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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Nonlinear control of an unmanned amphibious vehicle

Unknown Date (has links)
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.
52

System identification methodology for a wave adaptive modular unmanned surface vehicle

Unknown Date (has links)
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 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. / by Janine L. Mask. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
53

Acoustic tracking of an unmanned underwater vehicle using a passive ultrashort baseline array and a single long baseline beacon

Unknown Date (has links)
This thesis discusses a new approach to tracking the REMUS 100 AUV using a modified version of the Florida Atlantic University (FAU) ultrashort baseline (USBL) acoustic positioning system (APS). The REMUS 100 is designed to utilize a long baseline (LBL) acoustic positioning system to obtain positioning data in mid-mission. If the placement of one of the transponders of the LBL field is known, then tracking the position of the REMUS 100 AUV using a passive USBL array is possible. As part of the research for this thesis, the FAU USBL system was used to find a relative range between the REMUS 100 ranger and a LBL transponder. This relative range was then combined with direction of arrival information and LBL field component position information to determine an absolute position of the REMUS 100 ranger. The outcome was the demonstration of a passive USBL based tracking system. / by Kyle L. Seaton. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
54

A modular guidance, navigation and control system for unmanned surface vehicles

Unknown Date (has links)
The design and integration of an unmanned surface vehicle (USV) control system is described. A survey of related work in both USV control, and unmanned vehicle operating software is presented. The hardware subsystem comprising a modular Guidance, Navigation, and Control (GNC) package is explained. A multi-threaded software architecture is presented, utilizing a decentralized, mutex-protected shared memory inter-process communication subsystem to provide interoperability with additional software modules. A generic GNC approach is presented, with particular elaboration on a virtual rudder abstraction of differential thrust platforms. A MATLAB Simulink simulation is presented as a tool for developing an appropriate controller structure, the result of which was implemented on the target platform. Software validation is presented via a series of sea trials. The USV was tested both in open- and closed-loop control configurations, the results of which are presented here. Lastly recommendations for future development of the GNC system are enumerated. / by Thomas C. Furfaro. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.
55

Wind Feedforward Control of a USV

Unknown Date (has links)
In this research, a wind feedforward (FF) controller has been developed to augment closed loop feedback controllers for the position and heading station keeping control of Unmanned Surface Vehicles (USVs). The performance of the controllers was experimentally tested using a 16 foot USV in an outdoor marine environment. The FF controller was combined with three nonlinear feedback controllers, a Proportional–Derivative (PD) controller, a Backstepping (BS) controller, and a Sliding mode (SM) controller, to improve the station-keeping performance of the USV. To address the problem of wind model uncertainties, adaptive wind feedforward (AFF) control schemes are also applied to the FF controller, and implemented together with the BS and SM feedback controllers. The adaptive law is derived using Lyapunov Theory to ensure stability. On-water station keeping tests of each combination of FF and feedback controllers were conducted in the U.S. Intracoastal Waterway in Dania Beach, FL USA. Five runs of each test condition were performed; each run lasted at least 10 minutes. The experiments were conducted in Sea State 1 with an average wind speed of between 1 to 4 meters per second and significant wave heights of less than 0.2 meters. When the performance of the controllers is compared using the Integral of the Absolute Error (IAE) of position criterion, the experimental results indicate that the BS and SM feedback controllers significantly outperform the PD feedback controller (e.g. a 33% and a 44% decreases in the IAE, respectively). It is also found that FF is beneficial for all three feedback controllers and that AFF can further improve the station keeping performance. For example, a BS feedback control combined with AFF control reduces the IAE by 25% when compared with a BS feedback controller combined with a non-adaptive FF controller. Among the eight combinations of controllers tested, SM feedback control combined with AFF control gives the best station keeping performance with an average position and heading error of 0.32 meters and 4.76 degrees, respectively. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
56

Multichannel synthetic aperture radar

Rosenberg, Luke January 2007 (has links)
"In this thesis, the two problems of image formation for a Multichannel Synthetic Aperture Radar (MSAR) and suppressing interferences while forming a good quality image have been addressed. For the first problem, three wavefront reconstruction algorithms were presneted based on the multichannel Matched Filter (MF) imagining equation which demonstrated differing levels of performance and accuracy. A fourth algorithm known as multichannel backprojection was also presented to provide comparative quality with a reduced computational load. To address the second problem, a detailed jammer model was described and tested with a multichannel imaging algorithm to demonstrate the effect of hot-clutter on a SAR image. Multi-channel imaging and optimal slow-time Space Time Adaptive Processing (STAP) were shown to only partially suppress the hot-clutter interference, while optimal fast-time STAP demonstrated a much greater performance." --p. 185 of source document. / Thesis (Ph.D.)--School of Electrical and Electronic Engineering, 2007.
57

Adaptive noise cancellation for second-order delta-sigma A/D converters

Bribech, Habib 18 September 1992 (has links)
Oversampled analog-to-digital (A/D) converter architectures have been receiving increased attention for high-precision A/D converters. These architectures offer the means of exchanging resolution in time for that in amplitude. Among these oversampled A/D converters, delta-sigma modulators are the most popular method used due to their simplicity in the analog circuitry. The analog integrators in delta-sigma modulators suffer from non-idealities such as capacitor mismatches and finite op-amp gain. In the dual quantizer A/D converters, the system relies on the perfect matching of the analog and digital transfer functions to cancel the quantization noise. However, the non-ideality of the analog parameters makes this matching hard to achieve. In this thesis, an off-line adaptive scheme is presented to estimate the non-ideal parameters of the analog section for the second-order delta-sigma modulator. These estimates are then used in the digital part to reduce the quantization noise. The least-mean- square (LMS) algorithm is used to adaptively estimate the analog parameters. / Graduation date: 1993
58

Performance assessment of the finite impulse response Adaptive Line Enhancer

Campbell, Roy Lee. January 2002 (has links)
Thesis (Ph. D.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.
59

Novel adaptive signal processing algorithms for wireless communications : echo cancellation and multiuser detection /

Blunt, Shannon D. January 2002 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 137-143). Also available on the Internet.
60

Novel adaptive signal processing algorithms for wireless communications echo cancellation and multiuser detection /

Blunt, Shannon D. January 2002 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 137-143). Also available on the Internet.

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