20,462 research outputs found

    Viscous rotary vane actuator/damper

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    A compact viscous rotary actuator/damper for use on the Mariner '71 and Viking Programs was developed. Several functions were combined into this single mechanism to control the deployment, latching, and damping of the solar panel arrays used on these space vehicles. The design, development, and testing of the actuator/damper are described, and major problems encountered are discussed

    Micro Balloon Actuators for Aerodynamic Control

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    A robust, large-force, large-deflection micro balloon actuator for aerodynamic (manoeuvring) control of transonic aircraft has been developed. Using a novel process, high yield linear arrays of silicone balloons on a robust silicon substrate have been fabricated that can deflect vertically in excess of one mm. Balloon actuators have been tested under cyclic conditions to assess reliability. The actuators have been characterized in a wind tunnel to assess their suitability as aerodynamic control surfaces and flight-tested on a jet fighter to assess their resistance to varied temperatures and pressures at high velocity

    Offshore Turbine Arrays: Numerical Modeling and Experimental Validation

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    The interaction between wind turbines in a large wind farm needs to be better understood to reduce array losses and improve energy production. A numerical test bed for an array of offshore wind turbines was developed in the open-source computational fluid dynamics (CFD) framework OpenFOAM. It provides a computational tool which can be used in combination with physical model turbine array studies in the Flow Physics Facility (FPF) at UNH as well as other test facilities. Turbines were modeled as actuator disks with turbulence sources to reduce computational cost. Both k-ϵ and k-ω SST turbulence models were utilized to capture the flow in the near-wall, wake, and free stream regions. Experimental studies were performed in the FPF to validate the numerical results and to provide realistic initial and boundary conditions, for example turbulent boundary layer inlet velocity profiles. Mesh refinement and boundary condition studies were performed. Numerical simulations were executed on a custom-built server, designed to be the head node of a future CFD cluster. The entire project was built on open-source software to facilitate replication and expansion. The numerical model provides building blocks for simulations of large wind turbine arrays, computational resources permitting. The numerical model currently replicates a three by one array of wind turbines in the FPF, and provides detailed insight into the array fluid dynamics

    Strain transducers for active control - lumped parameter model

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    Tactile feedback display with spatial and temporal resolutions.

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    We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications

    Multispectral linear array multiband selection device

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    An apparatus for detecting multiple spectral bands, individually or concurrently, using linear detector arrays is described. The system employs a beamsplitter to divide the optical source into two or more optical beams which are directed at the linear detector arrays. Filter trays are positioned in the focal planes of the optical beams so that the beams pass through the filter trays prior to impinging upon the detector arrays. Multiple filters are placed on the filter trays. Linear actuators positioned adjacent the filter trays translate the trays across the focal planes of the optical beams so that individual filters are positioned in the path of beams such that those frequencies of the beams that fall within the spectral ranges of the individual bandpass filter through which it passes may be detected by the detector arrays for further examination and analysis

    Design of a 7kW power transfer solar array drive mechanism

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    With the availability of the Shuttle and the European launcher, Ariane, there will be a continuing trend towards large payload satellite missions requiring high-power, high-inertia, flexible solar arrays. The need arises for a solar array drive with a large power transfer capability which can rotate these solar arrays without disturbing the satellite body pointing. The modular design of such a Solar Array Drive Mechanism (SADM) which is capable of transferring 7kW of power or more is described. Total design flexibility has been achieved, enabling different spacecraft power requirements to be accommodated within the SADM design

    Method and apparatus for minimizing multiple degree of freedom vibration transmission between two regions of a structure

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    Arrays of actuators are affixed to structural elements to impede the transmission of vibrational energy. A single pair is used to provide control of bending and extensional waves and two pairs are used to control torsional motion. The arrays are applied to a wide variety of structural elements such as a beam structure that is part of a larger framework that may or may not support a rigid or non-rigid skin. Electrical excitation is applied to the actuators that generate forces on the structure. These electrical inputs may be adjusted in their amplitude and phase by a controller in communication with appropriate vibrational wave sensors to impede the flow of vibrational power in all of the above mentioned wave forms beyond the actuator location. Additional sensor elements can be used to monitor the performance and adjust the electrical inputs to maximize the attenuation of vibrational energy
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