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Title: Maximum likelihood estimates of azimuth and elevation for a frequency-hopped active source using a tetrahedral ultra-short baseline.
Creator: Warin, Raphael., Florida Atlantic University, Beaujean, Pierre-Philippe, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Ultra-Short-BaseLine (USBL) is the most practical underwater acoustic positioning system for autonomous underwater vehicles because of its small space requirement. The objective of this research is to develop a USBL system capable of estimating a source location transmitting frequency-hopped tones sequences. Such sequences are characteristic of spread spectrum signaling used in underwater acoustic communication network. It must be able to provide azimuth and elevation of a modem-type source...
Show moreUltra-Short-BaseLine (USBL) is the most practical underwater acoustic positioning system for autonomous underwater vehicles because of its small space requirement. The objective of this research is to develop a USBL system capable of estimating a source location transmitting frequency-hopped tones sequences. Such sequences are characteristic of spread spectrum signaling used in underwater acoustic communication network. It must be able to provide azimuth and elevation of a modem-type source with an accuracy of 0.3 degrees; for both angles using the synchronization stage of the transmission. The acoustic antenna is composed of four transducers arranged as a tetrahedron. Using the model of Quazi and Lerro, which provides an expression for the variance of the bearing angle, azimuth and elevation of the transmitter are estimated employing maximum likelihood estimation. This system is simulated, tested and calibrated in a tank. Simulated results satisfy the requirement with a SNR of 32dB and 8 symbols. The latest experimental measurements present an accuracy of 3 degrees.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13135
Subject Headings: Underwater acoustics--Instruments, Underwater acoustic telemetry, Signal processing--Technique, Adaptive signal processing
Format: Document (PDF)

Title: Influence of chlorides and surface condition on pitting potential of high performance reinforcing steel.
Creator: Leroux, Virginie Edwige., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In order to identify the influence of chlorides and surface finish on pitting potential of high performance reinforcing steel, cyclic polarization scans were performed on types 304, 2201 and 3Cr12 stainless steels and MMFX-II in simulated pore solution to which chloride was incrementally added. Furthermore, the surface condition was investigated with regard to the pitting potential. Pitting potential distributions versus the chloride content and surface finish were obtained. Pitting...
Show moreIn order to identify the influence of chlorides and surface finish on pitting potential of high performance reinforcing steel, cyclic polarization scans were performed on types 304, 2201 and 3Cr12 stainless steels and MMFX-II in simulated pore solution to which chloride was incrementally added. Furthermore, the surface condition was investigated with regard to the pitting potential. Pitting potential distributions versus the chloride content and surface finish were obtained. Pitting resistance was lowered as chloride was added and as the surface became rougher. Furthermore, a critical chloride to hydroxide ratio as a function of potential was determined for each material. Finally, according to the results of this study, the MMFX reinforcing steel was considered to have a corrosion performance close to that of Type 2201 stainless steel for bridge use. MMFX-II specimens with a polished surface exhibited more positive pitting potentials than did ones with an as-received finish.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13103
Subject Headings: Reinforcing bars--Corrosion, Steel, Structural--Corrosion, Chlorides
Format: Document (PDF)

Title: Design approaches for asymmetrical marine pipeline cathodic protection systems.
Creator: Qian, Haijun., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Marine pipeline cathodic protection systems for asymmetrical situation were systematically investigated by means of a newly proposed approach and Boundary Element Method (BEM). Potential attenuation profiles from BEM modeling indicate that far-field cathode potentials of different pipe sections approach identical values under different coating resistance and different electrolyte resistivity conditions provided anodes are separated by at least 10m and metallic resistance is negligible. A...
Show moreMarine pipeline cathodic protection systems for asymmetrical situation were systematically investigated by means of a newly proposed approach and Boundary Element Method (BEM). Potential attenuation profiles from BEM modeling indicate that far-field cathode potentials of different pipe sections approach identical values under different coating resistance and different electrolyte resistivity conditions provided anodes are separated by at least 10m and metallic resistance is negligible. A series of equations based on the Slope Parameter Method (SPM) has been modified for more extensive applicability. Several design examples have been analyzed and the results verified by BEM. Cathode potential and current demands projected by the new method are consistent with those of BEM. The inclusive equation for even anode spacing CP has been modified to include the cable parameters by combining cable resistance and the anode resistance. Current demand for existing pipelines can be determined by either of two methods. The first utilizes the inclusive equation and involves solving this for current demand based upon a known potential profile. The other is based on SPM.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13098
Subject Headings: Underwater pipelines, Pipelines--Cathodic protection, Boundary element methods
Format: Document (PDF)

Title: Modeling of bracelet anodes and anode arrays for pipeline CP systems.
Creator: Zhang, Xiaolin., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Two models for pipeline bracelet anodes depletion with time were analyzed: one with uniform corrosion and the other with localized corrosion. The potential of the pipeline was determined to become more positive with time due to corrosion of the anode. The pipeline protected by the anode with localized corrosion had more a positive potential than the one protected by the anode with uniform corrosion. A method based upon the equations of Sunde was developed for determining resistance of linear...
Show moreTwo models for pipeline bracelet anodes depletion with time were analyzed: one with uniform corrosion and the other with localized corrosion. The potential of the pipeline was determined to become more positive with time due to corrosion of the anode. The pipeline protected by the anode with localized corrosion had more a positive potential than the one protected by the anode with uniform corrosion. A method based upon the equations of Sunde was developed for determining resistance of linear and rectangular anode arrays. Accuracy of this approach was evaluated using Boundary Element Modeling (BEM). The difference between the two methods was defined as Error. A corrected function of Sunde's equation was developed in order to get a more accurate resistance of a 1 x N anode array. The influence on resistance of a M x N (M < N) anode array of anode size, separation distance and array number was analyzed. Error increased with increasing anode size and decreased with increasing number of anodes and separation distance. The application and limitations of commonly used anode resistance formulas are discussed.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13087
Subject Headings: Pipelines--Cathodic protection, Corrosion and anti-corrosives, Underwater pipelines, Anodes
Format: Document (PDF)

Title: Impact of noise on seafloor property estimation using Biot model parameters obtained through an inversion of chirp sonar data.
Creator: Munro, Lachlan I., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis describes the development and testing of an inversion method, based on the Biot-Stoll acoustic wave propagation model, for estimating sediments properties from acoustic reflection measurements of the seabed. The Biot-Stoll model is a physics-based model which describes the propagation of compressional and shear waves through porous media. Given the physical sediment properties of the seabed, the pressure reflection coefficient of the seabed is calculated using the Biot-Stoll model...
Show moreThis thesis describes the development and testing of an inversion method, based on the Biot-Stoll acoustic wave propagation model, for estimating sediments properties from acoustic reflection measurements of the seabed. The Biot-Stoll model is a physics-based model which describes the propagation of compressional and shear waves through porous media. Given the physical sediment properties of the seabed, the pressure reflection coefficient of the seabed is calculated using the Biot-Stoll model. The proposed inversion procedure varies sediment properties until a least squares fit is obtained between the output of the model and the measured reflection coefficient. Random errors are introduced into the reflection coefficient measurement to determine the effect of measurement error in the estimation of seabed properties such as permeability, porosity, mean grain diameter, and sediment type.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13084
Subject Headings: Underwater acoustics, Marine sediments--Acoustic properties
Format: Document (PDF)

Title: Dynamic simulation and control of an autonomous surface vehicle.
Creator: VanZwieten, Tannen S., Florida Atlantic University, Leonessa, Alexander, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Autonomous Surface Vehicle (ASV) research and development is inspired by the navigating and communicatiog challenges of Autonomous Underwater Vehicles (AUVs). The development objective is to provide real time positioning of and communication with AUVs through the air-sea interface. Despite extensive research on AUVs, the ASV has had limited research. The NAVY's desire to make AUV's defense capabilities realizable adds to the project's appeal. Guidance and control play an integral part in the...
Show moreAutonomous Surface Vehicle (ASV) research and development is inspired by the navigating and communicatiog challenges of Autonomous Underwater Vehicles (AUVs). The development objective is to provide real time positioning of and communication with AUVs through the air-sea interface. Despite extensive research on AUVs, the ASV has had limited research. The NAVY's desire to make AUV's defense capabilities realizable adds to the project's appeal. Guidance and control play an integral part in the ASV's success, motivating this thesis work. The overall vehicle dynamics were modeled and numerically simulated for 3 DOF lateral motion. These are development tools for the testing and tuning of PID and adaptive control algorithms. The results show the adaptive controller to be advantageous in terms of tuning, robustness and tracking performances. It uses a single layer neural network that bypasses the need for information about the system's dynamic structure and characteristics and provides portability.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13081
Subject Headings: Hydrodynamics, Adaptive control systems--Computer simulation, PID controllers--Computer simulation, Neural networks (Computer science)
Format: Document (PDF)

Title: Polyethylene duct cracking in post-tensioning tendons of Florida segmental bridges.
Creator: Suarez, Jorge Alejandro, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: For the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and...
Show moreFor the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and its validity verified. According to simulations performed on specimens that were fabricated and others developed by the finite element method, new major factors were found to explain the duct failure. Finally, a comparison of mechanical properties indicated a difference between virgin and aged materials.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13071
Subject Headings: Post-tensioned prestressed concrete construction, Bridges--Florida, Polyethylene
Format: Document (PDF)

Title: Characterizing the western boundary current front between the Florida current and the littoral waters at 26°N latitude.
Creator: Meir, Ariel., Florida Atlantic University, Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Six survey missions of one day duration were preformed at 26°N latitude off the coast of south Florida in order to examine the characteristics of the Florida Current front on the coastal side of the current. Observations were made from the R/V Stephan using a conductivity, temperature, and depth (CTD) package and an acoustic Doppler current profiler (ADCP), corresponding meteorological observations were recorded by NOAA C-MAN stations at Fowey Rocks and Lake Worth Florida. The six survey...
Show moreSix survey missions of one day duration were preformed at 26°N latitude off the coast of south Florida in order to examine the characteristics of the Florida Current front on the coastal side of the current. Observations were made from the R/V Stephan using a conductivity, temperature, and depth (CTD) package and an acoustic Doppler current profiler (ADCP), corresponding meteorological observations were recorded by NOAA C-MAN stations at Fowey Rocks and Lake Worth Florida. The six survey missions were preformed over an 8-month period of March 2002 to October 2002. The data collected confirms observations made by previous theoretical studies, which used dynamical models of the Florida Current. The overall picture is of a turbulent cyclonic front with strong vertical shearing and vertical mixing. In addition, the data suggest internal wave generation and intermittent episodes of upwelling that appear to be related to the position of the current and the steepness of the front.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13059
Subject Headings: Ocean currents--Florida, Oceanography--Gulf Stream, Atlantic Ocean, Gulf Stream
Format: Document (PDF)

$Boundary-integral analysis of nonlinear diffraction forces on a submerged body$

Title: Boundary-integral analysis of nonlinear diffraction forces on a submerged body.
Creator: Vinayan, Vimal., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A three-dimensional nonlinear time-dependent boundary-integral algorithm is developed to compute wave forces on an underwater vehicle. The effect of viscosity is neglected and the cases for which the effects could be important are discussed. The present algorithm is however an efficient tool to determine wave forces on a submerged body and can also be integrated into a viscous flow algorithm. A numerical wave tank is constructed for the simulation. A damping layer is introduced to minimize...
Show moreA three-dimensional nonlinear time-dependent boundary-integral algorithm is developed to compute wave forces on an underwater vehicle. The effect of viscosity is neglected and the cases for which the effects could be important are discussed. The present algorithm is however an efficient tool to determine wave forces on a submerged body and can also be integrated into a viscous flow algorithm. A numerical wave tank is constructed for the simulation. A damping layer is introduced to minimize spurious reflection of scattered waves at the open boundary. A sinusoidal progressive pressure patch is used to generate incident waves. Wave forces are determined using four different methods: viz., (1) Froude-Krylov volume integration method, (2) Froude-Krylov surface pressure integration method, (3) Linear diffraction analysis and (4) Nonlinear diffraction analysis for a range of parameters including incident wavelength and wave height. Results are compared to quantify effects of nonlinearity and diffraction effect of the body.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13048
Subject Headings: Waves--Diffraction, Boundary element methods, Hydrodynamics, Surface waves (Oceanography)
Format: Document (PDF)

Title: Compression failure of sandwich specimens with and without face/core debonds.
Creator: Vadakkeveedu, Vinod P., Florida Atlantic University, Carlsson, Leif A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this thesis is to report on an experimental study on the compressive behavior of foam cored sandwich composite specimens with and without face/core debond. A test fixture was designed which enables a precisely machined sandwich specimen instrumented with back-to-back strain gages to be loaded in edgewise compression. Tests were conducted on specimens without implanted face/core interface debonds over a range of core densities and gage lengths. The experimentally determined...
Show moreThe objective of this thesis is to report on an experimental study on the compressive behavior of foam cored sandwich composite specimens with and without face/core debond. A test fixture was designed which enables a precisely machined sandwich specimen instrumented with back-to-back strain gages to be loaded in edgewise compression. Tests were conducted on specimens without implanted face/core interface debonds over a range of core densities and gage lengths. The experimentally determined compression strengths and failure modes were compared to closed-form predictions and finite element analysis. Specimens with an implanted through-the-width face/core debond were also tested and mechanism of failure was analyzed using finite element analysis. Good agreement between collapse loads predicted using geometrically nonlinear analysis and experimentally measured strengths was observed.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13047
Subject Headings: Sandwich construction, Strains and stresses, Structural analysis (Engineering)
Format: Document (PDF)

Title: Atmospheric corrosion sensor studies in accelerated and natural environments.
Creator: Richard, Sebastien Laurent., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Tests in a cyclic chamber and in real atmospheric conditions resulted in the development of an improved corrosion coulometer sensor. First tests showed that it responded well in a reproduced environment but not satisfactorily in a real one, although it seemed to present a good correlation with the weather observations. However, these tests allowed a small time step data analysis of atmospheric corrosion and therefore an improved knowledge of this process. Also discussed are the possible ways...
Show moreTests in a cyclic chamber and in real atmospheric conditions resulted in the development of an improved corrosion coulometer sensor. First tests showed that it responded well in a reproduced environment but not satisfactorily in a real one, although it seemed to present a good correlation with the weather observations. However, these tests allowed a small time step data analysis of atmospheric corrosion and therefore an improved knowledge of this process. Also discussed are the possible ways of retrieving the corrosion coulometer data wirelessly, thus allowing a real-time analysis of atmospheric corrosion on steel structures. Ideas are proposed for improving both the sensor and the electronic package to make the system an efficient monitor of atmospheric corrosion.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13041
Subject Headings: Corrosion and anti-corrosives, Voltameters, Detectors
Format: Document (PDF)

Title: Simulation of reflection tomographic images of underwater targets with the effect of vehicle motion sensing errors.
Creator: Quentin, Gwendoline., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The Buried Object Scanning Sonar (BOSS) is being developed at Florida Atlantic University to image targets buried under the seabed. Tomographic images are constructed using a sequence of sonar transmissions while the vehicle is moving. This motion causes image distortion and should be measured and removed by mapping the echoes received to an absolute coordinate system. The aim of this thesis is to develop and simulate a technique for generating BOSS images that provide an accurate...
Show moreThe Buried Object Scanning Sonar (BOSS) is being developed at Florida Atlantic University to image targets buried under the seabed. Tomographic images are constructed using a sequence of sonar transmissions while the vehicle is moving. This motion causes image distortion and should be measured and removed by mapping the echoes received to an absolute coordinate system. The aim of this thesis is to develop and simulate a technique for generating BOSS images that provide an accurate representation of target shape and size, by removing vehicle motion while mapping the image pixels. Synthetic acoustic data sets are generated by convolving the auto-correlated FM transmission pulse with the impulse response of an elastic sphere. Synthetic outputs of a Doppler velocity log and a 3-axis inertial measurement unit are generated to simulate vehicle motion. Noise is added to the sensor data to show the effects of motion sensor errors on image quality.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13040
Subject Headings: Ocean tomography, Sonar, Underwater navigation
Format: Document (PDF)

Title: NOVEL KIRIGAMI-INSPIRED FLEXIBLE ROBOTIC EXTENSION FOR MOBILE PLATFORMS.
Creator: Den Ouden, Casey, Su, Tsung-Chow, Ouyang, Bing, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Since 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid...
Show moreSince 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid Kirigami-based robotic extension subsystem was created to expand the functionality of the HAUCS platform. The primary objective of this design was to limit the surface area of an extender arm on the drone during flight operations and minimize the in-flight drag. By utilizing a novel combination of shape memory polymer (SMP) and nitinol to extend and retrieve the sensing arm, the structure was able to conserve energy while operating under varying environmental conditions.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014324
Subject Headings: Aquaculture, Sensors, Robotics
Format: Document (PDF)

Title: BIOLUMINESCENCE OF THE CTENOPHORE MNEMIOPSIS LEIDYI: FIRST FLASH KINETICS.
Creator: Blackburn, Abigail, Twardowski, Michael, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The ctenophore Mnemiopsis leidyi is an opportunistic species that can be extremely abundant and invasive in many parts of the world. It is well known for its bright bioluminescence, but its light emission response to flow stimulation has not been rigorously quantified. The objective of this study is to determine the luminescent response of M. leidyi to several types of mechanical stimuli, an impeller pump with the Underwater Bioluminescence Assessment Tool (UBAT) bathyphotometer and stirring...
Show moreThe ctenophore Mnemiopsis leidyi is an opportunistic species that can be extremely abundant and invasive in many parts of the world. It is well known for its bright bioluminescence, but its light emission response to flow stimulation has not been rigorously quantified. The objective of this study is to determine the luminescent response of M. leidyi to several types of mechanical stimuli, an impeller pump with the Underwater Bioluminescence Assessment Tool (UBAT) bathyphotometer and stirring as the stimulus within an integrating sphere. Tests were conducted with three day old cydippid larvae, analyzing flash parameters of rise time, peak intensity, decay slope, decay time, total integrated emission, total mechanically stimulable luminescence (TMSL), integrated flash emission, and flash duration. There were four patterns of bioluminescent responses measured with the UBAT, but they did not have statistically different flash kinetics. For the integrating sphere, the average peak intensity and TMSL were much greater than for the UBAT due to the different forms of stimulation. This study provides a well-defined baseline of cydippid larvae flash responses which may be used for identifying this species at this life stage in situ.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014341
Subject Headings: Mnemiopsis leidyi, Bioluminescence, Ctenophores
Format: Document (PDF)

Title: CVD synthesis of carbon nanotubes as active materials for electrochemical capacitors.
Creator: Merritt, Ryan Patrick., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Results are reported on a method to synthesize multi-wall carbon Nanotubes (MWNTs) using a liquid injection chemical vapor deposition (CVD) method centered around ferrocene as the catalyst precursor. These materials were specifically targeted as active materials for electrochemical double layer capacitors (EDLCs). A parameteric study was developed to optimize material synthesis based on growth parameters, characterize physical growth properties, and evaluate the performance of the MWNTs as...
Show moreResults are reported on a method to synthesize multi-wall carbon Nanotubes (MWNTs) using a liquid injection chemical vapor deposition (CVD) method centered around ferrocene as the catalyst precursor. These materials were specifically targeted as active materials for electrochemical double layer capacitors (EDLCs). A parameteric study was developed to optimize material synthesis based on growth parameters, characterize physical growth properties, and evaluate the performance of the MWNTs as electrodes in electrochemical capacitors. Physical data includes scanning electron micrographs (SEM), transmission electron micrographs (TEM), and x-ray powder diffraction (XRD). Electrochemical performance data is given based on cyclic voltammetry (CV) and impedance spectroscopy (EIS).
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13037
Subject Headings: Chemical vapor deposition, Electric double layer, Electrolytic capacitors, Nanotubes
Format: Document (PDF)

Title: Design, implementation and testing of a bio-inspired propulsion system for autonomous underwater vehicles.
Creator: Le Goff, Ivan., Florida Atlantic University, Leonessa, Alexander, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Some Autonomous Underwater Vehicles have recently been designed to mimic the locomotion of underwater animals. A new way of propulsion which uses Oscillating Fin Thrusters (OFTs) has been implemented on the AUV Morpheus, with the Nektor module. In particular, first a low level adaptive controller has been developed with the purpose of studying the characteristics of the OFT. Then, a new vehicle using Morpheus' base has been built in order to implement this module and test it. This required...
Show moreSome Autonomous Underwater Vehicles have recently been designed to mimic the locomotion of underwater animals. A new way of propulsion which uses Oscillating Fin Thrusters (OFTs) has been implemented on the AUV Morpheus, with the Nektor module. In particular, first a low level adaptive controller has been developed with the purpose of studying the characteristics of the OFT. Then, a new vehicle using Morpheus' base has been built in order to implement this module and test it. This required for the Lonworks network to be interfaced with QNXnet to create a multi communication protocol vehicle. Concerning the high level control, some proportional controllers and a 6-degree of freedom adaptive controller have been implemented and tested on the new vehicle. The results from these tests have shown that the Nektor module is suitable for the Morpheus, providing high-maneuverability features unavailable when using more standard propulsion systems.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13000
Subject Headings: Oceanographic submersibles--Computer simulation, Underwater propulsion
Format: Document (PDF)

Title: Design of an adaptive nonlinear controller for an autonomous underwater vehicle equipped with a vectored thruster.
Creator: Morel, Yannick., Florida Atlantic University, Leonessa, Alexander, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The tasks Autonomous Underwater Vehicles (AUVs) are expected to perform are becoming more and more challenging. Thus, to be able to address such tasks, we implemented a high maneuverability propulsion system: a vectored thruster. The design of a vehicle equipped with such a propulsion system will be presented, from a mechanical, electronic and software point of view. The motion control of the resulting system is fairly complex, and no suitable controller is available in the literature....
Show moreThe tasks Autonomous Underwater Vehicles (AUVs) are expected to perform are becoming more and more challenging. Thus, to be able to address such tasks, we implemented a high maneuverability propulsion system: a vectored thruster. The design of a vehicle equipped with such a propulsion system will be presented, from a mechanical, electronic and software point of view. The motion control of the resulting system is fairly complex, and no suitable controller is available in the literature. Accordingly, we will present the derivation of a novel tracking controller, whose adaptive properties will compensate for the lack of knowledge of the system's parameters. Computer simulations are provided and show the performance and robustness of the proposed control algorithm to external perturbations, unmodelled dynamics and dynamics variation. We finally illustrate the advantage of using an adaptive controller by comparing the presented controller to a Proportional Integral Derivative controller.
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Date Issued: 2002
PURL: http://purl.flvc.org/fcla/dt/12986
Subject Headings: Hydrodynamics, Nonlinear control theory, Adaptive control systems, Oceanographic submersibles
Format: Document (PDF)

Title: Computation of hydrodynamic coefficients and determination of dynamic stability characteristics of an underwater vehicle including free surface effects.
Creator: Saout, Olivier., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The inviscid hydrodynamic coefficients of an underwater vehicle (Ocean EXplorer), including the nonlinear effects of the wave surface, are computed using a boundary-integral method. A mixed Eulerian-Lagrangian formulation (Longuet-Higgins and Cokelet, 1976) is used for the treatment of nonlinear free-surface conditions. The algorithm is validated using the work-energy theorem (Yeung, 1982) and experimental data. Results, in the form of free-surface elevations and hydrodynamic coefficients,...
Show moreThe inviscid hydrodynamic coefficients of an underwater vehicle (Ocean EXplorer), including the nonlinear effects of the wave surface, are computed using a boundary-integral method. A mixed Eulerian-Lagrangian formulation (Longuet-Higgins and Cokelet, 1976) is used for the treatment of nonlinear free-surface conditions. The algorithm is validated using the work-energy theorem (Yeung, 1982) and experimental data. Results, in the form of free-surface elevations and hydrodynamic coefficients, are obtained for a range of body geometries and maneuvers. The open-loop dynamics of underwater vehicles are then investigated by solving the 3DOF rigid-body equations of motion (OXY plane). The advantages and possible usage of the developed methodology for the design and control of underwater vehicles, as well as topics for further research, are addressed in the conclusion chapter of the thesis.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12981
Subject Headings: Hydrodynamics, Oceanographic submersibles, Water waves
Format: Document (PDF)

Title: Modeling and control of the "C-Plane" ocean current turbine.
Creator: VanZwieten, James H., Florida Atlantic University, Driscoll, Frederick R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The "C-Plane" is a submerged ocean current turbine that uses sustained ocean currents to produce electricity. This turbine is moored to the sea floor and is capable of changing depth, as the current profile changes, to optimize energy production. A 1/30th scale physical prototype of the C-Plane is being developed and the analysis and control of this prototype is the focus of this work. A mathematical model and dynamic simulation of the 1/30th scale C-Plane prototype is created to analyze this...
Show moreThe "C-Plane" is a submerged ocean current turbine that uses sustained ocean currents to produce electricity. This turbine is moored to the sea floor and is capable of changing depth, as the current profile changes, to optimize energy production. A 1/30th scale physical prototype of the C-Plane is being developed and the analysis and control of this prototype is the focus of this work. A mathematical model and dynamic simulation of the 1/30th scale C-Plane prototype is created to analyze this vehicle's performance, and aid in the creation of control systems. The control systems that are created for this prototype each use three modes of operation and are the Mixed PID/Bang Bang, Mixed LQR/PID/Bang Bang, and Mixed LQG/PID/Bang Bang control systems. Each of these controllers is tested using the dynamic simulation and Mixed PID/Bang Bang controller proves to be the most efficient and robust controller during these tests.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12980
Subject Headings: Marine turbines--Automatic control, Ocean energy resources, Marine turbines--Mathematical models
Format: Document (PDF)

Title: Characterization study of the Florida Current at 26.11 North Latitude, 79.50 West Longitude for ocean current power generation.
Creator: Raye, Robert Eric., Florida Atlantic University, Driscoll, Frederick R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Aquantis, LLC, Santa Barbara, California intends to construct and deploy an ocean current turbine (C-Plane) to extract electrical power from the kinetic energy of the Florida Current. This study characterizes the physical oceanographic environment of the Florida Current flow, at a proposed deployment site located at 26.11 North Latitude, 79.50 West Longitude, which will influence the physical and mechanical design of the C-Plane. Local characteristic features of the Florida Current were...
Show moreAquantis, LLC, Santa Barbara, California intends to construct and deploy an ocean current turbine (C-Plane) to extract electrical power from the kinetic energy of the Florida Current. This study characterizes the physical oceanographic environment of the Florida Current flow, at a proposed deployment site located at 26.11 North Latitude, 79.50 West Longitude, which will influence the physical and mechanical design of the C-Plane. Local characteristic features of the Florida Current were determined from data collected during a 19 month in situ study using an Acoustic Doppler Current Profiler (ADCP) moored at 330 meters, a ship-mounted, inertial-correcting ADCP, and data culled from adjacent studies. Principles of physical oceanography and direct observations are applied to characterize the velocity structure of the current and its variability. This thesis presents the motivation behind the study, methods of data collection, statistical and numerical analyses, and available energy analyses.
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Date Issued: 2002
PURL: http://purl.flvc.org/fcla/dt/12973
Subject Headings: Ocean energy resources, Ocean currents, Oceanography--Gulf Stream, Gulf Stream
Format: Document (PDF)

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