US3725764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo positioning system for magnetic disk memory including radial runout servo compensation
Assignee: International Business Machines Corp
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Filing: 1971-04-01
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Granted: 1973-04-03
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Expires: 1991-04-01
Abstract
Abstract Servo apparatus for accurately following a servo track on a moving surface. The track possesses a degree of radial runout from a nominal position. A first transducer is mounted on a movable arm to indicate the lateral direction and distance from the servo track. The movable arm is positioned laterally with respect to the servo track by a servo motor. A second transducer measures the velocity of said first transducer for generating a signal indicative of the magnitude of the radial runout existing within the servo positioning system. Correction means is used to combine the output from said first transducer and from second transducer to produce a positioning error signal to the servo motor such that the first transducer will exactly follow the radial runout present in the servo positioning system.
Inventors
- 👤 R Oswald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:28
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D3/14; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59627
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
Servo apparatus for following a servo track comprising: a first sensing means for generating a first signal as a function of said first sensing means position with respect to said servo track; a first detector for receiving said first signal and forming a first error position signal from said first signal; a second means for sensing the velocity of said first sensing means and for generating a second signal indicative of said sensed velocity, said second signal being representative of the magnitude and frequency of the radial runout associated with said servo track; a compensating means for combining said first and said second signals and for modifying said combined signals to form a second error position signal; and an actuating means for moving said first sensing means in response to said second error position signal such that said first sensing means follows any eccentricity in said servo track.
Claim 2
Dependent Claim
148 words
Servo apparatus for following a servo track comprising: a first sensing means for generating a first signal as a function of said first sensing means position with respect to said servo track; a first detector for receiving said first signal and forming a first error position signal from said first signal; a second means for sensing the velocity of said first sensing means and for generating a second signal indicative of said sensed velocity, said second signal being representative of the magnitude and frequency of the radial runout associated with said servo track; a compensating means for combining said first and said second signals and for modifying said combined signals to form a second error position signal; and an actuating means for moving said first sensing means in response to said second error position signal such that said first sensing means follows any eccentricity in said servo track.
Claim 3
Dependent Claim
72 words
A servo system as set forth in claim 1 wherein said compensating means further comprises: a first compensator for receiving said second signal from said second sensing means, said first compensator varying the phase and magnitude of said second signal; an adder means for adding together said first signal and the output from said first compensator; a second compensator for varying the phase and magnitude of the combined signal from said adder.
Claim 4
Dependent Claim
28 words
A servo apparatus as set forth in claim 2 wherein said first compensator has the transfer function of ( Tau 2 - Tau 1)/(S Tau 1 + 1)
Claim 5
Dependent Claim
27 words
A servo apparatus as set forth in claim 3 wherein said second compensator has the transfer function of (S Tau 1 + 1)/(S Tau 2 + 1)
Claim 6
Dependent Claim
19 words
A servo apparatus as set forth in claim 3 wherein said first compensator is an electronic low pass filter.
Claim 7
Dependent Claim
18 words
A servo apparatus as set forth in claim 4 wherein said second compensator is an electronic lead/lag network.
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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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |