Search NASA⌕ Search

SEARCH · Search NASA

Results for “ELECTROMAGNETIC CONTROL”

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.

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

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Imparting Motion to a Test Object Such as a Motor Vehicle in a Controlled Fashion

An apparatus imparts motion to a test object such as a motor vehicle in a controlled fashion. A base has mounted on it a linear electromagnetic motor having a first end and a second end, the first end being connected to the base. A pneumatic cylinder and piston combination have a first end and a second end, the first end connected to the base so that the pneumatic cylinder and piston combination is generally parallel with the linear electromagnetic motor. The second ends of the linear electromagnetic motor and pneumatic cylinder and piston combination being commonly linked to a mount for the test object. A control system for the linear electromagnetic motor and pneumatic cylinder and piston combination drives the pneumatic cylinder and piston combination to support a substantial static load of the test object and the linear electromagnetic motor to impart controlled motion to the test object.

Southward, Stephen C.↗
NASA NTRS2007

Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster with Anode Layer

Two prototype bismuth propellant feed systems were constructed and operated in conjunction with a propellant vaporizer. One system provided bismuth to a vaporizer using gas pressurization but did not include a means to measure the flow rate. The second system incorporated an electromagnetic pump to provide fine control of the hydrostatic pressure and a new type of in-line flow sensor that was developed for accurate, real-time measurement of the mass flow rate. High-temperature material compatibility was a driving design requirement for the pump and flow sensor, leading to the selection of Macor for the main body of both components. Posttest inspections of both components revealed no degradation of the material. The gas pressurization system demonstrated continuous pressure control over a range from zero to 200 torr. In separate proof-of-concept experiments, the electromagnetic pump produced a linear pressure rise as a function of current that compared favorably with theoretical pump pressure predictions, producing a pressure rise of 10 kPa at 30 A. Preliminary flow sensor operation indicated a bismuth flow rate of 6 mg/s with an uncertainty of plus or minus 6%. An electronics suite containing a real-time controller was successfully used to control the entire system, simultaneously monitoring all power supplies and performing data acquisition duties.

Polzin, K. A.↗
NASA NTRS1989

Dynamic response for thermal control and measurement and fast radiation thermometry

A preliminary evaluation was made by ORNL of a two-color ratio pyrometer (TCRP) for temperature control in the Modular Electromagnetic Levitation (MEL) experiment. A discussion was presented by Eric Spjut at the 1987 NASA Non-Contact Temperature Measurement Workshop (NASA Conf. Publ. 2503, pp. 182-213) in which he described the non-linear characteristics of the time response of TCPs. Researchers replicated his model and results and note that the non-linear response behavior is minimized for small temperature steps at high temperatures. They then used the predicted response in a model for a proportional or integral feedback controller and predicted the control characteristics for heating and cooling a 5-mm diameter sphere of niobium at high (1500 to 2750 K) temperatures. The analysis shows that for a slow (25-ms) time response for a commercial RCRP, overshoots of several hundred kelvins will result from a 100-K decrease in the setpoint, and temperature tracking errors of 14 to 45 K will occur for control temperature ramps of 1000K/s. For a fast (greater than 0.1 ms) time response, the overshoot and ramp response errors are largely eliminated.

Shepard, R. L.↗
NASA NTRSDate not supplied

CELA NextGen 2020 Abstract

Creating a new technology development is hard! But, experience canbe the best teacher. Through our journey in maturing CELA, africtionless, direct-drive Reaction Sphere (RS) (Figure 1), lessonsour team learned have given us valuable insights that can help youon your own technology development journey. CELA (CorrelatedElectromagnetic Levitation Actuator), like all state-of-the-art starts, is a technology development project. This idea started by addressing a problem posed in a classroom setting, and has morphed into its current state today. At first, the problem was to create a novel separation system. Then, as oftenhappens with new ideas, there was a bump in the road: CELA did not align with stakeholder priorities. So, we had to pivot. The team learned that the funding organization was more excited about an Attitude Control System solution than a Separation System solution. CELA then became a Reaction Wheel. Through more pivots, the technology development advanced into a RS. This example shows that the process for maturing an idea is just as important as the technology itself. Other aspects of the process include finding funding sources, conducting research, obtaining patents, engaging partners, and finally creating systems to keep you on track and pointed in the right direction. Going through this process will teach you many valuable lessons: you never know when an idea will arrive, you will experience rejection, and you will learn a lot about your own strengths and weaknesses.The importance of this is not to teach you to give up, but to teach you to keep going, and to learn what works and what does not work in order to set yourself up for success.

technology↗
NASA NTRS1990

A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

Tripp, John S.↗
NASA NTRS1991

A solid-state controllable power supply for a magnetic suspension wind tunnel

The NASA Langley 6-inch Magnetic Suspension and Balance System (6-in. MSBS) requires an independently controlled bidirectional dc power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance-coupled thyratron-controlled rectifiers as well as ac to dc motor-generator converters, is obsolete, inefficient, and unreliable. A replacement six-phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full-load efficiency is 80 percent compared with 25 percent for the resistance-coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20-kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

Daniels, Taumi S.↗
NASA NTRS1975

Bistatic radar sea state monitoring field test

Recent advances in understanding the physical phenomena controlling the interaction of electromagnetic energy with the ocean surface have revealed the possiblity of remote measurement of the two-dimensional surface wave height spectrum of the ocean using bistatic radar techniques. The basic feasibility of such a technique operating at frequencies in the HF region (3 to 30 MHz) was examined during previous studies and hardware for an experimental verification experiment was specified. The activities have resulted in a determination of the required hardware and system parameters for both satellite and aircraft systems, the development, assembly, and testing of hardware for an experimental aircraft system, the development and initial testing of data processing procedures, and the conduct of an initial flight test experiment. Activities were devoted to completing the assembly and testing of the experimental hardware, completing the experiment planning, conducting a field test experiment, and the processing and analysis of the experimental data. Even though directional spectrum maps of the test area cannot be generated from the measured data, the hardware concept employed appears viable, and solutions to the problems encountered have been identified.

Ruck, G. T.↗
NASA NTRS1979

Advanced solar space missions

The space missions in solar physics planned for the next decade are similar in that they will have, for the most part, distinct, unifying science objectives in contrast to the more general 'exploratory' nature of the Orbiting Solar Observatory and Skylab/ATM missions of the 1960's and 70's. In particular, the strategy for advanced solar physics space missions will focus on the quantitative understanding of the physical processes that create and control the flow of electromagnetic and particulate energy from the sun and through interplanetary space at all phases of the current sunspot cycle No. 21. Attention is given to the Solar Maximum Mission, the International Solar Polar Mission, solar physics on an early Shuttle mission, principal investigator class experiments for future spacelabs, the Solar Optical Telescope, the Space Science Platform, the Solar Cycle and Dynamics Mission, and an attempt to send a spacecraft to within 4 solar radii of the sun's surface.

Bohlin, J. D.↗
NASA NTRS1986

Space Station gas-grain simulation facility - Application to exobiology

The technical issues involved in performing experiments on the behavior and properties of aerosols in a microgravity environment provided by the Space Station are reviewed. The displacement of a particle resulting from g-jitter for ballistic, Knudsen, and Stokes flow regimes is examined in detail, and the radiation, acoustic, electrostatic, and electromagnetic mechanisms for the control of this motion are described. The simulation of organic haze production on Titan has been selected as an example experiment for detailed study. The purpose of this experiment was to simulate the photolysis of methane and the subsequent formation of the organic haze particles in the Titan upper atmosphere.

Mckay, C. P.↗
NASA NTRS1988

Switched steerable multiple beam antenna system

A steerable multibeam five element cross-feed cluster antenna system is described. The feed power is divided into five branches. Each branch includes a switching network comprised of a plurality of time delay elements each individually controlled by a respective electromagnetic latching switch. Frequency independent individual two-dimensional beam steering at intermediate (IF) scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident tranmsit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies. Diagonal quarter wave plates in the waveguides alter polarization from the circular to orthogonal linear to provide transmitter-receiver isolation.

Richard S Iwasaki↗
NASA NTRS2013

Magnetically Actuated Seal

This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

Pinera, Alex↗
NASA NTRS2018

Preliminary Aerodynamic Measurements from a Magnetic Suspension and Balance System in a Low-Speed Wind Tunnel

An existing Magnetic Suspension and Balance System (MSBS) has been restored to operation in a small (octagonal test section, 6-inches across flats) low-speed wind tunnel as the first phase of a project to develop new dynamic test capabilities for planetary entry capsules at supersonic speeds. The MSBS and associated wind tunnel were originally designed and built at MIT and were subsequently relocated to NASA Langley Research Center. NASA ceased operations of the system in the late 1990s and it was transferred to Old Dominion University where it had been mothballed until the present work started in 2015. All-new position sensor electronics, electromagnet power supplies, digital controller, and other hardware have been developed, leading to more efficient and reliable operation. Important features of the new hardware will be briefly described. Wind tunnel testing has commenced, focusing first on static aerodynamics of re-entry capsule shapes. Some preliminary results will be reviewed, including comparison to reference data. The proposed extension to dynamic stability testing, using a variety of free-to-pitch approaches will be described. Finally, the preliminary design of the all-new Phase II (supersonic) system will be briefly outlined.

Schoenenberger, Mark↗
NASA NTRSDate not supplied

Advancing Metasurfaces Towards New Frontiers: Nonvolatile Reconfigurable Optics

The applications of adaptive optics extend across multiple sectors, encompassing areas such as LiDAR, biological and chemical sensing, and free-space communications. In this study, we report on the design, fabrication, testing, and modeling of electrically reconfigurable metasurfaces using a low-loss high contrast phase change material, Ge2Sb2Se4Te integrated with an IR-transparent silicon microheater. Through this work, we introduce a reliable architecture for switching PCM-based metasurfaces within an integrated circuit configuration which is compatible with standard foundry fabrication processes. We demonstrate the capability of controlling the transmission of electromagnetic waves through the precise stimulation of PCM-based pixels, each spanning a few hundred microns, over numerous cycles. By leveraging PCM-based pixels, we unlock the potential to create metasurfaces encompassing a diverse range of functionalities such as dielectric filters, metalens, or beam steering devices, which is governed by the design of the meta-atoms. Further, we perform an in-depth investigation into the failure mechanism utilizing techniques such as Fourier transform IR spectroscopy (FTIR), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and thermal modeling. According to our results, due to a sharp temperature rise at the PCM/heater interface, we observe severe delamination of the PCM from the heater. More uniform PCM deposition, better adhesion at the PCM/heater interface, and a more uniform temperature distribution in the device could potentially mitigate the failure and lead to a longer life-time. By addressing these challenges, we aim to unlock the full potential of PCM-based devices and advance the field of adaptive optics.

Phase change material↗