Autonomous Underwater Vehicle (AUV) depth control methods typically use a pressure sensor to measure the depth, which results in the AUV following the trajectory of the surface waves. Through simulations, a controller is designed for the Ocean Explorer AUV with the objective of the AUV holding a constant depth below the still water line while operating in waves. This objective is accomplished by modeling sensors and using filtering techniques to provide the AUV with the depth below the still water line. A wave prediction model is simulated to provide the controller with knowledge of the wave disturbance before it is encountered. The controller allows for depth keeping below the still water line with a standard deviation of 0.04 and 0.65 meters for wave amplitudes of 0.1-0.25 and 0.5-2 meters respectively and wave frequencies of 0.35-1.0 𝑟𝑎𝑑⁄𝑠𝑒𝑐, and the wave prediction improves the depth control on the order of 0.03 meters. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

The DUCKW-Ling is an 8.3 foot long, amphibious water plane area twin hull (SWATH) concept vehicle which is propelled by a pair of crawler tracks on land and dual propellers when water-borne. In its operational zone, the vehicle's dynamics change dramatically as it transitions from being completely water-borne and buoyancy supported to being completely land-borne and track supported. In the water environment, a cascaded, first-order sliding mode controller was used to control the surge and heading of the vehicle, and was capable of having a faster response when compared to using a proportional controller. Additionally, field trials of the DUKW-Ling show the capability of the vehicle to navigate and track predetermined waypoints in both terrestrial and aquatic terrains. In the transitional zone, the electric motor current from the tracks was used as the feedback mechanism to adequately actuate the propellers and tracks in the system as the dynamics of the vehicle change. / by Josâe L. Alvarez. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

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

Fung, Kar Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 110-114). / Abstracts in English and Chinese. / 摘要 --- p.i / ABSTRACT --- p.ii / ACKNOWLEDGMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.vi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Background and Motivation --- p.1 / Chapter 1.2 --- Objective of the project --- p.4 / Chapter 1.3 --- Organization of the thesis --- p.5 / Chapter 2. --- Literature Review --- p.7 / Chapter 2.1 --- Control on Micro-Manipulation --- p.7 / Chapter 2.1.1 --- Visual Feedback Control --- p.8 / Chapter 2.1.2 --- Sensor-Based Feedback Control --- p.9 / Chapter 2.1.3 --- Bilateral Control --- p.9 / Chapter 2.2 --- Force Sensing System on Micro-Manipulation --- p.10 / Chapter 2.3 --- PVDF Sensor --- p.11 / Chapter 2.4 --- Summary of the Literature Review --- p.12 / Chapter 3. --- Micro-Manipulation --- p.14 / Chapter 3.1 --- Introduction of Micro-Manipulation --- p.14 / Chapter 3.2 --- Probe Station --- p.14 / Chapter 3.2.1 --- Micromanipulators --- p.15 / Chapter 3.2.2 --- Microscopes --- p.15 / Chapter 4. --- Piezoelectric Polyvinylidence Fluoride (PVDF) Sensor --- p.16 / Chapter 4.1 --- Charteristic of PVDF Sensor --- p.16 / Chapter 4.1.1 --- Piezoelectric Properties --- p.16 / Chapter 4.1.2 --- Dimensions of the PVDF Sensor --- p.18 / Chapter 4.2 --- Comparison of Piezoelectric Materials --- p.19 / Chapter 5. --- Theoretical Analysis of PVDF Sensor --- p.21 / Chapter 5.1 --- Sensitivity of PVDF Sensor --- p.21 / Chapter 5.2 --- Relationship between the Deflection and the Force of the PVDF --- p.22 / Chapter 5.3 --- Calculation of the Spring Constant K of the PVDF --- p.23 / Chapter 5.4 --- Simulation on the output from the PVDF Sensor --- p.23 / Chapter 6. --- Experimental Analysis of PVDF Sensor --- p.26 / Chapter 6.1 --- Force-Deflection Diagram --- p.26 / Chapter 6.2 --- Frequency Response of the PVDF Sensor --- p.27 / Chapter 7. --- 1-D PVDF-Based Sensing System --- p.30 / Chapter 7.1 --- Original Design of the Sensing System --- p.30 / Chapter 7.1.1 --- Plastic pipe and adapter --- p.31 / Chapter 7.1.2 --- PVDF Sensor --- p.32 / Chapter 7.1.3 --- Probe-tip holder --- p.32 / Chapter 7.2 --- Current Design of the Sensing System --- p.32 / Chapter 7.3 --- Analysis of the Sensing System --- p.34 / Chapter 7.3.1 --- Frequency Response of the Sensing System --- p.34 / Chapter 7.3.2 --- Sensitivity of the Sensing System --- p.41 / Chapter 8. --- Experiments on 1-D PVDF Sensing System --- p.49 / Chapter 8.1 --- Experimental Setup of the 1-D Sensing System --- p.49 / Chapter 8.1.1 --- Programmable Micromanipulator --- p.50 / Chapter 8.1.2 --- Charge Amplifier --- p.51 / Chapter 8.2 --- Calibration of the 1-D Sensing System --- p.53 / Chapter 8.2.1 --- Noise Signal from the system --- p.53 / Chapter 8.2.2 --- Signal from vibration --- p.55 / Chapter 8.3 --- Experimental Results on touching a substrate --- p.60 / Chapter 8.3.1 --- Description --- p.60 / Chapter 8.3.2 --- Results from touching a substrate --- p.62 / Chapter 8.3.3 --- Analysis of the deflection after touched a substrate --- p.67 / Chapter 8.4 --- Experimental Results on touching a micro mirror --- p.68 / Chapter 8.4.1 --- Description --- p.68 / Chapter 8.4.2 --- Results --- p.70 / Chapter 8.5 --- Experimental Results on lifting a mass platform --- p.74 / Chapter 8.5.1 --- Description --- p.74 / Chapter 8.5.2 --- Results --- p.76 / Chapter 9. --- Modification of 1-D Sensing System --- p.79 / Chapter 9.1 --- Design of the system --- p.79 / Chapter 9.2 --- Experimental Setup of the system --- p.80 / Chapter 9.3 --- Experimental Results on lifting a mass platform --- p.81 / Chapter 10. --- 2-D PVDF-Based Sensing System --- p.90 / Chapter 10.1 --- Design of the Sensing System --- p.90 / Chapter 10.2 --- Experimental Setup --- p.91 / Chapter 10.3 --- Calibration of the 2-D Sensing System --- p.92 / Chapter 10.3.1 --- Noise Signal from the system --- p.92 / Chapter 10.4 --- Experiments Results on touching a substrate --- p.94 / Chapter 11. --- Experimental Analysis --- p.97 / Chapter 11.1 --- Data Acquisition --- p.97 / Chapter 11.2 --- Spectrum Analysis of the Experimental Data --- p.101 / Chapter 12. --- Conclusion --- p.103 / Chapter 13. --- Future Work --- p.105 / Chapter 13.1 --- Control of the Sensing System --- p.105 / Chapter 13.2 --- Tele-operation System on force feedback sensing system --- p.107 / Chapter A. --- Appendix --- p.109 / Chapter A. 1 --- Procedures in using probe station --- p.109 / Bibliography --- p.110

Le but de la thèse est de développer des stratégies de contrôle efficaces pour la réduction de la trainée aérodynamique des véhicules terrestres. Nous examinons expérimentalement les effets d’un forçage fluidique sur le sillage d’un modèle de véhicule simplifié à culot droit. Le forçage est effectué par des jets pulsés aux arêtes et16 capteurs de pression répartis à la surface arrière permettent d’estimer la traînée instantanée. Nous abordons le problème difficile du contrôle de l’écoulement turbulent non linéaire---qui est souvent au-delà des capacités de la modélisation réduite---par le développement d'une stratégie de contrôle sans modèle: le contrôle via la programmation génétique linéaire (LGPC) dirigé par les données. Cette méthode explore et exploite la dynamique fortement non linéaire d'une manière non supervisée avec pas ou peu de connaissances antérieures sur le système.Le problème est de trouver une logique de contrôle qui optimise une fonction de coût donnée. Cette optimisation est réalisée par la programmation génétique linéaire comme un solveur de régression simple dans un espace de recherche de grande dimension. En particulier, cette recherche fait progresser et généralise les études antérieures sur le contrôle via la programmation génétique en incluant le forçage multi-fréquences, le signal des capteurs,l’historique des informations temporelles et leurs combinaisons dans l'espace de recherche de contrôle. La performance de LGPC est démontrée avec succès sur les expériences de contrôle de traînée du modèle de véhicule simplifié où le sillage turbulent présente une symétrie latérale et une asymétrie normale à la paroi. Environ 33% de récupération de pression au culot associée à 22% de réduction de trainée est obtenue dans toutes les classes de loisde contrôle considérées. L'énergie consommée du forçage ne représente que 30% de l'énergie aérodynamique récupérée. Dans ce travail, nous étudions également les sillages turbulents ayant une asymétrie latérale: un sillage intermittent et bi-modal à dérapage nul et un sillage asymétrique avec un angle de dérapage modéré de 5 degrés.Pour le sillage intermittent, un contrôle de rétroaction en opposition basé sur la physique est déduit à partir des essais précédents de contrôle en boucle ouverte. Le contrôleur supprime avec succès la bi-modalité du sillage et rend le sillage symétrique avec une réduction de traînée concomitante. Pour le sillage asymétrique en dérapage,nous construisons un contrôle bi-fréquence à l’arête au vent à partir des résultats de forçage à fréquence unique. Ce forçage bi-fréquentiel comprend deux fréquences ayant une différence d'un ordre de grandeur. Il combine les effets favorables de la vectorisation du sillage et le contrôle de l'équilibre des couches de cisaillement. Il est important de noter que la stratégie LGPC est également appliqué à cette situation en dérapage et converge vers le même forçage bi-fréquentiel. Les stratégies de contrôle proposées dans cette étude ouvrent de nouveaux chemins prometteurs pour le contrôle de la réduction de la traînée dans des conditions plus complexes de vitesse amont variable ou de rafale. / The thesis aims to develop effective active flow control strategies for aerodynamic drag reduction of road vehicles.We experimentally examine the effects of fluidic actuation on the wake past a simplified square-back car model.The actuation is performed with pulsed jets at trailing edges and the flow is monitored with 16 pressure sensors distributed at the rear side. We address the challenging nonlinear turbulence control---which is often beyond the capabilities of model-oriented approach---by developing a simple yet powerful model-free control strategy: the data-driven linear genetic programming control (LGPC). This method explores and exploits strongly nonlinear dynamics in an unsupervised manner with no or little prior knowledge about the system. The control problem is to find a control logic which optimizes a given cost function by employing linear genetic programming as an easy and simple regression solver in a high-dimensional control search space. In particular, the present work advances and generalizes the previous studies of genetic programming control by comprising multi-frequency forcing, sensor-based feedback including also time-history information feedback and combinations thereof in the control search space. The performance of LGPC is successfully demonstrated on the drag control experiments of the car model where the investigated turbulent wake exhibits a spanwise symmetry and a wall-normal asymmetry. Approximately 33% base pressure recovery associated with 22% drag reduction is achieved in all considered classes of control laws. The consumed actuation energy accounts for only 30% of the aerodynamic power saving. In this research, we also study the turbulent wakes having a lateral asymmetry: an intermittent bi-modal wake at zero yaw and an asymmetric wake at a moderate yaw angle of 5 degree. For the bimodal wake exhibiting are flectional symmetry-breaking, a physics-based opposition feedback control is inferred from the previous open loop control tests. The controller successfully suppresses the bi-modality of the wake and renders a symmetrized wake with a concomitant drag reduction. For the asymmetric wake at yaw, we infer from the single-frequency forcing results a bi-frequency control at the windward edge comprising two frequencies having one order of magnitude difference. This bi-frequency actuation combines the favorable effects of fluidic boat-tailing and balance control of the shear layers. Importantly, LGPC is also applied to this yawed situation and converges to the same bi-frequency actuation. The control strategies proposed in the present study open promising new paths for the control of drag reduction in more complex conditions such as the varying oncoming velocity and wind gust.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / Vita. / Includes bibliographical references. / Ph.D.

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.

Thesis. 1976. Elec.E.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / Microfiche copy available in Archives and Engineering. / Bibliography: leaves 138-140. / Elec.E.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Norman August Lehtomaki. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Paul Moroney. / Ph.D.