Angle-of-attack flight computer systems and methods

Patent metadata

Field	Value
Publication number	US-11853081-B2
Application number	US-202117373682-A
Country	US
Kind code	B2
Filing date	Jul 12, 2021
Priority date	Apr 30, 2019
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

According to one implementation of the present disclosure, a method for determining angle-of-attack for an unpowered vehicle is disclosed. The method includes: determining a monotonic portion of a look-up curve of an angle-of-attack operating plot; during flight, determining, by an accelerometer disposed on the unpowered vehicle, first and second accelerometer outputs, where the first and second accelerometer outputs correspond to first and second body-fixed load factor measurements, respectively; determining an operating point on the monotonic portion by applying a quotient of the first and second accelerometer outputs to the angle-of-attack operating plot; and determining an angle-of-attack parameter corresponding to the determined operating point.

First claim

What is claimed is:

1. A method for determining an angle-of-attack for an unpowered vehicle, comprising:
determining an operating point on an angle-of-attack operating plot;
determining an angle-of-attack parameter corresponding to the determined operating point;
adjusting, at least partially, an angle-of-attack setting of the unpowered vehicle based on the angle-of-attack parameter; and
bringing the unpowered vehicle to an optimal angle of attack based on the angle-of-attack setting.

2. The method of claim 1 , wherein the operating point is determined on a monotonic portion of a look-up curve of the angle-of-attack operating plot.

3. The method of claim 2 , wherein the monotonic portion corresponds to a plurality of body-fixed accelerations as a function of a plurality of angle-of-attack parameters, and wherein the plurality of angle-of-attack parameters corresponds to a respective range of prospective angle-of-attack directions.

4. The method of claim 3 , wherein the angle-of-attack parameter of the plurality of angle-of-attack parameters corresponds to one direction of the range of the prospective angle-of-attack directions, and wherein the angle-of-attack parameter corresponds to a lift-to-drag-optimized angle-of-attack, a minimum-sink rate-optimized angle of attack, or a combination thereof.

5. The method of claim 3 , wherein the plurality of body-fixed accelerations corresponds to a quotient of the pluralities of first and second body-fixed coefficients.

6. The method of claim 5 , wherein the plurality of a first body-fixed coefficient is based on a corresponding plurality of a first aerodynamic data characteristic and a range of angle-of-attack directions.

7. The method of claim 6 , wherein the plurality of a first aerodynamic data characteristic comprises a plurality of lift coefficient metrics.

8. The method of claim 5 , wherein the plurality of a second body-fixed coefficient is based on a corresponding plurality of a second aerodynamic data characteristic and a range of angle-of-attack directions.

9. The method of claim 8 , wherein the plurality of a second aerodynamic data characteristic comprises a plurality of drag coefficient metrics.

10. The method of claim 2 , wherein determining the monotonic portion of the look-up curve of the angle-of-attack operating plot comprises:
obtaining pluralities of first and second aerodynamic data characteristics as respective functions of a range of angle-of-attack directions;
computing, by a processor, pluralities of first and second body-fixed coefficients as the respective functions of the range of angle-of-attack directions;
determining, by the processor, a plurality of body-fixed accelerations as a function of a prospective range of the range of angle-of-attack directions based on respective pluralities of quotients of the first and second body-fixed coefficients as the respective functions of the range of angle-of-attack directions, wherein the determined plurality of body-fixed accelerations as a function of a prospective range of the range of angle-of-attack directions corresponds to the look-up curve of the angle-of-attack operating plot; and
determining the monotonic portion based on a filtering, by the processor, of the look-up curve.

11. The method of claim 10 , wherein the pluralities of first and second aerodynamic data characteristics are obtained by estimating the range of the body-fixed accelerations for the vehicle or by measuring wind tunnel data with respect to the vehicle.

12. The method of claim 10 , wherein a graph comparing a range of body-fixed accelerations as a function of the prospective range of the range of angle-of-attack directions corresponds to the angle-of-attack operating plot.

13. The method of claim 2 , wherein the operating point is determined by applying a quotient of first and second accelerometer outputs to the angle-of-attack operating plot, and wherein applying the quotient of the first and second accelerometer outputs comprises:
matching a quotient of the first and second accelerometer outputs to a substantially equivalent body-fixed acceleration, wherein the body-fixed acceleration corresponds to a particular quotient of a particular first and second body-fixed coefficients, and wherein the particular quotient of the first and second body-fixed coefficient corresponds to a particular respective first and second aerodynamic data characteristic.

14. The method of claim 13 , wherein the particular respective first and second aerodynamic data characteristic corresponds to a particular respective lift coefficient metric and drag coefficient metric.

15. The method of claim 1 , further comprising:
during flight, determining, by an accelerometer disposed on the unpowered vehicle, first and second accelerometer outputs, wherein the first and second accelerometer outputs correspond to first and second body-fixed load factors, respectively.

16. The method of claim 15 , wherein a measurement of the first body-fixed load factor corresponds to a quotient of a magnitude of axial force and weight, and wherein a measurement of the second body-fixed load factor corresponds to a quotient of a magnitude of normal force and weight.

17. The method of claim 1 , further comprising, in response to determining the angle-of-attack parameter:
generating, at least partially by a flight computer system, a flight profile of the unpowered vehicle.

18. The method of claim 1 , wherein the operating point corresponds to a particular body-fixed acceleration as function of a corresponding particular angle-of-attack parameter.

19. A flight computer system comprising:
a processor; and
a memory accessible to the processor, the memory storing instructions that are executable by the processor to perform operations comprising:
determining an operating point on an angle-of-attack operating plot;
determining an angle-of-attack parameter corresponding to the determined operating point;
adjusting, at least partially by the flight computer system, an angle-of-attack setting of an unpowered vehicle based on the angle-of-attack parameter; and
bringing the unpowered vehicle to an optimal angle of attack based on the angle-of-attack setting.

20. A non-transitory computer-readable storage device storing instructions that, when executed by a processor, cause the processor to:
determine an operating point on an angle-of-attack operating plot;
determine an angle-of-attack parameter corresponding to the determined operating point;
adjust, at least partially by the processor, an angle-of-attack setting of an unpowered vehicle based on the angle-of-attack parameter; and
bring the unpowered vehicle to an optimal angle of attack based on the angle-of-attack setting.

Assignees

• Textron Innovations Inc

Inventors

• Campbell Kip Gregory

Classifications

• G08G5/55

  for a single aircraft · CPC title

• G08G5/50

  Navigation or guidance aids · CPC title

• G05D1/0607 Primary

  specially adapted for aircraft · CPC title

• B64D45/00

  Aircraft indicators or protectors not otherwise provided for · CPC title

• G08G5/0047

  Physics · mapped topic