Showing papers on "Angular displacement published in 1994"

Sensorless control of permanent magnet synchronous motors

Abstract: The paper deals with the control of permanent magnet synchronous motors without any mechanical sensor. For this purpose a new flux model (“INFORM model”) is used, working properly at each operating condition, especially at low angular velocity. At higher angular velocity, an e.m.f.-based model is used. A Kalman filter estimates the angular position, the angular velocity and the torque. An optimal state controller is presented which yields good dynamic performance. The system is realized on a digital signal processor.

Milling force convolution modeling for identification of cutter axis offset

Abstract: This paper discusses the application of a convolution integral force model to the identification of the geometry of cutter axis offset in milling operations. This analysis builds upon the basis of linear decomposition of elemental local cutting forces into a nominal component and an offset-induced component. The convolution of each elemental local cutting force component with the chip width density in the context of cutter angular position provides an integral expression for the total cutting forces. By virtue of the convolution integration property, the total cutting forces in the frequency domain can be derived as closed-form functions of the cutting pressure constants, various cutting conditions, as well as the cutter offset geometry. Subsequently, the magnitude and phase angle of cutter axis offset are shown to be algebraic and explicit functions of the Fourier series coefficients of cutting forces at the spindle frequency. Following the theoretical analysis, experimental study is discussed to illustrate the implementation procedure for offset identification, and frequency domain data are presented to verify the analytical results. Potential industrial applications of this work include the real-time monitoring of dynamic cutter runout and the in-process compensation for the loss of tolerance or finish using automatic controls based on the feedback information of offset magnitude and phase angle.

Mechanical radial scan type ultrasound probe

Abstract: A mechanical radial scan type ultrasound probe which essentially includes: a tubular probe body having an ultrasound transducer element mounted at the fore end of a rotation transmission means; an operating unit accommodating a rotational drive means for driving a rotational shaft, and an angular position detector means for detecting angular positions of the rotational shaft; and a forcibly releasable joint means interposed between the rotation transmission means and the rotational shaft in association with forcibly turning means, the forcibly releasable joint means being arranged to couple the rotation transmission means securely with the rotational shaft to follow the rotation of the latter under normal condition and to permit relative rotations of the rotation transmission means and the rotational shaft when the forcibly turning means is manipulated with a force larger than the coupling force of the releasable joint means, for shifting the angular position of the ultrasound transducer element relative to an initial end position of radial scan field.

Variable speed constant frequency synchronous electric power generating system and method of using same

Abstract: A variable speed constant frequency synchronous electrical generating system includes a generator rotor (33) with a polyphase field winding (35) whereby the position of the electromagnetic field relative to the rotor structure (33) can be controllably varied. The system includes means (48) to substantially instantaneously determine the angular or rotational position of the generator rotor (33) relative to a reference member (44) rotating at a reference speed. The system further includes means (46) whereby the angular position of the generator electromagnetic field relative to the structure of the generator rotor (33) is maintained essentially the same as the angular position of the reference member (44), and is substantially independent of the rotational speed of the generator power input shaft (31).

Displacement machine with electronic motor synchronization

Abstract: In a displacement machine for compressible media having at least two rotors (14a-c) which are configured as profiled bodies and whose profiles engage with one another in the manner of gearwheels during rotation, the individual rotors are respectively driven by their own electric motors (9a-c) and are kept synchronous in rotational speed and angular position by electronic closed-loop and/or open-loop control units (1; 25a-c) in accordance with the transmission ratio of the displacer unit stage. The electronics can be employed for monitoring further operating data of the pump and also for matching the pump output by changing rotational speed. It can also be used as an overload protection. The rotational speeds and rotational attitudes of the rotors are controlled individually and independently of one another, the required attitude values being specified to the individual control units (25a-c) by means of a main control unit (1).

Light distribution control device for vehicular headlamp

Abstract: A light distribution control device includes a projection type headlamp for a motor vehicle in which a clear cut line in a light distribution pattern is varied by rotating a shade for forming a clear cut line about a horizontal support shaft. A vehicle-to-vehicle distance measuring sensor for measures a distance between a vehicle carrying the light distribution control device and another vehicle running in front of the former, and a shade rotation control unit controls the rotational position of the shade. The angular position of the shade at which the amount of glare at an eye point specified by a vehicle-to-vehicle distance and a rotation angle of the steering wheel is smaller than a tolerable quantity of glare is stored in the form of table data in the control unit. The control unit sets the rotational angle of the shade on the basis of distance information measured by the vehicle-to-vehicle distance measuring sensor, and the steering angle of the steering wheel.

Method and device for adjusting the angular position of a camshaft

Abstract: A method to adjust the angular position of a camshaft, which is related to the arc of a crankshaft rotation, to a setpoint angular position with the help of a final controlling element that is triggered by an actuating signal from a controlling device that becomes operational when a control program is run. The final controlling element is able to be triggered in each case by one of three values of the actuating signal; the re-adjustment rate (v-- ESTIMATED) of the camshaft is estimated for its level at the beginning of the subsequent program run; from this re-adjustment rate and the known time response (c, v-- END) of the camshaft re-adjustment, after the switch is made to the actuating signal from the hold value, a special adjustment angle (α-- ESTIMATED+) is estimated; and the change is already made from the early or late value of the actuating signal to its hold value when the deviation between the adjustment angle (α-- ESTIMATED+) and the setpoint angular position lies within a tolerance band. The angular position of the camshaft is thereby able to be adjusted in a rapid and stable manner.

Device for detecting the angular position of an object

Abstract: A device for detecting the angular position of an object uses an MR-sensor (2) arranged in a magnetic field. One component (H^¨B7 or H^¨B7g) and one axis of reference (3) of the MR-sensor (2) are rotatable in an axis of rotation (5) with respect to each other around an angle of rotation (THETA or PHI) which is unambiguously correlated with the angular position of the object, whereas the electric resistance of the MR-sensor (2) unambiguously depends from said angle of rotation (THETA or PHI). According to the invention, the MR-sensor (2) is designed with a giant MR-layered system having at least one measurement layer (12) with a magnetisation (M^¨B7M) which may be rotated by the magnetic field (H^¨B7 or H^¨B7g) and at least one biasing layer (16) with a constant magnetisation (M^¨B7B) and whose resistance depends from the angle (ALPHA) between both said magnetisations (M^¨B7M and M^¨B7B).

Device for detecting the angular position of an object using a magnetoresistive sensor

Abstract: A device for determining the angular position of an object uses an MR sensor which is set up in a magnetic field, where one magnetic field component (H or H g ) and a reference axis of the MR sensor can rotate relative to one another in a plane of rotation through an angle of rotation (Θ or φ) which has an unambiguous correlation to the angular position of the object; and the electric resistance of the MR sensor is an unambiguous function of this angle of rotation (Θ or φ). The MR sensor is designed with a giant MR layer system that contains at least one measurement layer with magnetization (M M ) that can be rotated through the magnetic field (H or H g ); the giant MR layer system also contains at least one biasing layer with a constant magnetization (M B ); and the resistance of the giant MR layer system is a function of the angle (α) between these two magnetizations (M m and M B ).

Piezoelectric torsional actuator

Abstract: Piezoelectric torsional actuators have been developed from single ceramic cylindrical bodies using PZT based high d constant piezoelectric ceramics. The actuator geometry is able to produce rotational motion directly by DC voltage control without conventional complex conversion from XY direction motions. The key feature of this actuator is the interdigital electrode on the outer surface of the cylinder at an angle of 45° from the length axis of the cylinder, and the design of this electrode is critical for adjusting torsional angle and driving voltage. When the cylinder wall thickness and the ratio between electrode width and pitch are kept constant, the rotational angle is approximately proportional to the electric field, i.e. the narrower electrode gap needs smaller driving voltage in order to obtain a certain rotational angle. Among the three different diameter samples tested, actual rotational displacements are the same under the same conditions. Therefore, the rotational angle is reversibly proportio...

Dual drive conveyor system with vibrational control apparatus and method of determining optimum conveyance speed of a product therewith

Abstract: A dual drive conveyor system which has a vibration control mechanism for adjusting the application of vibratory force to the material-conveying member without changing the direction of the resultant line of vibratory force generated thereby, wherein the vibration generator connected to the material-conveying member includes a pair of opposing parallel counter-rotating eccentrically weighted master shafts driven by a first drive motor, and a pair of opposing parallel counter-rotating eccentrically weighted slave shafts driven by a second drive motor, the master and slave shafts rotating in such manner that the direction of the resultant line of vibratory force is substantially only parallel with the longitudinal centroidal axis of the material-conveying member. The vibration control mechanism monitors the angular position of the eccentric weights carried by the slave shafts relative to the eccentric weights carried by the master shafts and compares the relative angular displacement therebetween to a preselected target angular displacement, and automatically and periodically adjusts the speed of the drive motor for the slave shafts in order to change the angular position of the eccentric weights carried thereby to cause the relative angular displacement between the eccentric weights carried by the slave and master shafts to match the preselected target angular displacement therebetween. The target angular displacement may be changed during the operation of the conveyor system to cause the vibration control mechanism to readjust the relative positions of eccentric weights carried by the master and slave shafts to meet a newly selected target angular displacement therebetween. By monitoring the speed of conveyance of a given material for various selected angular displacements between eccentric weights carried by the slave and master shafts, an optimal application of vibratory force can be determined for providing the best conveyance for any such material.

Computing Body Segment Trajectories in the Hybrid III Dummy Using Linear Accelerometer Data

Abstract: An analytical method was developed and tested using several mini-sled and Hyge sled tests to calculate the planar trajectory of a Hybrid III dummy head. Aimed at expediting the Hybrid III test analyses, it may provide an opportunity for cost savings through reduced hardware and manpower on film analyses. Transformation from the moving coordinate to the laboratory coordinate is based on the angular positions integrated from the derived angular accelerations. Gravitational correction of the linear accelerometers was found to be insignificant. The computed head trajectories were compared to the ones obtained from the high speed film images. Accuracy of the calculated head trajectory relies heavily on the accuracy of the computed angular acceleration. Strain-gaged accelerometers are not dependable at all times during an impact and an ill-behaved signal for a very short period may create a significant drift in computed displacement due to double integrations. Accuracy of the currently available accelerometers is not high enough for an angular displacement calculation. A new generation of accelerometers with higher accuracy, or an angular velocity sensor may provide more accurate angular displacement for trajectory analyses. The redundancy of the in-line accelerations helps improve the isolation of erroneous outputs and improve accuracy of the procedure. Language: en

Range of motion analysis system

Abstract: A system and method are disclosed for measuring range of motion of a body joint formed between a first body portion and a second body portion. The system includes a range of motion sensor comprising a support linkage having a first link joined to a second link for relative movement therebetween. The first link is adapted to be retained for movement with the first body portion and the second link is adapted to be retained for movement with the second body portion. An angular sensing device senses angular displacement of the second link relative to the first link and provides a representative indication thereof. A force sensing device joined to the support linkage senses the applied force to the first body portion and provides a representative indication thereof. Output signals from the angular sensing device and the force sensing device are provided to a signal processor for recording and analysis.

Vertical reference and attitude system

Abstract: The present invention provides a vertical reference that includes sensors providing signals indicative of angular tilt from the predetermined reference axis and the rate of angular tilt; an integrator to integrate the angular rate signal to provide a dynamic angular tilt signal; a pendulum to provide a signal indicative of angular displacement relative to the predetermined axis; a first amplifier for filtering and amplifying the dynamic angular tilt signal and the angular displacement signal to produce a first amplified signal; a second amplifier for filtering and amplifying the dynamic angular tilt signal and the angular displacement signal to produce a second amplified signal; and a dual input amplifier for combining and amplifying the first and second amplified signals to produce an output signal indicative of vertical reference and attitude. In another embodiment of the present invention a vertical reference apparatus includes a cascaded second-order filter or control loop having a first second-order loop that receives its inputs from the pendulum and the angular rate sensor and a second second-order loop that receives as its inputs the output signal of the first loop and the angular rate sensor. The output of the second loop is provided to a control system for the structure whose orientation is desired to be measured or stabilized. In this alternative embodiment of the present invention each control loop includes a summing amplifier, a summing damped integrator, an inverting amplifier, and an integrator.

Detector of range of laser

Abstract: PURPOSE: To determine not only an object space to which pulsed light is radiated but also the positioning angle by reflecting angulated continuous pulses and transmitting the angular position at that time to an evaluation circuit. CONSTITUTION: Light pulses 12 of a pulse laser 11 are reflected by the central region 24 of a rotation mirror 16 through a transmission lens 33, the transmitted light beam 12 is reflected by an object 14 in a measurement region 12 to become a reception beam 20 and the beam 20 enters the circular region 47 of the mirror 16. Then, a photodetection part 22 receives 23 the final light pulses 12' which pass through the photoreceptor lens 25 and a computer 38 of a connected evaluation circuit computes the space (d) of the object 14 based on the time interval between transmission and the light reception of the light pulses 12, 12'. At that time, in a light reflecting apparatus 15, the mirror 16 is continuously rotated by the rotation of a rotation plate 28 and continuous light pulses 12 having a fluctuated angle are reflected to the region 13. Simultaneously, the angle converter 29 sends the angle position of the apparatus 15 at the time to the evaluation circuit. Consequently, not only the space d of the object 14 but also the positioning angle can be determined.

Vehicle wheel with rim offset from axis of rotation

Abstract: The semifinished casting for an alloy road wheel undergoes three successive machining operations in which material is removed by stages to produce an inner circumferential seating, destined ultimately to accommodate one bead of a tire, a center hole coaxial both with the inner seating and with the axis of rotation of the wheel, also a set of fixing holes of which the axes describe a circle centered on the axis of rotation, and finally, an outer circumferential seating destined to accommodate the remaining bead of the tire, which is offset from the axis of rotation in such a way as to achieve a non-uniform distribution of mass, limited to the part of wheel affording the outer circumferential seating, that varies progressively with the change in angular position around the axis of rotation between a maximum and a minimum value.

Vibration suppression of multi-modal translational motion using a rotational actuator

Abstract: In recent the work of Wan et al. it was shown that a rotational torque actuator with attached eccentric mass can be used to globally stabilize a one-mode translational oscillator. A family of globally stabilizing nonlinear feedback control laws was derived by using partial feedback linearization and integrator backstepping. These control laws accounted for the strongly nonlinear coupling between the rotational motion of the eccentric mass and the translational motion of the oscillator. In the present paper, we extend these results to address the problem of stabilizing the translational motion of multi-mode systems with a rotational actuator. The controller synthesis methodology extends the previous work to address a system involving six state variables. Detailed numerical simulation of the closed-loop system illustrates the angular position of the eccentric mass and the harmonic content of its motion in suppressing both modal frequencies. >

A Trajectory Preprocessor for Antenna Pointing

Abstract: A trajectory-preprocessing algorithm has been devised which matches antenna angular position, velocity, and acceleration to those of a target This eliminates vibrations of the antenna structure caused by discontinuities in velocity and acceleration commands, and improves antenna-pointing performance by constraining antenna motion to a linear regime The algorithm permits faster acquisition times and preserves antenna-tracking capability in situations where there would otherwise be an unacceptably sudden change in antenna velocity or acceleration A simulation of DSS 13 shows that this preprocessor would reduce servo error to 1 mdeg during acquisition of a low-Earth-orbiting satellite

A simple angular alignment technique for a polarization-maintaining-fiber

Abstract: Simple and accurate techniques for angular alignment of a polarization-maintaining-fiber (PMF) to a linearly polarized input beam are required for many optical-fiber applications. We consider an alignment technique wherein a short length of PMF undergoes a large temperature excursion and the output beam from the fiber is simply monitored by a linear polarizer and a power meter. Upon carefully considering the results for rotation angles near alignment, an accuracy better than 0.2/spl deg/ as well as a measurement of the fiber crosstalk are obtained. >

Electric driving device, particularly for printing machines

Abstract: The system contains an electric motor (F,G) whose rotor (F) is designed for stiff direct connection to the functional part (D,D1-D4). One or more angular position transducers (44,46) detect the angular motion of the rotor and/or functional parts. A signal processing module (51) receives the transducer signals as actual angular position values and compares them with demand values. The signal processor drives the electric motor via a power amplifier (47,48) . The rotor can be integrated with the functional part and/or made in one piece with it.

Grinding out-of-round workpieces

Abstract: At least one eccentric cam of a camshaft 8 is ground by a tool employing an abrasive belt 17 or a grinding wheel while the camshaft is rotated about its axis at a constant angular speed or at a varying angular speed. The tool is mounted for controlled movement in a first direction X at right angles to the axis of the camshaft and also for controlled movement in a second direction Y at right angles to the axis as well as at right angles to the first direction. The movements of the tool in the first and/or in the second direction are regulated in dependency on changes of angular position of the camshaft. The tool can employ several belts or several grinding wheels for simultaneous treatment of two or more axially spaced-apart cams on a camshaft.

Optical reporting reproducing device having fixed and movable optical systems

Abstract: An optical record reproducing device including a movable optical system for moving along a radial direction of an optical disc, a separated optical system including a light source and a separated fixed optical system, a tracking control system having a reflective mirror for reflecting a laser beam irradiated from the light source toward the movable optical system and an accurate angular displacement mechanism including an angular displacement detector for directly detecting an angular displacement of the reflective mirror so as to control the movable optical system accuarately.

Performance of a double-star synchronous generator with bridge rectified output

Abstract: In this paper, the performance of a double-star synchronous generator with bridge rectified output is studied from the fundamental machine equations. The generator has two stator windings shifted by /spl pi//6 electrical radians, which with their bridges can be connected either in series or in parallel. Therefore the double-star synchronous generator with rectifier load can have two major operation modes. Using the fundamental machine equations, the expressions of displacement angles and commutation angles are derived under these operation modes. The performance of the double-star synchronous generator with bridge rectified output can be predicted from given load current, field current, generator speed, bridge delay angle and its parameters. Theoretical results are compared with experimental results obtained from a laboratory machine. >

Method for controlling the switching-off process in the phase windings of a reluctance motor

Abstract: A process is disclosed for controlling the switching-off process of the branches of a reluctance engine whose stator is provided with windings to which are transmitted current pulses calculated as a function of angular position and speed of rotation of the rotor according to a predetermined algorithm. The excited branch is switched off when a switching-off angle is reached after a zero crossing reference angle. Two ranges of operation called "chop" range and blocked voltage range must be differentiated. The switching-off angle for both ranges of operation of the reluctance engine is calculated according to the same algorithm and is set by a regulator. In the lower speed of rotation range, the "chop" range, a pulse width modulated voltage is applied to the conductive branch, and in the upper range, the blocked voltage range, a constant voltage is applied. In both ranges, the switching-off angle is calculated from engine parameters and actual operation values to maximize torque yield and to trigger the switching-off process by converting said values into a switching-off pulse that switches off the conductive branch.

Indexed operating head for automatic machine tools

Abstract: An operating head for automatic machine tools, which includes a fork fitted on a support having various degrees of freedom; a mechanism for the numerical control of rotation of the fork around its axis; a support for a chuck, being fitted up on said fork and rotatably relative to it around an axis which is orthogonal to the former, under a numerical control; a shaft coaxial with the axis of rotation of the support for the chuck and connected, by the use of bevel gears, at one end to devices for the transmission of motion and, at its other end, to the shaft of the chuck wherein devices are provided for allowing change of the angular position of both the fork and support for the chuck, keeping the tool in contact with the piece to be machined.

Fan beam computed tomography apparatus

Abstract: A computed tomography has a frame carrying an x-ray source and an x-ray detector which are rotated by the frame around an examination subject to obtain a series of exposures from different angular positions. The x-ray source emits a fan beam from a focus and includes a focus deflecting unit for adjusting the position of the focus in the event that, due to mechanical wear or play, the frame is caused to rotate around a point which differs from the intended rotational center. The intended rotational center is a point through which a straight line extending between the focus and the center of the radiation detector always proceeds for every angular position. Two sensors are disposed on the rotating center frame in addition to the x-ray source and the radiation detector, these two sensors respectively defining two measuring points and supplying output signals corresponding to the respective positions of these measuring points relative to a reference point on a stationary part of the apparatus. The output signals are supplied to correction electronics, which also receives an output signal from a focus control unit, and effects a deflection of the focus by means of the focus deflecting unit as needed to maintain rotation of the frame around the intended rotational center.

Electric drive for positioning one or more elements in a machine ; driving device with an angle indicator and printing machine

Abstract: The system contains an electric motor (F,G) whose rotor (F) is designed for stiff direct connection to the functional part (D,D1-D4). One or more angular position transducers (44,46) detect the angular motion of the rotor and/or functional parts. A signal processing module (51) receives the transducer signals as actual angular position values and compares them with demand values. The signal processor drives the electric motor via a power amplifier (47,48) . The rotor can be integrated with the functional part and/or made in one piece with it.

Method and device for adjusting the angular position of a cam shaft

Abstract: A method is disclosed in which the following procedure is adopted to adjust the angular position of a cam shaft in relation to the rotational angle of a crank shaft to a desired angular position with the aid of an actuator element which is driven with a control signal by a control device operating by running through a control program: - the actuator element can be driven with in each case one of three values of the control signal; - the adjustment speed (V_ESTIM) of the cam shaft which will be present at the start of the following program run is estimated; - a specific adjustment angle ( alpha _ESTIM+) is estimated from this adjustment speed and the known timing characteristic (c, v_END) for the cam shaft adjustment after the switching over to the control signal from the holding value; and - the system then switches over from the early value or late value of the control signal to its holding value even if the deviation between the adjustment angle ( alpha _ESTIM+) and the desired angular position lies within a tolerance margin. With this method and a device which operates according to it it is possible to adjust the angular position of the cam shaft in a quick and stable way.