Autonomous takeoff and landing with open loop mode and closed loop mode

• US 10,303,184 B1
• Filed: 12/20/2017
• Issued: 05/28/2019
• Est. Priority Date: 12/08/2017
• Status: Active Grant

• Current Assignee: Kitty Hawk Corporation
• Original Assignee: Kitty Hawk Corporation
• Inventors: Cutler, Mark Johnson, Selwa, Alexander David
• Primary Examiner(s): Goldman, Richard A
• Application Number:
  US15/848,847
• Publication Number:
  US 20190179343A1
• Time in Patent Office: 524 Days
• Field of Search: 701 3, 701 4, 701 5, 701 6, 701 7, 701 8, 701 10, 244 1713, 244180
• CPC Class Codes: B64C 29/0016 the lift during taking-off being created by free or ducted propellers or by blowers
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64U 2201/10 autonomous, i.e. by navigating independently from ground or air stations, e.g. by using inertial navigation systems [INS]
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/042 specially adapted for aircraft
• CPC Class Codes: G05D 1/0653 during a phase of take-off or landing
• CPC Class Codes: G05D 1/0669 specially adapted for vertical take-off
• CPC Class Codes: G05D 1/0676 specially adapted for landing

Abstract

Autonomous flight is performed in an open loop mode over a first range of altitudes, wherein a plurality altitude-related data from a plurality of altitude-related sensors is ignored while performing the autonomous flight in the open loop mode. The autonomous flight is performed in a closed loop mode over a second range of altitudes, wherein: the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes. The altitude-related data may include, among other things, a radar signal or a phase associated with a radar signal.

Claims

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;

perform autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

determine instructions for performing autonomous landing in the open loop mode including instructions for performing ground detection including by;

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

perform the autonomous flight in a closed loop mode over a second range of altitudes, wherein;

the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.

2. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

determine a confidence value;

compare the confidence value against a confidence threshold; and

in response to the confidence value exceeding the confidence threshold, switch from performing the autonomous takeoff in the open loop mode, wherein the plurality of altitude-related data is ignored, to performing the autonomous takeoff in the closed loop mode, wherein the plurality of altitude-related data is used.

3. The system recited in claim 1, wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain an altitude from the plurality of altitude-related data;

compare the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switch from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored.

4. The system recited in claim 1, wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain an altitude from the plurality of altitude-related data;

compare the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switch from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored, wherein the altitude threshold is selected based at least in part on a landing surface, including by;

determining whether an aircraft is above land or water; and

in response to the determination whether the aircraft is above land or water, selecting a land altitude threshold or a water altitude threshold accordingly.

5. The system recited in claim 1, wherein:

the determination of instructions for performing the autonomous landing in the open loop mode including instructions for performing ground detection further includes

obtaining a throttle value;

comparing the throttle value against a throttle threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold and the throttle value not exceeding the throttle threshold, deciding that a landing surface has been reached.

6. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

7. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing one or more of the following properties associated with the signal;

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

or

a slope of the signal; and

use the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

8. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing.

9. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing one or more of the following properties associated with the signal;

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

or

a slope of the signal; and

use the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing.

10. The system recited in claim 1, wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to;

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing, wherein updating the parameter includes using the pilot weight to select the parameter from a plurality of parameters associated with different pilot weights.

11. A method, comprising:

using a processor to perform autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

using the processor to perform autonomous landing in the open loop mode including performing ground detection including by;

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

using the processor to perform the autonomous flight in a closed loop mode over a second range of altitudes, wherein;

the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.

12. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

determining a confidence value;

comparing the confidence value against a confidence threshold; and

in response to the confidence value exceeding the confidence threshold, switching from performing the autonomous takeoff in the open loop mode, wherein the plurality of altitude-related data is ignored, to performing the autonomous takeoff in the closed loop mode, wherein the plurality of altitude-related data is used.

13. The method recited in claim 11, wherein:

the method further includes;

obtaining an altitude from the plurality of altitude-related data;

comparing the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switching from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored.

14. The method recited in claim 11, wherein:

the method further includes;

obtaining an altitude from the plurality of altitude-related data;

comparing the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switching from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored, wherein the altitude threshold is selected based at least in part on a landing surface, including by;

determining whether an aircraft is above land or water; and

in response to the determination whether the aircraft is above land or water, selecting a land altitude threshold or a water altitude threshold accordingly.

15. The method recited in claim 11, wherein:

the using the processor to perform the autonomous landing in the open loop mode including by performing ground detection further includes

obtaining a throttle value;

comparing the throttle value against a throttle threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold and the throttle value not exceeding the throttle threshold, deciding that a landing surface has been reached.

16. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

17. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing one or more of the following properties associated with the signal;

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

or

a slope of the signal; and

using the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

18. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing.

19. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing one or more of the following properties associated with the signal;

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

or

a slope of the signal; and

using the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing.

20. The method recited in claim 11, wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes;

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to update a parameter associated with one or more of the following;

the autonomous takeoff or the autonomous landing, wherein updating the parameter includes using the pilot weight to select the parameter from a plurality of parameters associated with different pilot weights.

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

performing autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

performing autonomous landing in the open loop mode including performing ground detection including by;

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

performing the autonomous flight in a closed loop mode over a second range of altitudes, wherein;

the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.