SEARCH · Search NASA

Results for “vibration sensing”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4

All sources NASA NTRS DOE OSTI

NASA NTRSDate not supplied

P-ACTIVE (PCM-Based Actively Tunable Filter) Project at NASA

Phase change material (PCM)-based actively tunable mid-wave IR filters have broad imaging and sensing applications—from probing molecular vibrations in chemical species to detecting radiant thermal signatures. We introduce the Phase-change actively tunable filter (P-ACTIVE) project lead by NASA Langley Research Center with collaborators MIT and the University of Cambridge. It covers background science, experimental and theoretical device performance, as well as recent results obtained from a MISSE-14 mission for space qualification of active metasurface optics and constituent PCM. We conclude with a prospective view of the technology and discuss the potential for these filters to serve multiple NASA missions.

phase change material↗

NASA NTRS2019

Technologies to Enable the Next Great Observatory

The Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR) is one of four mission concepts being studied by NASA for the 2020 Decadal Survey in Astronomy and Astrophysics. LUVOIR will be capable of a broad range of science, including: direct imaging and characterization of a wide range of exoplanets and the search for biosignatures on Earth-like planets around sun-like stars; studying galaxy formation and evolution; investigating star and planet formation; and remote sensing of bodies within the Solar System. Enabling a mission as ambitious as LUVOIR requires an array of technologies, such as ultra-stable structures and optics, precision metrology and wavefront sensing, high-contrast imaging techniques, large-format detectors with very low noise, and high-throughput ultraviolet instrumentation. Critically, a systems-level approach must be taken to developing these technologies, guided by architecture studies to place each technology in the appropriate system context.In this poster, we describe LUVOIR's technology needs, as well as current efforts that are actively developing these technologies. We will discuss recent advancements in: measuring picometer-level displacements of optical and structural elements; sub-milli-kelvin thermal sensing and control; non-contact vibration isolation for pointing and dynamic stability; coronagraph design for achieving 10-10 contrast on a segmented system; high-speed metrology for optical system alignment; low-order and out-of-band wavefront sensing for maintaining high-contrast images; low-noise detectors across the ultraviolet, optical, and near infrared bands; broadband coatings with high-reflectivity below Ly. We will also describe a systems approach to coordinating the development of these technologies to achieve the necessary maturity for a LUVOIR mission start in the next decade.

space telescopes↗

NASA NTRS1986

Blending Gyro Signals To Improve Control Stability

Interference by structural vibrations reduced by adding signals from spatially separated gyros. Technique involves blending signals from rate gyroscopes located at different parts of structure to obtain composite signal that more nearly represents rotation of entire structure. Aircraft vibrations perpendicular to pitch axis contribute to rotations sensed by pitch-rate gyros. Proper blending of signals from gyros suppress contribution of dominant vibrational mode. Most likely applications of concept are flight-control systems for aircraft.

J. F. L. Lee↗

NASA NTRS1986

Application of higher harmonic blade feathering on the OH-6A helicopter for vibration reduction

The design, implementation, and flight test results of higher harmonic blade feathering for vibration reduction on the OH-6A helicopter are described. The higher harmonic control (HHC) system superimposes fourth harmonic inputs upon the stationary swashplate. These inputs are transformed into 3P, 4P and 5P blade feathering angles. This results in modified blade loads and reduced fuselage vibrations. The primary elements of this adaptive vibration suppression system are: (1) acceleration transducers sensing the vibratory response of the fuselage; (2) a higher harmonic blade pitch actuator system; (3) a flightworthy microcomputer, incorporating the algorithm for reducing vibrations, and (4) a signal conditioning system, interfacing between the sensors, the microcomputer and the HHC actuators. The program consisted of three distinct phases. First, the HHC system was designed and implemented on the MDHC OH-6A helicopter. Then, the open loop, or manual controlled, flight tests were performed, and finally, the closed loop adaptive control system was tested. In 1983, one portion of the closed loop testing was performed, and in 1984, additional closed loop tests were conducted with improved software. With the HHC system engaged, the 4P pilot seat vibration levels were significantly lower than the baseline ON-6A levels. Moreover, the system did not adversely affect blade loads or helicopter performance. In conclusion, this successful proof of concept project demonstrated HHC to be a viable vibration suppression mechanism.

Straub, F. K.↗

NASA NTRS1970

Prediction of faults in components of machinery in motion

Mechanical vibrations of individual moving parts are sensed with piezoelectric accelerometers and measured electronically from outside the working machine.

Tatge, R. B.↗

NASA NTRS1985

Optical Mounts for Cryogenic Beam Splitters

Spring-loaded optical mounts maintain flatness and alinement of rigid, framed, or pellicle beam splitters over wide temperature range, despite differences in thermal expansion amoung materials. Mounts permit optical adjustments at ambient temperature even though optical system operated subsequently within few degrees of absolute zero. Mounts useful as holders for integrated-circuit master patterns, survey targets, vibrating membranes, noise- or pressure-sensing membranes, osmosis filters, and fuel-cell elements.

Rudman, A. A.↗

NASA NTRS1993

Remote tire pressure sensing technique

A remote tire pressure sensing technique is provided which uses vibration frequency to determine tire pressure. A vibration frequency measuring device is attached to the external surface of a tire which is then struck with an object, causing the tire to vibrate. The frequency measuring device measures the vibrations and converts the vibrations into corresponding electrical impulses. The electrical impulses are then fed into the frequency analyzing system which uses the electrical impulses to determine the relative peaks of the vibration frequencies as detected by the frequency measuring device. The measured vibration frequency peaks are then compared to predetermined data describing the location of vibration frequency peaks for a given pressure, thereby determining the air pressure of the tire.

Robinson, Howard H.↗

NASA NTRS1995

Performance Thresholds for Application of MEMS Inertial Sensors in Space

We review types of inertial sensors available and current usage of inertial sensors in space and the performance requirements for these applications. We then assess the performance available from micro-electro-mechanical systems (MEMS) devices, both in the near and far term. Opportunities for the application of these devices are identified. A key point is that although the performance available from MEMS inertial sensors is significantly lower than that achieved by existing macroscopic devices (at least in the near term), the low cost, low size, and power of the MEMS devices opens up a number of applications. In particular, we show that there are substantial benefits to using MEMS devices to provide vibration, and for some missions, attitude sensing. In addition, augmentation for global positioning system (GPS) navigation systems holds much promise.

Smit, Geoffrey N.↗

NASA NTRS2006

Isolated resonator gyroscope with a drive and sense plate

The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

Challoner, A. Dorian↗

NASA NTRS2006

Isolated resonator gyroscope with a drive and sense plate

Challoner, A. Dorian↗

NASA NTRS1988

Sensors research and technology

Information on sensors research and technology is given in viewgraph form. Information is given on sensing techniques for space science, passive remote sensing techniques and applications, submillimeter coherent sensing, submillimeter mixers and local oscillator sources, non-coherent sensors, active remote sensing, solid state laser development, a low vibration cooler, separation of liquid helium and vapor phase in zero gravity, and future plans.

Cutts, James A.↗

NASA NTRS1995

Modal Correction Method For Dynamically Induced Errors In Wind-Tunnel Model Attitude Measurements

This paper describes a method for correcting the dynamically induced bias errors in wind tunnel model attitude measurements using measured modal properties of the model system. At NASA Langley Research Center, the predominant instrumentation used to measure model attitude is a servo-accelerometer device that senses the model attitude with respect to the local vertical. Under smooth wind tunnel operating conditions, this inertial device can measure the model attitude with an accuracy of 0.01 degree. During wind tunnel tests when the model is responding at high dynamic amplitudes, the inertial device also senses the centrifugal acceleration associated with model vibration. This centrifugal acceleration results in a bias error in the model attitude measurement. A study of the response of a cantilevered model system to a simulated dynamic environment shows significant bias error in the model attitude measurement can occur and is vibration mode and amplitude dependent. For each vibration mode contributing to the bias error, the error is estimated from the measured modal properties and tangential accelerations at the model attitude device. Linear superposition is used to combine the bias estimates for individual modes to determine the overall bias error as a function of time. The modal correction model predicts the bias error to a high degree of accuracy for the vibration modes characterized in the simulated dynamic environment.

Buehrle, R. D.↗

NASA NTRS2017

A Multi-Wavelength IR Laser for Space Applications

We present a laser technology development with space flight heritage to generate laser wavelengths in the near- to mid-infrared (NIR to MIR) for space lidar applications. Integrating an optical parametric crystal to the LOLA (Lunar Orbiter Laser Altimeter) laser transmitter design affords selective laser wavelengths from NIR to MIR that are not easily obtainable from traditional diode pumped solid-state lasers. By replacing the output coupler of the LOLA laser with a properly designed parametric crystal, we successfully demonstrated a monolithic intra-cavity optical parametric oscillator (iOPO) laser based on all high technology readiness level (TRL) subsystems and components. Several desired wavelengths have been generated including 2.1 microns, 2.7 microns and 3.4 microns. This laser can also be used in trace-gas remote sensing, as many molecules possess their unique vibrational transitions in NIR to MIR wavelength region, as well as in time-of-flight mass spectrometer where desorption of samples using MIR laser wavelengths have been successfully demonstrated.

Laser↗

NASA NTRS2016

Vibrating-Wire, Supercooled Liquid Water Content Sensor Calibration and Characterization Progress

NASA conducted a winter 2015 field campaign using weather balloons at the NASA Glenn Research Center to generate a validation database for the NASA Icing Remote Sensing System. The weather balloons carried a specialized, disposable, vibrating-wire sensor to determine supercooled liquid water content aloft. Significant progress has been made to calibrate and characterize these sensors. Calibration testing of the vibrating-wire sensors was carried out in a specially developed, low-speed, icing wind tunnel, and the results were analyzed. The sensor ice accretion behavior was also documented and analyzed. Finally, post-campaign evaluation of the balloon soundings revealed a gradual drift in the sensor data with increasing altitude. This behavior was analyzed and a method to correct for the drift in the data was developed.

Icing↗

NASA NTRS2016

Vibrating-Wire, Supercooled Liquid Water Content Sensor Calibration and Characterization Progress

Icing↗

NASA NTRS2000

The Interplay Between Hardware and Control System Design in the Development of the Active Rack Isolation System

A primary mission of the International Space Station (ISS) is to provide a premier microgravity laboratory environment for conducting acceleration sensitive scientific research. In order to accomplish this goal, vibroacoustic disturbances caused by station activities that occur during the microgravity mode of operation, must be controlled. In addition to source isolation and other passive isolation methods, the ISS uses active isolation at the receiver, through the use of an Active Rack Isolation System (ARIS), as part of its overall vibration isolation strategy. A schematic diagram of a typical ARIS payload rack is shown. The ARIS isolation control system senses rack acceleration via three triaxial accelerometer heads and uses eight pushrod actuators to perform active vibration attenuation. Position sensors housed in the actuator assembly are used to sense the relative position between the rack and the station. Electrical power, data and other essential resources are routed through a set of umbilicals that interface with a passthrough panel at the bottom of the rack. A representative umbilical set is shown.

Fialho, Ian J.↗

NASA NTRS1986

An assessment of OH airglow interference on the remote sensing of stratospheric HCl via limb sounding in the near-I.R.

Chemiluminescent emission from the formation of vibrationally excited OH at an altitude of approximately 85 km presents a barrier to earth-limb measurements of NIR emissions originating in the stratosphere. High-resolution measured spectra of OH airglow have not been reported, and thus it is difficult to assess its impact on moderately-high-resolution earth-limb spectroscopy capable of looking between strong OH lines. Low-resolution rocketborne spectrometer earth-limb measurements of OH airglow are mathematically inverted to recover vibrational-state populations that are used to simulate a higher resolution spectrum in the neighbourhood of 2843/cm. Implications for remote sensing HCl are presented.

Mergenthaler, J. L.↗

NASA NTRS1971

Improved relay chatter detector

Detector provides go/no-go sensing of momentary relay or contact opening during vibration testing. Device compares duration of unwanted openings to calibrated standard and lights indicator if standard is exceeded. Stability and reliability are higher than in any other comparable device.

Reynolds, R. K.↗