Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 100 for “"hovering"”.
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Hummingbird Hovering Energetics and Flight Capacities Across Elevational Gradients
… Using hummingbirds, a group of animals with high hovering metabolic rates and wide elevational distributions, I examine the flight capacities and aerobic scopes across an 1800-m elevational gradient, as well as any morphological adaptations that permit high elevation flight. The angular velocity …
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Flapping foil propulsion for cruising and hovering autonomous underwater vehicles
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2003.
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Euler equation computations for the flow over a hovering helicopter rotor
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1987.
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Design and prototype of a hovering ornithopter based on dragonfly flight
Hovering is normally achieved using a horizontal wing path to create lift; bees, wasps and helicopters use this technique. Dragonflies hover using a unique method, by flapping along an inclined stroke plane. This seems to create a higher efficiency than is possible for normal hovering. The aim of …
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Vision-Assisted Control of a Hovering Air Vehicle in an Indoor Setting
… and magnetometers have inherent weaknesses on hovering vehicles. Thus, an additional vector measurement is necessary to correct attitude readings for long-term flights. Two methods of using image processing to determine vanishing points in a hallway are demonstrated. The more promising of the …
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Vision-based guidance and control of a hovering vehicle in unknown environments
… of a system capable of controlling and guiding a hovering vehicle in unknown environments, emphasizing cluttered indoor spaces. Six-axis inertial data and a low-resolution onboard camera yield sufficient information for image processing, Kalman filtering, and novel mapping algorithms to generate …
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Dynamic response and maneuvering strategies of a hybrid autonomous underwater vehicle in hovering
The Odyssey IV autonomous underwater vehicle (AUV) is the next generation of unmanned subsurface robots from the MIT Sea Grant AUV Laboratory. The Odyssey IV AUV has a novel propulsion system, which includes a pair of azimuthing thrusters for maneuvering in surge and heave. An analytical model was …
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CFD analysis and design of a low-twist, hovering rotor equipped with trailing-edge flaps
This thesis reports the analysis and design of a hovering rotor equipped with both slotted and blended trailing-edge flaps. This was accomplished by combining a simple blade element method with 3D inviscid and RANS CFD that allowed for a robust sequence of design specification, analysis, and …
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Constrained Motion Analysis and Control of Spacecraft Asteroid Hovering with Formulation Extension in Geometric Mechanics Framework
… studies the constrained motion for a spacecraft hovering over an asteroid, where the Udwadia-Kalaba (UK) formulation is applied for nominal control, and an adaptive controller is developed to account for unknowns in the dynamics. Then, the formulation is extended in the geometric mechanics …
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Design and performance evaluation of data dissemination and hovering information protocols for vehicular ad hoc networks (VANETs)
… by the Data Dissemination and the Information Hovering protocols for VANETs. For most of the VANETs' applications the data dissemination is a crucial process. Also, for many of them the availability of information over some time in a bounded region, or a Hovering Information protocol, is a key …
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Real-Time Implementation of Vision Algorithm for Control, Stabilization, and Target Tracking for a Hovering Micro-UAV
… results of completely autonomous control of a hovering micro-UAV using a complete on-board vision system. The on-board vision and control system is composed of a Helios FPGA board, an Autonomous Vehicle Toolkit daughterboard, and a Kestrel Autopilot. The resulting platform is referred to as the …
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Comparison of RANS Modeling to Dual-Plane PIV Measurements of the Turbulent Tip Vortex Trailed from a Hovering Rotor
… of the tip vortices in the wake produced by a hovering rotor. The computational results were compared to detailed, dual plane Particle Image Velocimetry (PIV) measurements of a turbulent tip vortex trailed from a single-bladed rotor. The work investigated both the required mesh resolution and …
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Coaxial contrarotating twin rotor aerodynamics
… interference effects between the two rotors of a hovering CCTR have been successfully modelled. By a similar approach, a Vortex-Glauert theory has been developed to model the wake of a CCTR in forward flight. Comparisons between theory and experimental results from model and full scale rotors are …
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Optimization of the Aerodynamics of Small-scale Flapping Aircraft in Hover
… for flapping flight with an emphasis on hovering with each their advantages and drawbacks. The first method was developed by Hall et al. It is an extremely fast and powerful three-dimensional approach. However, the assumptions made to develop this theory limit its use to lightly loaded …
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Design and Testing of a Hovercraft with Electroaerodynamic Propulsion
… generating sufficient pressure is crucial for hovering. This study explored the feasibility of a wire-to-airfoil corona discharge MSD thruster powered hovercraft through a scaled-down prototype and final design. The hovercraft was tethered to a ground-based power supply and carried a payload …
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