ON A METHOD OF INVESTIGATION NONLINEAR SYSTEMS OF OSCILLATIONS AND OF SERVOMECHANISMS
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Magnus, K.↗
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SERVOMECHANISMS AS USED ON VARIABLE-STABILITY AND VARIABLECONTROL-SYSTEM RESEARCH AIRCRAFT
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Foster, J. V.↗
Servomechanism for Doppler shift compensation in optical correlator for synthetic aperture radar
A method and apparatus for correcting Doppler shifts in synthetic aperture radar data is described. An optical correlator for synthetic aperture radar data has a means for directing a laser beam at a signal film having radar return pulse intensity information recorded on it. A resultant laser beam passes through a range telescope, an azimuth telescope, and a Fourier transform filter located between the range and azimuth telescopes, and forms an image for recording on an image film. A compensation means for Doppler shift in the radar return pulse intensity information includes a beam splitter for reflecting the modulated laser beam, after having passed through the Fourier transform filter, to a detection screen having two photodiodes mounted on it.
Constaninides, N. J.↗
Adaptive proximate time-optimal servomechanisms - Continuous time case
A Proximate Time-Optimal Servo (PTOS) is developed, along with conditions for its stability. An algorithm is proposed for adapting the PTOS (APTOS) to improve performance in the face of uncertain plant parameters. Under ideal conditions APTOS is shown to be uniformly asymptotically stable. Simulation results demonstrate the predicted performance.
Workman, M. L.↗
The effect of a visual/motion display mismatch in a single axis compensatory tracking task
The frequency response of visual systems is typically unity from 0 to 20 rad/sec, while that of motion systems typically falls off in the vicinity of 6 rad/sec. The question arises as to what effect, if any, such a difference in servomechanism performance has on the simulation. Is pilot performance reduced by the conflict between displays? Would a more realistic simulation occur if the visual servomechanisms were degraded to match the motion servomechanisms? Does the pilot need and use the higher frequency information present in the visual display? The purpose of the experiment is to take a step forward toward answering these questions. Work already in the literature which bears on these questions is outlined. A description is then given of an experiment used to check for the effects of a difference in the performance of the visual and motion servomechanisms (the experiment uses a single-axis, compensatory, roll-tracking task). The results of the experiment are then presented and analyzed.
Shirachi, D. K.↗
Simulator study of pilot-aircraft-display system response obtained with a three-dimensional-box pictorial display
The effect of varying the two important display parameters of a pictorial display on pilot opinion performance, and pilot aircraft display system servomechanism response is examined. The display presents a picture of a three dimensional box that moves along the desired path ahead of the aircraft. The two display parameters examined are the field of view of the picture (from + or - 5 deg to + or - 45 deg) and the distance to the box (from 92 m (300 ft) to 6100 m (20 000 ft)). The results show that the pilots prefer a distance to the box of 915 m (3000 ft) and a field of view of + or - 30 deg. The best performance, both in the sense of quickness of error correction and lowest standard deviation, is obtained with a distance to the box of 92 m (300 ft) and a field of view of + or - 15 deg. A pilot model analysis is used to determine the gains used by the pilots and the servomechanism response characteristics of the pilot aircraft display system.
Adams, J. J.↗
Remote pivot decoupler pylon: Wing/store flutter suppressor
A device for suspending a store from an aerodynamic support surface, such an an aircraft wing, and more specifically, for improving upon singlet pivot decoupler pylons by reducing both frequency of active store, alignment, and alignment system space and power requirements. Two links suspend a lower pylon/rack section and releasable attached store from an upper pylon section mounted under the wing. The links allow the lower pylon section to rotate in pitch about a remote pivot point. A leaf spring connected between the lower section and electrical alignment system servomechanism provides pitch alignment of the lower section/store combination. The servomechanism utilizes an electric servomotor to drive the gear train and reversibly move the leaf spring, thereby maintaining the pitch attitude of the store within acceptable limits. The damper strokes when the lower section rotates to damp large oscillations of store.
Hassler, J. M., Jr.↗
A Real-Time Method for Estimating Viscous Forebody Drag Coefficients
This paper develops a real-time method based on the law of the wake for estimating forebody skin-friction coefficients. The incompressible law-of-the-wake equations are numerically integrated across the boundary layer depth to develop an engineering model that relates longitudinally averaged skin-friction coefficients to local boundary layer thickness. Solutions applicable to smooth surfaces with pressure gradients and rough surfaces with negligible pressure gradients are presented. Model accuracy is evaluated by comparing model predictions with previously measured flight data. This integral law procedure is beneficial in that skin-friction coefficients can be indirectly evaluated in real-time using a single boundary layer height measurement. In this concept a reference pitot probe is inserted into the flow, well above the anticipated maximum thickness of the local boundary layer. Another probe is servomechanism-driven and floats within the boundary layer. A controller regulates the position of the floating probe. The measured servomechanism position of this second probe provides an indirect measurement of both local and longitudinally averaged skin friction. Simulation results showing the performance of the control law for a noisy boundary layer are then presented.
Whitmore, Stephen A.↗
Reconfigurable Flight Control Design using a Robust Servo LQR and Radial Basis Function Neural Networks
This viewgraph presentation reviews the use of a Robust Servo Linear Quadratic Regulator (LQR) and a Radial Basis Function (RBF) Neural Network in reconfigurable flight control designs in adaptation to a aircraft part failure. The method uses a robust LQR servomechanism design with model Reference adaptive control, and RBF neural networks. During the failure the LQR servomechanism behaved well, and using the neural networks improved the tracking.
Burken, John J.↗
The effect of dry friction and free play on the error with reversal in servosystems
Reversal errors of machine tool servomechanisms, and feedback control circuits
ERROR↗
Optics used to measure torque at high rotational speeds
In measuring torque transmitted by a high speed rotation shaft, an apparatus has been devised which includes a shaft, an optical system and readout servomechanism. This highly accurate method uses only optical contact with moving part and is statically calibrated.
Krsek, A., Jr.↗
Servo system facilitates photoelastic strain measurements on resins
To facilitate photoelastic measurements of the strains developed by stresses applied to birefringent resins, a servomechanism is employed.
Otts, J. W.↗
A counterbalance system for dynamic testing of equipment designed to operate in a zero-g field.
Counterbalance system using a servomechanism, for dynamic testing of equipment operating in a zero-g field
WEIGHTLESSNESS↗
Photosensors used to maintain welding electrode-to-joint alignment
Photosensors maintain electrode-to-joint alignment in automatic precision arc welding. They detect the presence and relative position of a joint to be welded and actuate a servomechanism to guide the welding head accordingly thus permitting alignment for more than straight line or true circle joints.
Bowen, J. B.↗
Brushless dc motor has high efficiency, long life
Brushless dc motor operates as a commutator in a vacuum environment with high efficiency and long life. Because of its excellent response time, it can be used in the servomechanism field.
Studer, P. A.↗
Human performance control monitoring system Final report, Jan. 1965 - Feb. 1966
Computer program simulation of servomechanism controlled by adaptive logic element trained by monitoring of human performance - mathematical model
MATHEMATICAL MODEL↗
Phase plane displays detect incipient failure in servo system testing
Computer based data conditioning and display technique detects incipient failure in servo system testing, for use in prelaunch checkout of complex nonlinear servomechanisms. These phase plane displays enable identification of, on line, unusual or abnormal servo responses which can be displayed compactly in the time domain on a cathode ray tube.
Affenito, F. J.↗
Digital laser-beam deflection sensor
Sensor automatically and accurately measures the two-dimensional deflection angles of a laser beam to provide closed-loop servomechanism control of laser beam directivity.
Fowler, V. J.↗