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- Title
- Simulator and location-aware routing protocol for mobile ad hoc acoustic networks of AUVs.
- Creator
- Carlson, Edward A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator...
Show moreAcoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the coding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages -- two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric., This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was the most novel addition: using only implicit communication coupled with the use of time-division multiple access (TDMA), the tracking system provided predicted node locations. These predictions made it possible for LASR to proactively respond to topology changes. In most cases, LASR outperformed flooding and DSR in message delivery reliability and message delivery volume.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/187208
- Subject Headings
- Ad hoc networks (Computer networks), Computer network protocols, Routers (Computer networks), Mobile communication systems, Design and construction, Remote submersibles, Design and construction
- Format
- Document (PDF)
- Title
- Source speed estimation using a pilot tone in a high-frequency acoustic modem.
- Creator
- Kathiroli, Poorani., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This thesis proposes to estimate the speed of a moving acoustic source by either linear or non linear processing of the resulting Doppler shift present in a high-frequency pilot tone. The source is an acoustic modem (Hermes) which currently uses moving average to estimate and compensate for Doppler shift. A new auto regressive approach to Doppler estimation (labeled IIR method in the text) promises to give a better estimate. The results for a simulated peak velocity of 2 m/s in the presence...
Show moreThis thesis proposes to estimate the speed of a moving acoustic source by either linear or non linear processing of the resulting Doppler shift present in a high-frequency pilot tone. The source is an acoustic modem (Hermes) which currently uses moving average to estimate and compensate for Doppler shift. A new auto regressive approach to Doppler estimation (labeled IIR method in the text) promises to give a better estimate. The results for a simulated peak velocity of 2 m/s in the presence of additive noise showed an RMSE of 0.23 m/s using moving average vs. 0.00018 m/s for the auto regressive approach. The SNR was 75 dB. The next objective was to compare the estimated Doppler velocity obtained using the two algorithms with the experimental values recorded in real time. The setup consisted of a receiver hydrophone attached to a towing carriage that moved with a known velocity with respect to a stationary acoustic source. The source transmitted 375 kHz pilot tone. The received pilot tone data were preprocessed using the two algorithms to estimate both Doppler shift and Doppler velocity. The accuracy of the algorithms was compared against the true velocity values of the carriage. The RMSE for a message from experiments conducted indoor for constant velocity of 0.4 m/s was 0.6055 m/s using moving average, 0.0780 m/s using auto regressive approach. The SNIR was 6.3 dB.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3171396
- Subject Headings
- Underwater acoustics, Measurement, SIgnal processing, Digital techniques, Digital filters (Mathematics), Radio frequency, Mathematical models
- Format
- Document (PDF)
- Title
- Some corrosion problems associated with underwater turbines.
- Creator
- Miglis, Yohann., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order...
Show moreThis thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order polynomial, along with a Least Square and Spline Interpolation of the experimental data. In a second part, the effect of the passive film, delaying the initiation of the corrosion process, is studied. Finally, an algorithm predicting the time of service of a cracked bar is provided, using the stress corrosion assumption, along with a validation using experimental data.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3342238
- Subject Headings
- Turbines, Stress corrosion, Testing, Computational fluid dynamics, Stress corrosion, Fracture mechanics, Measurement, Alloys, Stress corrosion, Testing, Alloys, Corrosion fatigue, Testing
- Format
- Document (PDF)
- Title
- Simulations and feedback control of nonlinear coupled electromechanical oscillators for energy conversion applications.
- Creator
- Psarrou, Dimitrios., Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This thesis discusses the coupling of a mechanical and electrical oscillator, an arrangement that is often encountered in mechatronics actuators and sensors. The dynamics of this coupled system is mathematically modeled and a low pass equivalent model is presented. Numerical simulations are then performed, for various input signals to characterize the nonlinear relationship between the electrical current and the displacement of the mass. Lastly a framework is proposed to estimate the mass...
Show moreThis thesis discusses the coupling of a mechanical and electrical oscillator, an arrangement that is often encountered in mechatronics actuators and sensors. The dynamics of this coupled system is mathematically modeled and a low pass equivalent model is presented. Numerical simulations are then performed, for various input signals to characterize the nonlinear relationship between the electrical current and the displacement of the mass. Lastly a framework is proposed to estimate the mass position without the use of a position sensor, enabling the sensorless control of the coupled system and additionally providing the ability for the system to act as an actuator or a sensor. This is of value for health monitoring, diagnostics and prognostics, actuation and power transfer of a number of interconnected machines that have more than one electrical system, driving corresponding mechanical subsystems while being driven by the same voltage source and at the same time being spectrally separated and independent.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3320109
- Subject Headings
- Renewable energy sources, Mechatronics, Nonlinear theories, Oscillators, System analysis
- Format
- Document (PDF)
- Title
- Model analysis of a mooring system for an ocean current turbine testing platform.
- Creator
- Cribbs, Allison Rose., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In response to Florida's growing energy needs and drive to develop renewable power, Florida Atlantic Universitys Center for Ocean Energy Technology (COET) plans to moor a 20 kW test turbine in the Florida Current. No permanent mooring systems for deepwater hydrokinetic turbines have been constructed and deployed, therefore little if anything is known about the performance of these moorings. To investigate this proposed mooring system, a numeric model is developed and then used to predict the...
Show moreIn response to Florida's growing energy needs and drive to develop renewable power, Florida Atlantic Universitys Center for Ocean Energy Technology (COET) plans to moor a 20 kW test turbine in the Florida Current. No permanent mooring systems for deepwater hydrokinetic turbines have been constructed and deployed, therefore little if anything is known about the performance of these moorings. To investigate this proposed mooring system, a numeric model is developed and then used to predict the static and dynamic behavior of the mooring system and attachments. The model has been created in OrcaFlex and includes two surface buoys and an operating turbine. Anchor chain at the end of the mooring line develops a catenary, providing compliance. Wind, wave, and current models are used to represent the environmental conditions the system is expected to experience and model the dynamic effects on the system. The model is then used to analyze various components of the system. The results identify that a mooring attachment point 1.25 m forward of the center of gravity on the mooring buoy is ideal, and that the OCDP and turbine tether lengths should be no shorter than 25 and 44 m, respectively. Analysis performed for the full system identify that the addition of the floats decreases the tension at the MTB attachment location by 26.5 to 29.5% for minimum current, and 0.10 to 0.31% for maximum current conditions.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2974432
- Subject Headings
- Marine turbines, Mathematical models, Structural dynamics, Rotors, Design and construction, Offshore structures, Testing
- Format
- Document (PDF)
- Title
- System identification methodology for a wave adaptive modular unmanned surface vehicle.
- Creator
- Mask, Janine L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The design, implementation, and testing of an experimental setup intended to evaluate the dynamic maneuvering performance of the Wave Adaptive Modular Vessel (WAM-V) class USV12, a 3.7 meter unmanned surface vehicle (USV) is described. A comprehensive sensor package was designed, fabricated and assembled to record the vehicle's dynamic response to various control inputs. All subsystems were fabricated and installed on a test vehicle, GUSS, and full system, open-loop maneuvering tests were...
Show moreThe design, implementation, and testing of an experimental setup intended to evaluate the dynamic maneuvering performance of the Wave Adaptive Modular Vessel (WAM-V) class USV12, a 3.7 meter unmanned surface vehicle (USV) is described. A comprehensive sensor package was designed, fabricated and assembled to record the vehicle's dynamic response to various control inputs. All subsystems were fabricated and installed on a test vehicle, GUSS, and full system, open-loop maneuvering tests were conducted to show validity of data collection technique. Simulations were performed using model parameters found in the literature to create a "simulated experimental" data set, upon which system identification techniques were used to rediscover a suitable model with similar parameterization. Combined, the sensor package and the method for creating this model support future work in the design of automatic control, navigation, and guidance systems for the WAM-V USV12.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3332720
- Subject Headings
- Oceanographic instruments, Evaluation, Wave motion, Theory of, Inertial navigation systems, Adaptive signal processing
- Format
- Document (PDF)
- Title
- Task allocation and path planning for acoustic networks of AUVs.
- Creator
- Deng, Yueyue, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Controlling the cooperative behaviors of a fleet of autonomous underwater vehicles in a stochastic, complex environment is a formidable challenge in artificial intelligence. The complexity arises from the challenges of limited navigation and communication capabilities of underwater environment. A time critical cooperative operation by acoustic networks of Multiple Cooperative Vehicles (MCVs) necessitates a robust task allocation mechanism and an efficient path planning model. In this work, we...
Show moreControlling the cooperative behaviors of a fleet of autonomous underwater vehicles in a stochastic, complex environment is a formidable challenge in artificial intelligence. The complexity arises from the challenges of limited navigation and communication capabilities of underwater environment. A time critical cooperative operation by acoustic networks of Multiple Cooperative Vehicles (MCVs) necessitates a robust task allocation mechanism and an efficient path planning model. In this work, we present solutions to investigate two aspects of the cooperative schema for multiple underwater vehicles under realistic underwater acoustic communications: a Location-aided Task Allocation Framework (LAAF) algorithm for multi-target task assignment and a mathematical programming model, the Grid-based Multi-Objective Optimal Programming (GMOOP), for finding an optimal vehicle command decision given a set of objectives and constraints. We demonstrate that, the location-aided auction strategies perform significantly better than the generic auction algorithm in terms of effective task allocation time and information bandwidth requirements. In a typical task assignment scenario, the time needed in the LAAF algorithm is only a fraction compared to the generic auction algorithm. On the other hand; the GMOOP path planning technique provides a unique means for multi-objective tasks by cooperative agents with limited communication capabilities. Under different environmental settings, the GMOOP path planning technique is proved to provide a method with balance of sufficient expressive power and flexibility, and its solution algorithms tractable in terms of mission completion time, with a limited increase of overhead in acoustic communication. Prior to this work, existing multi-objective action selection methods were limited to robust networks where constant communication available., The dynamic task allocation, together with the GMOOP path planning controller, provides a comprehensive solution to the search-classify tasks for cooperative AUVs.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/1927865
- Subject Headings
- Computer network protocols, Routers (Computer networks), Remote submersibles, Design and construction, Mobile communication systems, Design and construction, Ad hoc networks (Computer networks)
- Format
- Document (PDF)
- Title
- 2006-2007 Program Review Ocean Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2006-2007
- PURL
- http://purl.flvc.org/fau/fd/FA00007725
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2009-2010 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2009-2010
- PURL
- http://purl.flvc.org/fau/fd/FA00007728
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2013-2014 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2013-2014
- PURL
- http://purl.flvc.org/fau/fd/FA00007737
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2014-2015 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2014-2015
- PURL
- http://purl.flvc.org/fau/fd/FA00007740
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2010-2011 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2010-2011
- PURL
- http://purl.flvc.org/fau/fd/FA00007731
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2012-2013 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2012-2013
- PURL
- http://purl.flvc.org/fau/fd/FA00007734
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2015-2016 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2015-2016
- PURL
- http://purl.flvc.org/fau/fd/FA00007743
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2016-2017 Program Review Ocean and Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2016-2017
- PURL
- http://purl.flvc.org/fau/fd/FA00007746
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- 2006-2007 Program Review Mechanical Engineering.
- Creator
- Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Florida Atlantic University Departmental Dashboard Indicators. Department program reviews for College of Engineering and Computer Science, Florida Atlantic University.
- Date Issued
- 2006-2007
- PURL
- http://purl.flvc.org/fau/fd/FA00007724
- Subject Headings
- Florida Atlantic University -- History
- Format
- Document (PDF)
- Title
- Matlab for Newbies: The Bare Essentials.
- Creator
- Verma, Siddhartha
- Abstract/Description
-
This book will guide your first steps in programming in Matlab, no matter whether you want to learn it for work, fun, or just to satisfy your curiosity! Getting comfortable with the basics of programming in Matlab will be our main goal in this first of several segments that I hope to write. We will focus precisely on the things that you will need to get set up and running. You will be able to interpret simple code, and atleast be able to understand what the code’s author is trying to achieve.
- Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FAUIR000374
- Subject Headings
- Open Educational Resources
- Format
- Citation
- Title
- Boundary Layer Control on a Circular Cylindrical Body through Oscillating Lorentz Forcing.
- Creator
- Seltzer, Ryan K., Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Boundary layer control on a circular cylindrical body through oscillating Lorentz forcing is studied by means of numerical simulation of the vorticity-stream function formulation of the Navier-Stokes equations. The model problem considers axisymmetric seawater flow along an infinite cylinder controlled by an idealized radially directed Lorentz force oscillating spatially and temporally. Under optimum forcing parameters, it is shown that sustainable Lorentz induced vortex rings can travel...
Show moreBoundary layer control on a circular cylindrical body through oscillating Lorentz forcing is studied by means of numerical simulation of the vorticity-stream function formulation of the Navier-Stokes equations. The model problem considers axisymmetric seawater flow along an infinite cylinder controlled by an idealized radially directed Lorentz force oscillating spatially and temporally. Under optimum forcing parameters, it is shown that sustainable Lorentz induced vortex rings can travel along the cylinder at a speed equivalent to the phase speed of forcing . Wall stress is shown to locally change sign in the region adjacent to the vortex, considerably decreasing net viscous drag . Adverse flow behaviors are revealed as a result of studying the effects of the Reynolds numbers, strength of the Lorentz force, and phase speed of forcing for boundary layer control. Adverse flow behaviors inc I ude complex vortex configurations found for suboptimal forcing resulting in a considerable increase in wall stress.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00012549
- Subject Headings
- Mathematical physics, Lorentz transformations, Boundary layer control, Fluid dynamics
- Format
- Document (PDF)
- Title
- Effects of POSS Fiber Sizing on the Mechanical and Thermal Properties of CarbonNinyl Ester Composites.
- Creator
- Powell, Felicia M., Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and...
Show moreThe degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and mechanical procedures has been developed to coat carbon fibers with POSS, and fabricate layered composites using vinyl ester resin. lnterlaminar shear, transverse tension, and low velocity impact tests on composites have indicated around 10-38% improvement in mechanical properties with respect to control samples. Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) tests have also shown significant improvement in glass transition temperature (T9). Hygrothermal tests, under various environments, have demonstrated that POSS reduces water absorption by 20-30%.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/fau/fd/FA00012540
- Subject Headings
- Surface chemistry, Composite materials--Biodegradation, Carbon compounds--Testing, Thermodynamics, Fibrous compounds--Testing
- Format
- Document (PDF)
- Title
- Dynamic analysis of single- and multi-module platforms in waves.
- Creator
- Kling, Kaylie Ann., Florida Atlantic University, Ananthakrishnan, Palaniswamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The response of single- and multi-module floating platforms to surface waves is investigated theoretically. Wave exciting forces are computed using methods based on the Morrison equation and Froude-Krylov hypothesis. The radiation forces are obtained from experimental results of Vugt and where possible diffraction forces using the Haskind reciprocity relation. Heave and pitch response of a one-module platform and hinge-connected two-module platform are determined by integrating the...
Show moreThe response of single- and multi-module floating platforms to surface waves is investigated theoretically. Wave exciting forces are computed using methods based on the Morrison equation and Froude-Krylov hypothesis. The radiation forces are obtained from experimental results of Vugt and where possible diffraction forces using the Haskind reciprocity relation. Heave and pitch response of a one-module platform and hinge-connected two-module platform are determined by integrating the corresponding equations of rigid-body motion. A structural dynamic analysis is also carried out using the Green's function method to determine the elastic flexural response of the platform to waves. The results are compared with the experimental and numerical findings of others. The thesis contributes to a better understanding of rigid-body and elastic response of large ocean platforms subject to wave forces. The methodology is computationally less intensive and therefore can be effectively used for the design of platforms and the validation of numerical algorithms.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13399
- Subject Headings
- Ocean engineering, Wave motion, Theory of, Water waves--Mathematical models, Drilling platforms, Extreme value theory
- Format
- Document (PDF)
