Patent US4697768A successfully refreshed from Google Patents.
US4697768A
Expired / Lapsed
US
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Flight control system employing complementary filter
Assignee: Grumman Corp
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Filing: 1985-11-12
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Granted: 1987-10-06
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Expires: 2005-11-12
Abstract
Abstract Strake, flap and canard control surfaces of an aircraft are driven by an error signal which is comprised of a pilot stick command signal and feedback components including measured vertical acceleration and pitch rate of the aircraft and a third feedback component derived from a complementary filter. The filter has a high-pass filter section which operates upon canard position data and a low-pass filter section which operates upon pitch rate. A summation of the signals passing both filtering sections is summed with the vertical acceleration and pitch rate feedback signals to form a combined feedback signal.
Inventors
- 👤 Robert W. Klein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:26
CPC Classifications
B; B64; B64C; B64C13/00; B64C13/02; B64C13/16; G; G05; G05D; G05D1/00; G05D1/08; G05D1/0808; G05D1/0816
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
146 words
In a flight control system for reducing a multi-control surface aircraft wherein an error signal is formed from signal components including a pilot stick signal and a composite feedback signal, the system comprising: means for sensing vertical acceleration of an aircraft and generating a signal corresponding thereto; means for sensing pitch rate of an aircraft and generating a signal corresponding thereto; a complementary filter having (a) means for high-pass filtering a signal generated from a position sensor connected to one of the control surfaces; (b) means for low-pass filtering the signal generated from the position sensor connected to the control surface; (c) means for summing the low and high pass filtered signals; means for combining the stick signal, vertical acceleration, pitch rate, and summed filtered signals to form the error signal; and means for connecting the error signal to actuators for each of the multi-control surfaces.
Claim 2
Dependent Claim
146 words
In a flight control system for reducing a multi-control surface aircraft wherein an error signal is formed from signal components including a pilot stick signal and a composite feedback signal, the system comprising: means for sensing vertical acceleration of an aircraft and generating a signal corresponding thereto; means for sensing pitch rate of an aircraft and generating a signal corresponding thereto; a complementary filter having (a) means for high-pass filtering a signal generated from a position sensor connected to one of the control surfaces; (b) means for low-pass filtering the signal generated from the position sensor connected to the control surface; (c) means for summing the low and high pass filtered signals; means for combining the stick signal, vertical acceleration, pitch rate, and summed filtered signals to form the error signal; and means for connecting the error signal to actuators for each of the multi-control surfaces.
Claim 3
Dependent Claim
20 words
The structure set forth in claim 1 wherein said control surface having a position sensor connected thereto is a canard.
Claim 4
Dependent Claim
34 words
The structure set forth in claim 2 wherein the high-pass filtering means comprises means for differentiating the sensor signal from the canard with a time constant selected to maximize stability margin for the aircraft.
Claim 5
Dependent Claim
54 words
The structure set forth in claim 2 wherein the low-pass filtering means comprises: means for estimating a value of pitch rate from a two-point estimate; and means connected to the two-point estimating means for integrating the estimated value of pitch rate with a time constant selected to maximize the stability margin for the aircraft.
Claim 6
Dependent Claim
35 words
The structure set forth in claim 4 wherein the high-pass filtering means comprises means for differentiating the sensor signal from the canard with a time constant selected to maximize the stability margin for the aircraft.
Claim 7
Dependent Claim
102 words
A flight control method for use with a multi-control aircraft comprising the steps: sensing vertical acceleration of an aircraft and generating a signal corresponding thereto; sensing pitch rate of an aircraft and generating a signal corresponding thereto; high-pass filtering a signal generated from a position sensor connected to one of the aircraft control surfaces; low-pass filtering the signal generated from the position sensor connected to the control surfaces; summing the filtered signals; combining the stick signal, vertical acceleration, pitch rate and summed filtered signals to form the error signal; and connecting the error signal to actuators for each of the multi-control surfaces.
Claim 8
Dependent Claim
102 words
A flight control method for use with a multi-control aircraft comprising the steps: sensing vertical acceleration of an aircraft and generating a signal corresponding thereto; sensing pitch rate of an aircraft and generating a signal corresponding thereto; high-pass filtering a signal generated from a position sensor connected to one of the aircraft control surfaces; low-pass filtering the signal generated from the position sensor connected to the control surfaces; summing the filtered signals; combining the stick signal, vertical acceleration, pitch rate and summed filtered signals to form the error signal; and connecting the error signal to actuators for each of the multi-control surfaces.
Claim 9
Dependent Claim
36 words
The method set forth in claim 6 wherein the high-pass filtering further comprises the step of differentiating the sensor signal from a control surface with a time constant selected to maximize stability margin for the aircraft.
Claim 10
Dependent Claim
44 words
The method set forth in claim 7 wherein the low-pass filtering further comprises the steps: estimating a value of pitch rate from a two-point estimate; and integrating the estimated pitch rate with a time constant selected to maximize the stability margin for the aircraft.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-05 | 1991-04-06 | 1991-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-05 | 1995-04-06 | 1995-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-05 | 1999-04-06 | 1999-10-06 | $7700.00 | Window Closed / Lapsed |