US5072893A
Expired / Lapsed
US
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Aircraft modal suppression system
Assignee: Boeing Co
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Filing: 1987-05-28
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Granted: 1991-12-17
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Expires: 2007-05-28
Abstract
Abstract Accelerations due to excitation of the natural modes of an aircraft's body are suppressed by an active suppression system. Dedicated accelerometers are positioned in the aircraft at optimal locations for sensing modal induced lateral accelerations. The accelerometer produced signals are processed through control logic which, in response thereto, and in response to aircraft velocity and altitude related signals produces output control signals. The control signals effect rudder deployment creating forces to suppress the natural mode induced accelerations.
Inventors
- 👤 Abhijit J. M. Chakravarty
- 👤 Steven R. Cooper
- 👤 John K. H. Ho
- 👤 Chuong B. Tran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:18
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/08; G05D1/0808; G05D1/0816; G05D1/0825
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
112 words
An aircraft modal suppression control system for suppressing aircraft body deflections due to natural body flexure modes, the modal suppression system comprising: control surface means controllably deploying responsive to input control signals; sensor means including one sensor predeterminedly located on the aircraft body to produce an excitation signal representative of excitation of the body in at least two natural modes; velocity means for producing a velocity signal representative of aircraft velocity; and control logic means for producing predetermined control surface control signals responsive to said excitation signal and said velocity signal such that said control surface means is deployed to create forces on the aircraft body to suppress said natural mode excitations.
Claim 2
Dependent Claim
112 words
An aircraft modal suppression control system for suppressing aircraft body deflections due to natural body flexure modes, the modal suppression system comprising: control surface means controllably deploying responsive to input control signals; sensor means including one sensor predeterminedly located on the aircraft body to produce an excitation signal representative of excitation of the body in at least two natural modes; velocity means for producing a velocity signal representative of aircraft velocity; and control logic means for producing predetermined control surface control signals responsive to said excitation signal and said velocity signal such that said control surface means is deployed to create forces on the aircraft body to suppress said natural mode excitations.
Claim 3
Dependent Claim
41 words
The modal suppression system of claim 1 further comprising: altitude means for producing an altitude signal representative of aircraft altitude, and wherein said control logic means includes means responsive to said altitude signal for producing said predetermined control surface control signals.
Claim 4
Dependent Claim
51 words
The modal suppression system of either one of claims 1 or 2 wherein the sensor means comprises: an accelerometer positioned on the aircraft at a location to sense said body mode excitations; and a band pass filter means for predeterminedly attenuating signals other than the accelerometer produced body mode excitation signals.
Claim 5
Dependent Claim
22 words
The modal suppression system of claim 3 wherein said band pass filter means is comprised of a fourth order band pass filter.
Claim 6
Dependent Claim
41 words
The suppression system of either one of claims 1 or 2 wherein the sensor means includes an accelerometer located on the aircraft body to produce said acceleration signal representative of acceleration of the body in at least one lateral natural mode.
Claim 7
Dependent Claim
14 words
The suppression system of claim 5 wherein the control surface means comprises a rudder.
Claim 8
Dependent Claim
28 words
The suppression system of claim 3 wherein said accelerometer is positioned on the aircraft body at a location to sense the first and second body lateral natural modes.
Claim 9
Dependent Claim
14 words
The suppression system of claim 7 wherein the control surface means comprises a rudder.
Claim 10
Dependent Claim
89 words
An aircraft modal suppression control system for suppressing aircraft body deflections due to natural body flexure modes, the modal suppression system comprising: control surface means controllably deploying responsive to input control signals; sensor means including means predeterminedly located on the aircraft body to produce an excitation signal representative of excitation of the body in at least one predetermined natural mode; and control logic means including filtering means for predeterminedly filtering said excitation signal to produce control surface control signals of predetermined phase to optimally suppress said natural mode excitations.
Claim 11
Dependent Claim
89 words
An aircraft modal suppression control system for suppressing aircraft body deflections due to natural body flexure modes, the modal suppression system comprising: control surface means controllably deploying responsive to input control signals; sensor means including means predeterminedly located on the aircraft body to produce an excitation signal representative of excitation of the body in at least one predetermined natural mode; and control logic means including filtering means for predeterminedly filtering said excitation signal to produce control surface control signals of predetermined phase to optimally suppress said natural mode excitations.
Claim 12
Dependent Claim
47 words
The modal suppression system of claim 9 wherein the sensor means comprises: an accelerometer positioned on the aircraft at a location to sense at least one body natural mode; and a band pass filter means for predeterminedly attenuating signals other than the accelerometer produced body mode signals.
Claim 13
Dependent Claim
22 words
The modal suppression system of claim 10 wherein said band pass filter means is comprised of a fourth order band pass filter.
Claim 14
Dependent Claim
85 words
The modal suppression system of claim 9 wherein the sensor means comprises: a first accelerometer positioned on the aircraft at a location to sense a first body mode; a second accelerometer positioned on the aircraft at a location to sense a second body mode; a first band pass filter means for predeterminedly attenuating signals other than the first accelerometer produced first body mode signal; and a second band pass filter means for predeterminedly attenuating signals other than the second accelerometer produced second body mode signal.
Claim 15
Dependent Claim
38 words
The suppression system of claim 12 wherein: said first band pass filter means is comprised of a fourth order band pass filter; and a second band pass filter means is comprised of a second order band pass filter.
Claim 16
Dependent Claim
34 words
The suppression system of claim 9 wherein the sensor means includes an accelerometer located on the aircraft body to produce said acceleration signal representative of acceleration of the body in a lateral natural mode.
Claim 17
Dependent Claim
14 words
The suppression system of claim 14 wherein the control surface means comprises a rudder.
Claim 18
Dependent Claim
27 words
The suppression system of claim 10 wherein said accelerometer is positioned on the aircraft body at a location to sense the first and second body lateral modes.
Claim 19
Dependent Claim
14 words
The suppression system of claim 16 wherein the control surface means comprises a rudder.
Claim 20
Dependent Claim
44 words
The suppression system of claim 12 wherein: said first accelerometer is positioned on the aircraft at a location to sense the first body lateral mode; and said second accelerometer is positioned on the aircraft at a location to sense the second body lateral mode.
Claim 21
Dependent Claim
14 words
The suppression system of claim 18 wherein the control surface means comprises a rudder.
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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) | 1994-12-16 | 1995-06-17 | 1995-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-16 | 1999-06-17 | 1999-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-16 | 2003-06-17 | 2003-12-17 | $7700.00 | Window Closed / Lapsed |