Absolute resolver angle to digital converter circuit
First Claim
1. An absolute resolver digitizer for use in combination with a resolver having stator means and a rotor means comprising:
- reference generator means for generating resolver excitation signals exciting the resolver'"'"'s stator means to generate a rotating field and for generating digital field position data indicative of the instantaneous angular position of said ratating field; and
resolver follower means for generating digital sum position data indicative of the sum of the instantaneous position of the resolver'"'"'s rotor means in response to signals induced in the rotor means by said rotating field;
wherein said reference generator means comprisesreference generator counter means for storing counts at a predetermined frequency and for generating an overflow signal when the stored counts reach a predetermined number wherein the number of counts stored in said reference generator counter means is said field position data; and
resolver exciter means for generating said resolver excitation signals in response to said overflow signals; and
wherein said resolver follower means comprisesphrase modulator means for generating phase modulated signals and said digital sum data in response to correction signals;
phase comparator means for comparing the phase of the signals induced in said rotor means with said phase modulated signals to generate error signals indicative of the phase error between the two signals compared; and
correction circuit means for generating said correction signals in response to said error signals.
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Abstract
An absolute resolver digitizer for a numerical control system generating a digital number indicative of the absolute angular position of a resolver'"'"'s rotor within a given revolution is disclosed herein. The resolver digitizer comprises a reference generator generating resolver excitation signals and a digital number indicative of the phase of the generated excitation signals and a resolver follower generating a digital number indicative of the sum of phase of the excitation signal generated by the reference generator and the angular position of the resolver'"'"'s rotor. Subtraction of the digital number generated by the reference generator from the digital number generated by the resolver follower produces a digital number indicative of the resolver'"'"'s absolute position within a given revolution. This subtraction may be performed by a separate circuit within the absolute resolver digitizer or may be performed by the computer associated with the numerical control system.
30 Citations
22 Claims
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1. An absolute resolver digitizer for use in combination with a resolver having stator means and a rotor means comprising:
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reference generator means for generating resolver excitation signals exciting the resolver'"'"'s stator means to generate a rotating field and for generating digital field position data indicative of the instantaneous angular position of said ratating field; and resolver follower means for generating digital sum position data indicative of the sum of the instantaneous position of the resolver'"'"'s rotor means in response to signals induced in the rotor means by said rotating field; wherein said reference generator means comprises reference generator counter means for storing counts at a predetermined frequency and for generating an overflow signal when the stored counts reach a predetermined number wherein the number of counts stored in said reference generator counter means is said field position data; and resolver exciter means for generating said resolver excitation signals in response to said overflow signals; and wherein said resolver follower means comprises phrase modulator means for generating phase modulated signals and said digital sum data in response to correction signals; phase comparator means for comparing the phase of the signals induced in said rotor means with said phase modulated signals to generate error signals indicative of the phase error between the two signals compared; and correction circuit means for generating said correction signals in response to said error signals. - View Dependent Claims (2)
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3. The absolute resolver digitizer of claim wherein the error signals generated by said phase comparator means comprises a phase error signal indicative of the magnitude of the phase error between the signal induced in said rotor means and said phase modulted signal and a sign signal indicative of which compared signal was first received, said correction circuits means comprises:
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integrator means for integrating said phase error signals and said sign signals to generate pulse signals at a rate indicative of the average angular velocity of said rotor means and an integrated sign signal indicative of the direction in which said rotor means is moving; sign logic means receiving said phase error signal and said integrated sign signal for terminating the transmission of the integrated sign signal when the phase comparator is generating said error signal; a first summation circuit combining said phase error signal with the pulse signals generated by said integrator means to generate a correction pulse signal; and a second summation circuit combining said sign signal with the integrated sign signal transmitted by said sign logic means to generate a correction sign signal. - View Dependent Claims (4, 5, 6, 7)
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8. An apparatus for generating a digital signal indicative of an angular displacement comprising:
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a resolver having stator means for generating a field and rotor means responsive to an angular displacement for generating an induced signal indicative of the angular displacement between said field and said rotor means; reference generator means for generating resolver excitation signals exciting said stator means to generate a rotating field and for generating digital field position data indicative of the instantaneous angular position of said rotating field; and resolver follower means for generating digital sum position data indicative of the sum of the instantaneous angular position of said rotating field and the instantaneous position of said rotor means in response to signals induced in said rotor means by said rotating field; wherein said reference generator means comprises reference generator counter means for storing counts at a predetermined frequency and for generating an overflow signal when the stored counts reach a predetermined number wherein the number of counts stored in said reference generator counter means is said field position data; and resolver exciter means for generating said resolver excitation signals in response to said overflow signals; and wherein said resolver follower means comprises phase modulator means for generating phase modulated signals and said digital sum data in response to correction signals; phase comparator means for comparing the phase of the signals induced in said rotor means with said phase modulated signals to generate error signals indicative of the phase error between the two signals compared; and correction circuit means for generating said correction signals in response to said error signals. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. In combination with a numerical control system for controlling the displacement of a moveable member along at least one axis, said numerical control system comprising:
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a moveable member operable to move in response to command signals; a resolver having stator means for generating a field and rotor means angularly displaced with the movement of said moveable member, for generating a phase signal indicative of the position of said moveable member, said phase signal being indicative of the phase angle between a field generated by said stator means and the angular position of said rotor means; means for reading data from a permanent recording to generate input data indicative of the desired movement of said moveable member; and computer means having storage and computation capabilities for generating commanded position data indicative of the desired position of said moveable member in response to said input date and for generating said command signal in response to the difference between said commanded position data and actual position data indicative of the instantaneous actual position of the moveable member an improvement for generating the actual position data comprising reference generator means for generating signals exciting the resolver'"'"'s stator means to generate a rotating field and for generating digital field position data indicative of the instantaneous angular orientation of said rotating field; and resolver follower means for generating digital sum position data indicative of the instantaneous angular position of said rotating field and the instantaneous position of the resolver'"'"'s rotor means in response to signals induced in the rotor means by said rotating field wherein the difference between said sum position data and said field position data is actual position data indicative of the instantaneous position of said rotor means; wherein said reference generator means comprises reference generator counter means for storing counts at a predetermined frequency and for generating an overflow signal when the stored counts reach a predetermined number wherein the number of counts stored in said reference generator counter means is said field position data; and resolver exciter means for generating said resolver excitation signals in response to said overflow signals; and wherein said resolver follower means comprises phase modulator means for generating phase modulated signals and said digital sum data in response to correction signals; phase comparator means for comparing the phase of the signals induced in said rotor means with said phase modulated signals to generate error signals indicative of the phase error between the two signals compared; and correction circuit means for generating said correction signals in response to said error signals. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification