IP Library › Granted Patent US 10,293,927

Granted Patent B1

US 10,293,927 · App. 15/957,733 · Granted May 21, 2019

Control system for a stopped rotor aircraft

Inventors: Gregory Mainland Horn (Mountain View, CA); Damon Vander Lind (East Palo Alto, CA)

Assignee: Kitty Hawk Corporation

B64C27/24 B64C27/26 B64C27/82 B64C29/0025 G05B11/42 B64C2027/8236

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Quick Facts

Patent No.: US 10,293,927
App. No.: 15/957,733
Granted: May 21, 2019
Kind: B1

External Links

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Abstract

While an aircraft is mid-flight, a braking start point associated with a stoppable rotor is calculated where the stoppable rotor includes a first and second blade and the stoppable rotor is configured to rotate about a substantially vertical axis. A process to stop the stoppable rotor is started, while the aircraft is mid-flight, when the stoppable rotor reaches the braking start point, where the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward.

Claims (85)

1. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

calculate, while an aircraft which includes a stoppable rotor is mid-flight, a braking start point associated with the stoppable rotor, wherein the stoppable rotor includes a first blade and a second blade and the stoppable rotor is configured to rotate about a substantially vertical axis;

start a process to stop the stoppable rotor, while the aircraft which includes the stoppable rotor is mid-flight, when the stoppable rotor reaches the braking start point, wherein the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward; and

determine that the stoppable rotor is in an unstable position.

2. The system of claim 1 , wherein the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

adjusting an amount of torque applied to the stoppable rotor using feedback.

3. The system of claim 1 , wherein the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

adjusting an amount of torque applied to the stoppable rotor using feedback, including by using a proportional-integral-derivative (PID) controller which uses a rotational angle associated with the stoppable rotor and an angular rate associated with the stoppable rotor.

4. The system of claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to: while the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward, adjust a nominal torque of zero applied to the stoppable rotor using a proportional-integral-derivative (PID) controller which uses a rotational angle associated with the stoppable rotor and an angular rate associated with the stoppable rotor.

5. The system of claim 1 , wherein:

the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to: while the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward, adjust a nominal torque of zero applied to the stoppable rotor using a proportional-integral-derivative (PID) controller which uses a rotational angle associated with the stoppable rotor and an angular rate associated with the stoppable rotor.

6. The system of claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to: begin to search for the braking start point once the stoppable rotor has reached a searching start point.

7. The system of claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to: begin to search for the braking start point once the stoppable rotor has reached a searching start point, wherein a difference between the searching start point and the braking start point is a pre-defined amount.

8. The system of claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor, in response to the stoppable rotor being in a stable position, starting the process to stop to stoppable rotor.

9. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

adjust a braking start point based at least in part on a crosswind.

10. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

rotate the stoppable rotor at least one more rotation in a regular direction of rotation.

11. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

rotate the stoppable rotor at least one more rotation in a regular direction of rotation until the stoppable rotor is in a stable position.

12. A method, comprising:

calculating, while an aircraft which includes a stoppable rotor is mid-flight, a braking start point associated with the stoppable rotor, wherein the stoppable rotor includes a first blade and a second blade and the stoppable rotor is configured to rotate about a substantially vertical axis;

starting a process to stop the stoppable rotor, while the aircraft which includes the stoppable rotor is mid-flight, when the stoppable rotor reaches the braking start point, wherein the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward; and

determining that the stoppable rotor is in an unstable position.

13. The method of claim 12 , wherein the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

adjusting an amount of torque applied to the stoppable rotor using feedback.

14. The method of claim 12 , wherein the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

15. The method of claim 12 , further comprising: while the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward, adjusting a nominal torque of zero applied to the stoppable rotor using a proportional-integral-derivative (PID) controller which uses a rotational angle associated with the stoppable rotor and an angular rate associated with the stoppable rotor.

16. The method of claim 12 , wherein:

the stopping process includes:

applying an initial amount of torque to the stoppable rotor, wherein the magnitude of the initial amount of torque is strictly less than the magnitude of a maximum amount of torque; and

the method further includes: while the stoppable rotor is stopped with the first blade pointing forward and the second blade pointing backward, adjusting a nominal torque of zero applied to the stoppable rotor using a proportional-integral-derivative (PID) controller which uses a rotational angle associated with the stoppable rotor and an angular rate associated with the stoppable rotor.

17. The method of claim 12 further comprising: beginning to search for the braking start point once the stoppable rotor has reached a searching start point.

18. The method of claim 12 further comprising: begin to search for the braking start point once the stoppable rotor has reached a searching start point, wherein a difference between the searching start point and the braking start point is a pre-defined amount.

19. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

determining that the stoppable rotor is in an unstable position.

20. A method, comprising:

adjusting a braking start point based at least in part on a crosswind.

21. A method, comprising:

rotating the stoppable rotor at least one more rotation in a regular direction of rotation.

22. A method, comprising:

rotating the stoppable rotor at least one more rotation in a regular direction of rotation until the stoppable rotor is in a stable position.

23. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

adjusting a braking start point based at least in part on a crosswind.

24. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

rotating the stoppable rotor at least one more rotation in a regular direction of rotation.

25. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

rotating the stoppable rotor at least one more rotation in a regular direction of rotation until the stoppable rotor is in a stable position.

Assignments (6)

RELEASE OF SECURITY INTEREST Recorded May 22, 2023

From: ONE AERO, LLC

To: KITTY HAWK CORPORATION

Reel/Frame 063713/0367 →

SECURITY INTEREST Recorded Mar 25, 2022

From: KITTY HAWK CORPORATION

To: ONE AERO, LLC

Reel/Frame 059503/0382 →

SECURITY INTEREST Recorded Nov 4, 2021

From: KITTY HAWK CORPORATION