Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Joseph A. Rice, Joseph A. Rice. Includes bibliographical references (p. 47). Also available online.

Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2008. / Ruzzene, Massimo, Committee Chair ; Bottasso, Carlo L., Committee Member ; Costello, Mark, Committee Member ; Hodges, Dewey H., Committee Member ; Weston, Neil, Committee Member.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / In this thesis the mathematical modelling and simulation of an autonomous underwater vehicle is presented. A generic six degree of freedom model suitable for AUV control applications is presented. This model is then tailored to the AUV testbed developed by IMT. The model parameters are determined from vehicle geometry alone. In addition to this, a linear model is presented and analysed in order to determine the modes of motion for AUV. The development of a generic visualisation system suitable for underwater vehicle simulations is also presented. A generic MATLAB based AUV simulation system is developed, and used to supply the visualisation system with the necessary simulation data. Lastly, two example simulations are shown

Underwater vehicles often use acoustics or dead reckoning for global positioning, which is impractical for low cost, high proximity applications. An optical based positional feedback system for a wave tank operated biomimetic station-keeping vehicle was made using an extended Kalman filter and a model of a nearby light source. After physical light model verification, the filter estimated surge, sway, and heading with 6 irradiance sensors and a low cost inertial measurement unit (~$15). Physical testing with video feedback suggests an average error of ~2cm in surge and sway, and ~3deg in yaw, over a 1200 cm2 operational area. This is 2-3 times better, and more consistent, than adaptations of prior art tested alongside the extended Kalman filter feedback system. The physical performance of the biomimetic platform was also tested. It has a repeatable forward velocity response with a max of 0.3 m/s and fair stability in surface testing conditions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S. in Systems Technology)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Don Brutzman, Jeff Weekley. Includes bibliographical references (p. 107-111). Also available online.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis presents the design process of the movement control and guidance systems for an automated underwater vehicle (AUV) constructed by the Institute of Maritime Technology in Simon’s Town. The full non-linear mathematical model and simulation environment for the AUV were previously developed in [1]. The design process in this thesis covers an analysis of existing test data and the performance of the current systems in place on the AUV, derivation and analysis of the linear model for the AUV, design of upgraded control and guidance systems, analysis of the new designs including simulation results, practical implementation of the new designs and the results thereof. Over the course of this project a number of flaws were identified in the original control designs and other aspects of the AUV. Most notably, the capability of the AUV is limited owing to its construction, and the current control and guidance methods result in poor movement characteristics. The new control designs are executed through multiple SISO feedback loops, with the most complicated controllers consisting of proportional and integral control. A completely new guidance method was designed which grants theAUVthe ability to track both straight line and circular path segments with no steady state error. These designs were tested in simulation, with results showing good tracking performance, even in the presence of output disturbances. The new designs were implemented on the physical AUV, but testing was limited, with poor results being obtained. The poor test results were caused primarily by the construction of the AUV. / AFRIKAANSE OPSOMMING: Hierdie tesis stel die ontwerpsproses voor vir die bewegingsbeheer- en navigasiestelsels vir ’n outonome duikboot wat gebou is deur die Instituut vir Maritieme Tegnologie in Simonstad. Die volle nie-lineˆere wiskundige model en simulasieomgewing vir die duikboot is voorheen ontwikkel in [1]. Die ontwerpsproses in hierdie tesis behels ’n analise van bestaande toetsdata en van die werksverrigting van die stelsels wat tans op die duikboot ge¨ınstalleer is, die afleiding en analise van ’n lineˆere model vir die duikboot, die ontwerp van verbeterde beheer- en navigasiestelsels, die analise van die nuwe ontwerpe, wat simulasieresultate insluit, die praktiese implementering van die nuwe ontwerpe, en die resultate daarvan. Deur die loop van die projek is ’n aantal tekortkominge ge¨ıdentifiseer in die oorspronklike beheerstelselontwerpe en ander aspekte van die duikboot. Die mees beduidende tekortkominge is dat die vermo¨e van die duikboot beperk word deur die konstruksie daarvan, en dat die huidige beheer- en navigasietegnieke swak bewegingseienskappe lewer. Die nuwe beheerstelselontwerpe is uitgevoer deur ’n aantal enkelintree, enkeluittree terugvoerlusse, waar die mees komplekse beheerders bestaan uit proporsionele en integraalbeheer. ’n Heeltemal nuwe navigasiemetode is ontwerp, wat die duikboot in staat stel om beide reguit lyne en sirkulˆere padsegmente te volg sonder ’n stasionˆere volgfout. Hierdie ontwerpe is getoets in simulasie, waar die resultate goeie volging getoon het, selfs in die teenwoordigheid van uittreeversteurings. Die nuwe ontwerpe is ge¨ımplementeer op die fisiese duikboot, maar beperkte toetse is gedoen, en het swak resultate gelewer. Die swak toetsresultate was hoofsaaklik as gevolg van die konstruksie van die duikboot.

Current rates of technological advancement continue to translate into changes on our battlefields. Aerial robots capable of gathering reconnaissance along with unmanned underwater vehicles capable of defusing enemy minefields provide evidence that machines are playing key roles once played by humans within our military. This thesis explores one of the major problems facing both commercial and military UUVs to date. Successfully navigating in unfamiliar environments and maneuvering autonomously to avoid obstacles is a problem that has yet to be fully solved. Using a simulated 2-D ocean environment, the work of this thesis provides results of numerous REMUS simulations that model the vehicle's flight path over selected sea bottoms. Relying on a combination of sliding mode control and feedforward preview control, REMUS is able to locate obstacles such as seawalls using processed forward look sonar images. Once recognized, REMUS maneuvers to avoid the obstacle according to a Gaussian potential function. In summary, the integration of feedforward preview control and sliding mode control results in an obstacle avoidance controller that is not only robust, but also autonomous.

The ARIES Unmanned Underwater Vehicle (UUV) currently uses an Inertial Measurement Unit (IMU) with an inherent rotation rate error bias of 10 degrees/hour. Then need for a more accurate IMU for long term missions has led to the purchase of the Honeywell HG1700 IMU. The HG1700 is a ring laser gyroscope designed specifically as part of the navigation software in multiple U.S. missiles. The objective of this research is to perform numerous bench tests on the HG1700 to test its capabilities and to begin the process of implementing the IMU into the ARIES unmanned underwater vehicle. Specifically, the IMU is tested for correct setup configurations, angle of rotation accuracies, the rotation rate error bias, and positional accuracies. Also, guidelines for integrating the IMU with the current software in the ARIES vehicle are discussed.

Undulatory ribbon- n-based propulsion is an appealing propulsion mechanism due to its rich locomotor capabilities that can improve the propulsive performance and maneuverability of underwater vehicles. For instance, the swimming mechanics of weakly electric black ghost knife sh (Apteronotus albifrons) is of great interest to study because of their high swimming e ciency at low speeds and extraordinary agility such as rapid reversal swimming, hovering in presence of water disturbance, rolling and vertical swimming. In this thesis work, to facilitate our understanding on the exible undulatory ribbon n propulsion, we have four research motivations. The rst objective is to study how the use of exible rays and di erent n morphology can in uence the propulsive performance of ribbon- n propulsion. It is possible that natural swimmers using this locomotion method could take advantage of passive n motion based on the coupling of uid-structure interaction and the elasto-mechanical responses of the undulating n. Therefore, the second objective is to understand how an under-actuated undulating n can take advantage of natural dynamics of the uid-structure interaction for the propulsive force generation. In addition to the impressive propulsive performance of the undulatory n propulsion, the exceptional maneuverability of knife sh is also a key motivation that drives this thesis work. Thus, we dedicate to investigate how traveling wave shapes and actuation parameters (frequency, wavelength) can manipulate the maneuvering behaviors of a swimmer propelled by an undulating ribbon n. Lastly, we aim to uncover the e ect of varying traveling wave amplitudes and pectoral ns on its maneuvering performances. Two robotic devices were developed to study the propulsive performance of both fullyactuated and under-actuated ribbon n propulsion and investigate the maneuver control of a free-swimming underwater robot propelled by an undulatory n. For the rst research aim, we study the e ect of exible rays and di erent n morphology on the propulsive performance of ribbon- n propulsion. A physical model composed of fteen rays interconnected with an elastic membrane was used to test four di erent ray exural sti ness and four aspect ratios. Our results show that exible rays can improve the propulsive e ciency compared to a rigid counterpart. In addition, the morphology of the ribbon n a ects its propulsive performance as well, and there could exist an optimal n morphology. To understand how an underactuated undulating n can modify its active and passive n motion to e ectively control the hydrodynamic force and propulsive e ciency. We did a series of experiments using the same robotic n model but with some structural modi cations and we measured n kinematics, net surge force and power consumption. We nd that the under-actuated n can keep the equivalent propulsive e ciency as the fully-actuated counterpart within our experimental parameter range. Moreover, our results demonstrate that the thrust force and power consumption of an under-actuated n follow the same scaling laws as the fully-actuated n. To conduct the free-swimming maneuver study, we developed a self-contained, free-swimming robot propelled by an undulatory n, which is able to perform the following maneuvers: forward, reversed swimming and hovering motion. We also performed V3V PIV experiments to capture the ow structures generated by the robotic device. Our results show that the robot can reach higher swimming e ciency at low frequencies. As the number of traveling waves increases, the robot swims more stably in roll, pitch and yaw motions. For cases with varying wave amplitudes, traveling wave with incremental wave amplitude can achieve free-swimming velocity higher than that of decremental wave amplitude. However, the latter case can generate higher pitch angles. For the robot with slightly negative-pitched pectoral ns, it can perform slow diving maneuvers. These ndings demonstrate that we can take advantage of the undulating ribbon n propulsion to achieve high maneuverability for the future underwater vehicles in complex environment. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection