Showing papers on "Angular displacement published in 1977"

Enhanced accuracy optical radar

Abstract: An optical radar is disclosed in which fine vernier range and angular displacement accuracy is achieved by projecting a burst of coherent pulses so as to strobe a target passing through the field of view of the projection apparatus. The use of the pulse burst permits the most recent information to be utilized in obtaining the target track. Prior to projection, the pulses in the burst are sampled. The resulting signal is delayed by an amount corresponding to course range and is directed down one of a pair of oppositely directed delay lines. The signals returned from the target are detected by a sectorized receiver, with an electrical output signal from a detector in one of the sectors being applied to the other delay line in the corresponding pair, such that the signal corresponding to the returned pulse propagates in a direction opposite to that of the sampled signal corresponding to the transmitted pulse. The delay lines are tapped at various points corresponding to vernier range and each pair of taps is coupled to a device which ascertains the coincidence of counter-propagating pulses, thereby to establish the vernier range of the target from the projection apparatus. Angular displacement from boresight is measured as a function of the sector occupied by the target, with the number of pairs of oppositely directed delay lines corresponding to the number of sectors in the receiving apparatus. In one embodiment, a waterfall type display is used which displays angular displacement versus vernier range such that an accurate target track may be obtained. The receiving apparatus may be provided with zoom optics so as to vary the vernier range and angular displacement scales.

Apparatus and method for extrapolating the angular position of a rotating body

Abstract: An apparatus and method for predicting the time occurrence of the desired angular position of a rotating body, such as the crankshaft of an internal combustion engine. The apparatus includes means for storing a nonlinearly changing count that is set to a known starting value when the rotating body is at a known angular position. A computing means is included for computing the value of the count that corresponds to the time when the rotating body will be at the desired angular position. The computation is achieved by extrapolating from known count information based upon prior periods of angular displacement of the rotating body during periods of known duration. In addition, the apparatus includes means for reducing the error associated with extrapolating the desired angular position of a rotating body undergoing either acceleration or deceleration by basing the extrapolation on a known period of angular displacement that occurred earlier than the most recent period of rotation immediately prior to the extrapolation process.

Radar system for an anti-collision system for a vehicle

Abstract: A pair of antennas mounted on a vehicle receive an echo wave reflected from an obstacle to produce a pair of Doppler signals, the variation of the phase difference of which is used to indicate the direction of the relative movement of the obstacle. The phase difference also represents the difference in propagation lines and is proportional to the relative angular displacement of the obstacle so the rate of variation of relative angular displacement is detectable because the increase and decrease of phase difference negate each other.

Apparatus for measuring the angular displacement of a body

Abstract: A helmet sight system for use in an aircraft in which the angular displacement of the helmet in the reference frame of the aircraft is measured by measurement of the angular displacement of a set of three non-colinear radiation sources, fixed with respect to the helmet, whose angular positions are sensed by a sensor which is fixed with respect to the coordinate reference frame of the aircraft. The radiation sources may be light emitting diodes and the sensor may comprise an aperture having two mutually inclined rectilinear slits and an array of light sensitive charge coupled devices.

Electronic balancer for vehicle wheels

Abstract: This invention is directed to an off-the-vehicle type of wheel-tire balancer for vehicular wheels. A wheel and tire assembly which is to be balanced is disposed on a rotating shaft under the control of a signal responsive electronic control apparatus utilizing rotational velocity signals, rotational, directional, and positional signals and velocity of displacement of the mounting apparatus for the shaft to provide a suitably calibrated indicators, the amount of weight to be added at certain angular positions on the inner and outer planes of the wheel rim to provide a dynamic balance of the wheel-tire system. Further indicators are provided for relating the indicated weight to be added to an angular position of the wheel and tire system. The entire apparatus is automatic in operation in that once the system is started, a motor is energized to rapidly rotate the wheel-tire system up to a predetermined rotational velocity. Once this is attained, the magnitude and angular disposition of the weights to be disposed on the rims of the wheel-tire system is rapidly detected over but a few revolutions of the shaft and following this, the motor is energized in a reverse direction to provide a dynamic breaking force to rapdily bring the wheel-tire system to a rest position, the energization of the motor in the reversed direction being maintained until the shaft is actually reversed its direction of rotation for a predetermined angular displacement.

Wind driven power generator

Abstract: A journaled rotor is provided for rotation about an axis to be disposed transverse to a fluid flow path and the rotor includes a plurality of mounting portions spaced radially outwardly from and circumferentially about the axis having a plurality of vane assemblies rotatably mounted therefrom for angular displacement about axis generally paralleling the axis of rotation of the rotor. Vane assembly displacement control structure is operatively connected to the vane assemblies for angularly displacing the vane assemblies relative to the corresponding mounting portions 180 degrees each 360 degrees of angular displacement of the rotor and in directions opposite the direction of angular displacement of the rotor upon rotation of the latter. The vane assemblies are variously optimumly angularly positioned relative to the corresponding mounting portions and each other to effect substantially maximum thrust therefrom on the rotor as a result of fluid flow thereagainst from one side of the axis of rotation of the rotor. The vane assembly displacement control structure includes an adjustment feature operative to effect simultaneous adjusted angular displacement of the vane assemblies relative to the corresponding mounting portions independent of rotation of the rotor and the adjustment feature includes fluid flow direction sensing structure operative to sense changes in the direction of fluid flow toward the axis of rotation of the rotor and to accordingly variously angularly position the vane assemblies about their axes of rotation relative to the mounting portions in order to maintain the optimumly angularly displaced positions thereof relative to the changed fluid flow direction. One disclosed form of the invention includes a control for the adjustment feature whereby the vane assemblies may be manually variously angularly positioned relative to the corresponding mounting portions of the rotor toward positions displaced relative to the direction of fluid flow against the rotor whereby the vane assemblies will be inoperative to drive the rotor. Further, a second form of the invention includes structure whereby the vane assemblies each comprise a plurality of vanes which may be remotely feathered toward positions parallel to the fluid flow acting upon the rotor.

Self-aligning roller for belt conveyors

Abstract: A roller mounted for universal angular movement relatively to its nominal longitudinal axis of rotation so as to be angularly displaced by the weight and movement of the conveyor belt when the conveyor belt shifts away from running true. This angular displacement brings the rotating roller into engagement with reaction faces provided on the frame of the conveyor and causes the roller to be reactively displaced in a direction to restore the belt to running true.

Radiant energy detection system for the angular location of a light-radiating object

Abstract: A radiant energy detection system which allows angular location in bearing and elevation by using a simple detector element and a static mask preferably formed by a PLZT strip between two intersecting polarizers. A control circuit operates the mask to provide a configuration having a transparent zone equal to n measurement quadrants (n being a whole number equal to 1, 2 or 3) and an opaque zone equal to the remaining 4-n quadrants, and to bring about four successive operating states which are distinguished one from the next by an angular displacement of π/2 radians around the optical axis. The control circuit operates further a switching circuit synchronously with the mask to connect the output of the detector successively to four reception channels each of which includes a high speed memory. A measuring circuit calculates the angular location from the four detected signal values stored in the memory.

Multi-axis position determining system

Abstract: A position determining device having a distributed sensing element, such as a delay element, positioned at a selected angle greater than 0° with respect to at least one selected direction along which a position is to be measured. Means for determining the position along the distributed element are provided, e.g., a driver transducer and a receiver transducer relatively movable along the delay element by which the delay of a signal travelling along the delay element and, hence, the position therealong is determined. Means responsive to such position determination are further included for calculating from such position determination the position along the at least one selected direction. The invention is especially useful for multi-axis position determination wherein, for example, a single delay element can be positioned at a selected angle with respect to each of two axes, so that linear or angular position determination can be made with respect to each axis.

X-ray source moving mechanism intended for panoramic radiography

Abstract: A mechanism for moving an X-ray source around the patient's head so that the image of an object, having shape of the dental arch, can be obtained on the film, the mechanism including a stationary frame, a rotatably movable support arm with an X-ray source and a film holder attached to its opposite ends on different sides of the object to be radiographed, and means for moving the center of rotation of the support arm rectilinearly during the radio-graphing, throughout the procedure in the same direction, perpendicular to the axis of symmetry of the dental arch, in such a manner that the position of the center of rotation in its rectilinear movement is dependent on the angular position of the support arm at any given moment, with the purpose of directing the X-ray beam from the X-ray source so that at any given moment it is substantially perpendicular to that part of the object which has the shape of the dental arch.

Multi-hull self rescuing system

Abstract: A marine craft maintained floating in a capsized condition by flotation components which permit angular displacement substantially about a rotational axis established intermediate the bow and stern. Venting of air entrapped within the craft forwardly of the rotational axis initiates angular displacement of the hull until the craft assumes a stabilized position intermediate the capsized and upright positions. Continued angular displacement of the craft toward the upright position is induced by upward pivotal displacement of a counterweight suspended by a boom pivotally connected to the craft to establish the rotational axis.

Cam track for a circular knitting machine

Abstract: A closed cam track, characterized by curves corresponding essentially to the formula Y = f(X n ) where Y is the axial displacement of needles in grooves of the track, X is the peripheral rotational displacement of the track at constant angular velocity and n is greater than or equal to 3, is provided for a circular knitting machine.

Angular displacement transducer for IC engine - uses split pole detector to give sharp cut=off to response curve for ignition of injection system response signal

Abstract: The angular displacement transducer provides accurate positional information for ignition or injection systems of IC engines. The operation is unaffected by play in the crankshaft or distributor shaft. An armature (11) is attached to the rotating shaft and passes between two pole-pieces (12, 13) which form part of a magnetic circuit comprising a magnet (15) and a magnetic field detector (16). The pole-pieces are split into two sections (12a, b) to provide a main magnetic flux which passes through the detector and an auxiliary flux passing through an air-gap (18) and the second pole-piece section (12b). The first section is shaped so that it is bent away from the arc described by the tip of the revolving armature. This form of construction provides a detector response curve (1c) which rises linearly with time or angular displacement and falls off rapidly.

Air motor having angular displacement control means

Abstract: A power tool operated by an air motor having a rotor with radially moving vanes, and means for counting the vanes passing an electro-magnetic sensor mounted on the motor housing A valve connected to the counter is operative to terminate rotation of the motor and the tool when the vanes corresponding to a predetermined angle of rotation have passed adjacent the sensor

Position control apparatus for circular tables

Abstract: An angular position control apparatus for a machine tool circular table comprises a circuit for discriminating whether a command from a command register is such that the output from an absolute position detector for the table passes over the figure zero and an angular converter for converting a present or stopped position of the table detected by the position detector into an angular value. The output of the angular converter is compared with the command to drive the circular table. The resulting compared difference controls the clockwise or counterclockwise rotation of the table and table rotation in the neighborhood of the figure zero of the position detector is smoothed.

Preliminary orbit-determination method having no co-planar singularity

Abstract: It has long been recognized and demonstrated in the astrodynamic literature that three observations of angular position are not always sufficient to determine a preliminary orbit. One reason for this is due to the fact that as the plane of the observer's motion approaches the plane of the orbit of the observed object, the determination of the orbit of the object becomes indeterminant. Merely changing the coordinate system will not eliminate the inherent indeterminacy or singularity. When the observed object is moving in the same plane as the observer, their relative motion is described in two dimensions rather than three. The problem reduces to defining two components of position and two of velocity given only three angular measures and no solution is possible. Although this singularity is a rather old, albeit infrequently arising problem in celestial mechanics, it has received renewed interest due to the advent of satellite observatories that observe other spacecraft. In this new circumstance the plane of the observer's motion is rather frequently near the plane of the object (12% to 35% of the time) and the co-planar singularity becomes a subject that deserves additional attention.

A Posteriori Compensation for Rigid Body Motion in Holographic Interferometry by Means of a Moire-technique

Abstract: A Moire-technique is introduced that regenerates fringe systems due to some deformation, which are distorted by rigid body motion of the object under test. The kind of rigid body motions that can be eliminated is determined by the condition, that one has to be able to simulate the fringe system the motion would generate by itself. Theory is discussed starting from the Sampling Theorem of the Information Theory. The superposition is realized experimentally by a T.V.-technique.

Device for determining the direction towards a remote object

Abstract: An apparatus for measuring the coordinates of a target object with respect to a reference point within a particular field of view. A mask having a radiation transparent portion bounded by a straight line and a substantially logarithmic curve meeting at the reference point rotates about the reference point at a reference frequency to modulate a beam of radiant energy from the target object. The modulated beam is applied to a detector that generates corresponding electrical pulses having a duration that corresponds to the radial distance of the target object from the reference point. The phase shift of the pulses with respect to the reference frequency determines the angular position of the target.

Electromechanical high‐pressure torsion apparatus

Abstract: An apparatus for carrying out torsional shear tests of polymers under hydrostatic pressure environment at variable rotational speeds has been developed and tested. The apparatus is capable of containing pressures up to 7 kilobars and producing rotational speeds to 1000 rpm. A number of important and unique features have been incorporated into the design of the apparatus. The apparatus consists of two interconnected thick‐walled cylinders, one for testing and the other for pressure compensation. The rotation rate is automatically maintained at a constant level throughout a test by a feedback amplifier circuit. The magnitude of the applied torque is detected by a load cell mounted within the torque shaft, unexposed to the pressure medium and unaffected by the friction in the seals. The angular displacement is sensed both internally and externally, respectively, by an electrically activated contact point moving over a toothed wheel mounted on the rotating end of the specimen and by a rotary variable differen...

Feedback electrostatic wattmeter using a noncontact moving-coil actuator

Abstract: An electrostatic wattmeter employing automatic torque balance about a taut-band suspension has been developed. The only direct physical electrical connection to the suspension assembly is the normal load voltage connection to the vane of the quadrant electrometer. The feedback torque is provided by a noncontact precision actuator which consists of an inductive coupling to a moving coil fixed on the suspension assembly, and which uses magnetic field variation. Suspension angular displacement is determined by using the quadrant structure as a push-pull capacitance transducer. The experimental instrument provides a d.c. output proportional to load power whether the supply is a.c. or d.c. It has linearity of at least ±0.5% over its measuring range, and the instrument calibration is essentially independent of power supply voltages and load power factors. It is easy to set the zero, but zero drift has a temperature sensitivity of about 1% per degree centigrade. No special antivibration mount is used, and typical noise at the instrument output (without a lowpass filter) has a peak-peak value of about 5% of full-scale reading. The transducer bridge circuit limits the range of power frequencies that can be measured. Improvements to reduce drift and noise effects are proposed, and the use of an optical position detector is suggested.

Time-optimal Precise Positioning Control using a DC Servomotor

Abstract: This paper describes minimum-time positioning control using a DC servomotor. The control consists of two modes. One is Bang-Bang control, the other is linear feedback control. The angular position of shaft is controlled by Bang-Bang input at first. When the angular position arrives at the neiborhood of objective point, the feedback input acts to regulate the state instead of Bang-Bang input. The main conclusions are as follows.(1) The control system which consists of Bang-Bang control and feedback control is available for positioning on printer.(2) As the new feedback element to compensate the unknown disturbances, the integral of angular displacement is inserted in feedback control.(3) The rejection filter is inserted in velocity feedback loop to stabilize the control system.

Device for determining angles

Abstract: A device particularly suited for use in optics, having a planar sine plate mounted for rotation about a lateral axis, with the sine plate being capable of holding an optical device such as a diffraction grating. A pivot arm member is mounted for rotation about an axis perpendicular to the axis of rotation of the sine plate, and is in contact with the end of the plate over a portion of its rotational displacement. A calibrated drive such as a micrometer is mounted in position to make contact with the pivot arm near the end thereof, to drive the pivot arm inwardly and outwardly a determinable longitudinal distance. The distance that the pivot arm is driven by the micrometer is related to the angle of the plate as it rotates in contact with the pivot arm. Means are provided for minimizing frictional resistance at the contact between the pivot arm and the plate and between the pivot arm and the drive member of the micrometer.

Circumference measurement for irregular rotating bodies - using contactless laser scanning and high speed signal evaluation with differentiating and integrating functions

Abstract: The method and equipment are for measurement of circumference of rotating bodies, in partic. of rotating bodies with non round or irregular peripheries and are designed to produce exact measurement values with high measurement speed. The arc length differential produced for the body rim is integrated over an angle of 2 PI radians. The rim is scanned and electrical signals generated representing radius variations w.r.t. the corresp. angular position variation. These are differentiated and squared, then summed. The square root is then determined and the resulting signal integrated over the circumference. The periphery is scanned without contact using a laser method.