Vertical take-off-and-landing unmanned aerial vehicle system capable of landing on uneven or sloped terrain

• US 9,994,307 B2
• Filed: 03/25/2016
• Issued: 06/12/2018
• Est. Priority Date: 03/25/2016
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Nguyen, Hoa G., Burmeister, Aaron B.
• Primary Examiner(s): Zanelli, Michael J
• Application Number:
  US15/081,163
• Publication Number:
  US 20170274988A1
• Time in Patent Office: 809 Days
• CPC Class Codes: B64C 2025/008 Comprising means for modifying their length, e.g. for kneeling, for jumping, or for leveling the aircraft
• CPC Class Codes: B64C 2025/325 specially adapted for helicopters
• CPC Class Codes: B64C 25/28 with indicating or warning devices
• CPC Class Codes: B64C 25/32 characterised by elements which contact the ground or similar surface arrester hooks B64C25/68
• CPC Class Codes: B64C 25/52 Skis or runners
• CPC Class Codes: B64C 29/00 Aircraft capable of landing or taking-off vertically, e.g. vertical take-off and landing [VTOL] aircraft rotorcraft B64C27/00
• 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: B64U 60/20 specially adapted for uneven terrain
• CPC Class Codes: B64U 60/50 with landing legs
• CPC Class Codes: B64U 70/00 Launching, take-off or landing arrangements
• CPC Class Codes: B64U 70/80 Vertical take-off or landing, e.g. using rockets rotorcrafts B64U10/10; VTOL aircraft B64U10/20

Abstract

A system for landing, comprising a vertical-take-off-and-landing (VTOL) unmanned air vehicle (UAV) having landing gear, wherein the landing gear is telescopic and comprises a sensor, and wherein the landing gear is compressed upon landing on a surface, and the compression causes a signal to be sent to a system that computes the slope of the ground surface using the length of the compressed landing gear and the attitude of the UAV. If the center of gravity falls within the support area, the legs are locked and the UAV power is turned off. If the center of gravity falls outside the support area, the UAV is forced to take off and find a safer landing spot.

Claims

1. A system for landing, comprising:

a vertical-take-off-and-landing (VTOL) unmanned air vehicle (UAV) having a known center of gravity (CoG), wherein the UAV further comprises telescopic landing gear that is compressed upon landing on a surface, and an internal computer system configured to sense when the landing gear is compressed and the level of compression.

2. The system of claim 1 wherein the landing gear further comprises a plurality of sensors to detect when the landing gear touches the surface and the level of compression of the landing gear.

3. The system of claim 2 wherein the plurality of sensors are configured to send a signal to the internal computer system, and wherein the internal computer system is configured to use the level of compression of the landing gear to compute the slope of the surface and the attitude of the UAV.

4. The system of claim 3 wherein the computed slope projects the UAV'"'"'s CoG vertically onto an area of support, and wherein the internal computer system determines whether the UAV'"'"'s CoG falls inside the area of support.

5. The system of claim 4 wherein the CoG falls inside the area of support, and wherein the internal computer system is configured to lock the landing gear and shut the UAV'"'"'s power off.

6. The system of claim 5, wherein the CoG falls outside the area of support, and wherein the internal computer system is configured to direct the UAV to lift off and find a different landing site.

7. The system of claim 6, wherein the landing gear comprises three legs, and wherein each leg comprises a touch sensor and a compression sensor.

8. The system of claim 6 wherein the landing gear comprises two skids, and wherein each skid comprises at least one touch sensor and at least one compression sensor.

9. A system for landing comprising a UAV having landing gear, wherein the landing gear further comprises a plurality of sensors, and wherein the landing gear is compressed upon reaching a surface, and wherein the plurality of sensors sends a signal to a computer that computes the length of the compressed landing gear, then uses the length of the compressed landing gear to compute the slope of the surface.

10. The system of claim 9 wherein the UAV has a known Center of Gravity (CoG), and wherein the CoG falls within support area (S), and wherein the computer is configured to direct the landing gear to lock and the UAV'"'"'s power to be turned off.

11. The system of claim 10 wherein the CoG falls outside the support area (S), and wherein the computer is configured to direct the UAV to take off and find an alternate landing spot.

12. The system of claim 11 wherein the landing gear further comprises three legs.

13. The system of claim 12 wherein the support area (S) is a triangle.

14. The system of claim 11 wherein the landing gear comprises a circular landing ring.

15. The system of claim 14 wherein the support area (S) is an ellipse.

16. The system of claim 11 wherein the landing gear comprises two skids.

17. The system of claim 16 wherein the support area (S) is a quadrilateral.

18. A method of landing on a sloped surface comprising the steps of:

having a vertical-take-off-and-landing (VTOL) unmanned air vehicle (UAV) with a known center of gravity, wherein the VTOL UAV further comprises telescopic landing gear comprising touch and compression sensors, wherein the landing gear is compressed upon touching a surface;

sending touch and compression information via the sensors to a computer inside the VTOL UAV allowing for calculation of slope and area of support;

using the computer to determine whether the center of gravity falls inside the area of support;

using the computer to direct the VTOL UAV to land and fully power off if the center of gravity falls inside the area of support.

19. The method of claim 18 wherein if the center of gravity falls outside the area of support, the computer directs the VTOL UAV to take off and find an alternate landing site.