Showing papers on "Angular displacement published in 1969"

Angular rate coordinate transformer

Abstract: Apparatus for converting signals representing rates of change of the angular position of a body with respect to its own axes to Euler angle rates of change utilizing three resolvers and two feedback paths so as to avoid practical difficulties equivalent to the ''''gimbal-lock'''' problem in the gyroscope art.

Deep sea fishing

Abstract: A deep sea fishing pole holder has a tubular sleeve which slips over a seat pedestal. A vertical plate extends seaward from the sleeve and has ratchet serrations along its lower edge. A pin in the plate above the serrations receives a pole-holding staff. A pin at the bottom of the staff holds a ratchet-engaging pawl. A pawl operating rod extends upward along the tube and terminates in a lock collar and handle, which is held in either a locked or unlocked position. The pawl is held away from the ratchet when the pole is pumped, and the pawl is engaged when it is desired to lock the pole in a selected angular position.

Recording horizontal rotations of head and eyes in spontaneous shifts, of gaze

Abstract: In this paper, a method is described for simultaneous recording of horizontal rotation of the eyes in the head and rotation of the head about its natural vertical axis Angular positions of eyesand head are obtained as proportionate dc voltages that are summed to obtain a record of the horizontal direction of gaze sensitive to l-deg saccades and accurate to within ±2 deg for at least the central 90 deg of the visual field The apparatus is so light that it is hardly felt by the S, who, while seated, is free to move in any way he chooses and to perform any task In addition, the angular position of a target rotating around the head may also be recorded for observation of visual-pursuit behavior

Angular displacement indicating gas bearing support system

Abstract: This disclosure concerns a support arrangement incorporating a gas bearing especially adapted for frictionless pivotal support of test models together with a novel provision for measuring the angular displacement of the model in the support. This bearing features a zero power quartz lens forming the bottom of the gas chamber combined with a light beam angular displacement measuring system which cooperates with a reflector on the bearing ball to provide accurate indications of angular deflections of the ball and the attached model.

Control system synthesis for a launch vehicle with severe mode interaction

Abstract: The phenomenon of mode interaction between rigid-body and elastic motion of a large launch vehicle is described and illustrated. For severe interaction, control system synthesis by the usual approach of assuming pitch attitude and rate feedback and use of conventional servo analysis techniques is not suitable. By use of a new method based on the state variable formulations of modern control theory, a simple practical control system is synthesized without the trial and error associated with servo analysis methods. Specified closed-loop frequencies and damping ratios, including active control of structural mode dynamics, are achieved using only the booster thrust vector control. No frequency tracking filters or feedback signal discrimination is needed. The only feedback signals necessary are those provided by angular displacement and acceleration sensors. Five simple first-order passive filters are the only compensation network dynamic elements required.

Assessment of semicircular canal function. Part 2 - Individual differences in subjective angular displacement produced by triangular waveforms of angular velocity

Abstract: : Mean estimates (N = 26) of short arcs of passive whole-body rotation about an Earth-vertical axis were accurate when subjects used a psychophysical procedure that involved counterdisplacement of a pointer on a dial. The required retrospective displacement judgments yielded more accurate mean estimates of angular displacement than were obtained in an earlier experiment which probably involved concurrent velocity matching. The differences in response curves in the various conditions of the two experiments clearly illustrate the importance of attention to psychophysical procedures prior to attempting to develop models of the vestibular endorgans to explain results. The method used in this experiment is sufficient to detect prominent individual differences within a sample of aviation training candidates, and the results obtained thus far indicate high test-retest reliability (r12 = .94). (Author)

Assessment of semicircular canal function. Part 1 - Measurements of subjective effects produced by triangular waveforms of angular velocity

Abstract: : Two methods were compared for measuring subjective angular displacement produced by triangular waveforms of angular velocity while subjects (N = 11) were enclosed in a vertical-axis rotation device that excluded visual and auditory cues of angular motion. Accuracy of subjective estimates was influenced by the methods and by the magnitudes of the acceleration comprising the stimulus waveforms. Results suggest that one of the methods, with slight modification, will provide reliable indication of the subjective effects of controlled semicircular canal stimulation. (Author)

A fibre optical angular displacement transducer

Abstract: A glass fibre optical device is described which measures the static or dynamic angular displacement of a body Since it is non-contacting and also does not load the system in any way, the device is suitable for measuring torsional vibrations and/or the logarithmic decrement of torsional pendulums A sensitivity of approximately 100 mv per degree was obtained over a range of ±4 degrees of rotation for a 254 cm (1 in) diameter shaft Recommendations are given for eliminating the effects of lateral motion of the body while undergoing rotation

Hydrostatic displacement control system

Abstract: A HYDROSTATIC DISPLACEMENT CONTROL SYSTEM FOR CONTROLLING THE PUMP DISPLACEMENT IN A HYDROSTATIC UNIT COMPRISES A CONTROL PRESSURE REGULATOR VALVE WHICH PROVIDES A CONTROL PRESSURE ACCORDING TO HIGH HYDROSTATIC SYSTEM PRESSURE. A DISPLACEMENT CONTROL VALVE USING THIS CONTROL PRESSURE NORMALLY PROVIDES PRESSURE CONTROL AT TWO DISPLACEMENT CONTROL MOTORS TO CONTROL THE ANGULAR POSITION OF A SWASH PLATE WHICH DETERMINES THE HYDROSTATIC PUMP DISPLACEMENT. A DISPLACEMENT LIMITER VALVE INTERRUPTS THE CONTROL OF THE DISPLACEMENT CONTROL VALVE TO LIMIT HYDROSTATIC SYSTEM PRESSURE BY PROVIDING A DIFFERENT PRESSURE BIAS TO THE DISPLACEMENT CONTROL MOTORS. TWO LOAD FEEL DEVICES HAVING A HYDROSTATIC SYSTEM PRESSURE BIAS OPERATE ON THE DISPLACEMENT CONTROL VALVE TO PROVIDE THE OPERATOR WITH FEEL OF THE LOAD. TWO DISPLACEMENT INHIBITOR VALVES IN COOPERATION WITH A DISPLACEMENT INHIBITOR CONTROL VALVE OPERATE ON THE DISPLACEMENT CONTROL VALVE TO LIMIT PUMP DISPLACEMENT ACCORDING TO ENGINE SPEED AND OUTPUT SPEED.

Improvements in and relating to Electro-Motive Apparatus.

Abstract: 1,154,141. Control of stepping motors. NATIONAL RESEARCH DEVELOPMENT CORP. 9 Jan., 1967 [10 Jan., 1966], No. 1131/66. Heading H2J. A servo system comprises a stepping motor 13 and has error indicator 23 whose output represents the magnitude and sense of a difference in the angular positions of shafts 21, 24. Signals from a device 17, which detects the angular position of rotor 11, are combined with signals from the indicator 23 whereby field coils 14, 15, 16, are energized in sequence to turn the rotor in a direction tending to reduce the error. A signal from branch A of the detector 17 is amplified, rectified, and the resultant pulses are then fed to a bi-stable device 34 producing signals of opposite sign which tend to drive the rotor in one direction or the other. A servo amplifier 35 receives the error signal from the indicator 23 and is also connected to a sawtooth generator 36, the outputs on leads 47, 46, representing the sum and difference respectively of the error and sawtooth signals. These resultant signals are fed through resistors 37, 38, to diodes 39, 40, which also receive the signals from the device 34. The combined signals are isolated by the diodes, amplified, and then applied to trigger circuit 44 having a constant output when its input exceeds a given level, but providing no output below that level. During time intervals when the circuit 44 is effective, amplifier 18 energizes the field coil 14. The operation of branches B, C, of the detector 17 and similar to that of the branch A. When the sense of the servo error signal changes, the signals on lines 46, 47, are interchanged to reverse the motor. As the error signal increases in magnitude, the duration of the pulses passed by the trigger circuit 44 is increased. In a modification, the generator 36 may be replaced by a sine wave generator. The detector 17 may comprise a metal disc which is mounted on shaft 12 and has an asymmetric shape with regard to its axis of rotation. High frequency currents are produced in the disc by means of a fixed ring which is supplied from a H.F. source and is capacitively coupled with the disc. As the disc is rotated, pulses are cyclically induced in metal strips which are circumferentially spaced around the axis of rotation. In an alternative form of detector 17, the shaft 12 carries a flat ring which is divided into magnetic and non-magnetic parts. Iron cores carrying coils are spaced symmetrically around the ring, each core having a central coil which is fed with alternating-current, and two outer coils which are connected in opposition.

Self-compensated azimuth pickoff device

Abstract: A device for measuring a small angular displacement of the case of a spinning sphere gyro with relation to an east-west line as defined by the spinning sphere. The case is mounted on a stabilized platform. Although the device is subjected to angular displacements about the case vertical axis and about one of the case horizontal axes, it provides an electrical output proportional only to the input about the vertical axis. This is accomplished by employing a light source projecting on a mirror carried by the sphere, with two detectors arranged orthogonal to each other. Each detector includes two photosensitive elements. The outputs of the elements are so combined that horizontal axis displacement is nulled, but vertical axis displacement is not.

Improvements in or relating to the Measurement of Alignment Angles of the Wheels of a Road Vehicle

Abstract: 1,156,325. Gauges for vehicle wheels. SPERRY RAND Ltd., Nov. 23, 1966 [Sept. 3, 1965], No. 37644/ 65. Heading G1X. Apparatus for measuring the alignment angles of a steerable vehicle wheel e.g. castor angle, comprises rollers 12 to support a vehicle wheel on the vehicle, a roller 30 contacting a point on the vertical diameter of the wheel to sense lateral displacement of the wheel when steered through an angle to one side of the straight ahead position; the roller 30 being mounted on an arm 31 for pivotal movement about a horizontal axis intersecting the lowermost point of the wheel so that it can be pivoted to contact another point of the wheel where the lateral displacement is the same as that previously noted when the wheel is steered through the same angle to the other side of the straight-ahead position, and means for measuring the angle through which the arm 31 pivots this being approximately twice the castor angle. The Figure shows apparatus for use with one of the front wheels of a vehicle. Similar apparatus is provided for use with the other wheel. The apparatus is mounted on a base 14 for movement by means of a handle 15 to bring a roller 17 into engagement with the inside of the wheel to locate the apparatus with respect to the vehicle. The support rollers 12 are carried by a cradle 13 mounted on a vertical shaft having a disc 18 with three V-notches in its edge engageable by a hydraulically actuated wedge 20. The rollers can thus move the wheel to define a "straight-ahead" position and two positions equiangularly displaced on either side thereof say by 5‹. The roller 30 is carried by a head 24 which is urged by a spring 25 towards the wheel. The head 24 can be retracted by a hydraulic cylinder 26. The arm 31 is pivoted at 32 and its movements are fed to an electrical measuring device. In use the roller 30 is set against the wheel 11, which is continuously rotated, in the "straight-ahead" position. The wheel is steered to one side and locked in position by the wedge 20, and the displacement of the roller 30 measured by the electrical device being stored in a memory device. The wheel is steered through the same angle to the other side of the straight-ahead position and the arm 31 is rotated about a shaft 39 by a motor 41 until the displacement of the roller 30 is the same as that stored in the memory device. The angle of rotation of the arm 31 is measured and halved to give the castor angle. The camber angle of the wheel 11 can also be measured using the roller 30 which is first set in a true vertical position and its displacement measured when contacting the wheel. The movement of the arm 31 about the pivot 32 gives the camber angle direct. Two rollers 22 (one shown) mounted on an arm 27 pivoted at 28 are also provided to measure toe-in. The rollers 22 contact the horizontal diameter of the wheel 11 when set in the straight-ahead position, and the angular position of the arm 27 with respect to its support is noted to give the toe-in angle.

Improvements in and relating to ultrasonic inspection apparatus and methods.

Abstract: 1,173,481. Ultrasonic inspection; cathoderay tube operating circuits. PICKER ELECTRONICS Inc. 14 March, 1967, No. 11795/67. Headings H4D and H4T. The invention relates to ultrasonic inspection apparatus comprising an electroacoustic transducer directing a beam of ultrasonic energy at a test object and carried by an arm made up of at least three pivotally connected sections connected to respective position transducer means, the signals from which are utilized to control the position on a visual read-out device of a display which is produced by the signal output of the electroacoustic transducer due to the reception of ultrasonic energy reflected by the test object. The invention also relates to a method of ultrasonic inspection in which a beam of ultrasonic energy is directed, successively, at different points on the surface of a test object and at each point, swept through an angle, the echo signals due to reflection by the test object of the ultrasonic energy being utilized to produce a display the position of which is controlled in accordance with the position of the beam relative to the test object. Fig. 1 shows the construction in which the electroacoustic transducer 32 is carried by a first arm 40 pivotally connected to a second arm 36 pivotally connected to a third arm 34 the latter being pivotally connected to parallel members 28 (also Fig. 2, not shown) secured to a frame 10 adjustably mounted on a support 12, 14 by means 16, 17. Each arm is attached to a respective pulley 60, 54, 52 (see also Fig. 7) which rotates about the respective pivots 43, 39, 37 as the associated arms are rotated and this motion is transmitted via belt means, e.g. steel wire (the pivots 39 and 37 also carrying freely mounted additional pulleys) to pulleys 47, 62, 49 secured to sine-cosine potentiometers 22, 24, 26 (Fig. 4), carried by the frame 10. The outputs of potentiometers 22 and 26 indicative, respectively, of motion of arms 34 and 36 are combined in Y and X adders as shown in Fig. 9 to provide signals determining the position of the origin of a raster scan which is produced on a display tube 74 by sweep generators 80, 82. The latter generate sawtooth waveforms the time rate of rise of which is determined by the sine-cosine outputs from potentiometer 24 in accordance with the angular position of the arm 40 (i.e. in accordance with the angular position of the ultrasonic beam from transducer 32 relative to the horizontal). The scan is initiated by trigger pulses from a clock 84 which controls the pulses 88 driving transducer 32 via a delay device 86 which compensates for the time of travel of acoustic wave over a distance equal to that between the radiating face of transducer 32 and pivot 43 so that the sweep will have advanced an equivalent distance before energization of the transducer. In operation the transducer is positioned against the test object, which may compris eportions of the human body, and at each position it is oscillated through an angle as indicated in Fig. 10B, received echo signals being utilized via amplifier 90 to bright-up the beam of the display tube which is also brightened by the transmitted pulses so that the distance of the reflecting (impedance discontinuity) surface from the outside of the body is indicated. The size of the display may be varied by variation of the voltage supplied to potentiometer 24 (e.g. by rheostat 94 or by varying the gains of amplifiers 72, 78.