Este trabalho aborda o problema de controle baseado em eventos para sistemas em tempo discreto, considerando que o sistema possui os dispositivos atuadores e sensores em nós diferentes e separados por uma rede de comunicação. A estratégia baseada em eventos consiste em reduzir a utilização da rede ao transmitir as informações do sensor para o atuador apenas quando um evento é gerado pela violação de um determinado limiar pela função de disparo. Primeiramente, são formuladas condições para a estabilidade de um sistema linear com realimentação estática de estados sob a estratégia proposta, com base na teoria de Lyapunov. Como as condições são postas na forma de desigualdades matriciais lineares (LMIs, do inglês linear matrix inequalities), problemas de otimização convexos podem ser utilizados na determinação dos parâmetros da função de disparo, bem como na resolução do problema de co-design, ou seja, do projeto simultâneo do controlador e da função de disparo, os quais são providos na sequência. A partir deste resultado básico, a metodologia é estendida para o caso em que ocorre a saturação do atuador. A seguir, é apresentada a extensão da metodologia para o caso em que o estado da planta não está disponível para o sensor, sendo então utlizado um observador de estados, considerando-se tanto o caso em que o modelo da planta utilizado no observador corresponde exatamente à dinâmica real da planta quanto o caso em que este modelo apresenta incertezas. Exemplos numéricos são apresentados para ilustrar todas as classes de sistemas consideradas, com os quais constata-se que a estratégia proposta é eficiente na redução da utilização dos recursos da rede de comunicação. / This work approaches the problem of event-triggered control for discrete time systems, considering that the system has the actuator and sensor devices in different nodes, separated by a communication network. The event-triggered strategy consists in reducing the utilization of the network by only transmitting the information from the sensor to the actuator when an event is generated by the violation of a determined threshold by the trigger function. Firstly, conditions for the stability of a linear system with a static state feedback under the proposed strategy are formulated based on the Lyapunov theory. Since the conditions are given in the form of linear matrix inequalities (LMIs), convex optimization problems can be used for the determination of the trigger function parameters, as well as the co-design of the feedback gain and the trigger function, which are given next. From this basic result, the methodology is extended to the case where occurs the saturation of the actuator. Following, the extension of the methodlogy to the case in which the plant states are not available for measure is presented, and a state-observer is used, considering both the case that the plant model corresponds exactly to the real plant dynamics and the case where this model has uncertainties. Numeric examples are shown to illustrate all the system classes considered, with which it is found that the proposed strategy is efficient in the reduction of the network resources utilization.

La théorie du contrôle a d'abord été conçue pour des contrôleurs analogiques. Il était alors pertinent de synthétiser un contrôleur dans une représentation continue. De nos jours, les systèmes numériques ont majoritairement remplacés les systèmes analogiques pour différentes raisons (coût, résistance au bruit, intégration,...). Les signaux sont alors maintenus constants entre le cadencement périodique fixé par une horloge numérique.La commande événementielle vise à améliorer l’échantillonnage périodique en proposant une méthode dans laquelle les mises à jour sont déclenchées par une fonction événement.Dans cette thèse, de nouvelles méthodes de synthèse de contrôleurs evenementiels sont présentés et testés sur des systèmes temps-réels.La contribution la plus originale étant l'utilisation d'une commande événementielle appliquée à un problème d'anticollision entre une quadrirotor et un environnement supposé connu. / Control system theory has first been built for analog controllers. In this context, it was relevant to use a continuous framework to design a control feedback function. Nowadays, digital technologies are supplanting analog solutions due to several advantages (cost, noise, resistance, integration...). Signal is held constant between periodic triggers given by a digital clock.Event-based (or event-triggered) control aims to improve the periodic sampling scheme by proposing a method in which updates are triggered by an event function.In this thesis new event-based designs are detailled and tested on real-time systems.The most original contribution of this thesis is the use of an event-triggered design for a problem of collision avoidance between a quadrotor and a known environment.

Este trabalho aborda o problema de controle baseado em eventos para sistemas em tempo discreto, considerando que o sistema possui os dispositivos atuadores e sensores em nós diferentes e separados por uma rede de comunicação. A estratégia baseada em eventos consiste em reduzir a utilização da rede ao transmitir as informações do sensor para o atuador apenas quando um evento é gerado pela violação de um determinado limiar pela função de disparo. Primeiramente, são formuladas condições para a estabilidade de um sistema linear com realimentação estática de estados sob a estratégia proposta, com base na teoria de Lyapunov. Como as condições são postas na forma de desigualdades matriciais lineares (LMIs, do inglês linear matrix inequalities), problemas de otimização convexos podem ser utilizados na determinação dos parâmetros da função de disparo, bem como na resolução do problema de co-design, ou seja, do projeto simultâneo do controlador e da função de disparo, os quais são providos na sequência. A partir deste resultado básico, a metodologia é estendida para o caso em que ocorre a saturação do atuador. A seguir, é apresentada a extensão da metodologia para o caso em que o estado da planta não está disponível para o sensor, sendo então utlizado um observador de estados, considerando-se tanto o caso em que o modelo da planta utilizado no observador corresponde exatamente à dinâmica real da planta quanto o caso em que este modelo apresenta incertezas. Exemplos numéricos são apresentados para ilustrar todas as classes de sistemas consideradas, com os quais constata-se que a estratégia proposta é eficiente na redução da utilização dos recursos da rede de comunicação. / This work approaches the problem of event-triggered control for discrete time systems, considering that the system has the actuator and sensor devices in different nodes, separated by a communication network. The event-triggered strategy consists in reducing the utilization of the network by only transmitting the information from the sensor to the actuator when an event is generated by the violation of a determined threshold by the trigger function. Firstly, conditions for the stability of a linear system with a static state feedback under the proposed strategy are formulated based on the Lyapunov theory. Since the conditions are given in the form of linear matrix inequalities (LMIs), convex optimization problems can be used for the determination of the trigger function parameters, as well as the co-design of the feedback gain and the trigger function, which are given next. From this basic result, the methodology is extended to the case where occurs the saturation of the actuator. Following, the extension of the methodlogy to the case in which the plant states are not available for measure is presented, and a state-observer is used, considering both the case that the plant model corresponds exactly to the real plant dynamics and the case where this model has uncertainties. Numeric examples are shown to illustrate all the system classes considered, with which it is found that the proposed strategy is efficient in the reduction of the network resources utilization.

Este trabalho aborda o problema de controle baseado em eventos para sistemas em tempo discreto, considerando que o sistema possui os dispositivos atuadores e sensores em nós diferentes e separados por uma rede de comunicação. A estratégia baseada em eventos consiste em reduzir a utilização da rede ao transmitir as informações do sensor para o atuador apenas quando um evento é gerado pela violação de um determinado limiar pela função de disparo. Primeiramente, são formuladas condições para a estabilidade de um sistema linear com realimentação estática de estados sob a estratégia proposta, com base na teoria de Lyapunov. Como as condições são postas na forma de desigualdades matriciais lineares (LMIs, do inglês linear matrix inequalities), problemas de otimização convexos podem ser utilizados na determinação dos parâmetros da função de disparo, bem como na resolução do problema de co-design, ou seja, do projeto simultâneo do controlador e da função de disparo, os quais são providos na sequência. A partir deste resultado básico, a metodologia é estendida para o caso em que ocorre a saturação do atuador. A seguir, é apresentada a extensão da metodologia para o caso em que o estado da planta não está disponível para o sensor, sendo então utlizado um observador de estados, considerando-se tanto o caso em que o modelo da planta utilizado no observador corresponde exatamente à dinâmica real da planta quanto o caso em que este modelo apresenta incertezas. Exemplos numéricos são apresentados para ilustrar todas as classes de sistemas consideradas, com os quais constata-se que a estratégia proposta é eficiente na redução da utilização dos recursos da rede de comunicação. / This work approaches the problem of event-triggered control for discrete time systems, considering that the system has the actuator and sensor devices in different nodes, separated by a communication network. The event-triggered strategy consists in reducing the utilization of the network by only transmitting the information from the sensor to the actuator when an event is generated by the violation of a determined threshold by the trigger function. Firstly, conditions for the stability of a linear system with a static state feedback under the proposed strategy are formulated based on the Lyapunov theory. Since the conditions are given in the form of linear matrix inequalities (LMIs), convex optimization problems can be used for the determination of the trigger function parameters, as well as the co-design of the feedback gain and the trigger function, which are given next. From this basic result, the methodology is extended to the case where occurs the saturation of the actuator. Following, the extension of the methodlogy to the case in which the plant states are not available for measure is presented, and a state-observer is used, considering both the case that the plant model corresponds exactly to the real plant dynamics and the case where this model has uncertainties. Numeric examples are shown to illustrate all the system classes considered, with which it is found that the proposed strategy is efficient in the reduction of the network resources utilization.

Control over wireless sensor and actuator networks is of growing interest in process industry since it enables flexible design, deployment, operation, and maintenance. An important problem in industrial wireless control is how to limit the amount of information that needs to be exchanged over the network. In this thesis, network scheduling and remote control co-design is considered to address this problem. In the first part, we propose a design of an optimal network schedule for state estimation over a multi-hop wireless sensor network. We formulate an optimization problem, minimizing a linear combination of the averaged estimation error and transmission energy. A periodic network schedule is obtained, which specifies when and through which routes each sensor in the network should transmit its measurement, so that an optimal remote estimate under sensor energy consideration is achieved. We also propose some suboptimal schedules to reduce the computational load. The effectiveness of the suboptimal schedules is evaluated in numerical examples. In the second part, we propose a co-design framework for sensor scheduling, routing, and control over a multi-hop wireless sensor and actuator network. For a decoupled plant and LQG control performance, we formulate an optimization problem and show that the optimal schedule, routing, and control can be obtained locally for each control loop. In this part, we also introduce algorithms to reconfigure the schedules and routes when a link in the network is disconnected. The results are illustrated in a numerical example. In the third part, we consider event-based feedforward control from a wireless disturbance sensor. We derive stability conditions when the closed-loop system is subject to actuator saturation. Feedforward control with anti-windup compensation is introduced to reduce the effect of actuator saturation. The effectiveness of the approach is illustrated in some numerical examples. / <p>QC 20181029</p>

Les systèmes hybrides sont des systèmes dynamiques, caractérisés par un comportementdual, une interaction entre une partie discrète et une partie continue de fonctionnement.Dans le centre de notre travail se trouve une classe particulière de systèmeshybrides, plus spécifiquement les systèmes stochastiques à commutation que nous modélisonsà l’aide des Chaînes de Markov en temps continu et des équations différentielles.Le comportement aléatoire de ce type de système nécessite une commande spécialequi s’adapte aux événements arbitraires qui peuvent changer complètement l’évolutiondu système. Nous avons choisi une politique de contrôle basée sur les événements quiest déclenchée seulement quand il est nécessaire (sur un événement incontrôlable - parexemple un seuil qui est atteint), et jusqu’à ce que certaines conditions de fonctionnementsont remplies (le système revient dans l’état normal).Notre approche vise le développement d’un modèle probabiliste qui permet de calculerun critère de performance (en occurrence l’énergie du système) pour la politiquede contrôle choisie. Nous proposons d’abord une méthode de simulation à événementsdiscrets pour le système stochastique à commutation commandé, qui nous donne la possibilitéde réaliser une optimisation directe de la commande appliquée sur le système etaussi de valider les modèles analytiques que nous avons construit pour l’application ducontrôle.Un modèle analytique pour déterminer l’énergie consommée par le système a étéconçu en utilisant les probabilités de sortie de la région de contrôle, respectivement lestemps de séjour dans la chaîne de Markov avant et après avoir atteint les limites decontrôle. La dernière partie du travail présente la comparaison des résultats obtenusentre la méthode analytique et la simulation. / Hybrid systems are dynamical systems, characterized by a dual behaviour, a continuousinteraction between a discrete and a continuous functioning part. The center ofour work is represented by a particular class of hybrid systems, more specific by thestochastic switching systems which we model using continuous time Markov chains anddifferential equations.The random behaviour of such systems requires a special command which adapts tothe arbitrary events that can completely change the evolution of the system. We chose anevent-based control policy which is triggered only when it’s necessary (on an unforeseenevent - for example when a threshold that is reached), and until certain functioningconditions are met (the system returns in the normal state).Our approach aims to develop a probabilistic model that calculates a performancecriterion (in this case the energy of the system) for the proposed control policy. We startby proposing a discrete event simulation for the controlled stochastic switching system,which gives us the opportunity of applying a direct optimisation of the control command.It also allows us to compare the results with the ones obtained by the analytical modelswe have built when the event-based control is applied.An analytical model for computing the energy consumed by the system to apply thecontrol is designed by using the exit probabilities of the control region, respectively, thesojourn times of the Markov chain before and after reaching the control limits. The lastpart of this work presents the results we have obtained when comparing the analyticaland the simulation method.

In this thesis study, it is aimed to improve the performance of an Internet-based teleoperation system enabling the remote operation of a 6 DOF industrial robot. In order to improve the safety and efficiency of the teleoperation, stability and synchronization (hand-eye coordination) are considered. The selected communication medium between the human operator and remote robot is the Internet. The variable time delays and nondeterministic characteristics of the Internet may lead to instability of the teleoperation system. Considering the disturbing effects of the Internet onto the transmission, an event-based control approach is used in order to improve the stability of the teleoperation system. Besides, a visual feedback system is developed and a force-feedback mouse is designed in order to improve synchronization between the human operator and robot during the command generation according to the feedback obtained from the control system. A client-server software application is developed to interface the human operator with remote environment. It is observed that, using the event-based control approach in the operation makes the teleoperation stable and improves the synchronization ability. Implementation of visual feedback and force-feedback mouse to the teleoperation system improves the human operator&rsquo / s ability to perform remote operation.

La course à la miniaturisation des circuits électroniques pousse à développer des systèmes faible coût, quece soit en terme de consommation d’énergie ou de ressources de calcul. Il est ainsi possible de réduire la consommationen diminuant la tension d’alimentation et/ou la fréquence d’horloge, mais ceci a pour conséquence de diminuer aussila vitesse de fonctionnement du circuit. Une commande prédictive rapide permet alors de gérer dynamiquement un telcompromis, de manière à ce que la consommation d’énergie soit minimisée tout en garantissant de bonnes performances.Les stratégies de commande proposées ont notamment l’avantage d’être très robustes aux dispersions technologiquesqui sont un problème récurrent dans les nanopuces. Des solutions sont également proposées afin de réduire le coût decalcul du contrôleur. Les systèmes à échantillonnage non-uniforme, dont la loi de commande est calculée et mise à jourlorsqu’un événement est déclenché, sont ainsi étudiés. Ce principe permet de réduire le nombre d’échantillons et, parconséquent, d’économiser des ressources de calcul, tout en garantissant de bonnes performances du système commandé.Des résultats de simulation, et surtout expérimentaux, valident finalement l’intérêt d’utiliser une telle approche. / The demand of electronic components in all embedded and miniaturized applications encourages to developlow-cost components, in term of energy consumption and computational resources. Actually, the power consumption canbe reduced when decreasing the supply voltage and/or the clock frequency, but with the effect that the device runs moreslowly in return. Nevertheless, a fast predictive control strategy allows to dynamically manage this tradeoff in order tominimize the energy consumption while ensuring good performance of the device. Furthermore, the proposals are highlyrobust to tackle variability which is a real problem in nanometric systems on chip. Some issues are also suggested inthis thesis to reduce the control computational cost. Contrary to a time-triggered system where the controller calculatesthe control law at each (constant and periodic) sampling time, an event-based controller updates the control signalonly when the measurement sufficiently changes. Such a paradigm hence calls for resources whenever they are indeednecessary, that is when required from a performance or stability point of view for instance. The idea is to soften thecomputational load by reducing the number of samples and consequently the CPU utilization. Some simulation andexperimental results eventually validate the interest of such an approach.