Assisted takeoff

• US 9,126,693 B1
• Filed: 04/21/2014
• Issued: 09/08/2015
• Est. Priority Date: 03/27/2014
• Status: Active Grant

• Current Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Original Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Inventors: Shi, Jun, Pan, Xu Yang
• Primary Examiner(s): Collins, Timothy D
• Assistant Examiner(s): Stehle, Jamie S
• Application Number:
  US14/257,955
• Publication Number:
  US 20150274309A1
• Time in Patent Office: 505 Days
• US Class Current: 1/1
• CPC Class Codes: B64C 27/00 Rotorcraft; Rotors peculiar thereto
• 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: B64D 31/06 actuated automatically
• CPC Class Codes: B64U 10/10 Rotorcrafts
• CPC Class Codes: B64U 10/14 with four distinct rotor axes, e.g. quadcopters
• CPC Class Codes: B64U 10/70 Convertible aircraft, e.g. convertible into land vehicles
• CPC Class Codes: B64U 2201/00 UAVs characterised by their flight controls
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: G05B 11/42 for obtaining a characteristic which is both proportional and time-dependent, e.g. P. I., P. I. D.
• CPC Class Codes: G05D 1/042 specially adapted for aircraft
• CPC Class Codes: G05D 1/0669 specially adapted for vertical take-off

Abstract

Systems, methods, and devices are provided for assisted takeoff of an aerial vehicle. The aerial vehicle may takeoff using a first control scheme and switch to a second control scheme for normal flight when a takeoff threshold is met. The first control scheme optionally does not use integral control while the second control scheme may use integral control. The aerial vehicle may determine that a takeoff threshold is met, based on an output to a motor of the aerial vehicle and/or an acceleration of the aerial vehicle.

Claims

1. A method of assisted takeoff of an aerial vehicle, said method comprising:

increasing output to an actuator of the aerial vehicle under a first control scheme, wherein the output to the actuator results in the increase of an altitude of the aerial vehicle;

determining, with aid of a processor, whether the aerial vehicle has met a takeoff threshold based on the output to the actuator, the output measured from the actuator, or velocity or acceleration of the aerial vehicle, wherein determining whether the aerial vehicle has met the takeoff threshold is performed without (1) using signals from a source external to the aerial vehicle, or (2) using signals reflected to the aerial vehicle; and

controlling the output to the actuator using a second control scheme when the aerial vehicle has met the takeoff threshold.

2. The method of claim 1, wherein the aerial vehicle is capable of vertically taking off and/or landing.

3. The method of claim 1, wherein the first control scheme is a first integral feedback control scheme.

4. The method of claim 3, wherein an integral value under the first integral feedback control scheme is set to a default value.

5. The method of claim 4, wherein the default value is zero.

6. The method of claim 1, further comprising receiving a command to increase the altitude of the aerial vehicle.

7. The method of claim 6, wherein the command is provided by a remote terminal.

8. The method of claim 6, further comprising, prior to receiving the command to increase the altitude of the aerial vehicle, receiving a command to start the actuator and placing the actuator in an idle mode.

9. The method of claim 8, further comprising reducing the output to the actuator until the actuator is in an idle mode when the command to increase the altitude does not exceed a predetermined value.

10. The method of claim 1, wherein the second control scheme is a second integral feedback control scheme.

11. The method of claim 10, wherein controlling the output to the actuator using the second integral feedback control scheme includes integral control of the vertical direction.

12. The method of claim 1, wherein determining whether the aerial vehicle has met the takeoff threshold based on the degree of the output to the actuator includes determining that the aerial vehicle has met the takeoff threshold when the degree of the output to the actuator exceeds a predetermined output value.

13. The method of claim 1, wherein the aerial vehicle is an unmanned aerial vehicle comprising a plurality of rotors configured to generate lift for the aerial vehicle.

14. The method of claim 1, wherein determining whether the aerial vehicle has met the takeoff threshold based on the output to the actuator or the output measured from the actuator.

15. The method of claim 1, wherein the takeoff threshold is met when (1) the output to the actuator is greater than a first predetermined output value and when acceleration of the aerial vehicle in a vertical direction exceeds a predetermined acceleration value, or (2) the output to the actuator is greater than a second predetermined output value.

16. The method of claim 15 wherein the takeoff threshold is met when (2) the output to the actuator is greater than the second predetermined output value, and wherein the second predetermined output value is different from the first predetermined output value.

17. The method of claim 16, wherein the takeoff threshold is met when (2) the output to the actuator is greater than the second predetermined output value, and wherein the second predetermined output value is greater than the first predetermined output value.

18. A system for assisted takeoff of an aerial vehicle, said system comprising:

an actuator of the aerial vehicle, wherein an output to the actuator results in the increase of an altitude of the aerial vehicle; and

one or more processors, individually or collectively configured to;

(a) determine whether the aerial vehicle has met a takeoff threshold based on the output to the actuator, the output measured from the actuator, or velocity or acceleration of the aerial vehicle, wherein said determination whether the aerial vehicle has met the takeoff threshold is performed without (1) using signals from a source external to the aerial vehicle, or (2) using signals reflected to the aerial vehicle, and

(b) generate a signal used to control the output to the actuator (1) using a first control scheme when the aerial vehicle has not met the takeoff threshold, and (2) using a second control scheme when the aerial vehicle has met the takeoff threshold.

19. The system of claim 18, wherein the processor is on-board the aerial vehicle.

20. The system of claim 18, wherein the processor is provided on an external device separate from the aerial vehicle.

21. The system of claim 18, wherein the aerial vehicle is capable of vertically taking off and/or landing.

22. The system of claim 18, wherein the aerial vehicle is an unmanned aerial vehicle comprising a plurality of rotors configured to generate lift for the aerial vehicle.

23. The system of claim 22, wherein the unmanned aerial vehicle is a rotorcraft.

24. The system of claim 18, wherein the actuator is a motor driving a propulsion unit of the aerial vehicle.

25. The system of claim 18, wherein the first control scheme is a first integral feedback control scheme.

26. The system of claim 25, wherein an integral value under the first integral feedback control scheme is set to a default value.

27. The system of claim 18, wherein the second control scheme is a second integral feedback control scheme including integral control of the vertical direction.

28. The system of claim 18, wherein the takeoff threshold is met when one or more of the following conditions are met:

(1) an output to the actuator is greater than a first predetermined output value and when acceleration of the aerial vehicle in a vertical direction exceeds a predetermined acceleration value, or (2) the output to the actuator is greater than a second predetermined output value.

29. The system of claim 18 further comprising a receiver configured to receive a command to increase an altitude of the aerial vehicle.

30. The system of claim 18 wherein the processor determines whether the aerial vehicle has met the takeoff threshold based on the output to the actuator or the output measured from the actuator.