Showing papers on "Angular displacement published in 1992"

Reaction sensing torque actuator

Abstract: A reaction torque actuator has a sensor operatively coupled between a motor housing and an outer housing. A pair of bearings support the motor within the outer housing in a spaced, concentric relationship. The bearings allow a mutual angular displacement of the housing about the axis of rotation of the output shaft of the motor, but they isolate the sensor from the axial and radial moments. A resolver surrounds the shaft at its output end to produce a signal that accurately measures the angular position of the shaft. A controller regulates power to the motor windings as a function of signals from the resolver and the sensor and torque commands. In a preferred form for use in robotics where very accurate force control is desired, the motor: is a brushless D.C. motor, the sensor is of the strain gauge type, and the controller uses high quality amplifiers, sine wave commutation, cable shielding, and filtering to limit the noise generated by electronic switching.

Start-up procedure for a brushless, sensorless motor

Abstract: A method for starting-up in a desired forward sense of rotation a multiphase, brushless, sensorless, DC motor, while limiting the extent of a possible backward rotation. First, a predetermined initial phase is excited (thereby accelerating the rotor toward an equilibrium position for that initial phase), for only a fraction of the time necessary for the accelerated rotor to travel through a nearest angular position which would determine a "zero-crossing" in the waveform of any one of the back electromotive forces (BEMFs) which are induced by the rotor on the windings of the motor. After the elapsing of this brief impulse of excitation, the sign of the BEMFs induced in the windings of the motor are digitally read thus producing a first reading. The occurrence of a first "zero-crossing" event is monitored, and, if this happens within a preset interval of time subsequent to the instant of interruption of the first excitation impulse, the optimal phase to be excited first for accelerating the motor in the desired direction is decoded through a look-up table, and the start-up process may proceed. If such a zero-crossing occurrence is not detected within said period of time, the routine is repeated by exciting a different phase, which is functionally shifted by two phase positions from the initial phase. The maximum backward rotation that may occur in the worst of cases is sensibly less than the angular distance which separates two adjacent equilibrium positions of the rotor and in practice may be of just few degrees.

Adjustable dual-detector image data acquisition system

Abstract: An improved image acquisition system allows the angular displacement between two detectors to be adjusted between 90° and 180° to reduce the imaging time for both 360° and 180° scans. A patient table is displaced vertically and horizontally from a lateral axis to allow the body of a patient to be positioned next to the detectors and to improve resolution.

Two-dimensional coding of linear acceleration and the angular velocity sensitivity of the otolith system

Abstract: There exist otolith-sensitive vestibular nuclei neurons with spatio-temporal properties that can be described by two response vectors that are in temporal and spatial quadrature. These neurons respond to the component of a stimulus vector on a plane rather than a single axis. It is demonstrated here that these "two-dimensional" linear accelerometer neurons can function as one-dimensional angular velocity detectors. The two-dimensional property in both space and time allows these neurons to encode the component of the stimulus angular velocity vector that is normal to the plane defined by the two response vectors. The angular velocity vector in space can then be reconstructed by three populations of such neurons having linearly independent response planes. Thus, we propose that these two-dimensional spatio-temporal linear accelerometer neurons, in addition to participating in functions of the otolith system that are based on detection of linear acceleration, are also involved in the generation of compensatory ocular responses during off-vertical axis rotations.

Apparatus for monitoring the motion of the lumbar spine

Abstract: An apparatus is disclosed for monitoring the movement and force production of the lumbar spine during flexion and extension in each of several sagittal-frontal planes of the body, as well as during movement in the transverse (twisting) plane. The apparatus includes a rotatable platform upon which the patient is adapted to stand, and the platform is pivotable about a vertical axis, so that the platform may be pivoted to a selected angle and held in the selected position. For operation in the flexion/extension mode, there is provided a lever arm which is rotatable about a horizontal axis which is adapted to pass through the lumbro-sacral junction of the patient, and a first upper body engaging member is releasably mounted to the lever arm. A first computer controlled drive motor pivotally rotates the lever arm in opposite directions in accordance with a predetermined program. An overhead frame assembly is also mounted for rotation about the horizontal axis, and a second upper body engaging member is mounted to the overhead frame assembly for rotation about a generally vertical axis which is perpendicular to the horizontal axis. Thus the apparatus may be operated in a flexion/extension mode, or in a twisting mode, and with the foot platform in a selected angular position.

Measurement of steady-state and transient load-angle, angular velocity, and acceleration using an optical encoder

Abstract: The measurement of steady-state and transient load-angle, angular velocity, and acceleration using an optical encoder is described. The accuracy of measurement is assessed, and results are given for the run-up of a three-phase reluctance motor. Accurate values of speed and load-angle are determined, but the measurement of acceleration is more difficult, and significant errors are present for values in excess of approximately 50 mechanical rad/s/sup 2/. Predicted results for a computer model are in reasonable agreement. >

Constant image quality CT scanner with variable radiation flux density

Abstract: An x-ray source (20) rotates about a fixed cylinder (16) within which a subject of non-uniform cross-section is received. Radiation from the x-ray source passes through the subject and impinges on an arc of radiation detectors (28). Because the subject is of non-uniform cross-section, the average x-ray energy fluence impinging on the detectors across the arc varies with the relative angular position of the x-ray source and the subject. In one embodiment, a motor (18) which rotates the x-ray tube relative to the subject is controlled by a digital motor control (50). The digital motor control varies the rotational speed to a preselected angular velocity indicated by a look-up table (52) at each of a multiplicity of angular positions around the subject. The angular velocity is slowed when radiation is passing through thicker portions of the subject and accelerated when passing through thinner portions of the subject such that the average x-ray energy fluence received by the radiation detectors is substantially constant regardless of the angular position of the x-ray source. In another embodiment, an x-ray tube control circuit (82) alters the tube current such that the average x-ray energy fluence received by the detectors becomes angular position independent. In this manner, the signal-to-noise ratio at each angular position is the same and structural noise is eliminated in the resultant reconstructed image.

Method and apparatus for belt steering control

Abstract: A method for controlling lateral positioning of a longitudinally moving endless belt having at least two targets aligned with tolerances on a longitudinal fixed reference line, in which belt displacement from the fixed reference line is measured at least two times during each revolution of belt movement to provide a current value of measured displacement and at least one prior value of measured. The current value of measured displacement and the at least one prior value of measured displacement are averaged to provide a current average value of measured displacement and a current average value of measured displacement is calculated for each successive current value of measured displacement to provide a belt steering correction factor used to steer the belt as necessary to reduce the current average value of measured displacement to zero. Each of the targets is preferably an apertured pattern of N-shaped configuration formed in the belt. Apparatus for carrying out the method includes a steering roller about which a portion of said belt is trained, a yoke for supporting said steering roller for angular movement about a longitudinal axis, and a stepping motor/cam device for adjusting the angular position of said steering roller about said longitudinal axis.

Method and apparatus for surface-contour determination of rotor blades in hydraulic machines

Abstract: In order to determine the surface contour at points which are difficult to access, e.g. the blade shape of a hydraulic machine such as a water turbine, simultaneously on all sides of the blade, and in the installed state, provision is made for a linkage consisting of at least three or more arms (2, 3, 4, 5, 6) which are of fixed length and are connected to one another so as to be capable of pivoting in all directions by means of universal joints (7, 8, 9, 10, 11). Angular-position detectors (13, 14) in the joints (7, 8, 9, 10, 11) are used to determine the angular position of the adjacent arms about two mutually perpendicular axes (A, B) of rotation, and the angular position is evaluated in an evaluation unit (18) in order to determine the co-ordinates of the scanning tip (20) with increased measurement accuracy.

Clinical determination of the linear equation for the subtalar joint axis

Abstract: The authors present a methodology to measure the frontal plane angular and linear displacement and the transverse plane angular displacement of subtalar joint movement. This method is combined with a modification of the Kirby method for determining the transverse plane projection of the subtalar joint axis onto the plantar foot. A mathematical model is then used to construct the subtalar joint axis into a three-dimensional linear equation. Data are obtained from an in vivo series of 62 feet that indicates that within acceptable clinical errors of measurement the subtalar joint is a ginglymus type of joint that moves around a single fixed axis. Results also indicate that the subtalar joint axis is more superior and lateral to the neutral foot than any previous studies on cadaver feet have shown. Finally, the authors show that once the subtalar joint axis can be accurately located, the torque on the joint axis produced by ground reactive forces and muscular forces can be computed.

Modular machine for making cardboard packages

Abstract: A modular machine for making cardboard packages having a plurality of modules. A controlling automatic indexing device is provided which cooperates with a length of shaft and blocking means attached to each module for stopping the length of shaft at a predetermined indexing angular position. Thus, when the machine is stopped in order to change or clean the rotary members of the modules, each length of shaft of each module is stopped in the same position of the cycle and remains at its angular position during separation of the modules.

Device for recognising the angular position of a rotating part

Abstract: A device for recognizing the angular position of a rotating part is described in which the rotating part is a pick-up disc (14) provided with a multiplicity of regular angle marks (11) and a distinguishable reference mark (12), which is formed, for example, by two missing angle marks (11). The number of angle marks is (n-2), where n is a number which is divisible by as many numbers as possible corresponding to different numbers of cylinders and, for example, is 36. The voltage sequence generated in the sensor (15) is analyzed in the control unit (19), unambiguous cylinder recognition being obtained after the recognition of the reference mark (12) by comparison with a camshaft signal. The analysis of the voltage sequence also supplies the rotational speed and flanks, which can be predetermined, of the pulse sequence used for ignition and/or injection control.

Programmable electronic angular position indicator based upon engineering units

Abstract: A programmable, electronic, angular position indicator, based upon engineering units, estimates the angular displacement of a rotating rotor. The angular position indicator is programmed with the particular arrangement of teeth (or other markings) on the rotor. Intermediate angular displacements are interpolated between a limited number of positive angular displacement indications. Offsets, due to acceleration or deceleration of the rotor, are corrected at each positive angular displacement indication without skipping the output of each interpolated angular displacement. Angular displacement is determined in standard engineering units.

Measurement of small angular displacement by a modified moire technique

Abstract: Small angle measurement using a modified moire interference technique is reported. The range of angle measurement for 25-μm pitch gratings is about ± 25 μrad and the accuracy of measurement is of the order of 0.2 μrad with a time constant of 0.1 s. A piezoelectric transducer (PZT) is used for angular displacement. The angular sensitivity under the present experimental conditions is found to be of the order of 21.8 mV/μrad.

Attitude control process and device for a spacecraft to be rotated around an axis of a body

Abstract: This device is used for controlling the attitude of a spacecraft to be rotated about a body's axis of rotation Actuators generate torques about the axis of rotation and two lateral axes Angular velocity signals ω X , ω Y with respect to the lateral axes are in each case fed to first and second signal paths The latter contain an integrator Modulators, which each comprise a variable dead zone, supply control signals for the actuators In order to limit the nutation amplitude to a constant value in a reliable manner, multiplication elements are provided in the first and second signal paths The lateral-axis angular velocity signals ω X , ω Y or the angular position signals Φ, θ are acted upon by factors which are proportional to the rotation axis angular velocity signal ω Z or its square in the multiplication elements Furthermore, the thresholds of the dead zones of the modulators are varied proportionally to ω Z 2 A corresponding process for the attitude control is also described

Air-conditioning system for vehicle

Abstract: An air-conditioning system operates in an automatic control mode when an auto-switch is on. When a rotary member which is manually rotated to set one air-conditioning factor is rotated while the auto-switch is on, the air-conditioning system operates in a manual control mode as far as the one air-conditioning factor. The rotary member can be rotated endlessly. When the rotary member is rotated from one angular position to another when the air-conditioning system is operating in the automatic control mode, the one air-conditioning factor is set to a mode or a value which is determined on the basis of the amount of rotation and the mode or the value to which it had been set when the rotary member was in the one angular position.

Apparatus and method for controlling plasma size and position in plasma-activated chemical vapor deposition processes

Abstract: A block of dielectric material having a long axis and a short axis and having low losses at a selected microwave frequency and a dielectric constant selected to produce a desired degree of phase modulation is mounted on a rotatable shaft in an orientation perpendicular to the long and short axes and arranged inside a waveguide feeding a CVD reactor containing a plasma species. The block is spun by a rotational force applied to the shaft at an angular acceleration such that the two axes of the block successively intersect the axis of the waveguide within the decay period of the plasma species. The frequency of phase modulation can be varied by changing the angular acceleration of the shaft, and the amplitude of the phase modulation can be varied by changing the ratio of block length to thickness and/or by selecting a material with higher dielectric constant. The incident microwave power may be modulated as a function of angular position of the spin shaft. By moving the apparent plasma and modulating the applied microwave power, a customized temperature profile may be achieved over a desired substrate area.

A model for optimal processing of multisensory information in the system for maintaining body orientation in the human

Abstract: Considered is the optimal processing of multisensory information to maintain body orientation in the human. It is supposed that the orientation is performed by a system of angular stabilization with only small deviations from the equilibrium believed to be coincided with the local vertical. The linear transformation is determined which minimizes the square loss function for the stabilization error. This transformation comprises two successive steps. One of them is the averaging procedure on the the sensory inputs and the other is the optimal Kalman filtering in time domain. It is shown that the presence of two interacting channels for angular position and angular velocity in the structure of the optimal filter ensures sufficient accuracy of stabilization in both channels for the stabilization system as a whole in spite of the substantial unreliability in transmission in the channel of the angular position.

Angular displacement sensor with movable inductance affecting component

Abstract: An angular displacement sensor for limited angle applications (e.g., for sensing automotive throttle positions) comprising first (14) and second (16) relatively rotatable components arranged to confront each other axially. The first component (14) provides a plurality of poles (14A, B, C) which are angularly disposed about the rotation axis and extend towards the second component. These poles (14A, B, C) have axes which extend in the same direction as the rotation axis. Some poles have windings (14A, B), while others (14B) provide flux return paths. The second component comprises an inductance affecting component (16) which overlies only some of the wound poles at any given time, the relative rotation varying the poles which are overlaid. The sensor includes an output unit (17) for providing output signal data related to the inductances of the excitation poles and thus related to the rotary configuration of the components.

Optical-electrical measuring method for determining cross-sectional dimensions

Abstract: An optical-electrical measuring method for determining cross-sectional dimensions particularly of elongate articles with reference to at least one straight line, which is applied to the periphery of the cross-section and contacts the cross-section at, at least two points, and apparatuses for carrying out that method are presented. A light beam moved within a measuring field by a parallel displacement transverses at measurable locations in the measuring field boundaries of a region which is vignetted by the article disposed in the measuring field. The surface of the article is illuminated at a point by the same light beam when it has been deflected or by another light beam, and the distance from the axis of the light beam at the location of a predetermined boundary of the vignetted region to that illuminated point is determined in that an image of that point is formed at an angle which differs from the angle of the illumination and the location of the image is determined by triangulation. The entire measuring system is pivotally moved relative to the orientation of the cross-section of the article about an axis which is parallel to the longitudinal axis of the article. As a result, a detectable discontinuity of the change of the determined distance is detected, which discontinuity is characteristic of that angular position of the measuring system in which the axis of the light beam at the location of the predetermined boundary of the vignetted region contacts the periphery of the cross-section at at least two spaced apart points.

Device for the adjustment of the maneuver forces of movable members of an aircraft

Abstract: A device for the adjustment of the maneuver forces of movable members of an aircraft. The device includes: a pivoting control column (6); a shaft (7) which is articulated to the column and which is able to pivot around its axis following an angular displacement of the column (6) in a first plane; a first link (8) which is provided between the shaft and at least one first movable member (9), and which gives rise to the displacement of the at least one first movable member; a connecting rod (10) which is articulated to the column and which is able to be displaced in translation parallel to its longitudinal axis following an angular displacement of the column (6) in a second plane; a second link (11) which is provided between the connecting rod and at least one second movable member (12), and which gives rise to the displacement of the at least one second movable member; and friction unit (13) in order to apply the correct forces for the angular displacements of the column in the two planes, and which is arranged between the first and second links (8, 11). The device can be applied especially to the control of the cyclic plate of the rotor of a helicopter.

Gesture recognizing method and user interface method

Abstract: PURPOSE:To provide the gesture recognizing method which recognizes a gesture that a user sets without supplying much learning data. CONSTITUTION:A previously set standard gesture is represented as a time series of coordinates having constant time intervals and a velocity vector time series is calculated from the time series of coordinate values (104); and an angular displacement time series is found from the velocity vector time series (106) and stored. Each time coordinate values of an unknown gesture are inputted, velocity vectors are calculated from the coordinate values and coordinate values which are a certain time before (114) and angular displacement is calculated from the velocity vectors and previously set velocity vectors which are the certain time before; and the angular displacement time series of the input gesture and each of all standard gestures is used as feature vectors for DP matching to calculate distances (120), and the standard gesture having the shortest distance is employed as a recognition result.

Apparatus for detecting rotational angular position for internal combustion engine

Abstract: An apparatus for detecting the angular position for an internal combustion engine is capable of accurately detecting the angular position by a simple structure without being influenced by changes in the period of angular position signals due to inaccuracy of rotor contour and a change in rotational speed. Up-down counters up and down count clock pulses in response to the pulse train from a rotation sensor for determining information on unequal interval corresponding to a reference position in the pulse train. The frequency of the angular position is divided by a frequency dividing circuit. Up-down counting of clock pulses by the first and second up-down counters is terminated within two periods of the angular position signal. The outputs of the first and second up-down counters are alternatively up counted and down counted every one period of the angular position signal to determine the reference angular position based upon any one of determination outputs from up-down counters.

Automatic camcorder panning device

Abstract: An automatic panning device adapted for use with camcorders and similar equipment includes a bi-directional electric motor which is connected to rotate a mounting plate upon which the camcorder is secured. A control circuit controls the direction and speed of rotation of the mounting plate so as to pan the camcorder back and forth throughout a predetermined angular displacement. In a first embodiment, the amount of such angular displacement is controlled by a pair of limit arms which are pivotably secured to the mounting plate. A proximity sensor is provided for sensing panning movement of the limit arms with the mounting plate to a predetermined location. When this occurs, the proximity sensor generates a signal to the control circuit to reverse the direction of rotation. In a second embodiment, the proximity sensor is provided on the mounting plate and is moved relative to a pair of limit targets slidably mounted on a housing for the device. In a third embodiment, the amount of such angular displacement is controlled by an electronic rotational limit circuit connected to the control circuit. In a fourth embodiment, the amount of such angular displacement is controlled by an electronic rotational time circuit connected to the control circuit.

Optical motion and angular position sensing method and sensor

Abstract: An optical motion and angle sensor comprising a chamber, a light source for emitting light into a first half of the chamber along an axis of the chamber, and a plurality of light detectors for receiving light exiting from a second half of the chamber, at an angle relative to the axis of the chamber. When applied as a motion sensor, the sensor facilitates discrimination between various types of motion, and specifically allows the discrimination of slight normal motion from motion associated with incapacity of a person wearing the sensor. In addition, the sensor can provide this discrimination regardless of orientation. When applied as an angle sensor, the sensor facilitates the detection of the angle of inclination of the sensor relative to an axis, as well as the direction of the inclination.

Indcutive absolute angular position sensor

Abstract: Several novel structures of inductive absolute angular position sensors which are insensitive to mechanical plays are presented. It is shown how to design the sensor geometry, depending on the chosen signal shape and electronic treatment. A prototype built to give linear variations of the phase validates these principles. >

Six-axis operation monitoring apparatus

Abstract: PURPOSE:To make it possible to perform monitoring in real time by providing a means for measuring the angular displacement of a motion base and a means for the operation of six axes CONSTITUTION:One end of each of six shakes is connected to a motion base, and the other end is connected to a fixed base A freely rotatable joint is provided at each connecting point The motion base is made to operate in six degrees of freedom At this time, the displacements of the shakers are measured with, eg displacement gages, and A/D conversion is performed The amounts of the angular displacements of the motion base are measured with, eg gyroscopes, and A/D conversion is performed The displacements 1 of the shakers and the angular displacements 2 of the motion base are inputted at a sampling period inherent to an operating device 3 An operating part 3-1 is operated by a program stored in a program memory part 3-2 In a data memory part 3-3, inherent coordinate data, the data of the neutral lengths of the shakers and the intermediate results of operations are stored Motion displacements 3-4 as the results of the operations undergo A/D conversion, and the results are outputted In this way, the translation-displacement amounts are algebraically operated in a short time, and monitoring can be performed in real time

Observer-based control of permanent-magnet synchronous motors

Abstract: The so-called sensorless control problem for permanent magnet synchronous motors is studied. Specifically, discrete time observer algorithms are designed to estimate the angular position and velocity of the rotor using measurements of only the stator currents. These motion estimates are subsequently used for either velocity or position trajectory tracking discrete-time controller algorithms. The method for observer design is based on inversion of certain algebraic mappings that relate unknown state variables to measured outputs. The derivations of these mappings are facilitated by a time-scale decomposition that takes advantage of separated mechanical and electrical time constants. Rank assumptions related to these mappings clarify the underlying observability requirements and, in fact, lead to a method for maintaining observability at zero velocity. Detailed numerical simulations demonstrate successful sensorless motion control. >

Measuring angular position of rotor for imbalance measurement e.g. for electromotor core - scanning rotor circumference twice in succession to produce time offset signals

Abstract: A method of measuring the angular position of a rotor during imbalance measurement involves sensing the rotor in the peripheral direction and forming angle signals at angular intervals during each rotation. The rotor circumference is scanned twice in sequence and two angle signals which are offset in time are formed and stored taking account of their time separation. Both signals are evaluated to enable the rotor to be placed in the imbalance position for balancing.