Neste trabalho estuda-se a aplicação de um controlador preditivo não linear em reatores de policondensação visando à segurança, qualidade do produto, capacidade de “scale-up" e a produtividade. Nos processos de policondensação em batelada há formação de um produto volátil conhecido como condensado e a remoção deste torna-se necessária favorecer o avanço da reação a fim de obter alto grau de conversão. Na maioria dos trabalhos envolvendo a policondensação a separação não é levada em conta. Diante disso, desenvolveu-se um modelo de policondensação acoplado com a coluna de destilação a fim de verificar através das simulações em malha aberta o comportamento das variavéis de operação no sistema. O modelo de policondensação foi obtido na literatura (Shin et al.,1999) e em sua implementação foi levada em conta a inercia térmica entre as paredes do reator e as interações com a coluna destilação. A reação de policondensação estudada aqui corresponde à produção de polietileno-tereftalato (PET). Nesta reação, Tereftalato de dimetila (DMT) e Etilenoglicol (EG) geram como produtos grupos ésteres e metanol (M). O reator modelado corresponde ao reator piloto instalado no Laboratório de Simulação e Controle de Processos. A técnica de controle preditivo não linear (NMPC) foi implementada e testada em dois modelos de polimerização por radicais livres (sistema SISO e MIMO) e comparado com o desempenho de um controlador PID. O controlador preditivo não linear (NMPC) foi aplicado no modelo do reator de policondensação e foi utilizado um controlador PID como comparativo, nesta etapa realizou-se várias simulações em malha fechada e análises de sensibilidades. Para as análises de sensibilidades o controlador NMPC foi denominado de controlador NMPC com “feedback" e foi comparado com um controlador NMPC com retroalimentação de estado. Através dos estudos mostrou que o controlador NMPC tem um desempenho melhor do que o PID. Nos estudos de sensibilidade o controlador NMPC com “feedback" apresenta um desempenho superior ao do controlador NMPC com retroalimentação de estado. O controlador NMPC com “feedback" manteve o processo sob controle nas simulações que foram realizadas . / In this work the application of a non-linear predictive controller to policondensation reactors aiming the safety, quality of the product, capacity of scale-up and productivity is studied. In batch policondensation processes, a volatile product called condensate is generated, and its removal becomes necessary in order to favor the reaction progress as a mean to obtain high conversion rates. In most of the works involving policondensation the separation is not taken into account. Therefore, a policondensation model was developed which was coupled to a distillation column in order to verify the behavior of the variables in the system through open-loop simulations. The polycondensation model was obtained from the literature (Shin et al. ,1999) and was implemented taking into account the thermal inertia between the walls of the reactor and the interactions with the distillation column. The polycondensation reaction studied here corresponds to the production of polyethylene-terephtalate (PET). In this reaction, Dimethyl Terephtalate (DMT) and Etylene Glycol (EG) generate as products ester groups and methanol (M). The reactor that was modeled corresponds to a pilot reactor installed in the Laboratory of Simulation and Processes Control. A non linear predictive control (NMPC) was implemented and tested in two free radical polymerization models (SISO and MIMO systems) and compared with PID controllers performance. The NMPC was applied to the polycondensation model and a PID controller was also applied for comparison. In this stage several closed-loop simulations and sensitivity analyses were performed. For the sensitivity analyses the NMPC controller was denominated NMPC controller with "feedback" for comparison with an NMPC with full state feedback. The studies showed that NMPC controller has a better performance than PID. NMPC with "feedback" presents a superior performance to the NMPC with full state feedback in the presence of modeling gaps. In the simulations that were performed, the NMPC with "feedback" has kept the process under control.

Este trabalho apresenta a aplicação da teoria de controle robusto não linear por modos deslizantes a sistemas de posicionamento dinâmico para embarcações flutuantes, com validação experimental. O objetivo do sistema de controle projetado é manter a embarcação próxima a uma posição pré-ajustada (set-point) ou a uma trajetória preestabelecida (pathfollowing), por meio das forças geradas nos propulsores, mesmo estando o sistema na presença de distúrbios externos, ou seja, vento, ondas e correnteza. A princípio, realizaram-se simulações numéricas com o sistema projetado a fim de verificar o seu desempenho. O simulador utilizado foi implementado em ambiente Matlab/Simulink, considerando a dinâmica da embarcação e dos agentes ambientais. As simulações consistiram de manobras realizadas em condições nominais e na ausência de esforços ambientais, com embarcação cheia (plena) e vazia (lastro). Para validação do algoritmo implementado realizaram-se ensaios de manobra em condição de calmaria e na presença de vento, com a embarcação em plena carga e vazia. Os ensaios foram administrados no laboratório do Departamento de Engenharia Naval e Oceânica da USP (DENO). O algoritmo de controle por modos deslizantes demonstrou-se robusto a variações de condições ambientais (vento), mantendo o desempenho e estabilidade. Verificou-se que o ajuste dos parâmetros do controlador pode ser feito de forma intuitiva, utilizando-se fórmulas matemáticas. Além disso, a estrutura não linear do controlador e suas propriedades de robustez asseguram o desempenho e estabilidade para uma grande gama de condições ambientais e manobras realizadas com a embarcação. / This paper presents the application of the robust and nonlinear sliding mode control theory to the dynamic positioning systems for floating vessel, with experimental validation. The objective of the control system designed is to keep the vessel next a specific position (set-point) or follow a pre-defined trajectory (pathfollowing) through the action of propellers, in the presence of wind, waves and current external disturbances. In principle numerical simulations were carried out with the system designed to verify its performance. The simulator used was implemented in a Matlab / Simulink, considering the dynamics of the vessel and environmental agents. The simulations consisted of maneuvers carried out in nominal condition and in the absence of environmental efforts, with the vessel full and empty (ballasted). In order to validate the algorithm, small scale experiments were done, considering maneuvers in both calm and windy conditions, with the vessel at full or ballasted load. The tests were conducted at the laboratory of the Naval and Ocean Engineering Department (DENO) of the University of São Paulo. The sliding mode control was robust to variations in environmental conditions (wind), keeping the performance and stability. It was verified that the adjustment of controller parameters can be easily done, using mathematical equations. Moreover, the nonlinear structure of the controller and its robustness properties ensure the performance and stability for a large range of environmental conditions and maneuvers carried out with the vessel.

novel approach to extend the decision-making capabilities of unmanned surface vehicles (USVs) is presented in this work. A multi-objective framework is described where separate controllers command different behaviors according to a desired trajectory. Three behaviors are examined – transiting, station-keeping and reversing. Given the desired trajectory, the vehicle is able to autonomously recognize which behavior best suits a portion of the trajectory. The USV uses a combination of a supervisory switching control structure and a reinforcement learning algorithm to create a hybrid deliberative and reactive approach to switch between controllers and actions. Reinforcement learning provides a deliberative method to create a controller switching policy, while supervisory switching control acts reactively to instantaneous changes in the environment. Each action is restricted to one controller. Due to the nonlinear effects in these behaviors, two underactuated backstepping controllers and a fully-actuated backstepping controller are proposed for each transiting, reversing and station-keeping behavior, respectively, restricted to three degrees of freedom. Field experiments are presented to validate this system on the water with a physical USV platform under Sea State 1 conditions. Main outcomes of this work are that the proposed system provides better performance than a comparable gain-scheduled nonlinear controller in terms of an Integral of Absolute Error metric. Additionally, the deliberative component allows the system to identify dynamically infeasible trajectories and properly accommodate them. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

This dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of control surfaces to steer. When operating at low speeds or in relatively strong ocean currents, the performances of control surfaces will degrade. Internal actuators work independent of the relative ows, thus improving the maneuvering performance of the vehicle. We develop the mathematical model which describes the motion of an underwater vehicle in ocean currents from first principles. The equations of motion of a body-fluid dynamical system in an ideal fluid are derived using both Newton-Euler and Lagrangian formulations. The viscous effects of a real fluid are considered separately. We use a REMUS 100 AUV as the research model, and conduct CFD simulations to compute the viscous hydrodynamic coe cients with ANSYS Fluent. The simulation results show that the horizontal-plane motion of the vehicle is inherently unstable. The yaw moment exerted by the relative flow is destabilizing. The open-loop stabilities of the horizontal-plane motion of the vehicle in both ideal and real fluid are analyzed. In particular, the effects of a roll torque and a moving mass on the horizontal-plane motion are studied. The results illustrate that both the position and number of equilibrium points of the dynamical system are prone to the magnitude of the roll torque and the lateral position of the moving mass. We propose the design of using an internal moving mass to stabilize the horizontal-plane motion of the REMUS 100 AUV. A linear quadratic regulator (LQR) is designed to take advantage of both the linear momentum and lateral position of the internal moving mass to stabilize the heading angle of the vehicle. Alternatively, we introduce a tunnel thruster to the design, and use backstepping and Lyapunov redesign techniques to derive a nonlinear feedback control law to achieve autopilot. The coupling e ects between the closed-loop horizontal-plane and vertical-plane motions are also analyzed. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Autonomous Underwater Vehicle (AUV) depth control methods typically use a pressure sensor to measure the depth, which results in the AUV following the trajectory of the surface waves. Through simulations, a controller is designed for the Ocean Explorer AUV with the objective of the AUV holding a constant depth below the still water line while operating in waves. This objective is accomplished by modeling sensors and using filtering techniques to provide the AUV with the depth below the still water line. A wave prediction model is simulated to provide the controller with knowledge of the wave disturbance before it is encountered. The controller allows for depth keeping below the still water line with a standard deviation of 0.04 and 0.65 meters for wave amplitudes of 0.1-0.25 and 0.5-2 meters respectively and wave frequencies of 0.35-1.0 𝑟𝑎𝑑⁄𝑠𝑒𝑐, and the wave prediction improves the depth control on the order of 0.03 meters. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Dans ce travail de thèse, on s’intéresse au problème de déplacement et de la localisation d'un robot mobile autonome dans son environnement local. La première partie du manuscrit les deux tâches de mouvement de base : c'est-à-dire, la stabilisation et le suivi de trajectoire. Deux stratégies de commande ont été traitées: le mode de glissement intégral, et la méthode dite «Immersion et Invariance». La deuxième partie porte sur l'asservissement visuel, les deux techniques 2D et 3D d'asservissement visuel ont été appliquées. Les moments d'image ont été choisis comme indices visuels car ils sont moins sensibles au bruit d'image et autres erreurs de mesure. Une nouvelle approche de l'asservissement visuel qui repose sur l'image est ici proposée. Elle est basée sur la génération de trajectoires sur le plan de l'image directement (calcul des valeurs des primitives d’image correspondantes à une trajectoire cartésienne donnée). Cette approche garantit que la robustesse et la stabilité bien connues de l'asservissement 2D ont été étendues en raison du fait que les emplacements initial et désiré de la caméra sont proches. Les trajectoires obtenues garantissent aussi que la cible reste dans le champ de vue de la caméra et que le mouvement du robot correspondant est physiquement réalisable. Des tests expérimentaux ont été effectués et des résultats satisfaisants ont été obtenus à partir des implémentations des stratégies de commande et d'asservissement visuel. Bien qu'ils soient développés et expérimentés dans le cadre spécifique d'un robot de type unicycle, ces travaux sont assez génériques pour être appliqués sur autres types de véhicules. / This thesis focuses on the problem of moving and localizing an autonomous mobile robot in its local environments. The first part of the manuscript concerns two basic motion tasks, namely the stabilization and trajectory tracking. Two control strategies were discussed: the integral sliding mode, and the method known as “Immersion and Invariance” for nonlinear control. The second part focuses on both 2D and 3D visual servoing techniques. Image moments were chosen as visual features as they provide a more geometric and intuitive meaning than other features, and they are less sensitive to image noise and other measurement errors. A new approach to visual servoing based on image is herein proposed. It is based on the generation of trajectories directly on the image plane (Calculation of the image features corresponding to a given Cartesian path). This approach ensures that the robustness and stability are extended due to the fact that the initial and desired locations of the camera are close. The trajectories obtained guarantee that the target remains in the field of view of the camera and the corresponding movement of the robot is physically feasible. Experimental tests have been conducted, and satisfactory results have been obtained from both implementations regarding motion control and visual servoing strategies. Although developed and tested in the specific context of a unicycle type robot, this work is generic enough to be applied to other types of vehicles.

Lan Weiyao. / "December 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 163-172). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Cette thèse étudie les aspects de contrôle d'applications optique adaptative, une technologie utilisée pour améliorer la performance des systèmes optiques en réduisant l'effet des distorsions de front d'onde, à l'imagerie haute résolution angulaire. Le problème Adaptive Optics contrôle est présenté à travers une revue de la littérature. Par conséquent, la conception d'un contrôleur de rétroaction est adressée, d'un point de vue moderne de contrôle, au moyen de la méthode de contrôle Linéaire Quadratique Gaussienne. L'approche proposée met l'accent sur la capacité de la boucle d'optique adaptative de rejeter l'aberration atmosphérique. On dérive un système de représentation diagonale état-espace qui sépare nettement la dynamique de la plante (miroir déformable et le capteur de front d'onde) de la dynamique des perturbations (modèle atmosphérique). Cette représentation facilite la résolution numérique du problème. Une analyse de fréquence est effectuée pour vérifier les spécifications de performance et de robustesse de la multiple-input multiple-système de rétroaction de sortie. De plus, nous analysons les performances et la robustesse de LQG contrôle basé par rapport au témoin intégrante classique, au moyen de bout en bout des simulations et en considérant les différents niveaux de bruit du capteur de front d'onde. Durant le-ciel observations, l'énergie turbulente et la vitesse relative de chaque couche de l'atmosphère peut changer rapidement dégrader l'estimation de front d'onde. Pour cette raison, un algorithme de modèle numérique de conception garantissant une performance satisfaisante rejet de perturbations, même dans le cas de variables dans le temps caractéristique de la turbulence est dérivé. Expériences numériques en utilisant les CAOS du progiciel ont été menées pour démontrer la robustesse de chaque approche proposée. Compte tenu de la conviction auteur que l'avenir de l'optique adaptative repose également sur le développement d'un plus sophistiqués (par exemple, non linéaire) des modèles, une quantité importante de travail a été consacrée à l'étude de deux classes de méthodes de reconnaissance des formes répandues. À savoir Support Vector Machines et méthodes du noyau, dont la régression des capacités sont exploitées dans la solution du problème non linéaire suivi optimal. En ce qui concerne Support Vector Machines, grâce à la théorie du contrôle optimal singulier, les contraintes se relâchent permettant une résolution plus facile et plus rapide numérique du problème d'optimisation. Alors que, dans le cas totalement déterministe du contrôleur Support Vector résulte plus simple à synthétiser. En référence aux méthodes du noyau, une tentative originale de réunir leurs forces de régression avec le concept de contrôle adaptatif inverse est présentée. Le noyau récursif des moindres carrés algorithme est utilisé pour mettre en œuvre un contrôleur adaptatif inverse capable de forcer une dynamique non linéaire appropriés pour suivre une sortie désirée. Cette méthode très peut également être utilisé pour vérifier si une trajectoire donnée arbitraire est une sortie admissible pour le système non linéaire à l'étude. Un tel algorithme innovant pourrait être utilement appliquée dans les travaux futurs, le contrôle de Tip-Tilt miroirs. Finalement, une première esquisse du cadre théorique soutenant l'utilisation du contrôle adaptatif inverse pour la solution du problème de suivi général est donné. Après l'introduction de la formulation mathématique du problème de suivi et les définitions nécessaires mathématiques, des conditions suffisantes et nécessaires (cas linéaire) et des conditions suffisantes (cas non-linéaire) de l'existence de la solution sont dérivés. / His thesis investigates the control aspects of Adaptive Optics applications, a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions, to high angular resolution imaging. The Adaptive Optics control problem is presented through a survey of the literature. Consequently, the design of a feedback controller is addressed, from a modern control point of view, by means of the Linear Quadratic Gaussian control methodology. The proposed approach emphasizes the ability of the adaptive optics loop to reject the atmospheric aberration. We derive a diagonal state-space system representation which clearly separates the dynamics of the plant (deformable mirror and wavefront sensor) from the disturbance dynamics (atmospheric model). This representation facilitates the numerical resolution of the problem. A frequency analysis is carried out to check the performance and robustness specifications of the multiple-input multiple-output feedback system. Moreover, we analyze the performance and the robustness of LQG-based control compared to classic integral control, by means of end-to-end simulations and by considering different levels of wavefront sensor noise. During on-sky observations, the turbulent energy and relative speed of each atmospheric layer can change rapidly degrading the wavefront estimate. For this reason, a numerical model design algorithm guaranteeing satisfactory disturbance rejection performance even in the case of time-varying turbulence's characteristic is derived. Numerical experiments using the Software Package CAOS have been conducted to demonstrate the robustness of every proposed approach. Given the author firm belief that the future of Adaptive Optics also relies on the development of more sophisticated (i.e., nonlinear) models, a substantial amount of work was dedicated to the study of two classes of widespread pattern recognition methods. Namely Support Vector Machines and Kernel Methods, whose regression capabilities are exploited in the solution of the nonlinear optimal tracking problem. Concerning Support Vector Machines, thanks to the singular optimal control theory, constraints are loosened permitting an easier and faster numerical resolution of the optimization problem. So that, in the fully deterministic case the Support Vector controller results simpler to synthesize. With reference to Kernel Methods, an original attempt to bring together their regression strengths with the concept of Adaptive Inverse Control is presented. The Kernel Recursive Least-Square algorithm is used to implement an adaptive inverse controller capable of forcing a suitable nonlinear dynamics to follow a desired output. This very method can also be used to check if a given arbitrary trajectory is an admissible output for the nonlinear system under study. Such an innovative algorithm could be fruitfully applied, in future works, to the control of Tip-Tilt mirrors. Eventually, a first sketch of the theoretical framework supporting the use of Adaptive Inverse Control for the solution of the general tracking problem is given. After introducing the mathematical formulation of the tracking problem and the needed mathematical definitions, sufficient and necessary conditions (linear case) and sufficient (nonlinear case) conditions to the existence of the solution are derived.

Este trabalho apresenta a aplicação da teoria de controle robusto não linear por modos deslizantes a sistemas de posicionamento dinâmico para embarcações flutuantes, com validação experimental. O objetivo do sistema de controle projetado é manter a embarcação próxima a uma posição pré-ajustada (set-point) ou a uma trajetória preestabelecida (pathfollowing), por meio das forças geradas nos propulsores, mesmo estando o sistema na presença de distúrbios externos, ou seja, vento, ondas e correnteza. A princípio, realizaram-se simulações numéricas com o sistema projetado a fim de verificar o seu desempenho. O simulador utilizado foi implementado em ambiente Matlab/Simulink, considerando a dinâmica da embarcação e dos agentes ambientais. As simulações consistiram de manobras realizadas em condições nominais e na ausência de esforços ambientais, com embarcação cheia (plena) e vazia (lastro). Para validação do algoritmo implementado realizaram-se ensaios de manobra em condição de calmaria e na presença de vento, com a embarcação em plena carga e vazia. Os ensaios foram administrados no laboratório do Departamento de Engenharia Naval e Oceânica da USP (DENO). O algoritmo de controle por modos deslizantes demonstrou-se robusto a variações de condições ambientais (vento), mantendo o desempenho e estabilidade. Verificou-se que o ajuste dos parâmetros do controlador pode ser feito de forma intuitiva, utilizando-se fórmulas matemáticas. Além disso, a estrutura não linear do controlador e suas propriedades de robustez asseguram o desempenho e estabilidade para uma grande gama de condições ambientais e manobras realizadas com a embarcação. / This paper presents the application of the robust and nonlinear sliding mode control theory to the dynamic positioning systems for floating vessel, with experimental validation. The objective of the control system designed is to keep the vessel next a specific position (set-point) or follow a pre-defined trajectory (pathfollowing) through the action of propellers, in the presence of wind, waves and current external disturbances. In principle numerical simulations were carried out with the system designed to verify its performance. The simulator used was implemented in a Matlab / Simulink, considering the dynamics of the vessel and environmental agents. The simulations consisted of maneuvers carried out in nominal condition and in the absence of environmental efforts, with the vessel full and empty (ballasted). In order to validate the algorithm, small scale experiments were done, considering maneuvers in both calm and windy conditions, with the vessel at full or ballasted load. The tests were conducted at the laboratory of the Naval and Ocean Engineering Department (DENO) of the University of São Paulo. The sliding mode control was robust to variations in environmental conditions (wind), keeping the performance and stability. It was verified that the adjustment of controller parameters can be easily done, using mathematical equations. Moreover, the nonlinear structure of the controller and its robustness properties ensure the performance and stability for a large range of environmental conditions and maneuvers carried out with the vessel.

Cette thèse traite du problème de la stabilisation d'un système de lancement aéroporté (éventuellement non habité) pour satellites. Le lancement aéroporté consiste à ramener, à l'aide d'un avion, un satellite et son lanceur (fusée) à une certaine hauteur, et d'exécuter son lancement dans les airs (souvent en larguant la fusée). Ceci est similaire au lancement d'un missile par un avion chasseur. La plus grande différence réside dans le rapport de masse entre l'avion et le lanceur qui est beaucoup plus proche de l'unité (fusée lourde comparée à la masse de l'avion). Le système est composé de deux étages: le premier étage est dit avion porteur qui est un véhicule aérien automatisé. Il porte le lanceur qui constitue le deuxième étage (la fusée). Dans la première partie, sont proposées des approches de modélisation pour le système de largage pendant et après le largage. La première approche considère que la phase de séparation est instantanée, mais imparfaite. Par conséquent le système est vu comme un modèle d'aéroplane dont les variables d'état sont avec des larges conditions initiales dues à la séparation imparfaite. Une deuxième approche considère la séparation elle-même, représentée par une forte perturbation (un extrême cas) sur les forces et couples aérodynamiques du modèle au cours d'un intervalle de temps. Dans la deuxième partie, afin de stabiliser le système de largage après la séparation, la commande à intégrateur conditionnel modifié est développée dans un premier temps pour une classe des systèmes non-linéaires multi-entrées multi-sorties, avec comme point de départ la théorie introduite par Khalil et co-auteurs pour des systèmes mono entrée mono sortie. Cette commande a été ensuite étendue pour la commande à servo-compensateur conditionnel modifié pour une classe de systèmes non-linéaires multi-entrées multi-sorties. Les deux stratégies ont été appliquées pour stabiliser le système de largage pendant et après la phase de séparation. Ces techniques ont l'avantage d'être robustes et de pouvoir utiliser des modèles approximatifs. D'un autre côté, il était important d'examiner la possibilité d'obtenir de meilleures performances en utilisant de meilleurs modèles. Pour cette raison, la commande de linéarisation par bouclage dynamique a été étudiée. Finalement, les performances de toutes ces méthodes de commande (ainsi que certaines commandes de base additionnelles) ont été illustrées par des simulations sous Matlab/Simulink sur un modèle non-linéaire de F-16. / This thesis addresses the problem of the stabilization of an (unmanned) airlaunch system. Air launching consists in bringing a satellite and its launcher (rocket) to a certain height using an aircraft, and then launching it from the air (often by dropping the rocket), in a similar way of launching a missile from a fighter. The main difference is that the envisaged mass ratio is much closer to one (heavy rocket compared to aircraft mass). It is then composed of two stages: the first stage called carrier aircraft consists of an <unmanned> aerial vehicle that carries the launcher which constitutes the second stage (rocket). This thesis starts by introducing the problem and objectives, continues by presenting several approaches to model the airlaunch system, and ends by developing different advanced control methods to stabilize it after the launching phase. In the modeling part we propose a firstly approach called the initial condition model which assumes that the separation phase is instantaneous, and then the airlaunch system is composed of an aircraft model after the launching phase but with large initial conditions on its state variables, caused by a non-perfect split phase. A second approach assumes that the separation phase itself is modeled by a disturbance on aerodynamic forces and moments (from a worst case) during a time interval. In the control part a modified conditional integrator controller for a class of nonlinear multi-input multi-output systems is first developed starting from the conditional integrator theory developed by Khalil and co-workers. It is then extended to a modified conditional servocompensator control for a class of nonlinear multi-input multi-output systems. Both control strategies were then applied to stabilize the airlaunch system after the separation phase. They have the advantage of being very robust, and they don't depend so much on reliable models. Even if these control strategies gave good results, it was investigated in this thesis another control approach much more dependent on detailed and reliable models. This approach was based on dynamic feedback linearization theory, and the main idea is to obtain better performance in trade off better models. Finally, all proposed control methods (plus some standard ones) were compared and illustrated by simulations under Matlab/Simulink on a nonlinear F-16 model. These simulations have shown that the results were as expected, and that each control strategy was well fit for a particular situation.