This thesis presents a novel bilateral teleoperation algorithm for n degree of freedom nonlinear manipulators connected through time delays. Teleoperation has many practical uses, as there are many benefits that come from being able to operate machines from a distance. For instance, the ability to send a remote controlled robotic vehicle into a hazardous environment can be a great asset in many industrial applications. As well, the field of remote medicine can benefit from these technologies. A highly skilled surgeon could perform surgery on a patient who is located in another city, or even country. Earth to space operations and deep sea exploration are other areas where teleoperation is quite useful. Central to the approach presented in this work is the use of second order sliding mode unknown input observers for estimating the external forces acting on the manipulators. The use of these observers removes the need for both velocity and force sensors, leading to a lower cost hardware setup that provides all of the advantages of a position-force teleoperation algorithm. Stability results for this new algorithm are presented for several cases. Stability of each of the master and slave sides of the teleoperation system is demonstrated, showing that the master and slave are both stabilized by their respective controllers when the unknown input observers are used for state and force estimation. Additionally, closed loop stability results for the teleoperation system connected to a variety of slave side environments are presented. Delay-independent stability results for a linear spring-damper environment as well as a general finite-gain stable nonlinear environment are given. Delay-dependent stability results for the case where the slave environment is a liner spring-damper and the delays are commensurate are also presented. As well, stability results for the closed loop under the assumption that the human operator is modeled as a finite-gain stable nonlinear environment are given. Following the theoretical presentation, numerical simulations illustrating the algorithm are presented, and experimental results verifying the practical application of the approach are given.

This thesis presents a novel bilateral teleoperation algorithm for n degree of freedom nonlinear manipulators connected through time delays. Teleoperation has many practical uses, as there are many benefits that come from being able to operate machines from a distance. For instance, the ability to send a remote controlled robotic vehicle into a hazardous environment can be a great asset in many industrial applications. As well, the field of remote medicine can benefit from these technologies. A highly skilled surgeon could perform surgery on a patient who is located in another city, or even country. Earth to space operations and deep sea exploration are other areas where teleoperation is quite useful. Central to the approach presented in this work is the use of second order sliding mode unknown input observers for estimating the external forces acting on the manipulators. The use of these observers removes the need for both velocity and force sensors, leading to a lower cost hardware setup that provides all of the advantages of a position-force teleoperation algorithm. Stability results for this new algorithm are presented for several cases. Stability of each of the master and slave sides of the teleoperation system is demonstrated, showing that the master and slave are both stabilized by their respective controllers when the unknown input observers are used for state and force estimation. Additionally, closed loop stability results for the teleoperation system connected to a variety of slave side environments are presented. Delay-independent stability results for a linear spring-damper environment as well as a general finite-gain stable nonlinear environment are given. Delay-dependent stability results for the case where the slave environment is a liner spring-damper and the delays are commensurate are also presented. As well, stability results for the closed loop under the assumption that the human operator is modeled as a finite-gain stable nonlinear environment are given. Following the theoretical presentation, numerical simulations illustrating the algorithm are presented, and experimental results verifying the practical application of the approach are given.

Dans ce travail de thèse, nous développons des méthodes de synchronisation des systèmes chaotiques pour les applications de transmission d'informations. La première méthode de synchronisation que nous proposons est basée sur les observateurs adaptatifs à entrées inconnues pour une classe des systèmes chaotiques présentant des incertitudes paramétriques et des perturbations dans leurs dynamiques et du bruit dans les signaux de sortie (bruit dans le canal de communication). La méthode développée repose sur les techniques adaptatives pour la compensation des non-linéarités et des incertitudes paramétriques et pour la restauration des messages transmis. Elle se base également sur les méthodes de synthèse d'observateurs à entrées inconnues pour supprimer l'influence des perturbations et du bruit. Ensuite, nous développons une deuxième méthode de synchronisation utilisant un observateur adaptatif à ``modes glissants" pour une classe des systèmes chaotiques présentant des entrées inconnues et dont les signaux de sortie sont bruités. La synthèse de l'observateur s'appuie sur la théorie des modes glissants, les techniques de synthèse d'observateurs singuliers et les techniques adaptatives dans le but d'estimer conjointement l'état et les entrées inconnues malgré la présence du bruit dans les équations de sortie. Cette approche de synchronisation est ensuite employée dans un nouveau schéma de communication chaotique sécurisée dont l'objectif est d'augmenter le nombre et l'amplitude des messages transmis, améliorer le niveau de sécurité ainsi que la robustesse aux bruits présents dans le canal de communication. En outre, le scénario de présence des retards de transmission est étudié en élaborant une troisième approche de synchronisation à base d'observateurs adaptatifs pour une classe des systèmes chaotiques de Lur'e avec des non-linéarités à pente restreinte et des signaux de sortie retardés. En se basant sur la théorie de Lyapunov-Krasovskii et en utilisant une hypothèse d'excitation persistante, l'observateur adaptatif proposé garantit la synchronisation maitre-esclave et la restauration des informations transmises malgré l'existence des retards de transmission. Les résultats théoriques obtenus dans ce travail de thèse sont vérifiés à travers des applications de transmission d'informations utilisant différents modèles des systèmes chaotiques tout en étudiant les différents scénarios et cas de figure pouvant se présenter en pratique et en analysant les aspects de sécurité de ces systèmes. / In this thesis, we develop synchronization methods of chaotic systems for information transmission applications. The first proposed method is based on adaptive unknown input observers for a class of chaotic systems subject to parametric uncertainties and perturbations in their dynamics and noise in outputs signals (Channel communication noise). The developed method is based on adaptive techniques to compensate nonlinearities to compensate nonlinearities and parametric uncertainties and to reconstruct the transmitted messages. Furthermore, this approach is based on unknown input observers design to reject the influence of perturbations and noise. Then, we develop a second synchronization method using an adaptive ``sliding mode” observer for a class of chaotic systems subject to unknown inputs and such that the output equations are subject to noise. The observer design is based on sliding modes theory, descriptor observers design and adaptive control in order to join state and unknown input estimation despite the presence of noise in output equations. The latter synchronization approach is then exploited in a new secured communication scheme where the objective is to increase the number and amplitude of the transmitted messages, improve the level of security and the robustness to noise present in the communication channel. Moreover, the case of presence of transmission time-delays was investigated and a synchronization approach based on adaptive observers for a class of Lur’e systems with slope restricted nonlinearities and delayed outputs. Based on the Lyapunov-Krasovskii theory and using a persistency of excitation property, the proposed adaptive observer ensures master-slave synchronization and the reconstruction of the transmitted messages despite the existence of transmission time-delays. The obtained theoretical results in this thesis are verified through transmission information applications using different models of chaotic systems in different scenarios and case-studies which may occur in practice. Cryptanalysis and security aspects of the proposed communication systems are also investigated.

Les capacités installées d’énergie éolienne continuent à croître rapidement et prennent une place de plus en plus significative dans le monde. Au fur et à mesure, les études menées sur la conception, la sureté de fonctionnement et la supervision de la chaîne éolienne ont pris progressivement de l’importance. Deux axes de recherche ont été privilégiés dans cette thèse. Le premier concerne la continuité de service d'une éolienne connectée au réseau en présence de défaut de court-circuit entre spires dans une phase du stator de la génératrice asynchrone à cage d'écureuil. L'analyse du défaut ainsi que son impact sur le système éolien et notamment sur la qualité de la puissance produite souligne l'intérêt de développement d'un algorithme de détection et d'isolation rapide, dédié par la suite à la reconfiguration de la commande. Ainsi, une commande tolérante au défaut (CTD) a été conçue de manière à éviter l'arrêt de la production, compenser l'impact de défaut et garder des performances acceptables de la qualité d'énergie produite. Le travail effectué s'est articulé sur les observateurs à mode glissant (OMG), communément connus comme outil puissant pour la supervision et la commande à la fois. Le deuxième axe porte sur la sécurité structurale et la stabilité du système éolien sous contraintes vibratoires. Les travaux se répartissent en deux parties complémentaires : L'établissement d'un modèle numérique tridimensionnel (3-D) sous un logiciel d’analyse par éléments finis (ANSYS) et la réalisation des essais vibratoires sous différentes excitations au sein d'une plateforme vibratoire (TREVISE). Dans ce cadre, un modèle numérique (3-D) d'une éolienne à axe horizontal couplée à un mât et une fondation adéquats a été développé en utilisant la méthode de volumes finis (FVM) afin d'appréhender son comportement vibratoire. Les essais vibratoires expérimentaux valident le modèle numérique et permettent l’identification de la réponse dynamique de la structure d'une manière fine. De plus, nous avons élaboré un modèle expérimental de la tenue de l’éolienne aux contraintes vibratoires de formes aléatoire, sinusoïdale et impulsionnelle. / The wind energy capacity carries on growing quickly and taking an increasingly significant place in the world. Progressively, research studies dealing with designing and supervising wind turbines have become more important. Two areas of research were developed in this thesis. The first one concerns the continuity of service of a wind turbine connected to the grid while an inter-turn short-circuit fault is present in the stator phase of the induction squirrel cage generator. The analysis of the fault as well as its impact on the wind turbine system and mainly on the quality of the produced power highlights the interest of development of a fast detection and isolation algorithm, dedicated to the reconfiguration of the control law. Hence, a fault tolerant control scheme has been established in order to avoid stopping production, compensate the fault impact and maintain acceptable performances of the quality of the produced energy. The carried out work was based on sliding mode observers, commonly known as robust tools for monitoring and controlling at the same time. The second axis concerns the structural modeling and stability checking of the wind system under vibratory stresses. The work is divided into two complementary parts: The establishment of a three-dimensional (3-D) numerical model using a finite element analysis software (ANSYS) and the realization of vibratory tests under different excitations within the platform (TREVISE). In this framework, a numerical (3-D) model of a horizontal axis wind turbine coupled to a suitable tower and foundation was developed basing on the finite volume method (FVM) in order to analyze its vibratory behavior. The experimental vibratory tests validate the numerical model and allow the identification of the dynamic response of the structure in a precise way. In addition, we have developed an experimental model of the behavior of the wind turbine under vibratory stresses of random, sinusoidal and impulse shapes.