Sampled data controller Patent
Feedback controller for sampling error signals within single control formulation time interval
Gatlin, J. A.↗
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Results for “ERROR SIGNAL”
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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Computer simulation of human temperature control
Human temperature control computer simulation, considering sudomotor, vasomotor and metabolic as error signals from hypothalamic and cutaneous thermoreceptors
Linebarger, R. N.↗
Automatic theodolite for pre-launch azimuth alignment of the Saturn space vehicles
Prelaunch automatic azimuth alignment theodolites for Saturn 1B and Saturn 5 space vehicles inertial guidance system, discussing return images separation and error signal generation
Kokot, W.↗
Digital canopus tracker digital electronics
Circuitry has been developed for digital control of the Canopus tracker. A feasibility and demonstration breadboard has been constructed using microelectronic integrated circuits. The breadboard contains the digital circuits necessary for closed-digital logic necessary for star acquisition, particle rejection, programmable gate selection, cone angle selection, and routing of the digital roll error signal.
Crawford, W. E.↗
A technique to eliminate false lock in PCM demodulation
One loop provides error signal which adjusts voltage controlled oscillator. Second loop multiplies input signal with generated in-phase signal. Both signals are integrated over bit period. First loop detects null which indicates lockup, and second loop emphasizes impact signal information.
Kobayashi, H. S.↗
Circularly-polarized multiband telemetry tracking antenna
Utilize coaxial horn feed to illuminate reflector; feed has inner horn for X-band, and outer horn for S-band. Tracking error signals for servo correction are derived from measurements of relative phase and relative amplitude between two modes.
Woo, K. E.↗
Versatile, analog-to-digital, power-regulator controller
Power controller uses digital techniques to vary duty ratio of switching-type power regulators. Duty ratio is adjusted by comparing error signal with ramp voltage signal. As compared to previously-used switching regulators, controller uses fewer components and no magnetics and is readily adaptable to thick-film technology.
Mclyman, W. T.↗
A comparison of CMG steering laws for High Energy Astronomy Observatories (HEAOs)
A comparison of six selected control moment gyro steering laws for use on the HEAO spacecraft is reported. Basic equations are developed to project the momentum and torque of four skewed, single gimbal CMGs into vehicle coordinates. In response to the spacecraft attitude error signal, six algorithms are derived for controlling the CMG gimbal movements. HEAO performance data are obtained using each steering law and compared on the basis of such factors as accuracy, complexity, singularities, gyro hang-up and failure adaption. Moreover, each law is simulated with and without a magnetic momentum management system. The performance of any steering law is enhanced by the magnetic system. Without magnetics, the gimbal angles get large and there are significant differences in steering law performances due to cross coupling and nonlinearities. The performance of the pseudo inverse law is recommended for HEAO.
Davis, B. G.↗
Multispectral image dissector camera flight test
It was demonstrated that the multispectral image dissector camera is able to provide composite pictures of the earth surface from high altitude overflights. An electronic deflection feature was used to inject the gyro error signal into the camera for correction of aircraft motion.
Johnson, B. L.↗
Digital second-order phase-locked loop
A digital second-order phase-locked loop is disclosed in which a counter driven by a stable clock pulse source is used to generate a reference waveform of the same frequency as an incoming waveform, and to sample the incoming waveform at zero-crossover points. The samples are converted to digital form and accumulated over M cycles, reversing the sign of every second sample. After every M cycles, the accumulated value of samples is hard limited to a value SGN = + or - 1 and multiplied by a value delta sub 1 equal to a number of n sub 1 of fractions of a cycle. An error signal is used to advance or retard the counter according to the sign of the sum by an amount equal to the sum.
Holes, J. K.↗
Launch vehicle attitude control
The minor loop and minor loop support modules which maintain correct vehicle attitude control by generating vehicle attitude error signals were verified. The logic is checked during boost and orbit (unusual timing situations necessitate the additional orbit checks) and the constants used by these modules checked at every point during the flight. Since the same logic instructions are used throughout the flight with only the constants changing, verification of the logic at two points and the constants at all points verify the logic throughout the flight.
Source record↗
Servo corrects interferometer-mirror tilt
Three detectors sense He-Ne laser beam; one senses reference phase while others, at right angles to first, sense phase offset for each axis. Analog output of axis detectors is multiplied separately by reference output to give X and Y error signals that are then fed to respective X and Y actuators.
Schindler, R. A.↗
Z-axis control loop for cathode-ray tubes
Inexpensive PIN diode detector samples screen brightness between camera frames generating error signal for feedback control of intensity. System was tested by taking flat-field exposures at several density levels over 4 hour period. Results showed processed film density levels varied by less than + or - 10 percent usually centering around + or - 8 percent.
Ray, A. J., Jr.↗
Controlling the growth of silicon sheets
Automated systems regulates sheet width, thickness, and composition. Deviations from preset brightness levels create error signals that alter gas flow, crystal-pulling speed, and melt temperature to produce uniform single-crystal sheets.
Ciszek, T. F.↗
Digital image correlation techniques applied to LANDSAT multispectral imagery
The author has identified the following significant results. Automatic image registration and resampling techniques applied to LANDSAT data achieved accuracies, resulting in mean radial displacement errors of less than 0.2 pixel. The process method utilized recursive computational techniques and line-by-line updating on the basis of feedback error signals. Goodness of local feature matching was evaluated through the implementation of a correlation algorithm. An automatic restart allowed the system to derive control point coordinates over a portion of the image and to restart the process, utilizing this new control point information as initial estimates.
Bonrud, L. O.↗
Interferometer mirror tilt correcting system
An interferometer is described, having several means for automatically adjusting the angular tilt of a reflecting surface in one of two paths to maintain the exit beams from the two paths parallel to each other. Three detectors at the output of the interferometer were disposed on mutually perpendicular axes which define a plane normal to the nominal exit beam axis. One detector at the origin of the axes was used as a reference for separate phase difference comparison with the outputs of the other two detectors on the X and Y axes to develop servo error signals.
Schindler, R. A.↗
Analysis and design of optically pumped far infrared oscillators and amplifiers
A waveguide laser oscillator was designed and experimental measurements made of relationships among output power, pressure, pump power, pump frequency, cavity tuning, output beam pattern, and cavity mirror properties for various active gases. A waveguide regenerative amplifier was designed and gain measurements were made for various active gases. An external Fabry-Perot interferometer was fabricated and used for accurate wavelength determination and for measurements of the refractive indices of solids transparent in the far infrared. An electronic system was designed and constructed to provide an appropriate error signal for use in feedback control of pump frequency. Pump feedback from the FIR laser was decoupled using a vibrating mirror to phase modulate the pump signal.
Galantowicz, T. A.↗
The false lock performance of Costas loops with hard-limited in-phase channel
The ability of a Costas loop to false lock on a data sideband is a problem which must be dealt with in the design of suppressed-carrier receivers which employ such loops for carrier reconstruction. For conventional Costas loops wherein the error signal is formed from the product of two analog signals, the false lock problem has recently been investigated by the author and others and is now well understood. For implementation reasons associated with the reduction of dc offsets, it is often desirable to hard-limit the output of the in-phase channel and replace the analog multiplier which forms the above product with a chopper-type device. The false lock behavior of such a Costas loop with hard-limited in-phase channel is quite different from that of the conventional Costas loop and is the subject of investigation in this paper. Results are also presented for a modified version of the Costas loop wherein the quadrature arm filter is removed.
Simon, M. K.↗