Patent US3848172A successfully refreshed from Google Patents.
US3848172A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Yaw damper synchro system for aircraft
Assignee: Unisys Corp
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Filing: 1972-08-30
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Granted: 1974-11-12
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Expires: 1992-08-30
Abstract
Abstract A yaw rate signal is derived from a conventional three wire synchro transmitter positioned by a directional gyro and supplied to a yaw axis servomotor for providing short term automatic yaw damping of an aircraft. The three wire directional gyro synchro data is converted to a linear two wire signal from which the rate of change of aircraft heading is derived. The conversion to linear two wire data results in a triangular wave having linear leading and trailing edges that are changing slope at predetermined headings and the rate data derived from this wave is tracked and held at its last value for a predetermined interval during the discontinuity or peak point reversal of the triangular wave. Also, a predetermined hysteresis is provided at each discontinuity to assure a stable signal should the aircraft be on a discontinuity heading. A clampable synchronizer responsive to the two wire heading data for providing heading error to the roll channel of an autopilot is also disclosed.
Inventors
- 👤 R Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:39
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/02; G05D1/0202; G05D1/0204
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
181 words
In a lateral axis control system for an aircraft automatic flight control system, the combination comprising a stable directional reference means, means including a synchro control transformer having a rotor part positioned by said reference means and a stator part fixed to the aircraft and switching, demodulating and inverting means controlled by the relative positions of said rotor and stator parts for providing a continuous triangular wave d.c. signal voltage having substantially linear leading and trailing edge sectors corresponding to variations in aircraft heading between substantially plus and minus thirty degree sectors of aircraft heading and points of discontinuity at the leading and trailing edge junctions of said triangular wave, means responsive to said d.c. signal for deriving a signal proportional to the slope of said leading and trailing edge sectors and thereby proportional to the rate of change of aircraft heading, and means responsive to said switching means for tracking and holding the value of said rate signal at said points of discontinuity for a predetermined time interval whereby to eliminate any rate signal transients at said points of discontinuity.
Claim 2
Dependent Claim
181 words
In a lateral axis control system for an aircraft automatic flight control system, the combination comprising a stable directional reference means, means including a synchro control transformer having a rotor part positioned by said reference means and a stator part fixed to the aircraft and switching, demodulating and inverting means controlled by the relative positions of said rotor and stator parts for providing a continuous triangular wave d.c. signal voltage having substantially linear leading and trailing edge sectors corresponding to variations in aircraft heading between substantially plus and minus thirty degree sectors of aircraft heading and points of discontinuity at the leading and trailing edge junctions of said triangular wave, means responsive to said d.c. signal for deriving a signal proportional to the slope of said leading and trailing edge sectors and thereby proportional to the rate of change of aircraft heading, and means responsive to said switching means for tracking and holding the value of said rate signal at said points of discontinuity for a predetermined time interval whereby to eliminate any rate signal transients at said points of discontinuity.
Claim 3
Dependent Claim
20 words
The lateral axis control system as set forth in claim 1 wherein said directional reference means comprises a directional gyroscope.
Claim 4
Dependent Claim
79 words
The control system as set forth in claim 1 wherein said control transformer rotor includes a single phase winding excited by an a.c. carrier voltage and said stator includes a plurality of equiangularly displaced output windings for providing a corresponding number of a.c. output signals each sinusoidally modulated in accordance with the angular position of said stator with the respective ones of said output windings and each modulation component bearing a predetermined relation with the heading of said aircraft.
Claim 5
Dependent Claim
56 words
The control system as set forth in claim 3 wherein said demodulating means includes first switch means responsive to said output signals for converting said a.c. output signals to d.c. output signals, and second switch means responsive to predetermined relative magnitudes and predetermined phases of said modulated a.c. output signals for controlling said first switch means.
Claim 6
Dependent Claim
22 words
The control system as set forth in claim 4 wherein said predetermined relative magnitudes bear predetermined ratios corresponding to said aircraft headings.
Claim 7
Dependent Claim
28 words
The control system as set forth in claim 5 wherein said predetermined magnitude ratios correspond to craft headings between which said sinusoidally modulated output signals are substantially linear.
Claim 8
Dependent Claim
23 words
The control system as set forth in claim 6 wherein further predetermined phases correspond to the phases of said a.c. carrier voltage. change.
Claim 9
Dependent Claim
29 words
The control system as set forth in claim 5 wherein said tracking and hold means is initiated by said predetermined ratios of the magnitudes of said a.c. output signals.
Claim 10
Dependent Claim
37 words
The control system as set forth in claim 5 furthe including hysteresis means responsive to said predetermined magnitude ratios for altering said magnitude ratios once said predetermined magnitude ratio is reached in one direction of heading chane.
Claim 11
Dependent Claim
47 words
The control system as set forth in claim 9 wherein said hysteresis means comprises an amplifier means responsive to said predetermined magnitude ratios and means responsive to the output of said amplifier means for feeding back a signal to its input whereby to bias said amplifier input.
Claim 12
Dependent Claim
43 words
The aircraft control system as set forth in claim 3 wherein said means for deriving said rate signal includes further means responsive to said inverting means for inverting the sense of said rate signal for alternate sectors of said triangular wave d.c. signal.
Claim 13
Dependent Claim
65 words
The aircraft control system as set Forth in claim 3 further including heading synchronizing means responsive to said triangular wave signal, heading hold switching means for clamping said synchronizer at the heading then obtaining, and further switching means responsive to said heading hold switching means for rendering said triangular wave switching means ineffective whereby to provide a heading error signal at the heading then obtaining.
Claim 14
Dependent Claim
35 words
The control system as set forth in claim 12 further including means responsive to said inverting means for inverting the sense of said heading error signal for alternate sectors of said triangular wave d.c. signal.
Claim 15
Dependent Claim
50 words
The aircraft control system as set forth in claim 2 further including inhibit means responsive to the roll attitude of said aircraft for inhibiting said rate signal upon said roll attitude exceeding a predetermined value, whereby to avoid rate error signals produced by gimbal error effects of said directional gyroscope.
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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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |