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Results for “Accelerometers”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1967

Miniature electrostatic accelerometer /MESA/.

Miniature electrostatic accelerometer featuring suspension and force rebalance systems, discussing performance, applications and accuracy acceleration measurement

ELECTROSTATIC INSTRUMENT↗
NASA NTRS1994

(abstract) A Miniature, High-Sensitivity, Electron-Tunneling Accelerometer

A prototype low-noise accelerometer has been fabricated with an electron-tunneling transducer. By measuring the tunneling current between an electrode on the proof mass and a feedback-controlled monitor electrode, very small accelerations can be detected with high responsivity. This particular prototype (10x10x1.5 mm) was designed for underwater acoustic measurement from a few hertz to 1 kHz. The measured responsivity below the fundamental device resonance at 100 Hz is roughly 1500 volts per m/s(sup 2) with a measured noise spectral density of 10(sup -6) m/s(sup 2) per root hertz or less between 30 and 300 Hz. The noise floor is controlled primarily by 1/f noise in the tunneling current although the noise floor reaches the theoretical molecular-agitation limit at 100 hertz. The responsivity and directivity of the device were measured in a standard gradient-hydrophone calibrator; the noise floor was determined in a vacuum-ionization chamber assembled from commercial off-the-shelf components; and the detailed dynamics of the proof-mass motion were examined using a heterodyne laser interferometer that was scanned across the surface and synchronously detected with respect to the excitation.

accelerometer electron tunneling acoustic measurem↗
NASA NTRS1993

A New Force Balanced Accelerometer Using Tunneling Tip Position Sensing

In this paper, we report the initial development of a single-axis bulk micromachined accelerometer. The device employs an electron tunneling tip as a position detector in a force feedback control system. Control electrodes are placed above and below the proof mass and act as electrostatic force plates. Using the force plates, the position of the proof mass relative to the tunneling tip can be controlled.

accelerometers sensors position detectors↗
NASA NTRS2020

Calibrating a 3-Axis Accelerometer Instrument with a Less Accurate Calibration Device Part 1: Mathematical Methodology

A three-axis accelerometer instrument (3xAI) can provide the angular attitude of a 3D object using the gravity vector (g) as the sole reference. Calibrating such an instrument requires placing it at known (to some accuracy plus uncertainty) angular articulations with respect to g. This paper will show a potential process for calibrating a 3xAI by using a 2-axis rotary system (calibration device) to provide these articulations. Any calibration device (CD) with such capacity will contain internal misalignments. These misalignments, even if made relatively small or approximated to zero in the kinematics model (KM), can be detrimental to the calibration of the instrument when high measurement accuracy is required. This is especially true if the selected set of articulations chosen for calibration do not include their symmetrical counterpoints (a point where the misalignment has equal magnitude but is opposite in direction to a point chosen). The consequence of not including the combination, point and counterpoint, for any misalignment involved in the calibration, results in a biased instrument. This paper will demonstrate a calibration of the instrument using symbolic math resulting in a closed-form solution of the instrument coefficients. The main objective is to show the impact of all the CD misalignments to the instrument coefficients. This process is the basis for a more sophisticated method (shown in a future paper) for obtaining the instrument coefficients while simultaneously obtaining an estimate of the calibration device internal misalignments.

Angle↗
NASA NTRS1999

Development and Terrestrial Applications of a Nano-g Accelerometer

The ultra-sensitive accelerometer, developed for NASA to monitor the microgravity environments of Space Shuttle, free orbitors and Space Station, needed to measure accelerations up to 10mg with an absolute accuracy of 10 nano-g (10***sup-8***g) for at least two orbits (10***sup4*** seconds)to resolve accelerations associated with orbital drag.

Nano-gravity↗
NASA NTRS1966

Miniature piezoelectric triaxial accelerometer measures cranial accelerations

Tiny triaxial accelerometer whose sensing elements are piezoelectric ceramic beams measures human cranial accelerations when a subject is exposed to a centrifuge or other simulators of g environments. This device could be considered for application in dental, medical, and automotive safety research.

Deboo, G. J.↗