In this thesis, dynamic modeling and nonlinear control of autonomous underwater vehicle manipulator systems are presented. Mainly, two types of systems consisting of a 6-DOF AUV equipped with a 6-DOF manipulator subsystem (UVMS) and with an 8-DOF redundant manipulator subsystem (UVRMS) are modeled considering hydrostatic forces and hydrodynamic effects such as added mass, lift, drag and side forces. The shadowing effects of the bodies on each other are introduced when computing the hydrodynamic forces. The system equations of motion are derived recursively using Newton&ndash / Euler formulation. The inverse dynamics control algorithms are formulated and trajectory tracking control of the systems is achieved by assigning separate tasks for the end effector of the manipulator and for the underwater vehicle. The proposed inverse dynamics controller utilizes the full nonlinear model of the system and consists of a linearizing control law that uses the feedback of positions and velocities of the joints and the underwater vehicle in order to cancel off the nonlinearities of the system. The PD control is applied after this complicated feedback linearization process yielding second order error dynamics. The thruster dynamics is also incorporated into the control system design. The stability analysis is performed in the presence of parametric uncertainty and disturbing ocean current. The effectiveness of the control methods are demonstrated by simulations for typical underwater missions.

In this thesis, dynamic modeling and nonlinear control of autonomous underwater vehicle manipulator systems are presented. Mainly, two types of systems consisting of a 6-DOF AUV equipped with a 6-DOF manipulator subsystem (UVMS) and with an 8-DOF redundant manipulator subsystem (UVRMS) are modeled considering hydrostatic forces and hydrodynamic effects such as added mass, lift, drag and side forces. The shadowing effects of the bodies on each other are introduced when computing the hydrodynamic forces. The system equations of motion are derived recursively using Newton&ndash / Euler formulation. The inverse dynamics control algorithms are formulated and trajectory tracking control of the systems is achieved by assigning separate tasks for the end effector of the manipulator and for the underwater vehicle. The proposed inverse dynamics controller utilizes the full nonlinear model of the system and consists of a linearizing control law that uses the feedback of positions and velocities of the joints and the underwater vehicle in order to cancel off the nonlinearities of the system. The PD control is applied after this complicated feedback linearization process yielding second order error dynamics. The thruster dynamics is also incorporated into the control system design. The stability analysis is performed in the presence of parametric uncertainty and disturbing ocean current. The effectiveness of the control methods are demonstrated by simulations for typical underwater missions.

This thesis addresses the path planning problem for Autonomous Underwater Vehicles (AUVs) using homotopy classes to provide topological information on how paths avoid obstacles. Looking for a path within a homotopy class constrains the search into a specific area of the search space, speeding up the computation of the path. Given a workspace with obstacles, the method starts by generating the homotopy classes. Those which probably contain lower cost solutions are determined by means of a lower bound criterion before computing a path. Finally, a path planner uses the topological information of homotopy classes to generate a few good solutions very quickly. Three path planners from different approaches have been proposed to generate paths for the homotopy classes obtained. The path planning is performed on Occupancy Grid Maps (OGMs) improved with probabilistic scan matching techniques. The results obtained with synthetic s scenarios and with real datasets show the feasibility of our method. / Aquesta tesi aborda el problema de la planificació de camins per a Vehicles Submarins Autònoms (AUVs) mitjançant la utilització de classes d'homotopia per a proporcionar informació topològica de com els camins eviten els obstacles. Calcular un camí dins d'una classe d'homotopia permet limitar l'espai de cerca accelerant-ne el càlcul de la solució. Donat un workspace amb obstacles, el mètode primer genera les classes homotòpiques. Aquelles classes que probablement contenen les solucions de menor cost s'identifiquen per mitjà d'una heurística sense haver-ne de calcular el camí al workspace. Finalment, un planificador de camins utilitza la informació topològica de les classes d'homotopia per generar solucions segons les classes seleccionades molt ràpidament. El mètode de planificació de camins s’aplica sobre Mapes d’Occupació de Graella (OGMs) millorats amb tècniques de scan matching probabilístic. Els tests i resultats obtinguts tan en escenaris sintètics com en datasets reals mostren la viabilitat del nostre mètode.

A supercavitating vehicle, a next-generation underwater vehicle capable of changing the paradigm of modern marine warfare, exploits supercavitation as a means to reduce drag and achieve extremely high submerged speeds. In supercavitating flows, a low-density gaseous cavity entirely envelops the vehicle and as a result the vehicle is in contact with liquid water only at its nose and partially over the afterbody. Hence, the vehicle experiences a substantially reduced skin drag and can achieve much higher speed than conventional vehicles. The development of a controllable and maneuvering supercavitating vehicle has been confronted with various challenging problems such as the potential instability of the vehicle, the unsteady nature of cavity dynamics, the complex and non-linear nature of the interaction between vehicle and cavity. Furthermore, major questions still need to be resolved regarding the basic configuration of the vehicle itself, including its control surfaces, the control system, and the cavity dynamics. In order to answer these fundamental questions, together with many similar ones, this dissertation develops an integrated simulation-based design tool to optimize the vehicle configuration subjected to operational design requirements, while predicting the complex coupled behavior of the vehicle for each design configuration. Particularly, this research attempts to include maneuvering flight as well as various operating trim conditions directly in the vehicle configurational optimization. This integrated approach provides significant improvement in performance in the preliminary design phase and indicates that trade-offs between various performance indexes are required due to their conflicting requirements. This dissertation also investigates trim conditions and dynamic characteristics of supercavitating vehicles through a full 6 DOF model. The influence of operating conditions, and cavity models and their memory effects on trim is analyzed and discussed. Unique characteristics are identified, e.g. the cavity memory effects introduce a favorable stabilizing effect by providing restoring fins and planing forces. Furthermore, this research investigates the flight envelope of a supercavitating vehicle, which is significantly different from that of a conventional vehicle due to different hydrodynamic coefficients as well as unique operational conditions.

In this thesis, a simulation package for the Six Degrees of Freedom (6DOF) motion of an underwater vehicle is developed. Mathematical modeling of an underwater vehicle is done and the parameters needed to write such a simulation package are obtained from an existing underwater vehicle available in the literature. Basic equations of motion are developed to simulate the motion of the underwater vehicle and the parameters needed for the hydrodynamic modeling of the vehicle is obtained from the available literature. 6DOF simulation package prepared for the underwater vehicle was developed using the MATLAB environment. S-function hierarchy is developed using the same platform with C++ programming language. With the usage of S-functions the problems related to the speed of the platform have been eliminated. The use of Sfunction hierarchy brought out the opportunity of running the simulation package on other independent platforms and get results for the simulation.

Cooperative control enables combinations of sensor data from multiple autonomous underwater vehicles (AUVs) so that multiple AUVs can perform smarter behaviors than a single AUV. In addition, in some situations, a human-driven underwater vehicle (HUV) and a group of AUVs need to collaborate and preform formation behaviors. However, the collective dynamics of a fleet of heterogeneous underwater vehicles are more complex than the non-trivial single vehicle dynamics, resulting in challenges in analyzing the formation behaviors of a fleet of heterogeneous underwater vehicles. The research addressed in this dissertation investigates the collective dynamics and control of a fleet of heterogeneous underwater vehicles, including multi-AUV systems and systems comprised of an HUV and a group of AUVs (human-AUV systems). This investigation requires a mathematical motion model of an underwater vehicle. This dissertation presents a review of a six-degree-of-freedom (6DOF) motion model of a single AUV and proposes a method of identifying all parameters in the model based on computational fluid dynamics (CFD) calculations. Using the method, we build a 6DOF model of the EcoMapper and validate the model by field experiments. Based upon a generic 6DOF AUV model, we study the collective dynamics of a multi-AUV system and develop a method of decomposing the collective dynamics. After the collective dynamics decomposition, we propose a method of achieving orientation control for each AUV and formation control for the multi-AUV system. We extend the results and propose a cooperative control for a human-AUV system so that an HUV and a group of AUVs will form a desired formation while moving along a desired trajectory as a team. For the post-mission stage, we present a method of analyzing AUV survey data and apply this method to AUV measurement data collected from our field experiments carried out in Grand Isle, Louisiana in 2011, where AUVs were used to survey a lagoon, acquire bathymetric data, and measure the concentration of reminiscent crude oil in the water of the lagoon after the BP Deepwater Horizon oil spill in the Gulf of Mexico in 2010.

In the past decade, the design and manufacturing of intelligent multipurpose underwater vehicles has increased significantly. In the wide range of studies conducted in this field, the flexibility and autonomy of these devices with respect to their intended performance had been widely investigated. This work is related to the design and manufacturing of a small and lightweight autonomous underwater vehicle (AUV) with vision capabilities allowing detecting and contouring obstacles. It is indeed an exciting challenge to build a small and light submarine AUV, while making tradeoffs between performance and minimum available space as well as energy consumption. In fact, due to the ever-increasing in equipment complexity and performance, designers of AUVs are facing the issues of limited size and energy consumption. By using a pair of thrusters capable to rotate 360o on their axis and implementing a mass shifter with a control loop inside the vehicle, this later can efficiently adapt its depth and direction with minimal energy consumption. A prototype was fabricated and successfully tested in real operating conditions (in both pool and ocean). It includes the design and embedding of accurate custom multi-purpose sensors for multi-task operation as well as an enhanced coordinated system between a high-speed processor and accustomed electrical/mechanical parts of the vehicle, to allow automatic controlling its movements. Furthermore, an efficient tracking system was implemented to automatically detect and bypass obstacles. Then, fuzzy-based controllers were coupled to the main AUV processor system to provide the best commands to safely get around obstacles with minimum energy consumption. The fabricated prototype was able to work for a period of three hours with object tracking options and five hours in a safe environment, at a speed of 0.6 m/s at a depth of 8 m.

Veículos Submarinos Não Tripulados (UUVs Unmanned Underwater Vehicles) possuem muitas aplicações comerciais, militares e científicas devido ao seu elevado potencial e relação custo-desempenho considerável quando comparados a meios tradicionais utilizados para a obtenção de informações provenientes do meio subaquático. O desenvolvimento de uma plataforma de testes e amostragem confiável para estes veículos requer o projeto de um sistema completo além de exigir diversos e custosos experimentos realizados no mar para que as especificações possam ser devidamente validadas. Modelagem e simulação apresentam medidas de custo efetivo para o desenvolvimento de componentes preliminares do sistema (software e hardware), além de verificação e testes relacionados à execução de missões realizadas por veículos submarinos reduzindo, portanto, a ocorrência de potenciais falhas. Um ambiente de simulação preciso pode auxiliar engenheiros a encontrar erros ocultos contidos no software embarcado do UUV além de favorecer uma maior introspecção dentro da dinâmica e operação do veículo. Este trabalho descreve a implementação do algoritmo de controle de um UUV em ambiente MATLAB/SIMULINK, sua conversão automática para código compilável (em C++) e a verificação de seu funcionamento diretamente no computador embarcado por meio de simulações. Detalham-se os procedimentos necessários para permitir a conversão dos modelos em MATLAB para código C++, integração do software de controle com o sistema operacional de tempo real empregado no computador embarcado (VxWORKS) e a estratégia de simulação com Hardware In The Loop (HIL) desenvolvida - A principal contribuição deste trabalho é apresentar de forma racional uma estrutura de trabalho que facilite a implementação final do software de controle no computador embarcado a partir do modelo desenvolvido em um ambiente amigável para o projetista, como o SIMULINK. / Unmanned Underwater Vehicles (UUVs) have many commercial, military, and scientific applications because of their potential capabilities and significant costperformance improvements over traditional means of obtaining valuable underwater information The development of a reliable sampling and testing platform for these vehicles requires a thorough system design and many costly at-sea trials during which systems specifications can be validated. Modeling and simulation provide a cost-effective measure to carry out preliminary component, system (hardware and software), and mission testing and verification, thereby reducing the number of potential failures in at-sea trials. An accurate simulation environment can help engineers to find hidden errors in the UUV embedded software and gain insights into the UUV operation and dynamics. This work describes the implementation of a UUV\'s control algorithm using MATLAB/SIMULINK, its automatic conversion to an executable code (in C++) and the verification of its performance directly into the embedded computer using simulations. It is detailed the necessary procedure to allow the conversion of the models from MATLAB to C++ code, integration of the control software with the real time operating system used on the embedded computer (VxWORKS) and the developed strategy of Hardware in the loop Simulation (HILS). The Main contribution of this work is to present a rational framework to support the final implementation of the control software on the embedded computer, starting from the model developed on an environment friendly to the control engineers, like SIMULINK.

Neste trabalho, é abordado o problema da navegação de um veículo submarino autônomo. São propostos estimadores de estado que realizam fusão sensorial baseada em Filtro Estendido de Kalman. Esses estimadores de estado empregam as medidas dos seguintes sensores: uma unidade de medição inercial, um sensor de velocidade por efeito Doppler, um profundímetro e uma bússola. Primeiramente foi projetado um estimador de estados para o AUV Pirajuba, onde a estimação da orientação do veículo é realizada de forma desacoplada à estimação da velocidade e posição do veículo. Em seguida, foram desenvolvidos dois estimadores de estado que estimam orientação, velocidade e profundidade do veículo de forma acoplada. Para o projeto e testes dos estimadores mencionados anteriormente, foi empregada uma base de dados contendo um registro de medições reais dos sensores do veículo submarino autônomo Pirajuba, durante testes de campo no lago de uma represa. Os resultados dos testes validaram os estimadores de estado propostos nesse trabalho. Por último, foi realizada uma análise comparativa dos estimadores de estado mencionados. / This work concerns the navigation problem of an autonomous underwater vehicle. Some state estimators using sensorial fusion were proposed, the sensorial fusion is based in an Extended Kalman Filter. The state estimators are fed by measurements of the following sensors: an inertial measurements unit, a velocity sensor by Doppler effect, a depthmeter and a compass. In the first version of the EKF algorithm, the vehicles attitude estimation was decoupled from the vehicle velocity estimation. The second version considers the coupling between linear velocity and the attitude in the vehicle reference frame, taking the velocity reading for correction of the filter estimates. Finally, in the third version, the coupling between position and attitude is also considered, but the correction of the filters estimates is based on the depth readings. Experiments for supporting the design and validation of the navigation algorithms were based on a database constructed with motion measurements during the AUV maneuvers in the north coast of Sao Paulo, and the Guarapiranga lake in the São Paulo city. This work presents a comparative analysis of those algorithms.

Předkládaná práce se zabývá návrhem a konstrukcí dálkově řízené sondy pro průzkum zatopených krasových oblastí. Cílem práce je zhotovení cenově přijatelné sondy pro speleologický výzkum. Soustava senzorů a dálkově řízený kamerový systém umožňuje pořízení záběrů z velkých hloubek, které lze později analyzovat.