Flight control for an airborne wind turbine

Patent metadata

Field	Value
Publication number	US-9429954-B2
Application number	US-201314137286-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Dec 20, 2013
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

An example method may include receiving data representing an initial position and an initial attitude of an aircraft. The method further includes determining a change to a first attribute and a second attribute of the position or the attitude of the aircraft to achieve a subsequent position and a subsequent attitude. The method also includes determining a priority sequence for changing the first attribute and the second attribute of the position or the attitude of the aircraft based on a first thrust of the actuator to achieve the change to the first attribute and a second thrust of the actuator to achieve the change to the second attribute. The priority sequence is configured to cause changes to the first attribute before causing changes to the second attribute where the actuator is unable to concurrently provide the first thrust and the second thrust.

First claim

What is claimed is:

1. A method comprising:
receiving, by one or more processors, data indicating an initial position and an initial attitude of an aircraft configured to be coupled to a ground station via a tether, wherein the aircraft includes an actuator configured to change a position and an attitude of the aircraft;
based on the received data, determining, by the one or more processors, a first level of thrust that, when provided by the actuator, facilitates changing a first attribute of the position or the attitude of the aircraft to a subsequent position or a subsequent attitude;
based on the received data, determining, by the one or more processors, a second level of thrust that, when provided by the actuator, facilitates changing a second attribute of the position or the attitude of the aircraft to the subsequent position or the subsequent attitude;
determining, by the one or more processors, that the first level of thrust conflicts with the second level of thrust; and
in response to determining that the first level of thrust conflicts with the second level of thrust, causing the actuator to provide the first level of thrust based on a priority sequence that prioritizes the first attribute above the second attribute.

2. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is a pitch angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that aircraft is less than the threshold distance away from the ground station.

3. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is a roll angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

4. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is an azimuth angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

5. The method of claim 1 , wherein the first attribute is an altitude of the aircraft, and wherein the second attribute is a pitch angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

6. The method of claim 1 , wherein the first attribute is an altitude of the aircraft, and wherein the second attribute is a roll angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

7. The method of claim 1 , wherein the first attribute is an altitude of the aircraft, and wherein the second attribute is an azimuth angle of the aircraft, the method comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

8. The method of claim 1 , wherein the first attribute is a pitch angle of the aircraft, and wherein the second attribute is a roll angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

9. The method of claim 1 , wherein the first attribute is a pitch angle of the aircraft, and wherein the second attribute is an azimuth angle of the aircraft, the method further comprising:
determining that the aircraft is less than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is less than the threshold distance away from the ground station.

10. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is an azimuth angle of the aircraft, the method further comprising:
determining that the aircraft is greater than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is greater than the threshold distance away from the ground station.

11. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is an altitude of the aircraft, the method further comprising:
determining that the aircraft is greater than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is greater than the threshold distance away from the ground station.

12. The method of claim 1 , wherein the first attribute is a pitch angle of the aircraft, and wherein the second attribute is an altitude of the aircraft, the method further comprising:
determining that the aircraft is greater than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is greater than the threshold distance away from the ground station.

13. The method of claim 1 , wherein the first attribute is an azimuth angle of the aircraft, and wherein the second attribute is a roll angle of the aircraft, the method further comprising:
determining that the aircraft is greater than a threshold distance away from the ground station,
wherein causing the actuator to provide the first level of thrust is performed also in response to determining that the aircraft is greater than the threshold distance away from the ground station.

14. The method of claim 1 , further comprising:
receiving data representing a tension force on the tether;
determining that the tension force on the tether is not substantially equal to a predetermined tension force; and
causing the actuator to rotate the aircraft about a pitch axis of the aircraft so that the tension force on the tether becomes substantially equal to the predetermined tension force.

15. The method of claim 1 , wherein the first attribute is a yaw angle of the aircraft, and wherein the second attribute is a pitch angle of the aircraft, the method further comprising:
receiving data representing a speed of a wind within an am

Assignees

• Google Inc

Inventors

• Chubb Erik Christopher
• Vander Lind Damon
• Hachtmann Brian

Classifications

• B64C17/00 Primary

  Aircraft stabilisation not otherwise provided for · CPC title

• B64C39/022

  Tethered aircraft · CPC title

• B64C2201/021

  Operations & Transport · mapped topic

• G05D1/0816 Primary

  to ensure stability · CPC title

• G05D1/0866

  specially adapted to captive aircraft · CPC title