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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Automated Launch and Recovery of an Autonomous Underwater Vehicle from an Unmanned Surface Vessel

Unknown Date (has links)
Research on collaboration among unmanned platforms is essential to improve the applications for autonomous missions, by expanding the working environment of the robotic systems, and reducing the risks and the costs associated with conducting manned operations. This research is devoted to enable the collaboration between an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV), by allowing the first one to launch and recover the second one. The objective of this dissertation is to identify possible methods to launch and recover a REMUS 100 AUV from a WAM-V 16 USV, thus developing this capability by designing and implementing a launch and recovery system (LARS). To meet this objective, a series of preliminary experiments was first performed to identify two distinct methods to launch and recover the AUV: mobile and semi-stationary. Both methods have been simulated using the Orcaflex software. Subsequently, the necessary control systems to create the mandatory USV autonomy for the purpose of launch and recovery were developed. Specifically, a series of low-level controllers were designed and implemented to enable two autonomous maneuvers on the USV: station-keeping and speed & heading control. In addition, a level of intelligence to autonomously identify the optimal operating conditions within the vehicles' working environment, was derived and integrated on the USV. Lastly, a LARS was designed and implemented on the vehicles to perform the operation following the proposed methodology. The LARS and all subsystems developed for this research were extensively tested through sea-trials. The methodology for launch and recovery, the design of the LARS and the experimental findings are reported in this document. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
112

A high-level fuzzy logic guidance system for an unmanned surface vehicle (USV) tasked to perform an autonomous launch and recovery (ALR) of an unmanned underwater vehicle (UUV)

Unknown Date (has links)
There have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this thesis is to present the design and development a high-level fuzzy logic guidance controller for a WAM-V 14 USV in order to autonomously launch and recover a REMUS 100 AUV. The approach to meeting this objective is to develop ability for the USV to intercept and rendezvous with an AUV that is in transit in order to maximize the probability of a final mobile docking maneuver. Specifically, a fuzzy logic Rendezvous Docking controller has been developed that generates Waypoint-Heading goals for the USV to minimize the cross-track errors between the USV and AUV. A subsequent fuzzy logic Waypoint-Heading controller has been developed to provide the desired heading and speed commands to the low-level controller given the Waypoint-Heading goals. High-level mission control has been extensively simulated using Matlab and partially characterized in real-time during testing. Detailed simulation, experimental results and findings will be reported in this paper. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
113

An XML-based mission command language for autonomous underwater vehicles (AUVs)

Van Leuvan, Barbara C., Hawkins, Darrin L. 03 1900 (has links)
Approved for public release, distribution is unlimited / Autonomous Underwater Vehicles (AUVs) are now being introduced into the fleet to improve Mine Warfare capabilities. Several AUVs are under government-contracted development. Mission planning and data reporting vary between vehicles and systems. This variance does not pose an immediate problem, as only one AUV is currently in production. However, as more AUVs are put into production, commands will begin to get multiple AUVs. Without a single mission command language, multiple systems will require familiarity with multiple languages. Extensible Markup Language (XML) and related technologies may be used to facilitate interoperability between dissimilar AUVs and extract and integrate mission data into Navy C4I systems. XML makes archive maintenance easier, XML documents can be accessed via an http server, and, in root form, XML is transferable on the fly by stylesheet. This thesis presents an XML-based mission command for the command and control of AUVs. In addition, this thesis discusses XML technology and how XML is a viable means of achieving interoperability. Furthermore, this thesis provides an example mission file using existing software, and demonstrates the future of XML in AUV technology. Finally, this work ends with a compelling argument for the use of an XML-based mission command language to command all AUVs. / Ensign, United States Navy / Captain, United States Air Force
114

Collective dynamics and control of a fleet of heterogeneous marine vehicles

Wang, Chuanfeng 13 January 2014 (has links)
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.
115

An investigation into underwater navigation accuracy with regard to sensor combinations and quality

Herselman, Leo 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / A navigation performance sensitivity study with respect to the quality variation of sensors and sensor combinations is presented in this thesis. Navigation simulation software capable of using real-time and simulated sensor data is developed in this project. The simulation software is used to simulate different sensor combinations and therefore evaluate the best configuration for each AUV mission. A sensor module is also developed to capture real-time sensor data. The sensor module includes a low-cost 6-degreeof- freedom inertial measurement module (rate gyroscopes and accelerometers), a three-axes magnetometer and other sensor interfaces. The real-time sensor data are used to test and calibrate the navigation simulation software. Different sensor combinations are evaluated by using the navigation simulation software with simulated sensor data as input. The quality of each sensor is varied by changing its noise characteristics. The performance study, together with the developed simulation tools, simplifies the process of selecting a sensor combination to fulfill a specific navigation accuracy requirement.
116

Experiments with the REMUS AUV

Phaneuf, Matthew D. 06 1900 (has links)
Approved for public release; distribution is unlimited / This thesis centers around actual field operations and post-mission analysis of data acquired using a REMUS AUV operated by the Naval Postgraduate School Center for Autonomous Underwater Vehicle Research. It was one of many platforms that were utilized for data collection during AOSN II, (Autonomous Oceanographic Sampling Network II), an ONR sponsored exercise for dynamic oceanographic data taking and model based analysis using adaptive sampling. The vehicle's ability to collect oceanographic data consisting of conductivity, temperature, and salinity during this experiment is assessed and problem areas investigated. Of particular interest are the temperature and salinity profiles measured fromlong transect runs of 18 Km. length into the southern parts of Monterey Bay. Experimentation with the REMUS as a mine detection asset was also performed. The design and development of the mine hunting experiment is discussed as well as its results and their analysis. Of particular interest in this portion of the work is the issue relating to repeatability and precision of contact localization, obtained from vehicle position and sidescan sonar measurements. / Lieutenant, United States Navy
117

A robust AUV docking guidance and navigation approach to handling unknown current disturbances

Unknown Date (has links)
The main contribution in this thesis is the design of a robust AUV docking guidance and navigation approach that can guide and home an AUV towards an acoustic source located on an oriented bottom-mounted underwater docking station, under presence of unknown current disturbances and in the absence of any form of onboard velocity sensor. A Complementary Filter and various forms of Kalman Filters were separately formulated to estimate the current and vehicle positions with strategic vehicle manoeuvres. A current compensator uses the estimated current to maintain the desired vehicle course while under current disturbance. Tagaki-Sugeno-Kang Fuzzy Inference System was designed to realize fuzzy docking guidance manoeuvres. Finally, Monte Carlo runs were performed on a designed AUV docking simulator to evaluate the docking robustness against various docking conditions. Simulation results demonstrated robustness in the designed docking guidance and navigation approach. / by Hoe Eng Teo. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
118

Avaliação da aplicação de método de painéis para estimativa de resistência de ondas de submersíveis. / Avaliation of the aplication of a panel method to estimate submersibles wave resistance.

Nunes, Alvaro Luiz Silvestre 27 June 2012 (has links)
Submersíveis em velocidade constante e pequenas cotas de submersão são aqui considerados e os efeitos da superfície livre no fluxo são levados em conta. O problema de geração de onda devido ao avanço de corpos submersos é abordado no presente estudo. Neste problema de contorno, as condições de superfície livre são linearizadas. A formulação diferencial é condicionada como um problema de integração através da aplicação da segunda identidade de Green. A discretização do problema conduz a um sistema linear no potencial de velocidades, que se supõe ser distribuído através de B-splines parabólicas nos painéis. A contribuição desta dissertação tem foco em propor diretrizes para a aplicação do método descrito em condições operacionais típicas de cascos de submarinos em movimento de avanço em cotas periscópicas de submersão. Os resultados numéricos obtidos através destes procedimentos são comparados a resultados publicados existentes para sua de validação. / Submersibles in constant ahead velocity at small submergences are here considered, the free surface effects on the flow are taken into account. The wave generating problem due to submerged bodies advance is addressed in the present study. In this boundary value problem, the free surface conditions are linearized. The differential problem is conditioned into an integral problem through the application of Green\'s second identity. The discretization of the problem leads to a linear system in the velocity potential, that is supposed to be distributed according to parabolic B-splines into the panels. The contribution of this dissertation focus on guidelines for the application of the above method on typical operational conditions of submarine vessels under ahead motion at snorkelling submergences. The numerical results obtained through these procedures are compared to existent published results with the aim of validation.
119

Testing Momentum Enhancement Of Ribbon Fin Based Propulsion Using A Robotic Model With An Adjustable Body

Unknown Date (has links)
A robotic ribbon fin with twelve independent fin rays, elastic fin membrane, and a body of adjustable height was developed for this thesis specifically to test the 1990 theory put forth by Lighthill and Blake that a multiplicative propulsive enhancement exists for Gymnotiform and Balisiform swimmers based on the ratio of body and fin heights. Until now, the theory has not been experimentally tested. Proof of such a momentum enhancement could have a profound effect on unmanned underwater vehicle design and shed light on the evolutionary advantage to body-fin ratios found in nature, shown as optimal for momentum enhancement in Lighthill and Blake’s theory. Thrust tests for various body heights were conducted in a recirculating flow tank at different flow speeds and fin flapping frequencies. When comparing different body heights at different frequencies to a ’no-body’ thrust test case at each frequency no momentum enhancement factor was found. Data in this thesis indicate there is no momentum enhancement factor due to the presence of a body on top of an undulating fin. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
120

Characterizing magnetic noise of AUV for use in towed magnetometer study of internal waves

Unknown Date (has links)
As part of a project to study internal waves, FAU plans to utilize an AUV to tow a magnetometer to study electromagnetic signatures from internal waves. This research is focused on the electromagnetic noise issues related to using an AUV to tow the magnetic sensor package. There are active sources of electromagnetic noise caused by an AUV that are present in addition to those induced by the Earth's magnetic field and permanent magnets. To characterize the magnetic noise associated with the AUV magnetometer tow system, the various active source elements were identified, the orientation sensitivity of the sensors being used was determined, and the magnetic anomaly of a similar AUV which may be eventually be used in a magnetic sensing arrangement was measured. The results are used to show the proposed sensing arrangement will likely not achieve the necessary sensitivity to measure subtle internal wave signals. / by Dylan Tilley. / Vita. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

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