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Simulating the dynamic interaction of an AUV and towed magnetometer
Title
Simulating the dynamic interaction of an AUV and towed magnetometer.
Creator
Miller, Lea Gabrielle., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A magnetometer with a sensitivity of 0.01nT will be towed through the thermocline by a 2.87 meter long, 0.533 meter diameter autonomous underwater vehicle (AUV) to measure the magnetic fluctuations generated by oceanic internal waves. At this point, no research has been found that suggests towed magnetometer measurements have been done using an AUV. Simulations of the AUV, tow cable, and towfish are performed to provide an understanding of the effects of changing different input parameters,...
Show moreA magnetometer with a sensitivity of 0.01nT will be towed through the thermocline by a 2.87 meter long, 0.533 meter diameter autonomous underwater vehicle (AUV) to measure the magnetic fluctuations generated by oceanic internal waves. At this point, no research has been found that suggests towed magnetometer measurements have been done using an AUV. Simulations of the AUV, tow cable, and towfish are performed to provide an understanding of the effects of changing different input parameters, such as towing speed (0.5-2m/s), cable length (5-15m), vehicle trajectory (circle and vertical zig zag maneuvers), and current (0.25-1.25m/s). The AUV-cabletowfish system and equations of motion needed for the simulations are described herein. Results show that a 5m tow cable provides better towfish maneuvering than the longer cable lengths. High towfish pitch angle is decreased by decreasing the distance between CG and CB. Surface currents speed of 0.25m/s change the AUV and towfish circle maneuver to a spiral trajectory, while 1.25m/s current speed cause a zig zag trajectory.
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Date Issued
2011
PURL
http://purl.flvc.org/FAU/3318670
Subject Headings
Automatic control, Mathematical models, Electromagnetic measurements, Fluctuations (Physics), Oceanographic submersibles, Computer simulation
Format
Document (PDF)
Hydrodynamic analysis of underwater bodies for efficient station keeping in shallow waters with surface waves
Title
Hydrodynamic analysis of underwater bodies for efficient station keeping in shallow waters with surface waves.
Creator
Bradley, Matthew, Ananthakrishnan, Palaniswamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
To determine the effect of body shape on the response of underwater vehicles to surface waves in shallow water, the wave radiation hydrodynamic forces are evaluated for a family of (i) prolate spheroidal hull forms and (ii) cylindrical bodies with hemispherical nose and conical tail sections by systematically varying the geometric parameters but keeping displacement constant. The added-mass and wave damping coefficients are determined using a frequency-domain, simple-source based boundary...
Show moreTo determine the effect of body shape on the response of underwater vehicles to surface waves in shallow water, the wave radiation hydrodynamic forces are evaluated for a family of (i) prolate spheroidal hull forms and (ii) cylindrical bodies with hemispherical nose and conical tail sections by systematically varying the geometric parameters but keeping displacement constant. The added-mass and wave damping coefficients are determined using a frequency-domain, simple-source based boundary integral method. Results are obtained for a range of wave frequencies and depths of vehicle submergence all for a fixed water depth of 10 m. With the wave exciting force and moment determined using the Froude-Krylov theory, the response transfer functions for heave and pitch are then determined. The heave and pitch response spectra in actual littoral seas are then determined with the sea state modeled using TMA spectral relations. Results show that vehicle slenderness is a key factor affecting the hydrodynamic coefficients and response. The results show two characteristics that increase the radiation hydrodynamic forces corresponding to heave and pitch motions: namely, vehicle length and further-away from mid-vehicle location of the body shoulder. The opposite is true for the oscillatory surge motion. By utilizing these observed characteristics, one can design the lines for maximum radiation forces and consequently minimum hull response for the critical modes of rigid-body motion in given waters and vehicle missions. In the studies carried out in the thesis, a hull with a long parallel middle body with hemispherical nose and conical tail sections has better heave and pitch response characteristics compared prolate spheroid geometry of same volume. The methodology developed herein, which is computationally efficient, can be used to determine optimal hull geometry for minimal passive vehicle response in a given sea.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004084, http://purl.flvc.org/fau/fd/FA00004084
Subject Headings
Oceanographic submersibles -- Hydrodynamics, Surface waves (Oceanography) -- Mathematical models, Wave motion, Theory of
Format
Document (PDF)
graphical Windows(c)-based cable and underwater system simulation software
Title
A graphical Windows(c)-based cable and underwater system simulation software.
Creator
de Baudreuil, Jean., Florida Atlantic University, Driscoll, Frederick R.
Abstract/Description
Underwater systems behavior prediction has become an important success factor in the design and implementation of marine systems. Most marine systems involve cables for mooring, deployment, recovery, or towing; however, estimating the response of these systems is difficult because of their non-linear behavior. Thus, numerical models are used to simulate submerged cabled systems. At FAU, many mission specific cable simulations have been developed, but no single, all encompassing software...
Show moreUnderwater systems behavior prediction has become an important success factor in the design and implementation of marine systems. Most marine systems involve cables for mooring, deployment, recovery, or towing; however, estimating the response of these systems is difficult because of their non-linear behavior. Thus, numerical models are used to simulate submerged cabled systems. At FAU, many mission specific cable simulations have been developed, but no single, all encompassing software package exists. This thesis develops a Windows(c) based software package to quickly and easily create FEA models of underwater cabled systems and simulate their response. The model is based on a discrete finite element analysis using linear elements. The software provides fully integrated and interactive Graphical User Interfaces with a 3-dimensional graphical display of the model, and integrates adapted data analysis and visualization tools. The software provides an easy and efficient way to simulate an underwater system involving cables.
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Date Issued
2005
PURL
http://purl.flvc.org/fcla/dt/13232
Subject Headings
Oceanographic submersibles--Computer simulation, Computer software--Development, Simulation methods, Cables, Submarine
Format
Document (PDF)
Software development of a hardware-in-the-loop simulation and a three-dimensional viewer for autonomous underwater vehicles
Title
Software development of a hardware-in-the-loop simulation and a three-dimensional viewer for autonomous underwater vehicles.
Creator
Mahieu, Frederi., Florida Atlantic University, An, Edgar, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis describes the development of the hardware-in-the-loop simulation for FAU Autonomous Underwater Vehicles. The development was based on the existing simulation platform. For more efficiency and flexibility, this simulation package was ported to Linux. The hardware-in-the-loop simulation enables developers to connect the vehicle directly to a remote simulator. This kind of simulation is used to test the actual software components embedded in the vehicle system. The simulation package...
Show moreThis thesis describes the development of the hardware-in-the-loop simulation for FAU Autonomous Underwater Vehicles. The development was based on the existing simulation platform. For more efficiency and flexibility, this simulation package was ported to Linux. The hardware-in-the-loop simulation enables developers to connect the vehicle directly to a remote simulator. This kind of simulation is used to test the actual software components embedded in the vehicle system. The simulation package was enhanced by the addition of a 3D viewer. This thesis describes the whole development process, from feasibility study and implementation to qualification phases. This viewer is platform independent and designed to be connected to the simulator. It renders the AUV moving in a virtual environment. This tool can be used during all development steps, from tuning phases to post-mission analysis.
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Date Issued
2000
PURL
http://purl.flvc.org/fcla/dt/15778
Subject Headings
Oceanographic submersibles--Computer simulation, Computer software--Development, Simulation methods, Three-dimensional display systems
Format
Document (PDF)
Optical Characterization ofPort Everglades Focusing on Underwater Visibility
Title
Optical Characterization ofPort Everglades Focusing on Underwater Visibility.
Creator
Whipple, Dustin E., Frisk, George V., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The development of an unmanned underwater vehicle at Florida Atlantic University with onboard optical sensors has prompted the temporal and spatial optical characterization of Port Everglades, with in-situ measurements of the turbidity, conductivity, and temperature. Water samples were collected for laboratory analysis where attenuation and absorption were measured with a bench top spectrometer. All of the measurements showed a high degree of variability within the port on a temporal and...
Show moreThe development of an unmanned underwater vehicle at Florida Atlantic University with onboard optical sensors has prompted the temporal and spatial optical characterization of Port Everglades, with in-situ measurements of the turbidity, conductivity, and temperature. Water samples were collected for laboratory analysis where attenuation and absorption were measured with a bench top spectrometer. All of the measurements showed a high degree of variability within the port on a temporal and spatial basis. Correlations were researched between the measured properties as well as tide and current. Temporal variations showed a high correlation to tidal height but no relation was found between turbidity and current, or salinity. Spatial variations were primarily determined by proximity to the port inlet. Proportionality constants were discovered to relate turbidity to scattering and absorption coefficients. These constants along with future turbidity measurements will allow the optimization of any underwater camera system working within these waters.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00012569
Subject Headings
Oceanographic submersibles--Mathematical models, Image processing--Digital techniques, Optical pattern recognition, Port Everglades (Fort Lauderdale, Fla)
Format
Document (PDF)

Pages