Showing papers on "Angular displacement published in 1987"

Magnetic compass system for a vehicle

Abstract: A compass and method of operation are disclosed for finding the heading of a vehicle. The heading is found using a compass having a rotor with a compass magnet thereon and means on the rotor defining a reference line in known relation with the polar axis of the magnet. The angular displacement of the rotor is measured between alignment with the direction reference axis and alignment with the local magnetic field. A search coil is used to torque the rotor so that it reaches a reference position in which the reference line thereon is aligned with the direction reference axis. A reference position encoder generates a pulse when alignment is achieved. An angular displacement encoder produces a digital signal which changes with each predetermined increment of rotation of the rotor and which is indicative of the direction of rotation. A microcomputer processes the signals to provide a cumulative count of the increments of rotation. The microcomputer adds a stored magnetic variation value to the cumulative count to provide an indication of true heading. A direction display is adapted to exhibit one direction symbol of a set of symbols for different vehicle headings with each symbol corresponding to a different range of counts in the cumulative count. The microcomputer converts the cumulative count to a different direction value for each different range and the display is changed when there is a change of direction value. The microcomputer provides a logical hysteresis to prevent the display from flashing between different symbols when the cumulative count is at a marginal value of a given range. The microcomputer also provides a time damping of the display by imposing a time delay before changing the display from one symbol to another.

Method for continuous camlobe phasing

Abstract: A method of attaining a desired engine performance comprises the steps of changing the angular position of a variable camlobe (or cam) member relative to a fixed camlobe (or cam) member from a first angular position to a second angular position. In changing from the first to the second angular position, the variable camlobe (or cam) member moves in a predetermined direction relative to the direction of rotation of a camshaft. The predetermined direction and the magnitude of the angular movement of the variable camlobe (or cam) member is dependent at least in part upon at least one desired operating condition of the engine. The method further comprises changing the angular position of both camlobe (or cam) members relative to a reference point of a drive pulley. This change in the angular position of both of the camlobe (or cam) members relative to the reference point involves movement of the camlobes (or cams) in a direction relative to the direction of rotation of a camshaft. The direction and magnitude of this movement is based at least in part upon at least one desired operating condition of the engine.

Wafer centration device

Abstract: A device for centering an object and rotating it to a desired angular position relative to a discerning feature. The centration device is particularly adapted for use as a station in a semiconductor wafer handling apparatus, and includes a rotatably driven chuck on which a wafer may be placed by a robot manipulator arm. The perimeter of the wafer is rotated between a light source and a linear array of charge coupled device elements, casting a shadow on the light sensitive elements as the wafer is rotated. A processor connected to the charge couple devices and to an angular position encoder on a shaft of the chuck rotating the wafer is operative to collect data relating the displacement of the perimeter from a reference point to the angular position of the wafer. The processor determines from the data a distance over which the wafer should be shifted on the chuck to center it relative to the reference point. Once the robot manipulator arm has centered the wafer, a minimum displacement of a point on the perimeter corresponding to a flat or notch on the wafer is located and positioned at the desired angular orientation.

Velocity Observations From Discrete Position Encoders

Abstract: A discrete position encoder is an inexpensive means for sensing the angular position of a rotating device. Often a system with higher performance can be achieved if the angular velocity is known in addition to the position. Typically, the output of a discrete position encoder is two square wave signals in quadrature. This paper investigates various methods for processing these signals to observe the velocity in real time. High performance observers based on Taylor series expansions, backward difference expansions, and least square curve fits are developed. The accuracy of the different observers are analyzed by simulations for systems with time measurement truncation and imperfect encoders. The least square curve fit based observers are the most tolerant observers investigated due to the inherent low pass filtering.

System and method for automatically running a vehicle at a crusing speed

Abstract: A system and method for automatically running a vehicle at a desired cruising speed in which in order to properly control an opening angle of a throttle valve of a vehicular engine, the opening angle of the throttle valve is feedforward controlled. In the feedforward control, a wheel force of the vehicle is derived by storing an instantaneous angular displacement of the throttle valve for each period of controlling the angular displacement of the throttle valve, weighting transient characteristics of a transmission torque in a power train of the vehicle including dead times and first order lag to the stored instantaneous angular displacement of the throttle valve to derive each wheel force for the period of controlling the angular displacement of the throttle valve, and averaging each wheel force for each period of deriving a change rate of the vehicle speed to derive the wheel force. The wheel force is used to derive a running resistance of the vehicle based on deriving a target angular displacement of the throttle valve to maintain the vehicle speed at the cruising speed.

Apparatus and method for processing the output signals of a coriolis rate sensor

Abstract: Apparatus and method for increasing the resolution of angular rate of rotation and linear acceleration of a body with respect to three orthogonal axes. Three pairs of accelerometers (10, 12; 14, 16; and 18, 20) are arranged with their sensitive axes antiparallel to each other, and each pair is vibrated back and forth along one of the orthogonal axes. The signals output from the accelerometers are processed to determine S rate and S vel for each of the rate axes as a function of the sum and differences of the signals produced by each of the accelerometers. The value of S vel for each axis is used by a microprocessor (82) to produce a signal equal to an incremental change in velocity for each axis. The incremental change in velocity is then used in conjunction with errors estimated from previous fractional portions of the dither period for each pair of accelerometers to calculate the rate of rotation of the body about each of the axes as a function fo the values for S rate . As a further aspect of the invention, the incremental change in velocity and incremental changes in angular position may be determined as a running average of previous fractional portions of the dither frequency.

Method and device for digitally determining a number proportional to rotational speed of a body

Abstract: The subject matter of the invention is a method and a device for determining a number which is proportional to the rotational speed of a body by means of an angle sensor which generates digital signals during their rotation. The time is measured by counting the periods of a reference oscillation in cyclic sequence up to a prescribed maximum value. An angular position value is continuously updated in the case of changes in angular position of the body and stored, and the time value present up to the instant of the change is stored. The stored angular position value and the stored time value are read out at time intervals given by a constant interrupt interval. In each case, the angular position value read out in the preceding interrupt interval and the time value read out are subtracted from the read-out angular position value and the time value. The difference between the angular position values is divided by the difference of the time values and multiplied by a constant.

High precision angular position encoder using photo-electric detection

Abstract: In a high-precision angular position encoder for detecting the absolute angular position when the transmitter disc (GS) is standing still and the incremental angular position when the transmitter disc is rotating, the measurement signals (U1 to U4) obtained by photoelectric scanning of a group of tracks (S1 to S4) arranged on the transmitter disc are triangular functions of the angle of rotation. During the rotation of the transmitter disc by the angular range (WBS1) corresponding to one period (U1P1) of one of the measurement signals (U1), an integral multiple (10) of periods occurs in the measurement signal (U2) belonging to another track (S2). The sums of periods occurring in the individual measurement signals (U1 to U4) during a complete rotation (360 DEG ) of the transmitter disc are thus graded with respect to one another (1:10:10:10). The absolute angular position can be determined by means of progressive evaluation of the measurement signals of the individual tracks (S1 to S4) with higher precision than is possible in the case of the incremental angular position by evaluating one of the tracks (S4) of the group.

Downhole pressure and/or temperature gauges

Abstract: A pressure or temperature gauge includes a Bourdon tube which is coupled via a shaft to transmit rotation to a stylus carried by the shaft which makes a record on a cylindrical chart which moves axially of the shaft at a constant rate. The shaft is divided into two sections which are joined together by a flexible coupling; the upper section of the shaft is mounted for angular displacement about its longitudinal axis by the thrust bearing. One section has an integrally formed axial extension which is received in a recess in the facing end portion of the other shaft section. This construction of the stylus shaft allows the angular motion produced by the coiling and uncoiling of the Bourdon type generally through an angle less than 360° to be faithfully transmitted without any axial motion of the shaft which would give rise to erroneous recording of pressure or temperature readings in relation to time.

Sensor unit, particularly for operating electrically commutated synchronous electric motors in servo control loops

Abstract: To be able to determine the absolute angular position over several revolutions of the motor shaft in an inexpensive manner, a high-resolution resolver (10) which can be coupled to the motor shaft is followed by one or more resolvers (14) of low angular resolution via low-accuracy step-down transmissions (12) The step-down ratio of the step-down transmissions (12) and the angular resolution of the following resolvers (14) is selected in such a manner that it results in each case in one redundant bit which is used for angle synchronization

Angle sensor with inductive coil coupling

Abstract: An angle sensor (1) with a rotatably arranged transmitter part (5) and a fixed transmitter part (9). The rotatable transmitter part (5) has a coil (10) which can be connected to a source of alternating current, is wound helically on a support and extends on both sides of an axis of rotation (53) with longitudinal axis extending transverse to it. The fixed receiver part (9) contains at least one sensor for electromagnetic fields which is arranged facing and spaced from the coil (10). The sensor extends on both sides of the axis of rotation (53) transverse to it and is connected on the output side to a circuit which has circuit components (22, 23, 24, 25, 26) for compensating for the deviations of the output signal or signals of the stationary receiver part (9) from a fixed relationship of the angular position of the rotatable transmitter part (5) and the output signal or signals of the stationary receiver part (9) which are caused by asymmetries or inaccuracies in the arrangement of the transmitter and receiver parts (5, 9).

Angular position sensor and angular position determination means equipped with several of these sensors

Abstract: An angular position sensor for determining the relative angular position of two relatively rotatable ferromagnetic coaxial components, such as a rotor and stator. The components have the same number of regularly distributed teeth and the teeth in one component are separated by an air gap from the teeth in the other component. A plurality of coils are connected in series with each other and are disposed around the teeth in one of the components and correspond in number to the number of associated teeth. An electric excitation signal having a measurable constant electrical characteristic is fed to the plurality of coils from a source. The characteristic is modulatable in response to variations in the magnetic reluctance of the air gap effected by changes in the relative angular position between the two components. Electronic circuitry is connected to coils for measuring the modulation of the characteristics to determine the relative angular position of the components. In angular position determination apparatus comprising a plurality of angular position sensors, mechanical connections are provided between the rotors on the one hand and the stators on the other. The angular displacement between the rotor and stator teeth differs for each sensor, the difference generally being a multiple of the quotient of 2π by the number of teeth and the number of sensors. The sensor is well adapted for use in the robotics field.

Method and apparatus for measuring the weft or mesh serial position in textiles

Abstract: A system for measuring the weft or mesh serial position in textiles, in which the angular position of the weft/mesh series is measured for determining the angle of distortion passing over a partial amount of the length thereof, includes an illumination measuring system which measures values of light from a light source either passing through or reflected from the textile fabric to be tested, in a substantially linear range, and an adjusting assembly which reciprocally and oscillatingly rotates the linear range about a central angle to adjust the linear range at an angle relative to the textile fabric; rotating or measuring the reflection or transmission values in several discrete equidistant angular units; a group of memories for storing the measured values corresponding to at least a few angular units; and a digital unit connected to the memories for comparing the stored values in calculating a distortion angle in response to such comparison.

Active compliant end-effector with force, angular position, and angular velocity sensing

Abstract: A direct-drive active compliant end-effector (10) comprises a planar linkage (28) having input links (30, 44) driven by motors (24, 26). A force sensor (52) is connected between the output link (36) and a tool mount (48) for measuring tool interaction forces, signals representative of which together with those representative of angular displacement and velocity of the input links (30, 44) are used by a controller (82) for controlling the drive motors (24, 26) to provide active electronic compliancy.

Phase-responsive angular tracking device

Abstract: An apparatus for generating phase modulated angular positional signals in digital form. A phase tracking loop receives a phase modulated signal from the rotor of a resolver whose stator windings are excited in quadrature. The phase output of the resolver is proportional to the angular displacement of the rotor. Signals for exciting the stator windings of the resolver are applied in phase quadrature to a phase detector to develop an analog error signal when combined with the rotor output signal. The analog phase error signal provides an output indicative of the angular displacement of the rotor. The error signal is applied to a voltage controlled oscillator, converted to digital form, and combined with the excitation signals in a closed loop to force the error signal to a null, whereupon the indicated digital output angle is in coincidence with the angular displacement of the rotor shaft.

Machine for measuring generally circular objects in cylindrical coordinates

Abstract: A machine measures an object of generally circular cross-section by superimposing on the subject a cylindrical coordinate system having five axes, namely a vertical measuring axis Z, three radial axes R0, R120, R240 emanating at a common point along the measuring axis Z, and a rotational axis θ having its center at the measuring axis Z. The machine includes an elevating unit which supports the object with its axis generally parallel to the measuring axis Z and is further capable of moving the object parallel to the measuring axis Z as well as rotationally about the measuring axis Z along the rotational axis θ. A measuring device monitors the linear position of the object along the axis Z while another measuring device measures the angular position of the object along the rotational axis θ. In addition, the machine includes three measuring heads, there being one along each radial axes R0, R120, and R240, and each measuring head includes a base, a slide which is mounted on the base for movement parallel to the radial axis of its head, and a probe carried by the slide. The probe has a displaceable probe tip which bears against a surface on the object. Each measuring head has a measuring device for monitoring the position of its slide relative to the slide base and as well as another monitoring device which may be used to monitor the position of the probe tip relative to the slide along the radial axis R or the position of the probe tip parallel to the measuring axis Z. The machine scans the object by effecting relative movement between the object and probe tips parallel to one of the axes while at least one of the probe tips remains against the object, and by taking measurements at equally spaced intervals along another of the axes. Thus, it is possible to make an axial scan, a radial scan, a rotary scan along a circumferential surface or a rotary scan along an end surface.

Torque and angular displacement sensing in yield threshold controlled wrenches

Abstract: The torque and angular displacement transducers in a yield threshold controlled wrench apparatus are relocated to reduce the problems encountered therewith from the harsh physical environment experienced by such transducers in conventional designs. In one preferred embodiment, both the torque and angular displacement transducers are located at completely remote locations from the movable elements of the wrench mechanism and are each housed in a conventional hydraulic fitting to be more readily replaceable for maintenance purposes, as compared to the transducers of conventional designs.

Robot arm space stabilizer

Abstract: As a gyroscope is made to precess back and forth across a certain point; a servo, torquing about the axis causing precession, can stabilize the member containing the precession axis by maintaining the gyroscope at that point. In the subject invention, a signal generator measuring gyro movement on the precession axis, energizes the servo at the hinge between the member and its support toward the base and thus stabilizes said member against accidental oscillation of said support. After adding to the precession axis a velocity sensitive means for restraining gyro motion along with means for displacing the signal generator null, the servo will torque, and henceforth stabilize, the member to a new attitude signified by the angular displacement of the null. Momentum of the gyro wheel remembers its position in space and will return the member to its original null. In this manner, up to three orthogonally servoed robot arms may be space stabilized with attitude changes commanded remotely.

Burring and its device

Abstract: PURPOSE:To maintain a stable cutting conduction so as to extend the life of a cutting tool and improve the finishing of a workpiece by controlling the tool in the manner to detect the angular displacement, which is caused by the load that the tool receives from the condition of a burr, after converting it to a unidimensional direction. CONSTITUTION:A cutting tool 2, which is feasible to make an angular displacement in the composed direction of X, Y direction as it actuates with shaft supports 4, 5 in the center, makes the angular displacement in accordance with the condition of a burr after the tool 2 contacts the cutting surface Wa of a workpiece W and as ball 8 is pushed up on the inclined surface of a cone-shaped concaved portion 7a, an abutting member 9 and a rod 10 are raised as resisting to a spring 12. If the tool 2 encounters a large burr, a displacement sensor 13 sends a large detection signal to a control unit B through the medium of the rod 10 as the inclination of the ball 8 being pushed up is large. The control unit B recognizes a large burr according to the increase of the angular displacement by judging the detection signal compared with the set value; it sends out an optimum control signal after changing the moving speed, the path and the revolution speed of the tool 2; it lightens the load on the toll 2 as the burr is removed and it returns the displaced angular tool 2 to the regular state.

Rotational angle detector

Abstract: PURPOSE:To measure an angle with extremely high precision by arranging two Hall elements at a proper mutual angle. CONSTITUTION:The two Hall elements 9 and 10 are fixed in the gap between magnets 7 and 8 while having magnetic flux sensitive surfaces 9a and 10a at 90 deg. to each other, and angles of theta and theta-90 deg. of magnetic flux penetrating the two Hall elements 9 and 10 vary through the rotation of a rotating shaft 5. Further, feeders 11a and 11b and signal lines 12a and 12b are connected to the Hall elements 9 and 10 respectively and the current from a current supply circuit 13 is supplied to the Hall elements 9 and 10 through the feeders 11a and 11b. A microprocessor 15 calculates the angular displacement theta of the rotating shaft from the signals from the Hall elements 9 and 10 and the angular displacement is converted by a D/A converter 19 into an analog value, which is sent out.

Device and method for measuring moment of inertia of rigid bodies

Abstract: This invention provides a device and method for measuring the moment of inertia of a rigid body, particularly suitable for the rigid bodies with non-uniform mass distribution and regular sectional profile When a surporting table carrying a body to be tested rotates horizontally, the light chopping thin rods mounted underneath the table pass sequentially through photo-electric switches Said switches output siguals from which the angular displacement, angular speed, and angular acceleration etc of the rotating body can be measured derictly, and then the moment of inertia q said boky can be deduced by calculation Additionally, this device can be used to demonstrate the rotating law of rigid body and the theorem of parallel axes This device has the advantages of easy operation, small frictional moment, and small measuring error (< 2%), therefore being applicable to educational physical experiments in university industrial design, scientifical researches and so on

Device for measuring the load-dependent torque in a rotating shaft

Abstract: So that the load-dependent torsion in a rotating shaft (1) can be measured in a non-contacting manner, at least two marking groups (9, 9'), of which each comprises at least one marking (10, 10'), are attached to the shaft at an axial distance apart in such a way that they rotate with the shaft, and torsion of the shaft produces a relative angular displacement between the marking groups. Furthermore, a sensor arrangement (6) is provided which does not rotate with the shaft and scans the markings in a non-contacting manner in such a way that its output signal contains information about the respective angular position of the marking groups. Each of the marking groups is preferably arranged on a marking carrier (3, 4) which is mounted on the shaft in such a way that it rotates with the shaft.

Electric power steering system

Abstract: Herein disclosed is an electric power steering system which comprises: a detecting unit for detecting the direction and magnitude of a relative angular displacement betweeen input and output shafts; and an electric motor connected to the output shaft and having its revolutions controlled through a controller in accordance with the output signal of the detecting unit. The detecting unit includes a converting mechanism for converting the relative angular displacement into an axial displacement, and a displacement detecting unit for detecting the magnitude of the displacement in the axial direction. The displacement detecting unit can have its neutral position adjusted independently of other parts.

Angular or linear high precision capacitive position sensors

Abstract: The sensor is in the form of a compact integrated unit. In its basic version as a rotating sensor, it consists of a stator (1) with a series of electrodes (S1 to Sn) for creating a rotating field and a rotor (2) with a small number of electrodes (R1 to R3) having a different spacing between them. The latter electrodes pick up a voltage (SI) which is induced by the inter-electrode capacitive coupling and which depends on the angular displacement of the rotor (2). Circuits (7) integrate (12, 13) the induced voltage and determine the time corresponding to half the value at a reference time. In a preferred circular version, it amounts to two concentric sensors with one track forming a vernier, a second track enabling a rough absolute measurement to be made, and with a track to remove ambiguity by identifying the sector in which the capacitive coupling between the electrodes of the vernier and the electrodes of the stator occurs. The vernier is repeated sequentially and each sector is successively supplied with the same small set of polyphase voltages.

Automatic positioner with nonlinear drive

Abstract: A motor driven mechanical positioner is provided which will position a movable arm to any one of 840 discrete angular positions. A total angular range of +/-42° can be covered in 0.1° increments. Electronic circuitry controls the nonlinear drive mechanism. A drive shaft wheel has six evenly spaced holes through which light from an IR LED is allowed to shine on a phototransistor placed on the other side of the wheel. As a result of the intermittent light striking the phototransistor, six clock pulses are generated for every revolution of the drive shaft. A desired angular position is entered into the electronics via thumb wheel BCD switches. The BCD information from the switches is transformed into binary information to address EPROMs. For each possible binary address representative of a desired angular position, the selected EPROMs output binary data that is representative of the clock pulse count for that particular angular position. In order to compensate for the nonlinearity of the drive mechanism, the clock pulse count is incremented at a nonlinear rate as the angular position is increased. Additional circuitry in the automatic positioner senses when the mechanism is within a preset distance from where it should be, and when this occurs a presettable slow drive speed is implemented to minimize overshoot.

Speed of apparent motion and the wagon-wheel effect.

Abstract: The speed of apparent movement of a stroboscopically illuminated spoked wheel was measured by counting the number of spokes passing a particular position per unit of time. This measure gave very stable values of speed, which compared closely to predicted speeds calculated from stimulus onset asynchrony and angular displacement values. The results provide, for the first time, a reliable measure of speed of one form of apparent motion. The traditional explanation for the wagon-wheel effect in terms of beta motion is discussed in light of several differences between the classical demonstrations of apparent motion and stroboscopic motion as seen on the wagon wheel.

Acquiring dimensions of a large object

Abstract: A method of acquiring dimensional and gauge data of objects and work pieces, such as forgings or the like, uses two image producing sensors, each being up and down tiltable about a horizontal axis and swivable from side to side about a vertical axis. At least one of the sensors is directed initially towards the object for acquiring position data on a particular point of the object such as a point of intersection of two contrast lines. One of these sensors is then positioned, including tilting and/or swiveling until a particular image field point coincides with the intersection point whereupon the other sensor has a particular image field point trained on that same particular intersection point. Finally, dimensional and guage data of the object is derived from angular position data of multiple points as so acquired by the two sensors.