US4486845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resolver to incremental shaft encoder converter
Assignee: Kearfott Guidance and Navigation Corp
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Filing: 1982-07-23
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Granted: 1984-12-04
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Expires: 2002-07-23
Abstract
Abstract A circuit for duplicating the function of an incremental shaft encoder comprises a rugged resolver connected to a hybrid digital-analog circuit which generates output signals identical to those of a counterpart incremental encoder. The digital portion of the circuit includes terminals whereat absolute angle measurements of a shaft may be made.
Inventors
- 👤 James J. Duckworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:52
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/64; H03M1/645; H03M1/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
217 words
A device for measuring shaft angle comprising: a shaft driven resolver having a stator input and a rotor output; reference signal generating means for generating a digital zero reference signal; reference signal converting means for converting a digital zero reference signal to a corresponding analog zero reference signal which is connected to the stator's input resulting in a signal at the rotor output which is a sine waveform with a phase angle relative to the analog zero reference signal and equal to the mechanical angle of the resolver shaft; loop means having inputs connected to the digital zero reference signal generating means and the rotor output for tracking the phase angle of the resolver output and producing a digital angle signal corresponding thereto, wherein the reference signal converting means comprises: a first ROM storing a sine look-up table and connected at its input to the digital zero reference signal; first digital-to-analog converting means connected to the output of the first ROM for producing a first analog zero reference signal as a sine function; a second ROM storing a cosine look-up table and connected at its input to the digital zero reference signal; and second digital-to-analog converting means connected to the output of the second ROM for producing a second analog zero reference signal as a cosine function.
Claim 2
Independent Claim
217 words
A device for measuring shaft angle comprising: a shaft driven resolver having a stator input and a rotor output; reference signal generating means for generating a digital zero reference signal; reference signal converting means for converting a digital zero reference signal to a corresponding analog zero reference signal which is connected to the stator's input resulting in a signal at the rotor output which is a sine waveform with a phase angle relative to the analog zero reference signal and equal to the mechanical angle of the resolver shaft; loop means having inputs connected to the digital zero reference signal generating means and the rotor output for tracking the phase angle of the resolver output and producing a digital angle signal corresponding thereto, wherein the reference signal converting means comprises: a first ROM storing a sine look-up table and connected at its input to the digital zero reference signal; first digital-to-analog converting means connected to the output of the first ROM for producing a first analog zero reference signal as a sine function; a second ROM storing a cosine look-up table and connected at its input to the digital zero reference signal; and second digital-to-analog converting means connected to the output of the second ROM for producing a second analog zero reference signal as a cosine function.
Claim 3
Dependent Claim
151 words
The device set forth in claim 1 wherein the loop means comprises: a digital adder having a first input thereof connected to the digital zero reference signal; a phase detector having a first input connected to the most significant bit of the digital adder and a second input connected to the rotor output wherein the detector compares the most significant bit of the adder with the phase angle of the resolver rotor; voltage controlled means having an input connected to an output of the phase detector to generate a signal which is indicative of the polarity of an error output from the phase detector; an up/down counter for counting in a direction dependent upon the indicative signal, the up/down counter generating a signal at the output thereof which corresponds to the digital angle of the resolver rotor; and means for connecting the up/down counter output to a second digital adder input.
Claim 4
Dependent Claim
75 words
The device set forth in claim 2 wherein the voltage controlled means comprises: an input terminal; means connected to the input terminal for detecting the polarity of the error output from the phase detector; means connected to the input terminal for generating a voltage corresponding to the absolute value of the error output; and voltage-to-frequency converting means connected between the absolute value generating means and an input of the up/down counter for incrementing the counter.
Claim 5
Independent Claim
277 words
A device for measuring shaft angle comprising: a shaft driven resolver having a stator input and a rotor output; reference signal generating means for generating a digital zero reference signal; reference signal converting means for converting a digital zero reference signal to a corresponding analog zero reference signal which is connected to the stator's input resulting in a signal at the rotor output which is a sine waveform with a phase angle relative to the analog zero reference signal and equal to the mechanical angle of the resolver shaft; loop means having inputs connected to the digital zero signal generating means and the rotor output for tracking the phase angle of the resolver output and producing a digital angle signal corresponding thereto; gating means connected to the digital angle signal for generating a plurality of squarewave outputs with the same frequency but displaced from one another by a preselected portion of a cycle, wherein the reference signal generating means comprises: a clock oscillator; an up-counter driven by the oscillator for generating the digital zero reference signal at the output of the counter, and wherein the reference signal converting means comprises: a first ROM storing a sine look-up table and connected at its input to the digital zero reference signal; first digital-to-analog converting means connected to the output of the first ROM for producing a first analog zero reference signal as a sine function; a second ROM storing a cosine look-up table and connected at its input to the digital zero reference signal; and second digital-to-analog converting means connected to the output of the second ROM for producing a second analog zero reference signal as a cosine function.
Claim 6
Independent Claim
277 words
A device for measuring shaft angle comprising: a shaft driven resolver having a stator input and a rotor output; reference signal generating means for generating a digital zero reference signal; reference signal converting means for converting a digital zero reference signal to a corresponding analog zero reference signal which is connected to the stator's input resulting in a signal at the rotor output which is a sine waveform with a phase angle relative to the analog zero reference signal and equal to the mechanical angle of the resolver shaft; loop means having inputs connected to the digital zero signal generating means and the rotor output for tracking the phase angle of the resolver output and producing a digital angle signal corresponding thereto; gating means connected to the digital angle signal for generating a plurality of squarewave outputs with the same frequency but displaced from one another by a preselected portion of a cycle, wherein the reference signal generating means comprises: a clock oscillator; an up-counter driven by the oscillator for generating the digital zero reference signal at the output of the counter, and wherein the reference signal converting means comprises: a first ROM storing a sine look-up table and connected at its input to the digital zero reference signal; first digital-to-analog converting means connected to the output of the first ROM for producing a first analog zero reference signal as a sine function; a second ROM storing a cosine look-up table and connected at its input to the digital zero reference signal; and second digital-to-analog converting means connected to the output of the second ROM for producing a second analog zero reference signal as a cosine function.
Claim 7
Dependent Claim
151 words
The device set forth in claim 4 wherein the loop means comprises: a digital adder having a first input thereof connected to the digital zero reference signal; a phase detector having a first input connected to the most significant bit of the digital adder and a second input connected to the rotor output wherein the detector compares the most significant bit of the adder with the phase angle of the resolver rotor; voltage controlled means having an input connected to an output of the phase detector to generate a signal which is indicative of the polarity of an error output from the phase detector; an up/down counter for counting in a direction dependent upon the indicative signal, the up/down counter generating a signal at the output thereof which corresponds to the digital angle of the resolver rotor; and means for connecting the up/down counter output to a second digital adder input.
Claim 8
Dependent Claim
76 words
The subject device set forth in claim 5 wherein the voltage controlled means comprises: an input terminal; means connected to the input terminal for detecting the polarity of the error output from the phase detector; means parallel-connected to the input terminal for generating a voltage corresponding to the absolute value of the error output; and voltage-to-frequency converting means connected between the absolute value generating means and an input of the up/down counter for incrementing the counter.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |