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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

Seal, Daniel W.↗
DOE OSTI2024

Horn Location Sensors (HLS) for LBNF

The Long-Baseline Neutrino Facility (LBNF) will deliver the world's most powerful muon neutrino beam to the Deep Underground Neutrino Experiment (DUNE), initially operating at 1.2 MW and upgradeable to 2.4 MW. Ensuring the accurate direction of this beam is critical for DUNE's precision goals. This talk introduces the Horn Location Sensors (HLS) system, designed to provide precise, relative measurements of the focusing horns, targets, and beam position monitors in the neutrino beamline. The HLS system employs high-precision FSI-based hydrostatic leveling sensors to track vertical motion and tilt, achieving precision on the order of 0.1 mm. Built for minimal maintenance in radioactive environments, the HLS system ensures precise alignment of beamline components during high-power operations. This system is essential for maintaining beam accuracy and enhancing DUNE's scientific performance.

43 PARTICLE ACCELERATORS↗
NASA NTRS1986

Robust detection, isolation and accommodation for sensor failures

The objective is to extend the recent advances in robust control system design of multivariable systems to sensor failure detection, isolation, and accommodation (DIA), and estimator design. This effort provides analysis tools to quantify the trade-off between performance robustness and DIA sensitivity, which are to be used to achieve higher levels of performance robustness for given levels of DIA sensitivity. An innovations-based DIA scheme is used. Estimators, which depend upon a model of the process and process inputs and outputs, are used to generate these innovations. Thresholds used to determine failure detection are computed based on bounds on modeling errors, noise properties, and the class of failures. The applicability of the newly developed tools are demonstrated on a multivariable aircraft turbojet engine example. A new concept call the threshold selector was developed. It represents a significant and innovative tool for the analysis and synthesis of DiA algorithms. The estimators were made robust by introduction of an internal model and by frequency shaping. The internal mode provides asymptotically unbiased filter estimates.The incorporation of frequency shaping of the Linear Quadratic Gaussian cost functional modifies the estimator design to make it suitable for sensor failure DIA. The results are compared with previous studies which used thresholds that were selcted empirically. Comparison of these two techniques on a nonlinear dynamic engine simulation shows improved performance of the new method compared to previous techniques

Emami-Naeini, A.↗
DOE OSTI2020

A holistic cyber-physical security protocol for authenticating the provenance and integrity of structural health monitoring imagery data

Modern infrastructure systems, such as bridges, dams, power generation stations, and buildings increasingly have an intrinsic cyber-physical nature to them. Infrastructure now commonly, includes actuators, network connections, sensors, control systems, and computational resources. It is of increasing concern that modern infrastructure is vulnerable to cyber-attacks that can damage both the cyber and physical nature of the infrastructure. To date, the physical and cyber health of infrastructure has been considered separately. However, the increasing concerns associated with the cyber-physical security of infrastructure coupled with the emergence of 5G networks made using components that are not universally considered trustworthy, and the emergence of techniques for creating deepfakes and adversarial examples suggests the time has come to begin considering cyber health and structural health with a more holistic approach. In this work, a protocol is developed for ensuring the imagery data captured by a structural health monitoring system can be unambiguously attributed to legitimate sensors associated with the structural health monitoring system. A computer vision approach based on the idea of mutual information is then presented to detect damage in an image. This work presents the protocol for authenticating the provenance of imager data and demonstrates that this protocol does not have overly adverse effects when used with the mutual information-based technique for detecting damage in the resulting imagery data.

Jung, HweeKwon↗
DOE OSTI2025

xGFabric: Coupling Sensor Networks and HPC Facilities with Private 5G Wireless Networks for Real-Time Digital Agriculture

Advanced scientific applications require coupling distributed sensor networks with centralized high-performance computing facilities. Citrus Under Protective Screening (CUPS) exemplifies this need in digital agriculture, where citrus research facilities are instrumented with numerous sensors monitoring environmental conditions and detecting protective screening damage. CUPS demands access to computational fluid dynamics codes for modeling environmental conditions and guiding real-time interventions like water application or robotic repairs. These computing domains have contrasting properties: sensor networks provide low-performance, limited-capacity, unreliable data access, while high-performance facilities offer enormous computing power through high-latency batch processing. Private 5G networks present novel capabilities addressing this challenge by providing low latency, high throughput, and reliability necessary for near-real-time coupling of edge sensor networks with HPC simulations. This work presents xGFabric, an end-to-end system coupling sensor networks with HPC facilities through Private 5G networks. The prototype connects remote sensors via 5G network slicing to HPC systems, enabling real-time digital agriculture simulation.

Digital Agriculture↗
NASA NTRS1985

Theoretical and experimental investigations of sensor location for optimal aeroelastic system state estimation

One of the major concerns in the design of an active control system is obtaining the information needed for effective feedback. This involves the combination of sensing and estimation. A sensor location index is defined as the weighted sum of the mean square estimation errors in which the sensor locations can be regarded as estimator design parameters. The design goal is to choose these locations to minimize the sensor location index. The choice of the number of sensors is a tradeoff between the estimation quality based upon the same performance index and the total costs of installing and maintaining extra sensors. An experimental study for choosing the sensor location was conducted on an aeroelastic system. The system modeling which includes the unsteady aerodynamics model developed by Stephen Rock was improved. Experimental results verify the trend of the theoretical predictions of the sensor location index for different sensor locations at various wind speeds.

Liu, G.↗
NASA NTRS1992

Intelligent sensor-model automated control of PMR-15 autoclave processing

An intelligent sensor model system has been built and used for automated control of the PMR-15 cure process in the autoclave. The system uses frequency-dependent FM sensing (FDEMS), the Loos processing model, and the Air Force QPAL intelligent software shell. The Loos model is used to predict and optimize the cure process including the time-temperature dependence of the extent of reaction, flow, and part consolidation. The FDEMS sensing system in turn monitors, in situ, the removal of solvent, changes in the viscosity, reaction advancement and cure completion in the mold continuously throughout the processing cycle. The sensor information is compared with the optimum processing conditions from the model. The QPAL composite cure control system allows comparison of the sensor monitoring with the model predictions to be broken down into a series of discrete steps and provides a language for making decisions on what to do next regarding time-temperature and pressure.

Hart, S.↗
NASA NTRS1977

Investigation of a stall deterrent system utilizing an acoustic stall sensor

A simple rugged acoustic stall sensor which has an output proportional to angle of attack near wing stall has been evaluated on a Cessna 319 aircraft. A sensor position has been found on the wing where the sensor output is only slightly affected by engine power level, yaw angle, flap position and wing roughness. The NASA LRC General Aviation Simulator has been used to evaluate the acoustic sensor output as a control signal for active stall deterrent systems. It has been found that a simple control algorithm is sufficient for stall deterrence.

Bennett, A. G.↗
NASA NTRS1992

Video Guidance Sensor for automated capture

The paper describes a video-based sensor, the Video Guidance Sensor, which has been developed for use in automated docking systems or for automated capture with robotic systems. The sensor itself consists of several basic components: IR diode illuminators, a solid-state camera, a frame grabber, and a microprocessor. The target consists of three circular retroreflectors evenly spaced in a line with the middle reflector mounted on a short pole. Each retroreflector has a narrow bandpass optical filter in front of it. From this sensor and target configuration, the positions and attitudes of the target relative to the sensor can be determined. The position information can be differenced to with respect to time in order to obtain the relative positional and angular velocities. That information is sufficient to perform automated docking, berthing, or capture. The paper gives details of the sensor's make-up, including accuracies, noise characteristics, and operating ranges.

Howard, R. T.↗
DOE OSTI2024

A Hermetic Package Technique for Multi-Functional Fiber Sensors through Pressure Boundary of Energy Systems Based on Glass Sealants

This paper presents a hermitic fiber sensor packaging technique that enables fiber sensors to be embedded in energy systems for performing multi-parameter measurements in high-temperature and strong radiation environments. A high-temperature stable Intrinsic Fabry–Perot interferometer (IFPI) array, inscribed by a femtosecond laser direct writing scheme, is used to measure both temperature and pressure induced strain changes. To address the large disparity in thermo-expansion coefficients (TECs) between silica fibers and metal parts, glass sealants with TEC between silica optical fibers and metals were used to hermetically seal optical fiber sensors inside stainless steel metal tubes. The hermetically sealed package is validated for helium leakages between 1 MPa and 10 MPa using a helium leak detector. An IFPI sensor embedded in glass sealant was used to measure pressure. The paper demonstrates an effective technique to deploy fiber sensors to perform multi-parameter measurements in a wide range of energy systems that utilize high temperatures and strong radiation environments to achieve efficient energy production.

Optics↗
NASA NTRS1988

The Multichannel Ocean Color Sensor (MOCS)

The MOCS is an imaging spectroradiometer with a sensitivity that matches the light upwelling from open bodies of water. Twenty contiguous spectral channels in the visible are recorded in a line scanning mode from an aircraft. The system also supports a thermal infrared radiometer and will accept input from a position location system. The sensor in the MOCS system is an image dissector tube. A spectral curvature algorithm was developed. No atmospheric correction to the data is needed for low flying aircraft gathering chlorophyll data using this algorithm. Although the MOCS is now about 15 years old, because its response has been so stable, its data recording system was upgraded to the system used by the Aircraft Oceanographic Lidar where possible. The MOCS has been a reliable instrument for recording ocean color from low flying aircraft. As NASA enters the next period of ocean color investigations from space, such a device can play an important role in calibration of the space instrument, as well as provide support for programs developing the next generation of spaceborne devices.

Oberholtzer, J. D.↗
NASA NTRS1987

Active control of flexural vibrations in beams

The feasibility of using piezoelectric actuators to control the flexural oscillations of large structures in space is investigated. Flexural oscillations are excited by impulsive loads. The vibratory response can degrade the pointing accuracy of cameras and antennae, and can cause high stresses at structural node points. Piezoelectric actuators have the advantage of exerting localized bending moments. In this way, vibration is controlled without exciting rigid body modes. The actuators are used in collocated sensor/driver pairs to form a feedback control system. The sensor produces a voltage that is proportional to the dynamic stress at the sensor location, and the driver produces a force that is proportional to the voltage applied to it. The analog control system amplifies and phase shifts the sensor signal to produce the voltage signal that is applied to the driver. The feedback control is demonstrated to increase the first mode damping in a cantilever beam by up to 100 percent, depending on the amplifier gain. The damping efficiency of the control system when the piezoelectrics are not optimally positioned at points of high stress in the beam is evaluated.

Gerhold, Carl H.↗
NASA NTRS2002

Active Wireless Temperature Sensors for Aerospace Thermal Protection Systems

Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and Korteks to develop active wireless sensors that can be embedded in the thermal protection system to monitor sub-surface temperature histories. These devices are thermocouples integrated with radio-frequency identification circuitry to enable acquisition and non-contact communication of temperature data through aerospace thermal protection materials. Two generations of prototype sensors are discussed. The advanced prototype collects data from three type-k thermocouples attached to a 2.54-cm square integrated circuit.

Milos, Frank S.↗
NASA NTRS2006

Galfenol Tactile Sensor Array and Visual Mapping System

The smart material, Galfenol, is being explored for its uses as a magnetostrictive material. This project seeks to determine if Galfenol can be used as a tactile sensor in a 2-D grid array, magnetic circuit system. When used within a magnetic circuit, Galfenol indicates induced stress and force as a change in flux, due to a change in permeability of the material. The change in flux is detected by Giant MagnetoResistive (GMR) Sensors, which produce a voltage change proportional to the field change. By using Galfenol in an array, this research attempts to create a sensory area. Galfenol is an alloy made of Iron and Gallium. FexGax, where 15 less than or equal to x less than or equal to 28, creates a material with useful mechanical and transduction attributes (Clark et al and Kell). Galfenol is also distinguished by the crystalline structure of the material. Two types currently exist: single crystal and polycrystalline. Single crystal has higher transduction coefficients than polycrystalline, but is more costly. Polycrystalline Galfenol is currently available as either production or research grade. The designations are related to the sample growth rate with the slower rate being the research grade. The slower growth rate more closely resembles the single crystal Galfenol properties. Galfenol 17.5- 18% research grade is used for this experiment, provided by Etrema Products Inc. The magnetic circuit and sensor array is first built at the macro scale so that the design can be verified. After the macro scale is proven, further development will move the system to the nano-level. Recent advances in nanofabrication have enabled Galfenol to be grown as nanowires. Using the nanowires, research will seek to create high resolution tactile sensors with spatial resolutions similar to human finger tips, but with greater force ranges and sensitivity capabilities (Flatau & Stadler). Possible uses of such systems include robotics and prosthetics.

Hale, Kathleen↗
NASA NTRS2011

Design and Performance Evaluation of Sensors and Actuators for Advanced Optical Systems

Current state-of-the-art commercial sensors and actuators do not meet many of NASA s next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers. Keywords: Photonics, Adaptive Optics, Tunable Filters, MEMs., MOEMs, Coronagraph, Star Tracker

Clark, Natalie↗