Automatic welding speed controller Patent
Welding torch with automatic speed controller using speed sensing wheel and closed servo system
Wall, W. A., Jr.↗
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Energy limiter for hydraulic actuators Patent
System to control speed of hydraulically movable members by limiting energy applied to actuators with hydraulic servo loop
Steinmetz, C. P.↗
Fluidic power control systems
Pneumatic and hydraulic fluidic power control systems, discussing moving part position servos and cold gas reaction systems
Rose, R. K.↗
A method of eliminating hydrogen maser wall shift
Maser output frequency shift was prevented by storage bulb kept at temperature at which wall shift is zero and effects of bulb size, shape, and surface texture are eliminated. Servo system is shown, along with bidirectional counter.
Levine, M. W.↗
Flight instrument and telemetry response and its inversion
Mathematical models of rate gyros, servo accelerometers, pressure transducers, and telemetry systems were derived and their parameters were obtained from laboratory tests. Analog computer simulations were used extensively for verification of the validity for fast and large input signals. An optimal inversion method was derived to reconstruct input signals from noisy output signals and a computer program was prepared.
Weinberger, M. R.↗
A scanning mirror system for the Apollo telescope mount ultraviolet spectroheliometer
The scanning mirror system described is being developed as the primary mirror in the spectroheliometer. The system consists of a gimbaled mirror mount that is rotated through extremely small angles by the use of frictionless pivots and a closed-loop servo system. Design, fabrication, and test experience are discussed.
Highman, C. O.↗
A stellar tracking reference system
A stellar attitude reference system concept for satellites was studied which promises to permit continuous precision pointing of payloads with accuracies of 0.001 degree without the use of gyroscopes. It is accomplished with the use of a single, clustered star tracker assembly mounted on a non-orthogonal, two gimbal mechanism, driven so as to unwind satellite orbital and orbit precession rates. A set of eight stars was found which assures the presence of an adequate inertial reference on a continuous basis in an arbitrary orbit. Acquisition and operational considerations were investigated and inherent reference redundancy/reliability was established. Preliminary designs for the gimbal mechanism, its servo drive, and the star tracker cluster with its associated signal processing were developed for a baseline sun-synchronous, noon-midnight orbit. The functions required of the onboard computer were determined and the equations to be solved were found. In addition detailed error analyses were carried out, based on structural, thermal and other operational considerations.
Klestadt, B.↗
Computer controlled antenna system
Digital techniques are discussed for application to the servo and control systems of large antennas. The tracking loop for an antenna at a STADAN tracking site is illustrated. The augmentation mode is also considered.
Raumann, N. A.↗
The Goddard helical tape recorder
A spacecraft recorder was developed with the objective of functioning continuously for 5 years. The resulting design employed a metallic tape wound in a 200-turn helix. A direct drive, brushless dc torquer and servo speed control drove the recorder at 3 rpm for recording and 54 rpm for playback.
Martin, F. T.↗
An interim report on remote sensing of environmental pollutants with a Fourier interference spectrometer.
A small Fourier interference spectrometer for sensing environmental pollutants from spacecraft has been developed at the Jet Propulsion Laboratory. The instrument is intended for obtaining high spectral resolution infrared absorption spectra in the 1.2 to 5.5 micron region at speeds sufficiently high for medium altitude orbital satellite surveys. The paper reviews basic details of the instrument servo and infrared detection systems, previously described, as well as recent developments. In particular, the data-handling system, data reduction techniques and optical tolerance problems are discussed. Preliminary results are included.
Schindler, R. A.↗
Laser system detects tower deflections
Continuously measure and record deflection of facility during testing. Facility deflections are then subtracted from shroud deflections during data reduction on computer. System is based on tracking light beam by using two-axis photo detector and feeding signals into X and Y servo system.
Fabik, R. H.↗
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.↗
Linear kinematic air bearing
Bearing provides continuous, smooth movement of the cat's-eye mirror, eliminating wear and deterioration of bearing surface and resulting oscillation effects in servo system. Design features self-aligning configuration; single-point, pivotal pad mounting, having air passage through it; and design of pads that allows for precise control of discharge path of air from pads.
Mayall, S. D.↗
Estimation of automobile-driver describing function from highway tests using the double steering wheel
The automobile-driver describing function for lateral position control was estimated for three subjects from frequency response analysis of straight road test results. The measurement procedure employed an instrumented full size sedan with known steering response characteristics, and equipped with a lateral lane position measuring device based on video detection of white stripe lane markings. Forcing functions were inserted through a servo driven double steering wheel coupling the driver to the steering system proper. Random appearing, Gaussian, and transient time functions were used. The quasi-linear models fitted to the random appearing input frequency response characterized the driver as compensating for lateral position error in a proportional, derivative, and integral manner. Similar parameters were fitted to the Gabor transformed frequency response of the driver to transient functions. A fourth term corresponding to response to lateral acceleration was determined by matching the time response histories of the model to the experimental results. The time histories show evidence of pulse-like nonlinear behavior during extended response to step transients which appear as high frequency remnant power.
Delp, P.↗
Magnetic bearings for spacecraft
Magnetic bearings have been successfully applied to motorized rotor systems in the multi-kilogram range, at speeds up to 1200 radians per second. These engineering models also indicated the need for continued development in specific areas to make them feasible for spacecraft applications. Significant power reductions have recently been attained. A unique magnetic circuit, combining permanent magnets with electromagnetic control, has a bidirectional forcing capability with improved current sensitivity. The multi-dimensional nature of contact-free rotor support is discussed. Stable continuous radial suspension is provided by a rotationally symmetric permanent magnet circuit. Two bearings, on a common shaft, counteract the normal instability perpendicular to the rotational axis. The axial direction is servoed to prevent contact. A new bearing technology and a new field of application for magnetics is foreseen.
Studer, P. A.↗
Experiments with an electrohydrodynamic heat pipe
The experimental results with a working model of the electrohydrodynamic (EHD) heat pipe are presented along with descriptions of the experimental device and its operation. Conclusions reached are: (1) EHD flow structures can be used to provide liquid communication between the condenser and evaporator of a heat pipe. (2) The voltage provides a remote electrical servo linkage of possible use in certain thermal control applications. (3) At least one hybrid flow structure, utilizing capillary and electrohydrodynamic forces, has been found functional. Proposed further experiments are discussed.
Jones, T. B.↗
Evaluation of a high response electrohydraulic digital control valve
The application is described of a digital control valve on an electrohydraulic servo actuator. The digital control problem is discussed in general as well as the design and evaluation of a breadboard actuator. The evaluation revealed a number of problems associated with matching the valve to a hydraulic load. The problems were related to lost motion resulting from bulk modulus and leakage. These problems were effectively minimized in the breadboard actuator by maintaining a 1000 psi back pressure on the valve circuit and thereby improving the effective bulk modulus.
Anderson, R. L.↗
An ironless armature brushless torque motor
A high torque motor with improved servo mechanism is reported. Armature windings are cast into an epoxy cylinder and armature conductors are integrally cast with an aluminum mounting ring which provides thermal conductance directly into the structure. This configuration eliminates magnetic hysteresis because there is no relative motion between the rotating magnetic field and any stationary iron. The absence of destabilization forces provides a fast electrical response compared with a typical torquer of conventional construction.
Studer, P. A.↗