SIDED PERFORMANCE COAXIAL VERTICAL TAKEOFF AND LANDING (VTOL) UAV AND PITCH STABILITY TECHNIQUE USING OBLIQUE ACTIVE TILTING (OAT)

• US 20130105620A1
• Filed: 10/31/2011
• Published: 05/02/2013
• Est. Priority Date: 10/31/2011
• Status: Active Grant

• Current Assignee: King Abdullah II Design and Development Bureau
• Original Assignee: King Abdullah II Design and Development Bureau
• Inventors: Zweiri, Yahya, Alkhateeb, Basim, Abde Qader Alzu'bi, Hamzeh Mahmoud, Al-Majali, Yahya Taha Ayed, Abd Allateef, Imad
• Granted Patent: US 8,931,729 B2
• Time in Patent Office: Days
• US Class Current: 244/17.13
• CPC Class Codes: B64C 2203/00 Flying model aircraft, flying toy aircraft
• CPC Class Codes: B64C 27/20 Rotorcraft characterised by having shrouded rotors, e.g. flying platforms
• CPC Class Codes: B64U 10/13 Flying platforms
• CPC Class Codes: B64U 30/24 Coaxial rotors
• CPC Class Codes: B64U 30/297 Tilting rotors
• CPC Class Codes: B64U 50/19 using electrically powered motors

Abstract

A system for increasing the thrust and power capabilities of a side by side vertical takeoff and landing vehicle and to optimize the coaxial rotor performance. The system including a first coaxial rotor spaced from an aircraft body and a second coaxial rotor spaced from the aircraft body and opposite the first coaxial rotor. The first coaxial rotor having a first top propeller aligned with a first bottom propeller along a first rotational axis. The second coaxial rotor having a second top propeller aligned with a second bottom propeller along a second rotational axis. A gyroscopic moment to maintain pitch stability is controlled by modulating the first and second top propellers having a different angular speed or different torque from the first and second bottom propellers and tilting the first and second coaxial rotors towards the central axis with a common tilt angle and a common tilt rate.

Claims

1. A system for increasing the thrust and power capabilities of a side by side vertical takeoff and landing vehicle, the system comprising:

providing a first coaxial rotor spaced from a vehicle body and a second coaxial rotor spaced from the vehicle body and opposite the first coaxial rotor along a common axis, the first coaxial rotor including a first top propeller aligned with a first bottom propeller along a first rotational axis, the second coaxial rotor including a second top propeller aligned with a second bottom propeller along a second rotational axis; and

controlling a gyroscopic moment to maintain pitch stability by modulating the first and second top propellers having one of a different angular speed or different torque from the first and second bottom propellers.

2. The system according to claim 1, wherein the first and second coaxial rotors include propellers having blades with a fixed pitch.

3. The system according to claim 1 wherein the first top propeller and the second top propeller rotate with a common rotational speed and torque.

4. The system according to claim 1 wherein the first bottom propeller and the second bottom propeller rotate with a common rotational speed and torque.

5. The system according to claim 1 wherein the first and second top propellers are spaced from the first and second bottom propellers along each rotational axis by less than 3% of the length of the diameter of the first and second top propeller.

6. The system according to claim 1 wherein the first and second top propellers have a first length and the first and second bottom propellers have a second length such that the first length is greater than the second length.

7. The system according to claim 1 further comprises controlling the gyroscopic moment to maintain pitch stability by tilting the first and second coaxial rotor towards a central axis with a common tilt angle and a common tilt rate during use to improve a pitch stability of the vehicle.

8. The system according to claim 1 wherein the gyroscopic moment maintains pitch stability as the first and second top propeller are rotated with a different rotational direction from the first and second bottom propeller.

9. The system according to claim 2 wherein the relationship of a pitch angle of the first and second top propeller relative to the first and second bottom propeller is a function of a diameter length of the top and bottom propeller, a separation length between the top and bottom propeller, a thrust profile and a power profile of the system.

10. The system according to claim 1 wherein the first top and bottom propeller and the second top and bottom propeller each include a plurality of blades.

11. The system according to claim 1 wherein the first coaxial rotor has a first torque profile and the second coaxial rotor has a second torque profile such that the combination of the first torque profile and second torque profile provide a stable pitch balance of the vehicle while in use.

12. A side by side vertical takeoff and landing device comprising:

a first coaxial rotor attached to a first articulating member extending from a first arm and having a first top propeller and a first bottom propeller with fixed pitch blades that are configured to rotate along a first rotational axis, the first arm is rotably connected to a vehicle body along a longitudinal axis;

a second coaxial rotor attached to a second articulating member extending from a second arm and having a second top propeller and a second bottom propeller with fixed pitch blades that are configured to rotate along a second rotational axis, the second arm is rotably connected to the vehicle body along the longitudinal axis; and

a controller for modulating the rotational speed and torque of the top and bottom propellers to control a pitch stability of the device.

13. The device according to claim 12 wherein the first and second articulating members includes servo actuators controlled by the controller for laterally rotating the first and second coaxial rotor in proportion toward the vehicle body.

14. The device according to claim 13 wherein the first and second arms are rotably connected to the vehicle body by servo actuators controlled by the controller to longitudinally rotate the first and second arms in proportion toward a front portion of the vehicle body.

15. The device according to claim 12 wherein the first and second coaxial rotors are configured to operate the top propellers with different angular speed and torque than the bottom propellers while maintaining a pitch stability of the device.

16. The device according to claim 12 wherein the first and second coaxial rotors are controlled to rotate the first and second top propellers with common rotational speed and torque and the first and second bottom propellers with common rotational speed and torque.

17. The device according to claim 12 wherein the first and second top propellers are spaced from the first and second bottom propellers along each rotational axis by less than 3% of the length of the diameter of the first and second top propeller.

18. The device according to claim 12 wherein the first and second top propellers have a first length and the first and second bottom propellers have a second length such that the first length is greater than the second length.

19. The device according to claim 12 wherein the first coaxial rotor is controlled at a first torque profile and the second coaxial rotor is controlled at a second torque profile such that the combination of the first torque profile and the second torque profile stabilizes the vehicle when operated.

20. A method of stabilizing a side by side vertical take off and landing vehicle comprising:

providing a first coaxial rotor spaced from a vehicle body and a second coaxial rotor spaced from the vehicle body and opposite the first coaxial rotor along a common axis;

rotating a first top propeller at the same angular speed and torque as a second top propeller;

rotating a first bottom propeller at the same angular speed and torque as a second bottom propeller; and

controlling a gyroscopic moment by modulating first and second top propeller having a different angular speed or different torque from the first and second bottom propellers and tilting the first and second coaxial rotor towards the vehicle body with a common tilt angle and a common tilt rate during use to improve a pitch stability of the vehicle.

21. The method according to claim 20 further comprising controlling a lateral motion of the vehicle by longitudinally rotating the first and second coaxial rotors along the common axis.