Showing papers on "Angular displacement published in 1986"

Inertial mouse system

Abstract: A hand-held inertial mouse provides input data to a computer from which the computer can determine the translational and angular displacement of the mouse. The mouse includes accelerometers for producing output signals of magnitudes proportional to the translational acceleration of the mouse in three non-parallel directions. Pairs of these accelerometers are positioned to detect acceleration along each axis of a cartesian coordinate system such that an angular acceleration of the mouse about any axis of rotation causes representative differences in the magnitudes of the output signals of one or more of these accelerometer pairs. The translational velocity and displacement of the mouse is determined by integrating the accelerometer output signals and the angular velocity and displacement of the mouse is determined by integrating the difference between the output signals of the accelerometer pairs.

Fine positioning device

Abstract: A fine positioning device is constructed of a parallel flexible-beam displacement mechanism and/or a radial flexible-beam displacement mechanism. The former displacement mechanism comprises a first rigid portion rigid against forces, a second rigid portion rigid against forces, plural parallel flexible beams connecting the first and second rigid portions together, and a first actuator adapted to have the plural flexible beams undergo bending deformation. The latter displacement mechanism comprises a third rigid portion rigid against torques, a fourth rigid portion rigid against torques, plural radial flexible beams connecting the third and fourth rigid portions together, and a second actuator adapted to have the plural flexible beams undergo bending deformation. The fine positioning device can obtain fine linear displacements and/or fine angular displacement with good accuracy. This invention also facilitates the construction of multi-axis positioning devices.

Straight line motion mechanism

Abstract: A straight line motion mechanism is formed from a pair of parallelogram linkage mechanisms in combination with motion control means interconnecting the linkage mechanisms to provide for uniform angular displacement thereof. The mechanism is particularly adapted for use in supporting an object, such as a table top, for vertically directed stepwise movement or one step shifting between lower and upper reference positions corresponding to table top heights convenient for use alternatively by a person in seated and standing positions. In a preferred embodiment, means are provided to enable a user to selectively make fine adjustments of the height of the table top after it has been shifted into either of such lower and upper reference positions.

Absolute encoder for linear or angular position measurements

Abstract: An encoder device of the absolute position type for outputting a shift position or angle of rotation relative to the absolute position. The device comprises a code plate having first and second grid patterns wherein information is stored as 1 or 0 in a periodic manner at pitches slightly different from each other; first and second sensory arrays for detecting the first and second grid patterns; driving means for driving the sensors relative to the grid patterns and for obtaining an alternating signal from each array; and computation means for measuring the phase angle of the alternating signal from each array, and the phase angle difference therebetween and for calculating the position using such phase angles. Advantageously, the invention is suitable for miniaturization due to its simplicity, relaibility, and efficiency.

Flutter analysis of a two-dimensional airfoil with cubic non-linear restoring force

Abstract: Flutter analysis of a two-dimensional airfoil with a cubic nonlinear restoring force in the pitch degree of freedom is investigated. The structural dynamic equations of motion are integrated by a time marching finite difference scheme. Flutter is determined from conditions which give rise to either a divergent or limit-amplitude solution. Case studies using various airfoil parameters and coefficients of the non-linear term in the restoring force are carried out. The effect of initial conditions is studied by varying the displacement from equilibrium of the pitch angle at the start of the airfoil motion. For a soft spring, an increase in the initial angular displacement can induce flutter to occur below the linear flutter speed. Factors that have stabilizing and destabilizing effects are investigated. For a hard spring, divergent flutter is not encountered. Instead, the oscillations maintain a self-limited amplitude which is independent of initial angular displacement. The effects of airfoil parameters on the amplitudes of heave and pitch motions are studied.

Method and apparatus for trelemetry while drilling by changing drill string rotation angle or speed

Abstract: The cyclic angular dependence of the output of gravitational inclinometers and magnetometers is used to communicate from the well surface to a microprocessor downhole. The microprocessor controls an arbitrary downhole function. Information is communicated to the microprocessor via the inclinometer and magnetometer by selectively rotating the drill string during a data time interval through a predetermined magnitude of angular displacement or angular velocity. Each additional multiple of angular displacement or angular velocity is interpreted as a distinguishable unit of information. A command word is assembled from a sequential plurality of units of information in the microprocessor and a downhole function is executed according to the command word.

Torque control apparatus for rotary machine

Abstract: A torque control apparatus for a compressor driven by a motor through a main shaft, in which variations of the rotation speed of the main shaft due to torque variations are detected at selected angular positions of rotation of the main shaft. Current values to be supplied to the motor for eliminating the rotation speed variations depending on the angular positions of rotation of the main shaft are computed and stored during at least one revolution of the main shaft, and, in the next revolution of the main shaft, that is, when the main shaft rotates then to a 360° advanced angular position, the motor current is controlled on the basis of the current values supplied for at least one revolution of the main shaft, thereby eliminaitng variations of the rotation-speed of the main shaft.

Elevation measurement in high order surveying

Abstract: A surveying instrument and procedure are provided for the precise determination of elevation differences in the course of a surveying traverse. The instrument comprises an optical wedge 13 situated on the horizontal longitudinal line of sight axis 27 of the primary optical system between the objective lens 11 and a target under observation. The wedge is arranged for rotation about this axis and with such rotation angularly displaces the diverted line of sight 28 from the horizontal to the plane of the target. The degree of rotation required of the wedge to acquire the target 33 is measured by electro-optical angle encoder means 10, and the distance to the target by EDM means 24, 26. The difference in elevation is calculated trigonometrically by computer means utilizing as data the wedge diversion angle, the sine function of its rotation, the computed angular displacement of the line of sight, and the distance to the target. The procedure further includes the cooperative employment of two such instruments 20, 30 each as the target for the other, to thereby increase the accuracy of measurement through the averaging of the combined results. Also included in the instrument is a mislevel compensation system 60 which provides both optical and electronic correction in the event of mechanical deviations in the orientation of the instrument.

Auto-boresight technique for self-aligning phase conjugate laser

Abstract: A method and apparatus for providing a self-aligning phase conjugate laser beam that is automatically boresighted with an active or passive tracking sensor. A single-transverse-mode laser oscillator (12) and a tracking sensor (14) are mounted on opposite sides of an output coupling beamsplitter (15), all attached to a stabilized platform (13) which is part of the inner gimbal of a pointing and tracking system. A multipass laser amplifier (21) with a phase conjugation mirror (22) and an optional nonlinear frequency-conversion device (20) are located off the inner gimbal. The inner gimbal allows rotation of the stabilized platform about an elevation axis (16), and an outer gimbal or pedestal mount permits rotation about an azimuthal axis (17). The phase conjugation mirror (22) compensates the beam for the effects of optical aberrations caused by thermally induced changes in the amplifier medium and the nonlinear medium (if used) and also compensates the beam for angular tilt and jitter in the beam line of sight due to structural flexibility and motion of the stabilized platform. Part of the oscillator output passes through the beamsplitter to the tracking sensor to mark the far-field location of the amplified output beam. The tracking sensor also views a target image after it is reflected by the beamsplitter. The tracking system measures the angular displacement between the target aimpoint and the locus of the output beam as marked by the oscillator and generates tracking error signals which are used to close a servomechanical feedback loop around the gimbal orientation apparatus. Pointing errors resulting from misalignment of the oscillator, the tracking sensor, and the beamsplitter are compensated by this technique.

Maintenance of body orientation in the flight phase of long jumping.

Abstract: The purpose of this investigation was to examine the contributions of the various body segments to the maintenance of body orientation during the flight phase of the long jump. Proper maintenance of body orientation was defined to be achieved if the net angular displacement of the head-and-trunk segment was zero during the flight phase of the long jump. To achieve a zero net angular displacement of the head-and-trunk segment a long jumper needs to execute appropriate arm and leg movements relative to the head-and-trunk segment to counteract the effects of the whole body transverse centroidal angular momentum imparted at takeoff. The contributions of arm and leg movements to the maintenance of body orientation are discussed for the specific cases of a sail and a 2 1/2 hitch-kick long jump. Inherent weaknesses of the sail and hitch-kick techniques, as well as specific weaknesses of two athletes executing these techniques, are discussed with reference to body orientation during the flight phase of the long jump.

Machine tool structure

Abstract: 1. Machine tool comprising the essential elements of a conventional lathe, namely : - a rotary workpiece-holding lathe spindle (4) driven in rotation about a horizontal axis (l-l) by driving means (3) allowing its rapid rotation within the range of speeds normally used for lathes ; - a tool-carrier assembly (2) movable in translation horizontally with respect ot the spindle (4) along a longitudinal axis parallel to the axis (l-l) of the spindle and a transverse axis (ll-ll) at right angles to the axis to the spindle ; - tools (11) fixedly mounted on the tool-carrier assembly (2) ; - means (10) mounted on the tool-carrier assembly, for driving turning tools (7, 8) in rotation ; - the driving means for the spindle comprising at least one principal motor (31) allowing the rapid rotation of the spindle and electronic control means (33) allowing the speed of rotation of the motor and of the spindle to be controlled, then to stop it at specific successive angular position, characterized in that : - the workpiece-holding spindle (4) is mounted on a carriage (5) sliding on guideways (61) of the frame along a vertical axis (lll-lll), - the tools, stationary (11) and rotary (7, 8), are situated at different heights of the tool-carrier assembly (2) and at fixed positions with respect to the tool-carrier assembly (2).

Dynamics and control of slew maneuver of large flexible spacecraft

Abstract: In this paper, the dynamics and control of slewing maneuvers of a large flexible spacecraft namely. NASASpacecraft Control L aboratory Experiment (SCOLE) test article are studied. The dynamical equations o btained for slewing maneuvers are highly nonlinear and coupled. The maneuver is expressed in terms of four Euler parameters and is specified a s the angular displacement about an arbitrary axis. The slew maneuver control problem is developed in terms of rigid-body slewing and suppression of two elastic modes is analyzed using the method of nonlinear decoupling. Nomenclature: Position v ector of mass element on the beam from the point of attachment Position v ector from the point of attachment to the mass center Displacement vector of mass element i n the body- fixed frame Force applied at the orbiter mass center Force applied at the reflector mass center Moment applied about the orbiter mass center Hass moment of inertia matrix of the shuttle Mass moment of inertia matrix of the ref lector The length of the beam Total mass of the f lexible beam Iass of the orbiter Mass of the r eflector

Method and apparatus for measuring angular displacement

Abstract: An angle transducer includes input rotor and reference rotor assemblies that are mounted for rotation upon a common shaft and that cooperate with respective moveable input stator and fixed reference stator assemblies to produce signals whose phase difference represents an input angle. Diametrically opposed sensors in each stator assembly achieve enhanced eccentricity error reduction by producing separate signals whose phases are averaged after the phase of each is individually measured. A phase measurement technique does not rely upon the mechanical accuracy of the angular placement of the poles for the rotor assemblies. A phase measurement between two signals is performed by beginning on an arbitrary zero crossing of the signal from the reference stator and forming, for each rotor, the sum of the times for the zero crossings for one complete revolution. To avoid the effects of crosstalk the rotors may have different numbers of poles. The sums, the different numbers of poles, the time for one revolution, and, for each rotor, the number of poles from the pole corresponding to the first term in the associated sum to an absolute reference pole, are the variables in a phase formula producing a high accuracy and resolution unified answer free of separate coarse and fine components. The absolute reference poles may be missing poles whose absence is detected and replaced with an estimate. State and time of transition data for one revolution's worth of all of the signals from the stators are temporarily captured in a small high speed revolving buffer and then immediately stored in a larger wrap-around memory under the control of an interrupt system of a microprocessor. To perform an angle measurement the microprocessor analyzes the last complete revolution's worth of data, beginning at any point in the revolution.

Angular speed sensor and its application to a combined torque and angular speed sensor for a motor vehicle steering column

Abstract: This angular speed sensor comprises two coaxial discs 10, 11 which are electrically insulating and integral in rotation with respective members 1, 3 whose relative angular speed is to be measured. Each disc carries on one of its faces a detection winding consisting of an even number of conducting coils in the form of spiral sectors wound alternately in one direction and the other, and whose mutual inductance varies as a function of the relative angular position of the said discs. The sensor also comprises a supply circuit 16 applying a high-frequency AC voltage to one of the windings, and a circuit 17 for processing the signal collected at the terminals of the other winding. The processing circuit 17 is a demodulator which converts the said signal, which is amplitude-modulated, into an output signal with frequency directly proportional to the relative angular speed of the said members 1, 3. Application to measuring the angular speed of a steering shaft.

X-ray computed tomography system

Abstract: An X-ray CT system includes an X-ray source, a drive device, an X-ray detector, a data acquisition system, a reconstruction processor and a delay circuit. The X-ray source emits an X-ray fan beam onto an object and is rotated by the drive device on substantially the same plane as the fan beam. A graticule sensor detects an angular position of the X-ray source. The X-ray detector consists of detector elements fixed concentrically with a relative rotational path of the X-ray source. The data acquisition system responds to a position signal from the graticule sensor and samples the output data from the detector for each predetermined angular position of the X-ray source to obtain projection data. The projection data is reconstructed by the reconstruction processor to obtain a tomographic image of the object. The delay circuit delays the position signal from the graticule sensor to offset the sampling point of the projection data by a 1/4 sampling point pitch from the angle corresponding to the center of each detection element.

Torsional damper device

Abstract: A torsional damper device suitable for automobile vehicles comprises a driving part, an intermediate part and a driven part disposed coaxially and rotatable relative to each other within predetermined limits of relative angular displacement. Lost motion meshing teeth between the driving, intermediate and driven parts are adapted to determine these predetermined limits of relative angular displacement. First and second circumferentially acting spring units between the driving, intermediate and driven parts oppose relative angular displacement of these parts for at least two ranges of relative angular displacement. Lost motion meshing teeth between the driving, intermediate and driven parts define these two ranges of relative angular displacement. A first plurality of elements in the driving part include a friction disk and at least a disk to support and center it. An annular elastomer member has one side constrained to rotate with a guide ring and has its opposite side constrained to rotate with the intermediate member which is a hub plate. The first group of elements includes and rotates with the guide ring. At least one annular metal part which may be an adhesion plate separate from the guide ring or the guide ring itself is joined to one radial surface of the annular elastomer member. This annular elastomer member constitutes at least part of the first circumferentially acting spring unit. The annular elastomer member has at least an inner part of trapezoidal transverse cross section. The shorter parallel side of the trapezoidal cross section is nearer the axis of the device.

Automatic measuring device for underground displacement

Abstract: PURPOSE:To predict more accurately and speedily the deformation and destruction of the ground by connecting joint parts of measurement pipes of unit length through rotary joints and slide joints to necessary length, and installing an angle sensor which detects an angle of rotation and an extension sensor which detects a slide quantity. CONSTITUTION:A necessary number of measurement pipes 1 are connected mutually to necessary length by using a rotary joint 2 and a slide joint 3 at a node between a couple of pipes and used while buried perpendicularly in the boring hole at a place to be measured. If the ground slants or rotates to deform, the inclination between two adjacent measurement pipes 1 and 1 causes the angular displacement of the rotary joint 2 and appears as the relative angular displacement between a bracket 6 and a connecting part 8. This angular displacement is detected as the angle of rotation of the input shaft pulley 4a of the angle sensor 4. If the ground is displaced perpendicularly, it causes extension or contraction between two upper and lower adjacent measurement pipes 1 and 1 to displace the slide joint 3, which is detected a s the angle of rotation of the input shaft pulley 5a of the angle sensor 5.

Control of gripper position of a compliant link using strain gauge measurements

Abstract: A self-tuning type algorithm is proposed for the control of a single rotating compliant link. At each sampling time, strain measurements along the link are used to assess modal content. Knowledge of the first mode together with the hub position may be used to determine the angular position of a hub to tip projection. A self-tuning control is devised by treating this angle as belonging to an equivalent rigid link. Laboratory experiments show this control to lead to an improved performance over a control which ignores compliance.

Method of handling a vehicle body during an equipping operation

Abstract: A method of and a system for equipping a vehicle body, particularly a railroad car body, in which the vehicle body is supported for turning movement about a center axis of shafts extending longitudinally substantially through the center of gravity of the vehicle body, and the vehicle body is moved in turning movement to a desired angular position about the center axis of the shafts to perform equipping operations on both the interior and exterior thereof. The system includes a securing device connected to opposite end portions of the vehicle body, a support device for supporting the vehicle body through the securing device and moving same in turning movement about a center axis of shafts extending longitudinally substantially through the center of gravity of the vehicle body, a device for moving the vehicle body in turning movement about the center axis of the shafts, and a fixing device for fixing the vehicle body in place in an arbitrarily selected angular position.

Counterbalanced adjustable router bit

Abstract: A router bit having an adjustable blade for cutting various widths of grooves includes a mechanism for maintaining static balance about the axis of rotation for all positions of the cutting blade within the range of adjustment. The router bit includes a main body adapted to be held and rotated by a chuck, and which includes a bore whose axis is parallel to but displaced from the axis of rotation of the main body. An arbor with an offset cutting blade is adjustably mounted in the bore, and the width of the groove is determined by the angular position of the arbor within the bore. However, such adjustment alters the static balance of the router bit about its axis of rotation. In accordance with the present invention, this source of unbalance is compensated by providing a counterweight whose position is dependent on the angular position of the arbor within the bore. In the preferred embodiment a cam on the shaft of the arbor bears against and determines the position of the counterweight.

Angular measurement method for a rotating machine

Abstract: The invention relates to an angular measurement method for a rotating machine using at least one sensor 2 disposed opposite a track coded with binary information disposed on a wheel 1 linked in rotation with the machine. The angular values are obtained by reading and storing a given number n of bits, each bit read and stored corresponding to an angular position defined by a unique code consisting of this bit and the n 1 previously read bits. The invention allows the number of sensors to be optimised, a single one possibly being sufficient, while allowing rapid initialisation and simple verification of the information read. Application to monitoring engine ignition.

Linear type seat recliner

Abstract: The present invention provides an incremental linear vehicle recliner seat. The invention utilizes a polygonal rod with threaded apices which is pivotally connected with the seat back. The rod is surrounded with a nut connected with the seat cushion. The nut is rotated alternatively between a locking position to threadably engage the apices of the rod and a release position allowing the rod to slide through the nut thereby allowing the angular position of the seat back to be adjusted.

Electronically commutated DC motor for driving rotating storage media

Abstract: The rotor of an electronically commutated DC motor has at least one permanent magnet having at least four poles, which are arranged concentrically with respect to the rotor rotation axis, are polarised essentially at right angles to the rotation axis, and are arranged adjacent to an annular magnetic return path part. The stator winding, which is accommodated in the annular gap between the rotor and the magnetic return path part, has a meandering conductor-track arrangement whose straight meander sections running to and fro consist of a number of parallel conductor sections. A device which detects the angular position of the rotor with respect to the straight meander sections running to and fro supplies signals to a drive electronics device which, for its part, controls the current flow through the conductor-track arrangement such that, in consequence, said arrangement produces a magnetic field which drives the rotor. Fitted firmly to the rotor is a bearing flange whose flange plane can be set to a few micrometres precisely with respect to a motor reference plane. A DC motor which is constructed in such a manner, is electronically commutated and has, for example, 40 poles, has an extremely constant rated motor rotation speed and, because of the high space factor in the magnetic gap, produces a high e.m.f. Such a motor can preferably be used as a drive unit in Winchester-disk stores.

Servo control system

Abstract: PURPOSE:To execute servo control sufficiently accurately at the time of low speed operation by considering the minimum changing unit DELTAtheta of an angular position theta and measuring a time required for the change of the theta by DELTAtheta to detect the theta CONSTITUTION:A servo control system has a speed detecting circuit based upon a digital circuit and rotational displacement is outputted as a pulse string from a motor 1 for driving a load such as a robot through a rotary encoder 2 The pulse string is inputted to a waveform shaping rotational direction discriminating circuit 3 to shape the waveform and discriminate rotational direction The 1st counting circuit is formed by a counter 4 and a counted number discriminating circuit 5 to detect the algebraic sum obtained until the rotational displacement of the motor 1 reaches DELTAtheta The 2nd counting circuit consisting of a counter 7, a register 8, etc finds out the time T required until the rotational displacement obtained by the 1st counting circuit reaches DELTAtheta Even if the rotation of the motor 1 is extremely slow, the speed (dtheta/dt) can be calculated highly accurately

Power combiner, polarizer and structure including a waveguide section rotated by a stepper motor arrangement

Abstract: In a waveguide structure, there is provided a waveguide section rotatable about its longitudinal axis and an electric DC stepper motor arrangement. The rotor of such an arrangement is constituted by magnetic returns fixedly mounted on the waveguide section, and has a rotation axis which coincides with the longitudinal axis of the section. The rotor is therefore rotatable with the waveguide section about the longitudinal axis of the same. The motor arrangement further includes a stator provided with a plurality of poles which cooperate with the magnetic returns to rotate the waveguide section so as to adjust as desired its angular position. When the waveguide section has a circular cross section and is provided with two diametrically opposed lines of tuning screws, the waveguide structure forms a microwave polarizer which can be used in a variable power combiner.

Apparatus for detecting the degree of rotation of a rotational axis

Abstract: The present invention provides a rotation detection apparatus of a rotational axis connected to an output axis system of a reduction gear to count the rotation of a rotational axis driven rotationally, including a reduction gear, with an integer reduction ratio, whose rotational axis of a driving source is connected to an input axis. The apparatus provides a position signal once every rotation of the output axis, and a rotation angle signal in response to the rotation angle of said input axis is output to correlate said output position signal with one of said rotation angle signals to count the rotation of the rotational axis by these position and rotation angle signals. An accurate rotation can be detected even at one-way high-speed rotation.

Regulating method of step motor encoder

Abstract: PURPOSE:To shorten a regulating work time by regulating the displacement of a slit plate so that the output waveform of a rotary encoder becomes the prescribed corresponding relationship to the stationary point of a step motor in a counterelectromotive force waveform. CONSTITUTION:An output shaft 5 is rotated at the certain prescribed speed by the secondary rotary force, the counterelectromotive force waveforms 3A, 4B of the exciting windings 3, 4 are observed, and compared with the output waveform C form a rotary encoder 2 simultaneously indicated with them. Thus, the angular position of the slit plate 13 is regulated and the waveform C of the encoder 2 is regulated corresponding to counterelectromotive force waveforms 3A, 4B, thereby unitarily corresponding the stationary angle position of a step motor 1 and the detecting angle position from the encoder 2.

Angular displacement sensor with long raster film

Abstract: The angular displacement sensor with the long raster film is a digitization angular displacement measuring device with photoelectric encoder. Two long raster film bands copied (or photoetchinged) are respectively pasted on the cylindrical surface and arranged in the vicinity. After the raster is completely transmitted by the incident light, cylinder moire fringe is formed, hai flushed with the angular displacement is formed by photoelectric conversion, electronic segmentation, etc., and values of comparable degree, cent and second are displayed. Compared with the traditional circle raster disk, the utility model has the advantages of low cost, easy fabrication, resolution of approximate 10'and convenient application in industrial measure. If the utility model is for the instructional instrument, students can study a series of the technologies and methods of up-to-date measure.

Dynamometer steering wheel with angular velocity measuring unit

Abstract: A device which is suitable for the experiment of the steering portability of various vehicles in the type of steering wheels and is used to measure the rotary torque of the rotation of the steering wheel, the angle and the angular velocity comprises a spoke-shaped bending moment-typed torque sensor, an inductance-type angular displacement sensor and an angular velocity sensor which is a microgenerator.