Abstract: A method of correcting quadrature signal errors comprises the steps for generating an error function signal E by summing the squares of the quadrature signals and subtracting a constant K therefrom, saving the value of the error function E at .theta. equals approximately 0, .pi./2, .pi., and 3.pi./2, using the saved values of the error function to generate signals indicative of the quadrature errors, and generating corrected quadrature signals by processing the quadrature signals to eliminate the errors.

Abstract: A phase compensation circuit for use with a resolver circuit that compensates for resolver angle measurement error without the use of special compensation windings on the resolver or the buffer amplifier associated with the compensation windings. With the present invention, primary windings from a plurality of resolvers may be reduction over conventional circuits. A digital computer is employed to process integrated data indicative of the phase shift of signals generated by the resolver, and compute error correction signals that compensate sine and cosine angle data output signals of the resolver. No resolver compensation windings are necessary and no additional electronic equipment is necessary. The present invention provides increased accuracy to fulfill more stringent angle measurement specifications.

Abstract: This electrical resolver has an arcuate stator with a concave inner side concentric to a convex side of an angularly rotatable arcuate rotor limited to rotation within outer ends of the stator. The stator and rotor have arcuate magnetic cores with transverse slots in which are embedded windings made of insulated wire. Rotation of the rotor causes changes in voltages induced in the stator windings corresponding to the extent of angular position of the rotor. The stator windings include trimming coils which generate bucking voltages to reduce errors in determining angular position of the rotor. In an operating range of .+-.10.degree. from a centered position, magnitudes of rotor position can be determined with an accuracy of 5-10 arc seconds maximum, with a considerable savings in space, weight, cost, simplified installation, and increased stability over the operating temperature range.

Abstract: An electronic processing circuit 17 compares digital signals representing the position of a number of mutually connected control members to the contents of an electronic memory 18. On detecting a difference indicating the displacement of the position of one of the control members, the circuit 17 actuates those motors of motors 4, 5, 6 which are associated with the non-actuated control members in order to make them folllow the displacement. Excessive displacements indicating a fault are shown on an indicator 19.

Abstract: The invention relates to an electric motor comprising a rotor (1), a stator (2) and at least two pole pairs. One particularly preferred application of the electric motor according to the invention is small-size accurate servomotors of high capacity. At present the feed back information required by servomotors is generally obtained from at least partially separate transduced means attached to the servomotor, such as an optical or magnetic coder, a tachogenerator or resolver. A drawback of these known solutions is mainly that the volume and weight of the motors is high. This problem is eliminated in the motor according to the invention by providing it with an integral resolver so that primary windings (4a, 4b) of the resolver is arranged in the rotor (1) of the motor, and that secondary windings (11a, 11b) of the resolver are wound round the stator (2) of the motor in such a manner that the winding wire goes alternately inside and outside the stator.

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: The resolver input module for use in programmable controller systems is one of several modules mounted in a rack to form a programmable controller. The module's function is to provide position data from an externally located resolver which is connected to a machine's shaft to the programmable controller's processor module. This is accomplished by moving the resolver analog-to-digital conversion circuitry from an external module location to the programmable controller input/output rack and coupling this circuitry to circuits which synchronize the programmable controller's input fetch signals. Additionally, a user operable entry mechanism for digitally offsetting the resolver position by a user-selectable amount while accommodating different scale factors is provided. Synchronization and alignment circuitry are provided for synchronizing and aligning data to compensate for different resolver gear ratios in coarse-fine geared resolver decoding circuitry.

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 three-coordinate measuring machine has a probe (22) connected to an output member (11). A driving system (10) is made up of three carriages (15, 17, 19) on guide rails (14, 16, 18). In parallel with this, there is provided a driven system (20) made up of three carriages (25, 27, 29) on guide rails (24, 26, 28). The carriages 19, 29) are connected together via the output member (11). The other pairs of carriages (15, 25 and (17, 27) are linked via respective devices (55). The devices (55) each apply a force between the respective carriages in dependence on acceleration or deceleration of the carriages of the driving system (10). This compensates for dynamic deflections of the guide rails of the driven system (20) which would otherwise be caused by the accelerations. Measuring devices such as scales and readheads are provided on the driven system (20) to determine the position of the probe (22).

Abstract: A linear, analog, synchro control differential transmitter for implementing he common synchro CDX function whereby a scaled linear analog voltage is used as input instead of a mechanical shaft angular displacement. Alternate synchro functions of CT and CX that the invention implements are also disclosed.

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 self guided vehicle employs a highly accurate velocity sensor to determine vehicle speed and position. The velocity sensor includes a resolver connected to and rotatable with a ground engaging wheel. A resolver to digital converter (R/D) provides a highly accurate 8-bit digital signal representative of the angle of wheel rotation. A second less expensive and less accurate velocity sensor also receives the modulated sine and cosine signals from the resolver and produces a series of pulses representative of vehicle speed. The pulses are produced by detecting the zero crossings of the sine, cosine, and combinations of the sine and cosine signals. The velocity information present in the second velocity sensor signal is not used to actually guide the vehicle, but merely to generally validate the information present in the R/D signal.

Abstract: A digital-to-synchro converter is provided where a binary input code specifies a desired shaft angle and where an resolver type position transducer is employed with additional circuitry to generate a shaft position error signal indicative of the angular difference between the desired shaft angle and the actual shaft angle. The additional circuitry corrects for known and calculated errors in the shaft position detection process and equipment.

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: 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: In the field of automated guided vehicles it is particularly important that speed and steering angle feedbacks be accurate and reliable. Any deviations in these feedback signals should be promptly detected and used to alter operation of the vehicle. An apparatus constantly monitors the time varying output signals of a pair of resolvers respectively associated with wheel rotation and steering angle. The loss of either of the resolver signals for more than a preselected duration of time related to the excitation frequency and vehicle speed results in the power delivered to an electric drive motor being discontinued and the vehicle brakes being applied.

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: 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: An incremental length measuring instrument generates analog scanning signals S.sub.1, S.sub.2 with a certain period P which are applied to a comparator in conjunction with two reference signals R.sub.S1, R.sub.S2. The measuring instrument causes the scanning signals S.sub.1, S.sub.2 to change as a function of relative displacement to two components of the measuring instrument. The comparator generates an analog control signal S.sub.D as a function of the difference of the momentary values of the signals applied as inputs to the comparator. The analog control signal S.sub.D is applied as an input to a signal generator which includes an oscillator. The oscillator generates a number of pulses in dependence on the momentary value of the analog control signal S.sub.D. These pulses cause the reference signals R.sub.S1, R.sub.S2 to be modified by the signal generator. In addition, the pulses are fed in a direction dependent manner into an incremental counter which includes a numerical display.

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: The resolver drive circuit on a numerical control system includes a microprocessor system which monitors the phase and amplitude of the sinusoidal wave forms applied to the resolver. Any changes in amplitude or phase shift of the applied wave forms due to such factors as time and temperature are automatically corrected by the microprocessor system. A highly accurate resolver position feedback system is thus formed with a minimal number of temperature sensitive components and a minimal number of required manual adjustments to analog circuitry.

Abstract: Circuitry for producing the signals necessary for driving and controlling a synchro-resolver is disclosed. The circuitry includes a reference generator (84) which is driven by an AC reference signal and thus, the resulting output DC reference voltage on line (82) is locked to the AC reference signal. The DC reference voltage is then combined with a computer generated digital command signal by a MDAC (Multiplying Digital to Analog Converter) (74) to provide a control signal which varies around a selected reference level. A pulse-width modulator (112) provides a high frequency square wave output which square wave is pulse-width-modulated by the AC reference voltage. The pulse-width-modulated high frequency square wave is then provided to an amplitude modulator circuit (106) where the high frequency square wave is itself amplitude modulated by the control signal.

Abstract: This disclosure describes a device for converting binary coded angle information into the analog angular position of the rotor winding of a conventional counter-reaction resolver. The device is operative to provide two periodic rectangular wave signals of equal amplitudes and of time durations respectively proportional to the absolute values of the sine and cosine of the angle. These periodic rectangular wave signals are respectively applied to the stator windings of the resolver via two amplifiers respectively. Each of these amplifiers comprises a counter-reaction loop comprising a compensation winding and a capacitor. The rotor winding of the resolver is inserted in a servocontrol loop comprising an amplifier and a commutator which are connected only in the simultaneous absence of the two periodical rectangular wave signals.

Abstract: An arrangement for controlling a plurality of synchro receivers from a single command position. The system requires very little power relative to the torque produced in the controlled synchros. The desired synchro movement is achieved by selective interconnection of the stator terminals at appropriate times to effect desired rotation of the rotor.

Abstract: A device is disclosed for damping the critical frequencies of a rotor suspended by a radial electromagnetic bearing which has means associated therewith for detecting the radial position of the rotor, comprising a servo-circuit for connection between the detecting means and windings of the electromagnetic bearing and including a circuit for controlling the current supply to the windings in response to signals from the detecting means to keep the rotor in a predetermined radial position. The servo-circuit is provided with means for the selective amplification of the phase advance gain of said circuit in a frequency equal to the speed of rotation of the rotor for damping said critical frequencies.

Abstract: This invention relates to an electronic apparatus for automatic positioning and distance measurement of mobile members. The apparatus according to the invention comprises a rotary electromagnetic transducer with two pairs of windings, in which the primary circuits receive electrical voltages representative of the controlled angular distance values and the secondary circuits deliver accordingly an electrical response voltage, whose shape and amplitude depend on the difference between said controlled distance and the mechanical angle between rotar and stator portions containing said secondary and, respectively, primary circuits. The electrical voltages representative of the controlled angular distance values are generated by electronic circuits comprising a first binary counter which translates the controlled distance into binary code, a second binary counter which generates a binary ramp, two adders, a combining network, four sequential networks and two analogue amplification and sign circuits.

Abstract: A system for controlling the position of a movable element, such as a microscope slide in one embodiment thereof, which system includes a unique high resolution digital-to-analog converter which converts a digital command signal to an analog servo input command for moving the element along an arcuate path in two orthogonal directions and for moving the element in a third orthogonal direction along a linear path. The unique digital-to-analog converter which would be broadly useful in many different applications includes means responsive to selected combinations of the most significant bits of a digital input signal for supplying equally weighted selected combinations of a reference signal and responsive to selected combinations of the least significant bits thereof for supplying binary weight selected combinations of the reference signal, the equally weighted binary weighted combinations being combined to produce the analog output signal.

Abstract: An absolute positioning servo for positioning a shaft in response to a digital command input which utilizes a resolver, for providing an analog position indication of the shaft, an analog to digital converter, which provides a digital indication of the shaft position, a comparator for comparing the digital command input signal with the digital indication signal and providing a differential digital error signal which is converted to an analog signal and fed back to position the shaft so that the differential digital error is 0. An analog fine control positioning means is provided which positions and maintains the shaft near the center point of the position represented by the digital command input signal when the digital differential error is 0. A signal representing the difference between the exact analog position of the shaft and the digital approximate position of the shaft is provided at the output of the translator.

Abstract: A manual control system including a powered feed for a numerically controlled machine tool. The system includes a manually operable differential resolver located in the position feedback loop of the servo control system for each slide and a variable speed motor for driving that differential resolver at a controlled rate so as to effect controlled feeding movement of the slides independent of the numerical control unit.