the hydraulic network composed of free-surface channels, hydraulic structures and mesh subnetwork of pressurized pipes. By coupling the Saint-Venant equations for describing the physics of free-surface fluid and the Lattice Boltzmann method for the fluid simulation, a discrete-time nonlinear model is obtained for channel reaches. The hydraulic structures are usually treated as internal boundaries of reaches and modeled by algebraic relationships between the flow and pressure variables. To enable the exchange of information among the control system’s components, a communication network is considered in the second layer. Solving challenging problems of heterogeneous devices and communication issues (e.g., network delay, packet loss, energy consumption) is investigated in this thesis by introducing a hybrid network architecture and a dynamic routing design based on Quality of Service (QoS) requirements of control applications. For network routing, a weighted composition of some standard metrics is proposed so that the routing protocol using the composite metric achieves convergence, loop-freeness and path-optimality properties. Through extensive simulation scenarios, different network performance criteria are evaluated. The comparison of simulation results can validate the interest of this composition approach for dynamic routing. Finally, the third layer introduces an optimal reactive control system developed for the regulatory control of large-scale irrigation network under a Distributed Cooperative Model Predictive Control (DCMPC) framework. This part discusses the implementation of different control strategies (e.g., centralized, decentralized, and distributed strategies) and how the cooperative communication among local MPC controllers can be included to improve the performance of the overall system. Managing divergent (or outdated) information exchange among controllers is considered in this thesis as a consensus problem and solved by an asynchronous consensus protocol. This approach based on the multi-agent system paradigm to distributed control requires each controller to agree with its neighbors on some data values needed during action computation. For simulations, a particular benchmark of an irrigation channel is considered. The comparison of simulation results validate the benefits of the distributed cooperative control approach over other control strategies.

Cette thèse développe les lois de coordination de systèmes de Lagrange. Elle propose en premier lieu une stratégie complètement décentralisée qui se base sur la technique de cross-coupling pour la commande d'un groupe de robots, appelé réseau, qui synchronisent leurs mouvements en suivant une trajectoire désirée. Cette stratégie est étendue pour faire face à l'incertitude paramétrique des robots ainsi qu’aux retards fréquemment rencontrés dans les applications pratiques de réseaux de communication. Une deuxième architecture basée sur la théorie des graphes est proposée pour les réseaux à leader. L'approche développée est considérée hybride. Une extension adaptative à base de réseaux de neurones est développée pour traiter les cas d'incertitude paramétrique. La stratégie conçue prend en considération les délais dans la réception des données. En se basant sur la notion de système en chaîne, la théorie des graphes, le concept de la passivité et la technique du backstepping, une nouvelle méthodologie de la conception de contrôleur de synchronisation pour une classe de systèmes sous-actionnés est développée. Afin d’avoir la possibilité d’implémenter ces stratégies de contrôle, on a développé une plate-forme d'expérimentation pour la robotique industrielle coopérative. / This thesis investigates the issue of designing decentralized control laws to cooperatively control a team of robot manipulators. The purpose is to synchronize their movements while tracking common desired trajectory. Based on a combination of Lyapunov direct method and cross-coupling technique, To account for unmatched uncertainties, the proposed decentralized control laws are extended to an adaptive synchronization tracking controllers. Moreover, due to communication imperfection, time delay communication problems are considered in the performance analysis of the controllers. Another relevant problem for distributed synchronized systems is the leader-follower control problem. In this strategy, a decentralized control laws based on the backstepping scheme is proposed to deal with a leader-follower multiple robots structure. Based on graph theory, the coordination strategy combines the leader follower control with the decentralized control. The thesis, also considers the cooperative movement of under- actuated manipulators tracking reference trajectories defined by the user. The control problem for a network of class of under-actuated systems is considered. The approach we adopted in this thesis consists in decomposing the under-actuated manipulators into a cascade of passive subsystems that synchronize with he other neighbors subsystems. The resulting synchronized control law is basically a combination of non-regular backstepping procedure aided with some concepts from graph theory. The proposed controllers are validated numerically, assuming that the underlying communication graph is strongly connected. To implement these control strategies, we developed an experimental platform made of three robot manipulators.

166f. / Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-04-10T19:35:07Z No. of bitstreams: 1 Luciana Pacheco seg.pdf: 3529890 bytes, checksum: 13857ac04543f1bbc9fd4d7ed9849eba (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-11T15:30:28Z (GMT) No. of bitstreams: 1 Luciana Pacheco seg.pdf: 3529890 bytes, checksum: 13857ac04543f1bbc9fd4d7ed9849eba (MD5) / Made available in DSpace on 2013-05-11T15:30:28Z (GMT). No. of bitstreams: 1 Luciana Pacheco seg.pdf: 3529890 bytes, checksum: 13857ac04543f1bbc9fd4d7ed9849eba (MD5) Previous issue date: 2011 / Em sistemas industriais automatizados, a inatividade provocada pela escassez não planejada de recursos, ou por falhas de processo, tem grande influência no desempenho dos sistemas por conta das descontinuidades e instabilidades geradas. Sistemas de controle distribuídos e autônomos podem ajudar a lidar com esses tipos de problemas devido à melhoria de desempenho possibilitada. Entretanto, aspectos relativos à segurança e ao tempo de resposta devem ser bem tratados nesses sistemas devido aos riscos envolvidos (humanos, financeiros e ambientais). A proposta de sistemas autônomos e distribuídos visa a que decisões de controle sejam tomadas mais próximas do objeto controlado, reduzindo assim o tempo de atuação no processo e sistematizando algumas decisões, antes tomadas de forma empírica. Consequentemente, se espera aumentar a disponibilidade e a continuidade do processo, bem como garantir os aspectos de confiabilidade. Entretanto, quando tais sistemas se tornam mais autônomos e distribuídos, podem tender ao comportamento global caótico, caso suas interações não estejam bem definidas. Assim, é importante que seja avaliado e dimensionado o acoplamento entre os sistemas autônomos relacionados. O grau de inteligência de um sistema pode variar de uma entidade completamente controlada a entidades completamente autônomas. O primeiro nível de inteligência é verificado quando um sistema é capaz de gerenciar suas próprias informações, obtidas por meio de sensores e demais técnicas e dispositivos, e não somente manipular informações. Em um segundo nível, o sistema pode notificar o seu gestor quando há um problema. Em um terceiro nível, o sistema já é capaz de tomar decisões e se autogerenciar, mesmo sem intervenção externa. Neste caso, o sistema tem controle total sobre suas tarefas e não há nenhum controle externo a ele. A alternativa proposta pelo GCAD visa a que Sistemas Industriais Automatizados atinjam até o terceiro nível de inteligência, sendo que intervenções externas podem ser admitidas nos casos em que uma ação puramente local e autônoma de fato não é recomendável ou não é possível, por exemplo, havendo necessidade de substituição de equipamentos ou dispositivos. O GCAD propõe um módulo de controle inteligente instanciado predominantemente em nível local que visa a permitir que cada Sistema Industrial Automatizado, distribuído em células, tome decisões críticas de uma forma autônoma. Adicionalmente, um módulo remoto deve gerenciar situações mais complexas que estão além da capacidade de decisão ou atuação do sistema de controle local. O modelo proposto visa a permitir ajustes automáticos e autônomos no sistema, a fim de melhorar seu desempenho, e prevenir ou tratar as falhas inesperadas,assegurando a continuidade da operação. / Salvador

Dans un contexte de développement des énergies renouvelables et des liaisons HVDC dans les systèmes électriques, les travaux présentés s’attachent au fonctionnement technique de tels systèmes. La génération éolienne, photovoltaïque et les liaisons HVDC sont interfacées par dispositifs d’électronique de puissance au réseau de transport électrique. Dès lors, serait-il envisageable d’alimenter la demande électrique uniquement via des sources électriques interfacées par des convertisseurs statiques ?Le pilotage du système électrique par électronique de puissance constitue un changement radical du fonctionnement dynamique des réseaux. La traditionnelle stratégie de commande « grid-following » des onduleurs a montré ses limites lorsque la pénétration de ces dispositifs devient importante. Elle doit être révisée au profit de stratégies dîtes « parallel grid-forming ».Dans cette thèse, les besoins fondamentaux du système électrique sont d’abord analysés pour définir les exigences de la stratégie « parallel grid-forming », ainsi que les défis associés. Selon ces spécifications, une méthode de synchronisation de sources « grid-forming » est ensuite proposée ainsi qu’un contrôle de tension, adapté aux limitations physiques des convertisseurs de tension PWM. La stabilité de la solution est discutée pour différentes configuration de réseau. Enfin, une stratégie de limitation du courant a été spécifiquement développée pour palier la sensibilité des VSC aux sur courants, lors d’évènements réseaux éprouvant. Les idées développées sur un convertisseur unique sont appliquées à petits réseaux afin d’extraire des interprétations physiques depuis des simulations temporelles / In the context of renewable energy and HVDC links development in power systems, the present work concerns the technical operations of such systems. As wind power, solar photovoltaics and HVDC links are interfaced to the transmission grid with power-electronics, can the system be operated in the extreme case where the load is fed only through static converters?Driving a power system only based on power electronic interfaced generation is a tremendous change of the power system paradigm that must be clearly understood by transmission grid operators. The traditional “grid-feeding” control strategy of inverters exhibits a stability limit when their proportion becomes too important. The inverter control strategy must be turned into a “parallel grid-forming” strategy.This thesis first analyses the power system needs, proposes the requirements for “parallel grid-forming” converters and describes the associated challenges. Accordingly, the thesis gives a method for designing a stable autonomous synchronization controls so that grid-forming sources can operate in parallel with a good level of reliability. Then, a method is proposed to design a voltage control for a grid-forming PWM source taking into account the limited dynamic of large converters. The robustness of the solution is discussed for different configuration of the grid topology. A current limiting strategy is presented to solve the current sensitivity issue of grid-forming converters, subject to different stressing events of the transmission grid. The ideas developed on a single converter are then applied on small grids with a limited number of converters to allow a physical interpretation on the simulation results.

Le travail présenté dans cette thèse porte sur la modélisation et la commande d'un système thermodynamique non linéaire de dimension infinie, le réacteur tubulaire. Nous abordons le problème de commande sur ce système non linéaire en nous appuyant sur les propriétés thermodynamiques du procédé. Cette approche nécessite l'utilisation d'un modèle ayant comme variables d'état les variables extensives thermodynamiques classiques. Nous utilisons la fonction de disponibilité thermodynamique ainsi qu'une autre fonction déduite de la précédente, la disponibilité réduite, comme fonction de Lyapunov candidate pour résoudre le problème de stabilisation du réacteur autour d'un profil d'équilibre en utilisant comme commande distribuée la température de la double enveloppe. Des simulations illustrent ces résultats ainsi que l'efficacité des commandes en présence de perturbations. Nous nous intéressons aussi à la représentation hamiltonienne à port des systèmes irréversibles de dimension infinie. La structure de Stokes-Dirac pour un modèle réaction diffusion est obtenue en étendant les vecteurs de variables de flux et d'effort. Nous présentons cette démarche pour les équations du système réaction-diffusion en prenant premièrement l'énergie interne comme Hamiltonien puis deuxièmement l'opposé de l'entropie. Nous montrons dans les deux cas qu'en utilisant une extension des couples de variables effort-flux thermodynamiques classiques nous obtenons une structure de Stokes-Dirac. Enfin nous donnons quelques résultats aboutissant à une représentation pseudo hamiltonienne. Enfin nous abordons le problème de commande à la frontière. L'objectif est d'étudier l'existence de solutions associées à un modèle linéarisé de réacteur tubulaire complet commandé à la frontière / The main objective of this thesis consists to investigate the problem of modelling and control of a nonlinear parameter distributed thermodynamic system : the tubular reactor. We address the control problem of this non linear system relying on the thermodynamic properties of the process. This approach requires to use the classical extensive variables as the state variables. We use the thermodynamic availability as well as the reduced thermodynamic availability (this function is formed from some terms of the thermodynamic availabilty) as Lyapunov functions in order to asymptotically stabilize the tubular reactor aroud a steady profile. The distributed temperature of the jacket is the control variable. Some simulations illustrate these results as well as the eficiency of the control in presence of perturbations. Next we study the Port Hamiltonian representation of irreversible infinite dimensional systems. We propose a Stokes-Dirac structure of a reaction-diffusion system by means of the extension of the vectors of the flux and effort variables. We illustrate this approach on the example of the reaction-diffusion system. For this latter we use the internal energy as well as the opposite of the entropy to obtain Stokes-Dirac structures. We propose also a pseudo-Hamiltonian representation for the two Hamiltonians. Finally we tackle the boundary control problem. The objective is to study the existence of solutions associated to a linearized model of the tubular reactor controlled to the boundary

<div>Multi-robot systems have demonstrated strong capability in handling environmental operations. In this study, We examine how a team of robots can be utilized in covering and removing spill patches in a dynamic environment by executing three consecutive stages: deployment, coverage, and rendezvous. </div><div> </div><div>For the deployment problem, we aim for robot allocation based on the discreteness of the patches that need to be covered. With the deep neural network (DNN) based spill detector and remote sensing facilities such as drones with vision sensors and satellites, we are able to obtain the spill distribution in the workspace. Then, we formulate the allocation problem in a general optimization form and provide solutions using an integer linear programming (ILP) solver under several realistic constraints. After the allocation process is completed and the robot team is divided according to the number of spills, we deploy robots to their computed optimal goal positions. In the robot deployment part, control laws based on artificial potential field (APF) method are proposed and practiced on robots with a common unicycle model. </div><div> </div><div>For the coverage control problem, we show two strategies that are tailored for a wirelessly networked robot team. We propose strategies for coverage with and without path planning, depending on the availability of global information. Specifically, in terms of coverage with path planning, we partition the workspace from the aerial image into pieces and let each robot take care of one of the pieces. However, path-planning-based coverage relies on GPS signals or other external positioning systems, which are not applicable for indoor or GPS-denied circumstances. Therefore, we propose an asymptotic boundary shrink control that enables a collective coverage operation with the robot team. Such a strategy does not require a planned path, and because of its distributedness, it shows many advantages, including system scalability, dynamic spill adaptability, and collision avoidance. In case of a large-scale patch that poses challenges to robot connectivity maintenance during the operation, we propose a pivot-robot coverage strategy by mean of an a priori geometric tessellation (GT). In the pivot-robot-based coverage strategy, a team of robots is sent to perform complete coverage to every packing area of GT in sequence. Ultimately, the entire spill in the workspace can be covered and removed.</div><div> </div><div>For the rendezvous problem, we investigate the use of graph theory and propose control strategies based on network topology to motivate robots to meet at a designated or the optimal location. The rendezvous control strategies show a strong robustness to some common failures, such as mobility failure and communication failure. To expedite the rendezvous process and enable herding control in a distributed way, we propose a multi-robot multi-point rendezvous control strategy. </div><div> </div><div>To verify the validity of the proposed strategies, we carry out simulations in the Robotarium MATLAB platform, which is an open source swarm robotics experiment testbed, and conduct real experiments involving multiple mobile robots.</div>

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 global. / In 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.

The ability to gather and process information regarding the condition of forest fires is essential to cost-effective, safe, and efficient fire fighting. Advances in sensory and autopilot technology have made miniature unmanned aerial systems (UASs) an important tool in the acquisition of information. This thesis addresses some of the challenges faced when employing UASs for forest-fire perimeter surveillance; namely, perimeter tracking, cooperative perimeter surveillance, and path planning. Solutions to the first two issues are presented and a method for understanding path planning within the context of a forest-fire environment is demonstrated. Both simulation and hardware results are provided for each solution.

We address the question of performance of large-scale networks with distributed feedback control. We consider networked dynamical systems with single and double integrator dynamics, subject to distributed disturbances. We focus on two types of problems. First, we consider problems modeled over regular lattice structures. Here, we treat consensus and vehicular formation problems and evaluate performance in terms of measures of “global order”, which capture the notion of network coherence. Second, we consider electric power networks, which we treat as dynamical systems modeled over general graphs. Here, we evaluate performance in terms of the resistive power losses that are incurred in maintaining network synchrony. These losses are associated with transient power flows that are a consequence of “local disorder” caused by lack of synchrony. In both cases, we characterize fundamental limitations to performance as networks become large. Previous studies have shown that such limitations hold for coherence in networks with regular lattice structures. These imply that connections in 3 spatial dimensions are necessary to achieve full coherence, when the controller uses static feedback from relative measurements in a local neighborhood. We show that these limitations remain valid also with dynamic feedback, where each controller has an internal memory state. However, if the controller can access certain absolute state information, dynamic feedback can improve performance compared to static feedback, allowing also 1-dimensional formations to be fully coherent. For electric power networks, we show that the transient power losses grow unboundedly with network size. However, in contrast to previous results, performance does not improve with increased network connectivity. We also show that a certain type of distributed dynamic feedback controller can improve performance by reducing losses, but that their scaling with network size remains an important limitation. / <p>QC 20160504</p>

Evolving technology in wireless telecommunication, such as 5G, provides opportunities to utilize wireless communication more in an industrial setting where reliability and predictability are of great concern. More capable Industrial Internet of Things devices (IIoT) are, indeed, a catalyst for Industry 4.0. Still, before the IIoT devices can be deemed capable enough, a method to evaluate the IIoT systems unobtrusively—so that the evaluation does not affect the performance of the systems—must be established. This thesis aims to answer how the performance of a distributed control system can be unobtrusively evaluated, and also determine what the state-of-the-art is in latency measurements in distributed control systems. To answer the question, a novel diagnostics method for time-critical control systems in cloud-fog automation is proposed and extensively evaluated on real-life testbeds that use 5G, WiFi 6, and Ethernet in an edge-computing topology with real control systems. The feasibility of the proposed method was verified by experiments conducted with a diagnostics framework prototype developed in this thesis. In the proposed diagnostics framework, the controller application is monitored by a computing probe based on an extended Berkeley Packet Filter program. Network communication between the controller and control target is evaluated with a multi-channel Ethernet probe and custom-made software that computes several metrics related to the performance of the distributed system. The data from the unobtrusive probes are sent to a time-series database that is used for further analysis and real-time visualization in a graphical interface created with Grafana. The proposed diagnostics method together with the developed prototype can be used as a research infrastructure for future evaluations of distributed control systems.