Download or read book Path Planning for an Identification Mission of an Autonomous Underwater Vehicle in a Lemniscate Form written by Ayushman Barua and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Der Fokus der vorliegenden Arbeit diskutierten Forschungsarbeit liegt auf der Entwicklung eines Algorithmus für ein Autonomous Underwater Vehicle (AUV), um ein fortschrittliches autonomes Verhalten zu ermöglichen. Die Aufgabe des AUV ist die Inspektion, Überwachung und visuelle Identifizierung von Objekten wie beispielsweise Schiffswracks, Ölpipelines, Leichen und nicht detonierter Kampfmittel, die durch das vorausschauende oder das seitliche Scan-Sonar detektiert werden. Der Entwurf des Algorithmus beinhaltet auch eine effiziente Strömungskorrektur und die Aufrechterhaltung des Fahrtweges des AUV. Der Algorithmus wurde auf SeaCat AUV implementiert und von ATLAS ELEKTRONIK GmbH entwickelt. Um gründliche und detaillierte Daten des zu untersuchenden Objekts zu erhalten, muss das Fahrzeug aus verschiedenen Richtungen mehrere Überfahrten durchführen. Die ausgewählte Trajektorie nimmt die Form einer lemniskatenförmigen Kurve an. Die Kurve ist adaptiv, was bedeutet, dass sie einen glatten Übergang hat und gedreht werden kann, um sich der Richtung des Meeresstroms und der Annäherungsrichtung an das interessierende Objekt anzupassen. Die Mitte dieser Kurve wird automatisch über dem Objekt positioniert. Der Referenzkurs und die Geschwindigkeit des AUV werden ebenfalls auf adaptive Weise berechnet, wobei Richtung und Stärke der Strömung und die Orientierung des Fahrzeugs in Bezug zu dieser berücksichtigt werden. Der Algorithmus berechnet Fahrtrichtung und Geschwindigkeiten kontinuierlich über die gesamte Trajektorie, sodass der Drift aufgrund der Strömung ausgeglichen wird. Eine bekannte Methode, die "Jagd auf das Kaninchen", wird verwendet, um den durch die Strömung verursachten Querspurfehler abzuschätzen. Diese Methode platziert ein virtuelles Ziel, welches Kaninchen genannt wird und sich vor der aktuellen Position des AUV entlang der gewünschten Trajektorie bewegt. Die Forschung muss Lösungen für die folgenden vier Hauptherausforderungen finden: Erstens eine genaue Schätzung der Strömung unter Verwendung von DVL-Daten; zweitens die Berechnung der aktuellen Position des AUV und der Position des detektierten Objekts in Verbindung mit der Fähigkeit, das AUV in Richtung des zu untersuchenden Ziels zu führen; drittens die Platzierung des virtuellen Punkts für das AUV; viertens die Korrektur des AUV-Steuerkurses auf der Grundlage der Strömung, um den Spurfehler zu kompensieren.

Download or read book A Mission Planning Expert System with Three Dimensional Path Optimization for the NPS Model 2 Autonomous Underwater Vehicle written by Seow Meng Ong and published by . This book was released on 1990 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned vehicle technology has matured significantly over the last two decades. This is evidenced by its widespread use in industrial and military applications ranging from deep-ocean exploration to anti-submarine warfare. Indeed, the feasibility of short range, special-purpose vehicles (whether autonomous or remotely operated) is no longer in question. The research efforts have now begun to shift their focus on development of reliable, longer range, high-endurance and fully autonomous systems. One of the major underlying technologies required to realize this goal is Artificial Intelligence (AI). The latter offers great potential to endow vehicles with the intelligence needed for fully automated and extended range capability; this involves the increased application of AI techniques to support mission planning and execution, navigation and contingency planning. This thesis addresses two issues associated with the above goal for Autonomous Underwater Vehicles (AUV's). Firstly, a new approach is proposed for path planning in underwater environments that is capable of dealing with uncharted obstacles and which requires significantly less planning time and computer memory. Secondly, it explores the use of expert system technology in the planning of AUV missions. (KR).

Download or read book Path Planning Methods for AUVs written by Konuralp Yiğit and published by . This book was released on 2011 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: From naval operations to ocean science missions, the importance of autonomous vehicles is increasing with the advances in underwater robotics technology. Due to the dynamic and intermittent underwater environment and the physical limitations of autonomous underwater vehicles, feasible and optimal path planning is crucial for autonomous underwater operations. The objective of this thesis is to develop and demonstrate an efficient underwater path planning algorithm based on the level set method. Specifically, the goal is to compute the paths of autonomous vehicles which minimize travel time in the presence of ocean currents. The approach is to either utilize or avoid any type of ocean flows, while allowing for currents that are much larger than the nominal vehicle speed and for three-dimensional currents which vary with time. Existing path planning methods for the fields of ocean science and robotics are first reviewed, and the advantages and disadvantages of each are discussed. The underpinnings of the level set and fast marching methods are then reviewed, including their new extension and application to underwater path planning. Finally, a new feasible and optimal time-dependent underwater path planning algorithm is derived and presented. In order to demonstrate the capabilities of the algorithm, a set of idealized test-cases of increasing complexity are first presented and discussed. A real three-dimensional path planning example, involving strong current conditions, is also illustrated. This example utilizes four-dimensional ocean flows from a realistic ocean prediction system which simulate the ocean response to the passage of a tropical storm in the Middle Atlantic Bight region.

Download or read book Mission Planning and Mission Control Software for the Phoenix Autonomous Underwater Vehicle AUV written by Bradley J. Leonhardt and published by . This book was released on 1996-03-01 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Naval Postgraduate School Autonomous Underwater Vehicle (AUV), Phoenix, has a well developed lower level architecture (Execution level) while the upper, Strategic and especially the Tactical, levels need refinement. To be useful in the fleet an easier means of creating mission code for the Strategic level is required. A software architecture needed to be implemented at the Tactical level on-board Phoenix which can accommodate multi-processes, multi- languages, multiprocessors and control hard real time constraints existing at the Execution level. Phoenix also did not have a path replanning capability prior to this thesis. The approach taken is to provide Phoenix a user friendly interface for the autogeneration of human readable mission code and the creation and implementation of a Tactical level control architecture onboard Phoenix to include path replanning. The approach utilizes Rational Behavior Model (RBM) architectural design principles. This thesis focuses on the Officer of the Deck and replanning at the Tactical level, and refinement of the Captain at the Strategic level. While further testing is necessary, Phoenix is now capable of behaving as a truly autonomous vehicle. Results of this thesis show that nontechnical personnel can generate Prolog code to perform missions on-board Phoenix. Path replanning and obstacle avoidance software are also implemented. Most important this thesis demonstrates successful operation of all three levels of the RBM architecture on-board Phoenix.

Download or read book Adaptive Path Planning for an Autonomous Marine Vehicle Performing Cooperative Navigation for Autonomous Underwater Vehicle written by Jonathan Hudson and published by . This book was released on 2012 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Adaptive path planning of an autonomous marine vehicle (surface or subsurface) in the role of a communication and navigation aid (CNA) for multiple autonomous underwater vehicles (AUVs) for survey missions is studied. This path planning algorithm can be run before deployment, based on the planned paths of the survey AUVs, or underway, based on information transmitted by the survey AUVs. The planner considers the relative depth of the CNA and survey AUVs (not previously done) allowing the CNA to better aid survey AUVs that maintain a set distance over the ocean floor while surveying. Results are presented from simulations and in-water trials for both pre-deployment and underway planning modes, the latter being preferred since it can adapt to the survey AUV path during the mission. The necessity of bounding the distance between the CNA and any survey AUV in order to bound survey AUV position error is also described.

Download or read book Towards Combined Task and Motion Planning for Autonomous Underwater Vehicles written by James William McMahon and published by . This book was released on 2016 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: In oceanic research and development, autonomous underwater vehicles (AUVs) provide scientists with the ability to augment expensive manned operations at a lower cost while simultaneously exploring regions that were previously inaccessible to scientists. While the cost of these AUVs is often nontrivial, the ability to autonomously sample data from varying regions over extended time periods removes the necessity of human operations which require much higher overhead costs. Scientists are now leveraging the unique abilities of AUVs to explore new environments, scientists are now starting to use AUVs to perform sophisticated missions in deep ocean environments, under the polar ice caps, or throughout dangerous minefields in the littoral. The success of these missions, however, depends on the ability of the AUV to autonomously perform complex tasks. Toward this goal, this dissertation seeks to enhance the capabilities of AUVs so that they are able to autonomously plan the high-level actions and the low-level motions needed to accomplish complex missions. A framework is developed which makes it possible to specify such missions in a structured language resembling English, and it automatically plans the actions and motions that the AUV needs to execute in order to accomplish the mission. The mission-specification language is grounded in well-established logical formalisms such as Regular Languages and Linear Temporal Logic. The inherent structure of the mission-specification language makes it possible to construct sophisticated mission such as exploring unknown areas, searching for objects of interest, or collecting data. In doing so, the framework alleviates the burden imposed on human operators who currently need to manually input highly detailed mission specifications into multiple configuration files, which increases the risk for mission failure due to human error. Instead, the framework makes it possible for the human operators to specify the missions in an easy-to-use, structured language. The technical contribution of the dissertation stems from a novel treatment of the combined mission and motion-planning problem as a hybrid search over discrete and continuous layers. Leveraging advances in AI and Robotics, a hybrid-planning framework is developed which combines high-level AI mission planning with low-level sampling-based motion planning. High-level planning, which operates over a discrete and abstract layer, breaks down the overall mission into a sequence of tasks. Sampling-based motion planning conducts a search over the feasible motions of the AUV in order to compute a trajectory that enables the AUV to accomplish each task. When sampling-based motion planning fails to make progress it requests another high-level plan from the AI planning layer. This interplay between high-level discrete planning and sampling-based motion planning is crucial to the success of the framework. The hybrid framework can be used with any AUV. Extensive experiments have been conducted with high-fidelity simulators and real AUVs, such as OceanServer Iver2 AUV and Reliant Bluefin-21 AUV. The experimental results show the ability of the approach to effectively plan collision-free and dynamically-feasible trajectories that enable the AUV to carry out sophisticated missions, such as inspection of numerous areas, data collection, and reacquisition and identification in Mine Countermeasures. The success of the hybrid framework highlight the potential of the approach to enhance the autonomy of AUVs, making it possible to carry out sophisticated missions at a lower operational cost.

Download or read book Coverage Path Planning for Autonomous Underwater Vehicles written by Enric Galceran Yebenes and published by . This book was released on 2014 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Path Planning of AUVs for Adaptive Sampling written by Namik Kemal Yilmaz and published by . This book was released on 2005 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) A real-world problem is also solved by the second method taking two different approaches. The first approach (static approach) involves a three-day-long adaptive sampling mission using the uncertainty information available on the first day. The second approach (dynamic approach) involves updating of the uncertainty information for each day using data assimilation features of the Harvard Ocean Prediction System and the Error Subspace Statistical Estimation system. The dynamic method is illustrative of how path planning for adaptive sampling fits into modern dynamic data driven oceanography. The results from the dynamic approach show that the uncertainty of the forecast decreases and becomes confined to a smaller region, indicating the strength of the method.

Download or read book Underwater Multi dimensional Path Planning for the Naval Postgraduate School Autonomous Underwater Vehicle II written by Joseph Bonsignore and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Path Planning in Time Dependent Flows Using Level Set Methods written by Sri Venkata Tapovan Lolla and published by . This book was released on 2012 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autonomous underwater vehicles such as gliders have emerged as valuable scientific platforms due to their increasing uses in several oceanic applications, ranging from security, acoustic surveillance and military reconnaissance to collection of ocean data at specific locations for ocean prediction, monitoring and dynamics investigation. Gliders exhibit high levels of autonomy and are ideal for long range missions. As these gliders become more reliable and affordable, multi-vehicle coordination and sampling missions are expected to become very common in the near future. This endurance of gliders however, comes at an expense of being susceptible to typical coastal ocean currents. Due to the physical limitations of underwater vehicles and the highly dynamic nature of the coastal ocean, path planning to generate safe and fast vehicle trajectories becomes crucial for their successful operation. As a result, our motivation in this thesis is to develop a computationally efficient and rigorous methodology that can predict the time-optimal paths of underwater vehicles navigating in continuous, strong and dynamic ow-fields. The goal is to predict a sequence of steering directions so that vehicles can best utilize or avoid ow currents to minimize their travel time. In this thesis, we fist review existing path planning methods and discuss their advantages and drawbacks. Then, we discuss the theory of level set methods and their utility in solving front tracking problems. Then, we present a rigorous (partial differential equation based) methodology based on the level set method, which can compute time-optimal paths of swarms of underwater vehicles, obviating the need for any heuristic control based approaches. We state and prove a theorem, along with several corollaries, that forms the foundation of our approach for path planning. We show that our algorithm is computationally efficient - the computational cost grows linearly with the number of vehicles and geometrically with spatial directions. We illustrate the working and capabilities of our path planning algorithm by means of a number of applications. First, we validate our approach through simple benchmark applications, and later apply our methodology to more complex, realistic and numerically simulated ow-fields, which include eddies, jets, obstacles and forbidden regions. Finally, we extend our methodology to solve problems of coordinated motion of multiple vehicles in strong dynamic ow-fields. Here, coordination refers to maintenance of specific geometric patterns by the vehicles. The level-set based control scheme that we derive is shown to provide substantial advantages to a local control approach. Specifically, the illustrations show that the resulting coordinated vehicle motions can maintain specific patterns in dynamic flow fields with strong and complex spatial gradients.

Download or read book Autonomous Underwater Vehicle AUV Path Planning and Adaptive On board Routing for Adaptive Rapid Environmental Assessment written by Ding Wang (Ph. D.) and published by . This book was released on 2007 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) As a special case, a thermocline- oriented AUV yoyo control and control parameter optimization methods for AREA are also developed. Finally, some AUV control algorithms for capturing fronts are developed. A frame-work for real-time TL forecasts is developed. This is the first time that TL forecasts have been linked with ocean forecasts in real-time. All of the above ideas and methods developed were tested in two experiments, FAF05 in the northern Tyrrhenian Sea in 2005 and MB06 in Monterey Bay, CA in 2006. The latter MB06 sea exercise was a major field experiment sponsored by the Office of Naval Research and the thesis compiles significant findings from this effort.

Download or read book Guidance Control and Path Planning for Autonomous Underwater Vehicles written by Kantapon Tanakitkorn and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Computer Simulation Study of Mission Planning and Control for the NPS Autonomous Underwater Vehicle written by Douglas B. Nordman and published by . This book was released on 1989 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Minefield Search and Object Recognition for Autonomous Underwater Vehicles written by Mark A. Compton and published by . This book was released on 1992 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Online Path Planning for Autonomous Underwater Vehicles Under Motion Constraints written by Juan David Hernández Vega and published by . This book was released on 2017 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most common applications of autonomous underwater vehicles (AUVs) include imaging and inspecting different kinds of structures on the sea. Most of these applications require a priori information of the area or structure to be inspected, either to navigate at a safe and conservative altitude or to 2/2 pre-calculate a survey path. However, there are other applications where it's unlikely that such information is available (e.g., exploring confined natural environments like underwater caves). In this respect, this thesis presents an approach that endows an AUV with the capabilities to move through unexplored environments. To do so, it proposes a computational framework for planning feasible and safe paths online. This approach allows the vehicle to incrementally build a map of the surroundings, while simultaneously (re)plan a feasible path to a specified goal. The framework takes into account motion constraints in planning feasible paths, i.e., those that meet the vehicle's motion capabilities.

Download or read book Information driven Multi view Path Planning for Underwater Target Recognition written by Shin, Jane Shin and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: By utilizing onboard sensors such as side-scan or forward-looking sonar, autonomous underwater robots can perform many useful tasks, such as exploring and searching for targets in underwater environments. In order to recognize and classify objects with high confidence, however, these mobile sensors must obtain multiple looks or "views" for each target using different positions and orientations that allow for a different interpretation based on local occlusions and environmental conditions. As a result, when tasked with classifying many targets, the mobile sensor must find the most efficient path through multiple configurations in an effort to reduce the cost and time required by each underwater mission. This dissertation presents a novel and general approach, referred to as informative multi-view planning (IMVP), that simultaneously determines the most informative sequence of views and the shortest path between them. The approach is demonstrated both in simulations and sea tests using an unmanned underwater vehicle (UUV) equipped with a side-scan sonar (SSS) and engaged in underwater multi-target classification. Both simulation and experimental results show that IMVP achieves excellent classification performance while reducing the total time required by the mission by up to half the time required by state-of-the-art multi-view path planning methods. One reason is that IMVP utilizes knowledge of the automatic target recognition (ATR) algorithm, as well as prior measurements, in order to determine the most informative views. Additionally, by using knowledge of the target location and field-of-view (FOV) geometry, IMVP is able to find the shortest path between them by solving a traveling salesman problem with neighborhoods (TSPN). In this dissertation, a novel physics-inspired algorithm based on Lin-Kernighan heuristic (LKH) is developed for searching for the optimal TSPN path for multiple non-disjoint neighborhoods. It is shown that the LKH algorithm is able to decrease the computational complexity of TSPN solutions by leveraging the intersections of valuable neighborhoods using computational geometry constructs known as coverage cones. When compared to state-of-the-art TSPN algorithms, the proposed method is able to find shorter paths with either comparable or reduced computation. The advantages of the LKH algorithm are found to become more significant as the number of intersecting neighborhoods increases, thus also allowing the mobile sensor to observe multiple targets from a single configuration.

Download or read book Modeling and Guidance of an Underactuated Autonomous Underwater Vehicle written by Ali H M Wadi and published by . This book was released on 2017 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Autonomous Underwater Vehicles (AUVs) have become an indispensable tool that is employed by an array of fields. From the inspection of underwater cables and pipelines, to the monitoring of fish pens and coral reefs, to the detection and disposal of mines, and to the executing search and rescue operations, AUV research and development has received a lot of attention. This thesis is concerned with the mathematical modeling of an underactuated AUV to execute its missions. The modeling task entails identification of the numerous parameters of the vehicle. A finite element analysis software was used to estimate the parameters describing drag and hydrodynamic mass phenomena. While the proposed underactuated configuration promotes the deployment of more energy-efficient vehicles, this configuration imposes complications on the guidance and motion control tasks as the vehicle becomes constrained in the way it can reach certain positions or perform certain motions (anholonomy). To tackle this trajectory tracking guidance problem, a model-based controller that overcomes the underactuated nature of the vehicle was designed. This controller was further enhanced by the novel development and application of a Universal Adaptive Stabilizer-based adaptation law that aims to minimize controller effort, reject noise, and provide robust trajectory tracking. The adaptation is governed by a statistical management system to ensure proper operation in a noisy underwater environment. Moreover, the navigation problem is touched upon by implementing a sensor fusion algorithm to estimate the vehicle state in its noisy environment. The algorithm investigates an Extended Kalman Filter as well as an Unscented Kalman Filter to fuse the available information from sensors with the modeled dynamics of the vehicle and provide better estimates of the vehicle state. Additionally, the hardware and software was integrated in a Robot Operating System setting, and a Gazebo-based simulation environment that enables the visual depiction and testing of algorithms on the considered AUV was developed. The parameter identification methodology compared well to published analytical and empirical forms, the proposed adaptation law outperformed traditional techniques like Adaptive Proportional Controllers, and the gain management system demonstrated excellent potential at maintaining stable operation of the vehicle in very noisy environments."--Abstract.