Abstract: Phase information in a multiple-coil indictive displacement sensor is retained by summing the excitation signal with each of the secondary signals to provide augmented secondary signals which may then be converted to a digital format. A signal processor may then be employed to extract both the magnitude and phase information from the augmented secondary signals by subtracting the magnitude of the primary excitation signal from each of the augmented secondary signals. The resulting signals retain both phase and magnitude information.

Abstract: An absolute position detecting system for a servocontrol system which has its operation controlled in accordance with a numerical control program. Resolvers 202 and absolute encoders 110 made rotatable with a servomotor 105, are set at a predetermined revolving ratio so that the absolute positions of operating axes may be detected highly accurately from the revolution outputs of the two. The detecting operations can be performed for the plural operating axes by using one detecting circuit commonly.

Abstract: The invention relates to a remotely-operable remote handling arrangement use in radioactively loaded large-area cells of facilities containing process equipment for reprocessing irradiated nuclear fuels. The remote handling apparatus has an industrial robot which is controlled by a process computer and which, for the purpose of detecting the position of an arm of an articulated joint of the robot, is provided with a rotary sensor for determining the angular position of the arm. The rotary sensor is configured as a resolver and is configured pursuant to the induction principle. A second resolver is arranged coaxially with respect to the first resolver in order to be able to check the true position of the arm of the joint. On its shaft, the second resolver has a suitable indicator which is rotatable with the shaft relative to a zero mark.

Abstract: A servo system for controlling the rotational speed of a rotating body or the moving speed of a moving body to be a desired speed. The system comprises a voltage source which generates at least two predetermined voltages, a comparator which compares a voltage of an AC signal containing a speed information of the moving body with each of the voltages generated by the voltage source and outputs at least two output signals in each half period of the AC signal, a counter for counting reference clock signals, a memory for storing a count value of the counter when the comparator outputs each of the output signals, a processor for producing a speed error signal from the count value stored in the memory, and a driver for supplying a driving power to the moving body in accordance with the speed error signal thereby to keep a desired speed of the moving body. Further, an error compensator may be provided for compensating a voltage shift of the predetermined voltages.

Abstract: A device for reducing the vibrations of a rotating machine equipped with an active magnetic suspension comprises at least two vibration detectors located on the machine frame for detecting disturbances applied to the frame, and at least an additional selection feedback loop with narrow band and high gain whose central frequency is synchronized with a reference frequency and which receives signals delivered by the vibration detectors. The additional selective feedback loop comprises means for integrating the signals delivered by the vibration detectors and filtering means for eliminating the transient signals whose frequency is not linked to the reference frequency.

Abstract: An apparatus and a process for detecting an absolute positional value relating to mechanical movement of a member to be measured from a reference point. The apparatus includes a detecting means with a plurality of detectors having periods which are different from one another. Each detector generates an electric signal having a period corresponding to the movement of the member. The signals are stored in a memory. Then, the absolute value of mechanical movement between one of the detectors and the member is specified by using two values. The first value is derived by multiplying the period of the signal corresponding to the one detector by an integer N. The second value is stored in the memory and corresponds to the one detector's partial movement which is less than one period thereof. The value of the integer is decided by using periods and stored values corresponding to other detectors.

Abstract: A control device suitable for synchros comprising three stator windings. The device comprises four circuit branches with the inputs of the first and the second branches interconnected to receive a first voltage from the ends of the stator windings of the synchro transmitter and with the inputs of the third and the fourth branches interconnected to receive a second voltage from the ends of the stator windings of the synchro transmitter. Two adder elements supply control voltages to the stator windings of the synchro receiver. Two inputs of the first adder are connected to the outputs of the first and the third branches, respectively and the two inputs of the secnd adder are connected to the outputs of the second and the fourth branches. These branches have transfer functions in the form sin (.alpha.+.phi.1), sin (.alpha.+.phi.2), sin (.alpha.+.phi.3), sin (.alpha.+.phi.4), respectively, wherein .alpha. represents the information supplied by a digital element and .phi.1, .phi.2, .phi.3, .phi.

Abstract: A system for measurement of shaft angles wherein a synchro resolver (10) is sequentially pulsed, and alternately, a sine (32) and then a cosine (36) representative voltage output of it are sampled. Two like type, sine or cosine, succeeding outputs (V.sub.S1, V.sub.S2) are averaged and algebraically related to the opposite type output pulse (V.sub.c) occurring between the averaged pulses to provide a precise indication of the angle of a shaft (18) coupled to the resolver (10) at the instant of the occurrence of the intermediately occurring pulse (V.sub.c).

Abstract: In an absolute position detecting system for a servocontrol system operatively controlled according to a numerical control program or the like, the absolute position of an operating shaft is detected with a high accuracy based on outputs of a resolver 106 and an absolute encoder 110. The resolver 106 and absolute encoder 110 rotate with a servomotor 105 at a prescribed revolution ratio, so that variations in the absolute position of the operating shaft at the time of a malfunction in the servocontrol system can be stabilized quickly.

Abstract: A synchro/resolver, preferably for use in combination with a similarly constructed servo motor, having an annular stator with circumferentially arranged poles, each having a plurality of regularly pitched teeth and each pole with its own coil winding thereon, and with the coils being connected in phases, an annular, toothed rotor positioned adjacent to the stator so that a change in rotational position of the rotor changes the inductance of the coil windings as a function of the position of the rotor's teeth vis-a-vis the stators' teeth, and a detecting circuit for sensing alternating current flowing in each coil phase and for amplifying the differences between the currents in each phase to produce a rotational position output signal for commutating the motor, the stator being divided at its longitudinal midpoint into two halves which are rotated with respect to each other by a distance equal to one tooth pitch divided by the number of phases and being separated from each other by a lamina of non-magnetic mat

Abstract: A synchronous decode circuit for an incremental encoder is disclosed which comprises analog-to-digital converters for converting in phase and quadrature encoder signals to transistor-to-transistor logic (TTL) compatible signals, a latch for receiving current logic level signals and the previous logic level signals for a gray code, a programmable read only memory (PROM) for decoding the logic level signals and generating clock and direction enable signals, and gating logic connected to the PROM for gating clock and direction signals to counters of the system, the counters are connected to a latch under control of the computer to latch the count of movement in preselected directions for the computer. In another embodiment the PROM includes scaling jumper means or error detection means or both for, respectively, adjusting the range of measurement (scale factor) and indicating error in the logic level signals.

Abstract: A synchro/resolver, preferably for use in combination with an identically constructed servo motor, having an annular stator with circumferentially arranged poles, each with its own coil winding thereon, and with the coils being connected in phases, an annular rotor positioned adjacent to the stator so that a change in rotational position of the rotor changes the inductance of the coil windings as a function of the rotational position of the rotor, and a detecting circuit for sensing alternating current flowing in each coil phase and for amplifying the differences between the currents in each phase to produce a rotational position output signal for commutating the motor.

Abstract: To reduce adverse effects due to a dead zone in a pulse-width modulation circuit provided for avoiding short-circuiting in an inverter circuit, distortions of sine wave currents generated when low-frequency current commands are given, sound produced due to the excitation, and torque variations, a synchronous motor drive apparatus has been provided.

Abstract: A motorized nut for use in conjunction with a fixedly secured lead screw for displacing a movable member along a fixed member into which the lead screw is journaled parallel to the desired path of member movement, includes an induction motor whose case is rigidly secured to the movable member. The motor rotor is made hollow so as to allow the lead screw to extend coaxially therethrough. A pair of nuts are each secured in a separate one of the ends of the tubular motor rotor for threadedly engaging the lead screw so that as the motor rotor rotates in response to motor excitation, the motor stator and hence, the movable member, are displaced on the movable member along the axis of the ball screw.

Abstract: A resolver type motor speed control arrangement including an exciting signal generating circuit including a first frequency division counter for producing from a clock pulse an exciting voltage signal supplied to the primary winding of the resolver coupled to the motor, reference signal generating means in the form of a up-down counter for generating a reference signal having a predetermined period from the clock pulse, circuit means for supplying a feed pulse to the reference signal generating means for varying the phase of the reference signal, phase detecting means for synchronously rectifying the output signal of the secondary winding of the resolver in accordance with the reference signal, speed signal generating means for generating a speed signal corresponding to the speed of the motor or the resolver and a servo-amplifier responsive to outputs of the phase detecting means and the speed signal generating means.

Abstract: A system for converting mechanical movement of a body under detection to a digital signal comprises a synchro generator having a primary and a secondary windings movable relative to each other, one of the windings capable of being coupled to said body, an exciting circuit for providing multiple-phase exciting currents to the primary winding at a frequency higher than the frequency corresponding to the maximum speed of the body, and a phase-locked-loop control circuit responsive to the output of the secondary winding for generating a frequency-multiplied digital signal at a frequency equal to the product of the frequency of an AC signal induced in the secondary winding and a predetermined factor.

Abstract: A servomechanism regeneratively controls motion by a brushless coreless axial-field motor, exerting torque thru its permanent-magnet disk rotor, resulting from synchronized polyphase sinusoidal stator currents, controlled by a switching controller responsive to input commands and to Hall-effect transducer signals that vary sinusoidally with rotor angle and respectively correspond to stator phases. The controller operates with a dc power source and sink. Its signal processors derive from the transducer signals instantaneous magnitudes and polarities thereof and continuous lagless speed feedback. The instantaneous magnitudes are multiplied by a torque amplitude signal to provide respective synchronized amplitude control signals. Current transformers having primary windings in series with power switching transistors provide current feedback pulses with amplitude proportional to instaneous current in associated stator windings.

Abstract: A synchro system having a microprocessor control element emulating a synchro transmitter. Current sensing circuits measure current developed in a synchro receiver responsive to drive signals generated by the microprocessor control element; the microprocessor control element alters the drive signals to maintain control of current dissipated in the synchro receiver within predetermined limits.

Abstract: In an improved motor control system for a pulse width modulated synchronous brushless motor, means for adaptively controlling the "torque angle", i.e. the angle between the rotating magnetic field created by the stator windings and the rotor field created by the permanent magnets on the rotor, is provided. The relationship between the two magnetic fields is controlled as a function of load and speed to provide the optimum operating point at all times. Controlling the torque angle effectively varies the back EMF constant K.sub.e (V/RPM), and the torque constant K.sub.+ (torque/ampere) of the motor.

Abstract: A method and apparatus by which the output value of a resolver position detection system is compensated for systematic phase shift errors produced by signal conditioning circuitry through which the signal passes.

Abstract: A measurement system for converting the outputs of dissimilar transducers into digital numbers by means of a phase conversion technique. The outputs of a plurality of dissimilar transducers are generated as pairs of amplitude modulated sinusoidal signals. All AM signal pairs are converted into phase modulated signal pairs by a plurality of identical conversion circuits where the phase difference between at least one PM signal pair is linearly related to the measured parameter of the transducer associated therewith. The phase differences for each transducer is converted into a digital number by counting increments of time between the zero crossings of each pair of phase modulated signals and outputting the resulting count to a data buss of a control processor. Transducer parameters which are nonlinearly related to their phase differences are compensated by a correction factor which is calculated by knowing the error between any particular measured input and the linear input.

Abstract: In an electric drive for a DC shunt propulsion motor which is supplied from a battery, the armature winding is connected to the battery, and the field winding is connected to the battery via an electronic DC control element. The electronic DC control element is associated with the field winding and also serves as a control element for charging the battery. The DC control element is further equipped with a voltage control device in addition to a current control device. A multiposition switch is arranged so that when the switch is in one position the field winding is connected via the electronic DC control element to the battery, and when the switch is in another position, the electronic DC control element is shunted across the battery.

Abstract: A digitizer for receiving sine and cosine encoder signals and providing a digital output representative of the phase angle of the encoder. A counter is used to generate a variable reference angle, and memories are used to generate digital signals representing the sine and cosine of the output of the counter. These signals are multiplied by the analog cosine and sine inputs, respectively, in order to determine the direction of the difference between the encoder phase angle and the counter angle. The counter is incremented or decremented so as to make the digital angle output provided by the counter equal to the phase angle of the encoder. A velocity indication may be provided by the addition of a low pass filter to the circuit.

Abstract: For each axis, a cyclic transducer has a scale supplied with a sinusoidal signal from a timing unit and a cursor which provides two output signals which are proportional to the sine and to the cosine, within the elementary interval of the transducer. Sin .alpha. and cos .alpha. and the corresponding inverted signals are supplied to squaring circuits and logic which generates a three-bit number in a register defining the octant (000 to 111, i.e. 0 to 7) within which the electric angle .alpha. lies. The three-bit number controls multiplexers each having inputs for quadrants 0 to 7 and feeding respective sample and hold circuits and whose signals are NUM and DEN. An analog-to-digital converter system forms the digital value n=NUM/DEN and n along with the lowest order octant bit address a ROM which outputs the value of .alpha. within the range of a quadrant. A microprocessor responds to the higher two bits to create the final value of .alpha..

Abstract: In a speed control system of a synchronous motor, a pulse modulated signal containing a signal representing rotational angle of the motor is formed to control the speed. The pulse modulated signal is passed through a synchronous rectifier to obtain currents supplied to stator windings of the motor.

Abstract: A synchro signal-to-digital signal converter for providing a digital signal representation of synchro angle value in response to sensed synchro signals representative of actual synchro stator voltage signals and actual synchro rotor voltage signals, includes an analog signal interface responsive to the sensed synchro signals for providing a digital signal representative of the ratio of the smaller of the difference signal magnitudes between each of two stator winding voltage signals and a third stator winding voltage signal selected as a reference, divided by the larger, and for providing discrete signal manifestations of the particular one of a plurality of successive ranges of synchro angle values associated with the sensed synchro signals received, the synchro to digital signal converter further including a signal processor responsive to the digital ratio signal and to the discrete signal manifestations of synchro angle range, for providing a signal representation of actual synchro angle value associated w

Abstract: An improved ladder network for use in a converter utilizing a single ladder network with single pole double throw switches to simultaneously implement nonlinear sine and cosine functions.

Abstract: In a speed detector having a fixed frequency oscillator for producing two-phase sine waves to excite two-phase exciting windings of a resolver, first and second multipliers for multiplying the output of the detecting winding of the resolver by the two-phase sine waves respectively, and a position conversion circuit and speed conversion circuit, the speed conversion circuit comprises: a third multiplier for multiplying a signal of the first multiplier by a signal of a VFO; and a fourth multiplier for multiplying a signal of the second multiplier by a signal of the VFO, the outputs of the third and fourth multipliers being applied through a comparator to a proportional integration amplifier, the output of which is used as the rotation speed signal and applied to the VFO, thereby to eliminate the necessity for provision of a countermeasure against harmonics and harmonic noise involved in the use of an integration circuit required when a resolver is used as a detector.

Abstract: A device for measuring the rotation of a member includes an angular error sensor having a movable sensor element connected to the rotatable member and a pair of guadrature-spaced stationary elements for inducing the error in the sensor element. A detector measures the polarity and amplitude of the error and delivers it to a processor that accumulates successive error signals. The accumulated signal is averaged, corrected and displayed as the measurement. Also the accumulated signal is used to control a set of multiplier devices that create different driving signals from a single signal source for application to the guadrature elements of the error sensor. The output of these multiplier devices is controlled by the processor such that the error signal is driven toward zero.

Abstract: To generate a signal having at all times an amplitude directly proportional to the velocity of relatively moving members, a plurality of phase displaced position indicative signals are first generated. A pair of the position signals that are phase displaced by 90.degree. are then differentiated to provide velocity signals. Each velocity signal is applied in both its regular form and its inverted form to an analog multiplexer which receives the other position signals as control signals. The composite output of the multiplexer, after filtering to remove high frequency glitches due to sampling, is a signal having an amplitude at all times directly proportional to velocity.

Abstract: In a control device of an AC motor wherein a torque equivalent to that of a DC motor is created by controlling the instantaneous values of its stator current, or in a vector control device, signals from a position detector such as a resolver coupled to the AC motor are utilized to form stator current instruction signals and to provide rotation position feed-back signals and rotation speed feed-back signals for the AC motor, thereby to perform precise servo-control.

Abstract: A method and apparatus for correcting an error in a position sensing circuit employing a resolver, an Inductsyn (trade name) or the like. Accurate position sensing is not possible in a position sensor using a resolver or the like when the electromagnetic coupling between the secondary winding and a cosine excitation coil is different from that between the secondary winding and a sine excitation coil. To eliminate a position sensing error caused by such a disparity in electromagnetic coupling, the present invention varies an electrical angle .alpha.

Abstract: A control system for rigidly stopping the spindle of a machine tool at a prescribed angular position when a tool is to be changed, without the use of a mechanical brake. Provided for this purpose is an orientation control circuit adapted to produce an output signal of zero potential when the spindle is at a prescribed stopping position, and an output signal of a potential proportional to the amount of angular deviation when the spindle is displaced from the prescribed stopping position. To stop the spindle at a prescribed stopping position, the output signal from the orientation control circuit is delivered in place of a speed command signal to a speed control loop of the type which limits to zero the difference between the speed command signal and a speed feedback signal. When the spindle is at rest, the feedback function of the speed control loop holds the rotary shaft of the spindle motor rigidly at the stopping position as if a mechanical brake were applied thereto.

Abstract: A circuit for overcoming variations in the output signals from a synchro device resulting from a.c. supply voltage variations includes means to provide a pulse train in which the pulse widths are modulated in accordance with supply voltage variations. A signal derived from a pair of synchro output terminals is applied to a rectifier/filter which is intermittently actuated by the pulse width modulated signal. The resultant d.c. signal is effectively divided by a factor proportional to the supply voltage so as to be independent of variations in that voltage.

Abstract: An apparatus for accurately controlling the rotary position of a high speed position control servo system having a servo motor which is fed by a conventional servo amplifier and drive amplifier means with a tachometer feedback to the drive amplifier. Incorporated in the system is a high frequency quadrature phasing network which receives timing signals from the servo amplifier and conditions these signals into a balanced sine cosine function which excites a rotary position transducer that is directly coupled to the motor. The high frequency sine cosine signal produces a reference feedback signal which is the difference between the actual rotor position of the motor and the sine cosine field of the position transducer stator. The error signal is fed back to the servo amplifier and is conditioned through a transformer, pre-amp and filter means and then fed into the servo amplifier means to tract the servo motor.

Abstract: In a device having a synchro resolver and a microprocessor, the apparatus of the present invention utilizes a pulse excitation technique for converting a synchro output signal to a digital format. A pulsed waveform is selectively applied to the input windings of synchro resolver and output voltages are induced in the output windings. A sample and hold circuit is selectively enabled and selectively coupled to the output windings of the synchro resolver, and the sampled output signal of the output windings is converted into a digital format via an analog-to-digital converter.

Abstract: A digital resolver incorporates an adder for periodically and repetitively calculating the sum of two operands, one of which is increasing and the other decreasing at a rate determined by the excitation frequency of a resolver. The phase of the one of the operands is responsive to the angular position of the resolver rotor, while the phase of the other operand is responsive to forward and reverse command pulses. The sum produced by the adder is zero when the resolver assumes its commanded position, and at other times identifies the magnitude and direction of the resolver error. A digital-to-analog converter is provided for converting the error signal to an analog voltage.

Abstract: A device for position control including a first generator for delivering first and second identical signals dephased to each other by 90.degree.. A position pickup having two inputs connected to the first and second signals and an output for delivering a measurement signal whose phase is representative of the actual angular position of the component part to be controlled. A second generator for receiving a digital binary word instruction and for delivering an instructional signal of the same frequency as the first and second signals and having a phase representative of the desired angular position of the component part. A deviation signal generator connected to the output of the angular position pickup and the second generator for delivering a deviation signal representative of the dephasing between the measurement and instruction signals and a control device for controlling the angular position of the component as a function of the deviation signal.

Abstract: A spindle control system which is provided with a first motor for rotating a spindle, a second motor for positioning the spindle, a pulse generator for generating pulses proportional in number to the rotational angle of the spindle, a counter for counting the pulses from the pulse generator in order to detect the rotational position of the spindle, and circuitry response to the counter means to control positioning of the spindle by the second motor.

Abstract: A positioning system is provided in which command and feedback signals are processed to develop an analog error signal for application to a servo drive to position a controlled element. The command signals are in the form of pulses each of which corresponds to a certain incremental distance of movement. The feedback signals are developed from phase shifts of a low frequency resolver signal, such phase shifts being proportional to movement of the element. Such feedback signals are applied to a resolver digitizer circuit which develops a train of resolver pulses in response to the phase shift represented by each feedback signal. Each such resolver pulse corresponds to the same incremental distance of movement as a command pulse and both the resolver pulses and the command pulses are applied to a comparator and error signal circuit in which any cumulative error in either direction is stored as a digital number and is converted to an analog error signal of the proper polarity.

Abstract: A synchro resolver angular position sensor provides the sine and cosine of angular position by applying a square wave excitation to the resolver stator winding. The corresponding square wave outputs of the sine and cosine windings of the resolver rotor are sampled in time synchronism with the excitation at a predetermined time phase of the square wave excitation cycle. The sampled sine and cosine amplitudes are converted into digital format via an analog-to-digital converter for application to a digital processor. The upper corners of the positively-going leading edges and the lower corners of the negatively-going leading edges of the square wave excitation waveform are rounded to minimize ringing of the sine and cosine square wave outputs from the resolver.

Abstract: A position pickup for numerically controlled machine tools having a resolver which is fed on the primary side by two voltages shifted 90.degree. relative to each other and which is coupled to the moving machine part. The voltages are generated in a digital sine-cosine generator made of decimal frequency divider stages. When the secondary voltage in the resolver goes through zero, as detected by a comparator coupled thereto through a filter, the state of the generator is transferred to a memory and serves as the actual position value. To compensate for phase drift in the filter used on the secondary side, the filter is connected at fixed intervals to a reference signal derived from the primary side and changes in the measured values so obtained, and stored in the memory, used for correcting the actual position value.

Abstract: In a control apparatus for a machine tool, a resolver interface circuit is utilized to determine whether or not the axis motors have driven the machine tool to the selected position. The resolver interface circuit synthesizes sine and cosine wave forms which are applied to a resolver which is mechanically coupled to the corresponding axis motor. The resolver interface circuit also synthesizes a signal which is phase related to the resolver excitation wave forms by the selected rotational displacement of the resolver and axis motor shafts required to achieve the selected position for the machine tool. The phase related signal and a positional feedback signal from the resolver are compared to generate an error signal to the driver for the axis motor. The selected position can be each incremental step where the axis motor is a stepping motor.

Abstract: The control system uses shaft angle controlled synchro resolver devices for producing reversible polarity signals related to the variable shaft angle position and independent of variations in the amplitude of the electrical carrier excitation of the synchro resolver and of spurious phase shifts seated therein.

Abstract: A welding machine includes a programming device to move a welding head relative to horizontal main X and Y axes, and to rotate the head about a vertical C axis. A sensor is connected to rotate with the welding head on a rotator. A sine cosine resolver is mounted on the rotator so that its shaft is geared to the rotator gear. Deviations from the programmed path which may occur in the weld groove are sensed by the sensor, which in turn causes the resolver output to drive a slide mechanism which defines deviation axes X.sub.d and Y.sub.d and which causes the weld head to move from its programmed path to the desired corrected path, when needed. The resolver includes a deviation correction control rotor winding and a second rotor winding, the latter selectively impressing signals on the X.sub.d and/or Y.sub.d slide mechanism drive to cause the welding head to effectively change speed independent of the program or of the existence of any deviation.

Abstract: An electromechanical positioner indicator is provided which comprises first and second relatively movable parts, the first part including two oppositely facing surfaces which are everywhere equidistant and the second part including two surfaces which are everywhere equidistant and which are everywhere equispaced from and lie, closely adjacent to respective ones of the two surfaces of the first part. A first coil, preferably in printed circuit form, is secured to the first part and sensing coils, also preferably in printed circuit form, are secured to each of the two surfaces of the second part. The inductive coupling between the coils is dependent on the relative positions of the parts and thus the output of the sensing coils provides an indication of position. In one embodiment, the surfaces in question are formed by cylinders and in another, the first part is a disc and the main coil comprises an annulus. Particular coil and coil conductor shapes are also disclosed.

Abstract: A high accuracy control system for driving a motor to move a member. The control system includes feedback means for generating a cyclical signal for providing an indication of the actual position of the member. The accuracy of the feedback means is maximized by introducing a gear mechanism between the motor output and the feedback means. Further provided are means for generating command pulses, each of which is indicative of an increment of commanded or desired movement of the member, and means for generating a command signal indicative of the desired commanded movement of the member. In one mode of operation, the incremental command pulses are multiplied by a factor of K to change the command signal by K increments for each incremental command pulse. In another mode of operation, M number of incremental command pulses are converted to a single incremental pulse, and this single incremental pulse is used to change the command signal by one increment of movement for M number of incremental command pulses.

Abstract: A system for measuring the displacement of a workpiece from a reference coordinate system. Position information with respect to the various axes of the coordinate system is acquired by rotary resolver assemblies that measure the angular position of rotatable elements. Each resolver assembly includes a coarse and a fine resolver. Signals representative of the SIN and COS of the angles of the coarse and fine resolvers for each rotor assembly (or referred to as a channel) are applied to a multiplexer. The multiplexer sequentially selects the appropriate channel and the signals are then converted into angular information for each channel. An accurate count of the number of revolutions of the rotatable elements is then obtained. Offset error correction may be provided for each channel. The number of counted revolutions, corrected for offset error, may be multiplied by a scaler for conversion into a linear displacement.

Abstract: An absolute resolver position measuring device for a numerical control apparatus that controls a machine having a plurality of movable members. A resolver is operatively connected to each movable member such that the rotor of each resolver rotates as the corresponding member moves. The resolver position measuring device includes a real time counter that provides a multi-digit data word that is cyclically redundant. A first PROM is addressed by the real time counter and provides a sequence of digital data words which represent a sine waveform; and a second PROM is addressed by the real time counter and provides a sequence of digital data words which represent a cosine waveform. A first digital to analog converter is responsive to the first PROM to provide a sine wave to the first stator winding of each resolver, and a second digital to analog converter is responsive to the second PROM to provide a cosine wave to the second stator winding of each resolver.

Abstract: A transducer coupled to a motor shaft provides both position and velocity information for use in a closed loop control system. The transducer includes a disk with deposited metallic parallel conductors each conductor carrying current in a direction opposite to the adjacent conductor. Relative movement of one disk with respect to another produces a position signal in a manner well known in the art. However, multiple windings are used to provide multiple position signals displaced in space phase which are then processed by differentiation and commutation to provide a velocity signal used as a control voltage in the control loop. A reference signal is also derived by commutation from the position signal.