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.
Results
Showing 1 to 20 of 86 for “"Dynamics and Controls"”.
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Propeller-Driven Rotor Twirl Phenomenon: Hover Performance, Dynamics, and Controls
… rotors use compact electric motors and propellers, mounted on the main rotor blade, to generate the mechanical torque needed to rotate the main rotor. The presented work details experiments and model developments in three major areas: hover performance, dynamics, and controls. The …
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Elastic Cable-Driven Bipedal Walking Robot: Design, Modeling, Dynamics and Controls
… (like trunk). </p><p>The main results and contributions of the dissertation are:(a) The new actuation system has better acceleration capabilities of the walking robot, when compared to the conventional actuation system, which is based on joint attached motors,(b) The new actuation …
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A vortex panel method for potential flows with applications to dynamics and controls
… varying. The wake emanates from the sides and trailing edges of the thin lilting surfaces and is modeled as a progressively formed collection of vortex filaments. This model provides a continuous pressure distribution on the surface while allowing the wake to roll up as tightly as needed. …
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Quasi-Monte Carlo and Picard Iteration Algorithms for the Nonlinear Hydrodynamics, Dynamics and Controls of Wave Energy Converters
… in the power take off (PTO) mechanism, controls, and, more recently, geometry, while often assuming linear hydrodynamics and small body motions. Yet, in the most energetic sea states, large WEC motions and hydrodynamic nonlinearities may become appreciable, potentially resulting in a …
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Lab experiences for teaching undergraduate dynamics
… projects developed to teach undergraduate dynamics and controls. The materials were developed primarily for the class 2.003 Modeling Dynamics and Control I. These include (1) a set of ActivLab modular experiments that illustrate the dynamics of linear time-invariant (LTI) systems and (2) a …
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Modeling and controls for a laser glass cutting machine workcell robot
… three main areas of robot behavior: kinematics, dynamics and controls for the purpose of improving the performance of the Laser Glass Cutting Machine (LGCM) workcell. The thesis deals with developing kinematic and dynamic models of this robot arm and their application to task planning of this …
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Quantification of an Ultrasound Test Apparatus and its Potential Use to Control Nuisance Species in Commercial Aquaculture Settings
… an anechoic environment to mimic pond absorption and sholower efficacy rates, ranging from 0% at short durations to 25% at 90 seconds. Several transducers operating between 80-500 kHz were built and calibrated to provide alternate driving frequencies but could not provide enough power to be of any …
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Characterizing The Acoustic Properties Of The Jet Lab At The National Center For Physical Acoustics
… problems due to jet noise must be researched and addressed. Anechoic chambers were proposed as a testing facility for research in aerodynamic noise because of their supposed free-field characteristics. The international standard ISO 3745-1977 was introduced to determine whether the facilities …
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Incorporating Flight Dynamics and Control Criteria in Aircraft Design Optimization
… significant reductions in fuel burn, emissions, and noise via efficient aeroelastic design and improvements in propulsion systems. As modern transport airplane designs become increasingly lightweight and incorporate high aspect-ratio wings, aeroservoelastic effects gain prominence in modeling and …
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Reconstruction Resolution Of Coherent Point Sources With Helmholtz Equation Least Squares
… coefficients are solved for by least squares and used to reconstruct pressures at the source surface. By approximating the pressure radiation with expansion functions, field and surface pressures can be synthesized, resulting in the possibility of higher spatial resolution than previous …
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Dynamic tailoring and tuning for space-based precision optical structures
… Michelson interferometers meet these demands, but pose specific challenges in the areas of system dynamics and controls, uncertainty management and testing. The telescope optics must meet stringent positional tolerances in the presence of environmental and on-board disturbances, resulting …
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Effects of a Heated Turbulent Boundary Layer on Surface Pressure Fluctuations
… can give information about the velocity field and turbulence. This is of particular importance to the future of wind energy to predict the incoming velocity flow field of wind turbines so as to actively control them for peak operating efficiency and damage reduction. All of the environmental …
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Rigid Body Constrained Motion Optimization and Control on Lie Groups and Their Tangent Bundles
… motion requires formulations where rotational and translational motion are accounted for appropriately. Two Lie groups, the special orthogonal group SO(3) and the space of quaternions H, are commonly used to represent attitude. When considering rigid body pose, that is spacecraft position and …
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Predicting the Acoustic Response of the Golf Club & Ball Impact Using Finite Elements and the Boundary Element Method
<p>An improved and repeatable method for meshing golf club heads using finite elements in TrueGrid® was developed. Using solid brick elements through the thickness of the club head instead of shell elements better represents the many thickness variations throughout each section of a club head. This …
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Astronaut-centric analysis of a jetpack with integrated control-moment gyroscopes for enhanced extravehicular activity performance
… unit that offers counter reaction forces and torques during movements and tasks will likely be required. The next-generation maneuvering and stability system proposed in this research incorporates control moment gyroscopes (CMGs) into an extravehicular activity (EVA) jetpack device …
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Optimization Of Wind Fence Enclosures For Infrasonic Wind Noise Reduction
… porous wind barrier enclosure has been built and tested to optimize wind noise reduction at infrasonic frequencies between 0.01-10 Hz in order to develop a technology that is simple, cost effective, and improves upon the limitations of pipe and porous hose arrays. The effects of varying the …
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Three Degree-of-Freedom Parallel Actuator Telescope Mount
… thesis contains the design, implementation, and testing of an original, small-scaled two degree-of-freedom telescope mount and a medium-scaled three degree-of-freedom telescope mount inspired by the six degree-of-freedom Stewart-Gough platform telescope mount. The end product is intended to …
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The dynamics of reactivated landslides: Utiku and Taihape, North Island, New Zealand
… research was to study the relationship between landslide motion and its causes, with reference to large, slow moving, reactivated translational rock slides. The movement of such slides has often been assumed to be uniform over time because poor temporal and spatial monitoring resolutions have not …
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