Abstract: A sensor for measuring the angular position of a rotor relative to a stator has firstly a rotor made of a magnetic material and including 2 p lobes, where p is an integer. A stator is positioned around the rotor. The stator is made of a magnetic material and includes a number of teeth equal to 2n.p, where n is the number of phases of the sensor. Each tooth is surrounded both by an excitation first winding and by reception second winding. The excitation windings are connected together in series and disposed on the teeth such that the windings on two circumferentially adjacent teeth produce magnetic flux in opposite directions. The set of said excitation windings are powered by an alternative current or voltage. The reception windings of the same phase and offset by 180 electrical degrees are connected together in series. The envelope of the signal at the terminals of each of the pairs of reception windings represent the angle of rotation of the rotor relative to the stator, to within a scaling factor.

Abstract: An encoder interface for interfacing an encoder having a first part defining a first axis to a structure having a second part defining a second axis substantially parallel to the first axis includes a portion for translating the first part with respect to the second part in a direction transverse to the first axis and a portion for rigidly rotationally stabilizing the first part with respect to the second part against a rotation of the first part about the first axis induced by a translation of the first part with respect to the second part in the direction transverse to the first axis.

Abstract: Disclosed is herein a rotational position detector for a robot which can always accurately detect the rotational positions of each rotational member based on the output values from each absolute value detector regardless of the rotational conditions of the rotational member. Each absolute value detector (resolver) is connected to each rotational member such that the ratio of the rotational angle period of the absolute value detector to the rotational angle period of the rotational member is set to be 1:N (N is an integer larger than 1).

Abstract: An encoder system and method wherein an encoder element driven by a motor has a series of segments arranged along a path with adjacent segments having different properties meeting at an edge or transition, two adjacent segments of different properties comprising a cycle and the encoder element having a number of cycles equally spaced along the path and defining a relatively coarse pitch relationship. A coupling medium, preferably optical, images the encoder segments onto a number of individual sensor elements of an array, such as a charge-coupled device sensor, wherein the sensor elements are spaced at a relatively fine pitch along the array.

Abstract: A variable reluctance resolver comprises a rotor core and stator magnetic poles structured to enable reluctance in the space between the rotor core and stator magnetic poles to be changed by the positions of the rotor core and to make the fundamental wave component of the reluctance variation N cycles per revolution of the rotor core, N being an integer of 1 or more; first magnetic poles having a predetermined number 3N phases arranged at equal intervals on the stator magnetic poles; second magnetic poles having a predetermined number of 3N phases formed in the central positions between the first magnetic poles; excitation coils arranged individually between the first and second magnetic poles and connected in series to each other for each phase of the magnetic poles; a current change detecting device for detecting current value change due to the variation of the reluctance when an alternating current is applied to the magnetic coils of each phase of the magnetic poles; 3N difference value calculating devices

Abstract: An improved servomotor control method where a multiplier ratio DMR is computed in advance by an arithmetic unit (20) from a traveling distance L of a movable machine element per revolution of a servomotor, a traveling distance R per pulse of a move command, and a number N of incremental pulses generated by an absolute position-detecting pulse coder (18) per revolution of the servomotor. A move command (.DELTA.R.sub.n) is accumulated by a move command accumulator (11), an absolute position (P.sub.A ') output by the absolute position-detecting pulse coder (18) is multiplied by the multiplier ratio DMR. A difference (E.sub.r) between a value (P.sub.c) obtained by accumulating the move commands and the result (P.sub.A) of the multiplication operation is computed as a position error, and rotation of the servomotor (17) is controlled by using the position error.

Abstract: An auxiliary resolver position tracking (RPT) system for an industrial robot includes a resolver excitation and monitoring system which is powered by an uninterruptable power supply which includes a battery. The RPT system generates trapezoidal excitation pulses for the resolvers in the robot when no external excitation signal is applied, for example when the robot is shut down. Since there is relatively little motion to be detected in these instances, the RPT system switches between a slow position sampling rate, when no motion is detected, and a fast sampling rate when motion is detected. When operating on battery power, the RPT only switches to the fast sampling rate when motion is detected. To ensure that no motion data is lost when the system switches back to the slow sampling rate, the high sampling rate is maintained for a time sufficient to capture any residual motion of the robot.

Abstract: An auxiliary resolver position tracking (RPT) system for an industrial robot includes a resolver excitation and monitoring system which is powered by an uninterruptable power supply which includes a battery. The RPT system generates trapezoidal excitation pulses for the resolvers in the robot when no external excitation signal is applied, for example when the robot is shut down. Since there is relatively little motion to be detected in these instances, the RPT system switches between a slow position sampling rate, when no motion is detected, and a fast sampling rate when motion is detected. When operating on battery power, the RPT only switches to the fast sampling rate when motion is detected. To ensure that no motion data is lost when the system switches back to the slow sampling rate, the high sampling rate is maintained for a time sufficient to capture any residual motion of the robot.

Abstract: An auxiliary resolver position tracking (RPT) system for an industrial robot includes a resolver excitation and monitoring system which is powered by an uninterruptable power supply which includes a battery. The RPT system generates trapezoidal excitation pulses for the resolvers in the robot when no external excitation signal is applied, for example when the robot is shut down. Since there is relatively little motion to be detected in these instances, the RPT system switches between a slow position sampling rate, when no motion is detected, and a fast sampling rate when motion is detected. When operating on battery power, the RPT only switches to the fast sampling rate when motion is detected. To ensure that no motion data is lost when the system switches back to the slow sampling rate, the high sampling rate is maintained for a time sufficeint to capture any residual motion of the robot.

Abstract: A waveform generator for a resolver transducer or the like is described. Such generator forms two 3-level waveforms which approximate sinusoidal waveforms for the excitation and/or output detection of such a resolver. Each of the sinusoidal waveforms is formed by combining a pair of digitally programmed bi-state signals which have their phases shifted relative to one another by an amount proportional to an angular input variable. The result is that the amplitude of these sinusoidal waveforms which are formed are representative of the sine and cosine of such variable.

Abstract: The present invention pertains to a process and a device for adjusting an axis, especially an axis of rotation, wherein an adjusting sensor (4) is provided on the axis (2). A position-measuring system (1) with internal cyclic absolute signaling is provided, by means of which the mechanical zero point marking on the axis is reached, and the cyclic absolute actual position value found there is read and entered into the axis control unit (16). Starting from this, the displacement to the desired adjusted position of the adjusting sensor is calculated in the axis control unit (16), and this position is reached with the axis (2) automatically or manually. At this adjustment position, which is located in the middle of a selectable transducer cycle of the position-measuring system, the adjustment of the adjusting sensor (4) is performed.

Abstract: A simplified magnetic resolver for measurement of rotary or linear position which comprises a permanent magnet rotor and two pairs of sensing coils. The resolver produces sine and cosine outputs compatible with known resolver-to-digital converters.

Abstract: A rotational position detection encoder includes at least two detection heads located along a slit string of a code plate. The detection signals of one of the detection heads are processed to generate a plurality of phase offset signals having successively differing phases with respect to each other. The phase offset signals are compared with the detection signals of another of the detection heads, and the phase offset signals having a phase closest to that of the detection signals of the other detection head are selected and added to the detection signals of the other detection head. As such, detection signals having conforming phases are obtained without minute positional adjustment of the detection heads.

Abstract: A robot control apparatus includes a sine wave signal-outputting device, an operating device, a command device for outputting a current value, a substracting device, an electric power amplifying device, and a programmable filter. The outputting device outputs sine wave signals of first and second phases having a phase difference of approximate 90.degree. generated by a position shift of a movable portion of a motor for driving an arm of a robot. The operating device determines the difference between a product of a value corresponding to the first phase signal and a value obtained by first-order differentiating a value corresponding to the second phase signal and a product of a value corresponding to the second phase signal and a value obtained by first-order differentiating the value corresponding to the first phase signal.

Abstract: An apparatus for measurement of absolute position of a movable machine member is provided. The machine member is moved by a motor and reduction device producing rotation of the machine member in proportion to relative rotation of the motor rotor and motor stator. Two angular position measuring devices provide output signals representing relative positions related to the machine member position and differentiated one from another.

Abstract: Position indicating apparatus that allows position detection with windings provided on only one of two members and an output signal in which the position of one of the members relative to the other member is directly encoded in the phase of the output signal. A first member has a plurality of spaced ferromagnetic protuberances. A second member, movable with respect to the first member, contains at least first, second and third poles located in proximity to the protuberances and spans 360 spatial degrees. Each pole contains a winding with one terminal of each winding connected to a common point. The windings are driven at a fundamental carrier frequency with individual signals of equal amplitude but different temporal phases that span 360 temporal degrees. Circuit means detect the phase of the resulting carrier signal at the common point, which phase is linearly representative of position.

Abstract: The synchronous motor has a pick-up (C) measuring the position of its rotor and a power-varying circuit (VP) operating as a current generator. A power-varying circuit (VP) is controlled by a programmed microprocessor (MP) receiving information specifying the desired speed for the motor (M), information representative of the difference between the current speed and the desired speed for the motor, information from said pick-up relating to the position of the rotor of the motor, and stored information in order to enable it to force zero phase difference between the current I delivered by the power-varying circuit and the potential difference U across the terminals of the motor windings, thereby minimizing the installed power required of the power-varying circuit in order to run the synchronous motor and power-varying circuit at constant power. A control system operates the motor at constant power.

Abstract: A motor feedback control system which in addition to a quantized digital position feedback value, uses a feedback signal which represents the error between the actual motor position and the quantized digital position. The error function is combined with the quantized digital position value to produce a digital position value with greater resolution. The combined value is differentiated to produce a velocity value for velocity feedback control of the motor.

Abstract: Disclosed is a microcontroller based Resolver-to-Digital converter in which synchronous sample-and-hold type demodulation is used with an optimum time of the sample-and-hold established by control of the phase and the magnitude of the reference voltage supplied to the resolver as a function of the resolver's electrical characteristics, thus minimizing the quadrature and the even harmonics effects which are a byproduct of the resolver. The demodulated resolver outputs are filtered and are converted to digital form with the use of an A/D converter integral or external to the microcontroller. The magnitude of the reference voltage is set to an optimum value in order to utilize the full range of the A/D converter. Using digital signal processing techniques and known trigonometric identities the shaft angle of the resolver is extracted from the A/D outputs and supplied to the output latches in continuous or bus controlled fashion.

Abstract: A DC to DC sine/cosine positioning servo system has an electro-mechanical DC to AC converter. The latter includes a DC torquer, having a rotor with respective windings for receiving two DC input signals proportional to the error signals detected. Mechanial movement of the rotor is proportional to the relative values of the two input signals. The rotor of a synchro control transmitter is mechanically coupled to the rotor of the DC torquer. A reference oscillator is provided which produces an AC output voltage at a predetermined frequency. The oscillator output is connected to the rotor of the control transmitter. The stator windings of the control transmitter are connected to the stator windings of a control transformer. The rotor of the control transformer produces an output voltage directly proportional to the relative angle between the rotor of the control transformer and the stator windings.

Abstract: A resolver driver circuit uses sine and cosine values stored in a read only memory to generate sine and cosine waveforms by sequentially reading the stored values and passing them through a clocked data latch to a digital-to-analog converter. The output of the digital-to-analog converter is filtered to remove quantization error. Phase error produced by the filtering and other sources is detected by timing the zero crossings of the sine and cosine waveforms and comparing them to a master synchronization signal. Phase error is corrected by controlling the timing of the latch which passes data to the digital-to-analog converter.

Abstract: A rotary control signal generating device, such as a resolver, which comprises an internal stator including a magnetic system having first and second ring-shaped pole pieces with generally cylindrical, axially spaced, outwardly facing first and second pole surfaces. These pole surfaces are generally concentric with respect to a central axis and have the same outer diameter. The two pole pieces each include a given number of equally spaced coil receiving slots with axially spaced pole pieces aligned to form sets of circumferentially spaced slots. The stator includes a multiturn or primary exciter winding between the two pole pieces and wound concentric with the axis, whereby an AC voltage magnetizes the pole pieces. The stator further includes two offset sensing windings on the same pole pieces and in the axially aligned sets of slots.

Abstract: A sector is provided on a rotary shaft of a stepping motor. Two end edges of this sector define two reference positions. When a sensor detects one of the end edges, a reset signal generator generates a reset signal to reset a counter which counts driving pulses for the stepping motor or fractions thereof. The reset signal generator also generates a distinguishing signal representing which end edge of the sector is detected. The rotary position of the stepping motor is determined based on the content of the counter and the distinguishing signal.

Abstract: A separate adaptive noise canceller receiving a reference input of a rotor speed synchronization pulse is connected in the X and Y axis positional control loops of a magnetic bearing utilized to position a rotor suspended thereby. The output of the noise canceller is self-adjusting by the inclusion of an adaptive filter implementing a least mean square algorithm to force the gain of the control loop to zero at not only the fundamental of the rotational speed, but all harmonic frequencies thereof, thereby reducing the vibration and control system power dissipation of the magnetic bearing at the rotational fundamental as well as at the rotational harmonics.

Abstract: A double motor feed control system for controlling a relative linear feed motion between two objects, such as a rail and a table of a linear motion rolling contact bearing assembly. The double motor feed control system includes a first motor, a threaded feed shaft driven to rotate by the first motor, and a slider assembly threadably connected to the feed shaft. The slider assembly includes a nut which is fitted onto and in thread engagement with the feed shaft, an inner ring fixedly attached to the nut and provided with a rotor, and a motor housing rotatably supported on the rotor through a pair of ball bearings and provided with a stator in opposite arrangement with the rotor to thereby define a second motor. By controlling the direction of rotation of each of the first and second motors, the feed speed may be selectively set at a fast or slow speed.

Abstract: A linear resolver utilizes multiple pairs of nulled coil sets arranged co-linearly for sensing the position of multiple edges of a magnetically permeable object. An excitation coil produces an alternating magnetic field which is normally weakly coupled to the nulled coil sets across a magnetic gap. As the object covers the area of the gap, the coupling between the excitation and the individual coils in a nulled coil set is increased. Each nulled coil set produces an output which varies cyclically with increasing coverage of the object. The two nulled coil sets in each pair of nulled coil sets are offset from each other so that their cyclical outputs are offset by one quarter cycle, or 90.degree. with respect to the area of coverage by the object. Detection means are provided which resolve the outputs from a pair of nulled coil sets to precisely determine the position of the object edge. Each nulled coil pair is processed separately by the detection means so that multiple edges can be detected.

Abstract: An improved torque control for a brushless DC motor is disclosed. A torque command A of a time varying nature is applied to an excitation winding which is magnetically coupled through a resolver to produce output signals respectively on sensing windings of Acosine .theta. and of Asine .theta. wherein .theta. is the angular position of an armature and resolver of the motor. Armature windings respectively coupled to the sensing windings are driven by signals proportional to or equal to the signals sensed by the sensing windings to produce a torque equal to A.

Abstract: A numerical control apparatus according to the invention reliably eliminates the influence on positional accuracy of static resistance and dynamic resistance, which act as disturbance upon a servo loop, when a semi-closed loop forms a servo system for positioning, by numerical control, a machine tool or the like driven by a servomotor. The numerical control apparatus has a backlash correction function and supplies the servo system with a backlash correction data BL(i) distinguished from an ordinary move command BL(i). In order to eliminate a shift from a commanded position due to the aforementioned disturbance, an offset command corresponding to frictional torque Fa in the mechanical system of the machine tool or the like is applied to the servo system as a torque correction signal FR(i) in accordance with the backlash correction data BL(i).

Abstract: A closed loop motor system having a motor with a plurality of poles and motor windings associated therewith. The poles define full step motor output positions. The system is of the type that assigns intermediated current values to the motor windings for fine step positions of the motor. The system also comprises a motor output position encoder for generating an integral and fixed number of encoder pulses as the motor moves between any two motor poles. The pulses are equally spaced and at least some corresponding to the fine step positions. An initializing current comprising components for applying full step current values to motor windings for a time interval in which the motor output is assumed to align with a full step position, and components for zeroing the count in the counter and assigning the torque angle value, whereby the encoder does not require alignment relative to the motor.

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.

Abstract: A relative position indication system comprises a cyclical position sensor which includes first and second plates having cyclical windings thereon. The position indication system is operative for determining the relative cycle position between the windings on the first plate and the windings on the second plate within a single cycle and for determining a cycle count representing the number of whole cycles by which the first and second plates have been repositioned relative to each other. The position indication system is further operative for combining the relative cycle positions with the cycle count in order to determine the overall relative position of the plates, and it is operative for updating the cycle count without updating the relative cycle position each time the plates are aligned in a zero or initialized position.

Abstract: In a sensor having a drive winding for establishing a forward field, an electrically conductive screen is displaceable relative to a sense winding. In the presence of the drive field, eddy currents are generated in the screen to establish a counter-field opposing the forward field, so that the sense winding is shaded by the screen to a varying extent during relative displacement of screen and sense winding and the voltage induced in the sense winding is accordingly correspondingly varied. Application of a high frequency input to the drive winding results in a modulated output from the sense winding which may be demodulated to provide a signal indicative of screen position relative to sense winding. The position signal may be further processed to provide a speed signal. The sensor may assume a multiplicity of linear or planar, rotational and axial or solenoidal configurations.

Abstract: A direct drive motor system for controlling driving of the joints of a multi-jointed robot, comprising a motor portion, a rotation detecting portion, a position control portion, a speed control portion, a driving circuit and a tuning portion, wherein the motor portion is of an inductor type, the rotation detection portion uses an optical rotary encoder or magnetic resolver, and the position control portion is arranged to control in a feedback manner the rotational position of the motor with a tertiary servo system with software. The system's driving circuit has a feedback control loop for the current of the motor coil, and a detection circuit for the current includes a small signal isolator. The tuning portion tunes the servo systems of the speed control portion and the position control portion. As a result, the system simultaneously satisfies various requirements of such a direct drive motor.

Abstract: A current and torque feedback system for use with sine-wave controlled brushless servo motors each having a plurality of stator windings, a permanent magnet rotor and a rotor position sensor. Current sensors detect instantaneous values of electrical currents in each of the stator windings; and circuitry computes peak current values and electrical polarity of each current. Circuitry uses sensor signals from the rotor position sensor to divide the electrical revolution of the brushless motor into a number of regions equal to the number of phases of the brushless motor with each of the regions centered about the peak values of the sensed currents. The peak values of the currents and the current polarities are coupled to circuitry which generates an output signal having a value proportional to the peak values of the currents and having a polarity indicative of the direction of the torque generated by the brushless motor.

Abstract: To the primary winding of a synchronous electric machine, a polyphase a.c. excitation signal from an excitation circuit is applied. Thus, an induced voltage signal, the phase of which varies by an angle proportional to a rotational position of a rotary body, is produced on the secondary winding of the synchro. A phase difference produced between the a.c. excitation signal and the induced voltage signal is detected by a phase difference detecting circuit. This phase difference detecting circuit detects not only a phase difference itself, but also detects the time at which the phase difference has been detected. On the basis of the phase difference and the time thus detected, a predictive computation circuit predicts a rotational position of the rotary body at an arbitrary time.

Abstract: A spindle positioning apparatus for positioning the spindle of a machine tool, for example, includes an absolute angle detector such as a resolver operatively coupled to a spindle motor which drives the spindle, and an absolute position detector such as a resolver operatively coupled to the spindle. A position control processing system derives a positional error from detected signals from the absolute angle detector and the absolute position detector and a target position command signal.

Abstract: A method and apparatus for controlling a resolver of two-phase excitation and one-phase detection type wherein an erroneous component in the output of the resolver is eliminated by periodically reversing the rotational direction of a rotating magnetic field generated in the resolver.

Abstract: Two-phase voltage signals for use with a resolver-to-digital converter (RDC) are produced as a periodic function of permeance developed across an air gap between a rotor and stator wherein the permeance varies as a periodic sinusoidal function which can be related to the electrical angle of the position of the rotor. The two-phase voltage signals are developed as a function of inductive reactance and follow the form ##EQU1## wherein the phase angle between V.sub.x and V.sub.y is exactly 90.degree. and the term [A+A.sub.n +B+B.sub.n ] is completely free of second harmonics.

Abstract: A high-accuracy position detection apparatus comprises a position detector for detecting a position signal indicating the rotation position of a motor; a coupler for coupling the motor to the position detector with a certain eccentricity; a coupling eccentricity detector, connected to the position detector, for detecting an eccentricity signal, corresponding to a coupling eccentricity of the coupler, from the position detection signal; and a true position signal synthesizer, connected to the position detector and the coupling eccentricity detector, for combining the position signal with the eccentricity signal so as to produce a true position signal which indicates the true position of the motor and is independent of the coupling eccentricity of the coupler.

Abstract: A rotational position transducer comprising a rotor having annularly spaced teeth and a stator with a pole face configuration comprising annularly spaced teeth opposing the rotor teeth. One or more pole windings are energized by an alternate current source, and one or more output voltages induced in pole windings are produced with components having a characteristic which varies as a function of the angular position of the rotor relative to the stator. The output voltages may be either amplitude or phase modulated as a function of rotor position. The transducer may be combined with a stepping motor having an identical pole configuration.

Abstract: A synchro generator comprising a stator having a signal coil with at least two signal windings offset at predetermined angles relative to each other, and an exciter coil having an exciter winding concentric with the signal coil. A core of magnetically conductive material is allocated to at least one of the coils, and comprises a rotor of magnetically conductive material asymmetric relative to its axis of rotation. The signal coil is a cylindrical coil with obliquely wound windings, and the exciter coil is a cylindrical coil with a straight (spool) wound winding. A substantially cylindrical shell of magnetically conductive material is allocated to the coils and the rotor comprises at least a pair of diametrically opposed conducting members of magnetically conductive material.

Abstract: A brushless resolver has first and second ring-shaped magnetic pole elements spaced from each other along a common axis. An excitation coil is wound axially between the two pole elements. First and second output coils are wound through the first and second pole elements and spaced radially from each other. A rotor is within the pole elements and has a shaft extending along the axis. First and second magnetic coupling elements are spaced along the shaft each of which being coplanar with a different one of the pole elements. Each coupling element providing 180 degrees of magnetic coupling with respect to the corresponding pole element. A high frequency signal applied to the excitations coil is transformer coupled to the output signals. The degree of coupling varies with the position of the coupling elements. The demodulated signal from each of the output coils has a triangular shaped waveform which may be directly differentiated to produce the angular velocity of the rotor shaft.

Abstract: In a sensor having a drive winding for establishing a forward field, an electrically conductive screen is displaceable relative to a sense winding. In the presence of the drive field, eddy currents are generated in the screen to establish a counter-field opposing the forward field, so that the sense winding is shaded by the screen to a varying extent during relative displacement of screen and sense winding and the voltage induced in the sense winding is accordingly correspondingly varied. Application of a high frequency input to the drive winding results in a modulated output from the sense winding which may be demodulated to provide a signal indicative of screen position relative to sense winding. The position signal may be further processed to provide a speed signal. The sensor may assume a multiplicity of linear or planar, rotational and axial or solenoidal configurations.

Abstract: The pole members of each phase of a synchro have quadrifilar windings wherein each conductor is wound over six poles associated with a given phase. A voltage signal from an alternating current source is impressed across one conductor from each phase connected in series. The remaining conductors are connected to produce resolver-based Rsin.theta. and Rcos.theta. signals directly from the synchro without conversion from the normal three 120.degree. out-of-phase signals.

Abstract: An apparatus for sensing the location of a structural member on which a working operation is to be performed. The apparatus includes a probe that is connected to a rack and is mounted for movement between an inoperative position and an operative position, where the probe will be in engagement with the structural member. The rack is carried by a piston which is slideable within a cylinder and by introducing fluid pressure into one end of the cylinder, the rack will be extended to thereby move the probe from the inoperative to the operative position. Engaged with the rack is a pinion and linear movement of the rack will rotate the pinion and rotation of the pinion acts through a resolver to generate a signal indicating the precise position of the structural member.

Abstract: A phase analog encoding system with compensation for the phase shift error inherent in a resolver position transducer. The inherent phase shift error in a resolver position transducer is compensated independent of a resolver position in a time multiplexed fashion by periodically applying a known reference signal to the resolver and measuring the electrical phase shift across only the resolver. The newly measured value of the inherent electrical phase shift is compared with the last measured value of the inherent electrical phase shift and any deviation is calculated. This deviation is used to determine the appropriate compensation value for the inherent electrical phase shift. The compensation value is subtracted from the resolver phase shift during normal operation resulting in an output signal which is independent of the inherent electrical phase shift error in the resolver position transducer. Additionally, compensation for encoding errors is developed in a calibration mode.

Abstract: A linear synchro/resolver comprised of an opposed pair of stator assemblies, each of which has a plurality of corresponding, opposed, toothed pole piece pairs, a toothed slider movably mounted between the opposed sets of pole piece pairs, and wherein the pole piece pairs on each stator assembly are spaced apart along the assembly's length by a non-integral multiple of the pitch of the stator teeth. Separate coils are wound on the stator pole pieces, with the coils of adjacent and opposed pairs of coils being connected together in phases. The inductance of the coils is thus a function of the alignment of the slide teeth with the stator pole piece teeth. A source of alternating current is connected to the phases of coils, the current magnitude flowing through each phase of the coils is detected, and the current magnitude differences between the phases are amplified.

Abstract: Resolvers are in common use as angular position sensing devices. Such resolvers normally require difficult to generate sine-wave excitation signals, and extensive decoding circuitry for producing an output signal related to angular position. The subject apparatus utilizes a generator to produce a rectangular-wave timing signal. A logic circuit receives the timing signal and responsively produces first and second rectangular-wave excitation signals, which are delivered to respective stator coils of a resolver. A decoding circuit receives one of the excitation signals and the phase encoded signal magnetically induced in the rotor coil of the resolver, and produces an angular position signal having a duty cycle responsive to the phase difference between the received signals.

Abstract: A circuit for a function generator, or resolver, employing large air gaps between its stator and rotor and between primary and secondary coils of an automatic transformer supplying its excitation signal is disclosed. The circuit operates to insure that the rotor signal is of sufficient voltage to convey the angular position of the rotor. The voltage of the rotor signal is otherwise subject to variations which are temperature dependent. The function generator and circuit of the present invention allows the use of economic function generators without excess drain on associated power supplies. Frequency of the excitation signal is established by a capacitor in parallel with the excitation terminals. A negative feedback path about an excitation amplifier include a nonlinear member comprising antiparallel diodes. The excitation amplifier determines the amplitude of the excitation signal and hence the amplitude of the rotor signal conveying angular rotor position information.

Abstract: An improved drive control circuit is disclosed for enabling the multiplexed drive of synchro receivers. A zero crossing detector is coupled to sense the zero crossings of a signal driving the excitation winding of a synchro receiver. A counter coupled to the output of the zero crossing detector responds to one of every n counts to provide a count signal for operating a synchro driver associated with each one of multiple synchro receivers. The count signal causes the synchro driver to provide a signal output to the respective synchro receiver during a period defined by the count signal to reduce average power dissipation and provide effective damping without sacrificing peak current capability.