Inertia measurement module for unmanned aircraft

• US 9,841,432 B2
• Filed: 08/08/2016
• Issued: 12/12/2017
• Est. Priority Date: 09/02/2011
• 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: Wang, Tao, Zhao, Tao
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US15/231,674
• Publication Number:
  US 20160349280A1
• Time in Patent Office: 491 Days
• Field of Search: 73493, 7350404, 7350412
• CPC Class Codes: B64D 45/00 Aircraft indicators or protectors not otherwise provided for camouflage F41H3/00
• CPC Class Codes: B64U 2201/00 UAVs characterised by their flight controls
• CPC Class Codes: F16F 15/00 Suppression of vibrations in systems damping of non-rotary systems using inertia effect F16F7/10; prevention or isolation of vibrations in machine tools B23Q11/0032; suppression of driveline vibrations in hybrid vehicle transmissions B60W30/20 ; vehicle seat suspension devices B60N2/50; methods or devices for protecting against, or damping of, acoustic waves, e.g. sound G10K11/16; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion vibration absorbing or balancing means for aircraft propellers B64C11/008, for rotorcraft rotors B64C27/001 ; testing static and dynamic balance of machines or structures G01M1/00
• CPC Class Codes: F16F 7/104 the inertia member being resiliently mounted F16F7/1022 takes precedence
• CPC Class Codes: G01C 19/16 Suspensions; Bearings
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5628 Manufacturing; Trimming; Mounting; Housings
• CPC Class Codes: G01C 19/5663 Manufacturing; Trimming; Mounting; Housings
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01C 19/5783 Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01C 21/166 Mechanical, construction or arrangement details of inertial navigation systems
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01P 1/003 used for damping
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 15/0802 Details

Abstract

The present disclosure relates to an inertia measurement module for an unmanned aircraft, which comprises a housing assembly, a sensing assembly and a vibration damper. The vibration damper comprises a first vibration-attenuation cushion; and the sensing assembly comprises a first circuit board, a second circuit board and a flexible signal line for connecting the first circuit board and the second circuit board. An inertia sensor is fixed on the second circuit board, and the first circuit board is fixed on the housing assembly. The inertia measurement module further comprises a weight block, and the second circuit board, the weight block, the first vibration-attenuation cushion and the first circuit board are bonded together. The present disclosure greatly reduces the influence of the operational vibration frequency of the unmanned aircraft on the inertia sensor and improves the measurement stability of the inertia sensor.

Claims

1. An inertia measurement module for an unmanned aircraft, the inertia measurement module comprising:

a second circuit board with an inertia sensor;

a first circuit board with a processor to process one or more signals from the inertia sensor;

a signal line between the first circuit board and the second circuit board;

a weight block comprising a recess, wherein the second circuit board is embedded in the recess of the weight block, and wherein the weight block comprising the recess is of a mass such that an inherent frequency of the inertia measurement module is reduced to be less than an operation frequency of the unmanned aircraft; and

a vibration damper provided to attenuate vibration of the inertia sensor.

2. The inertia measurement module of claim 1, wherein the vibration damper comprises a cushion between the weight block and the first circuit board.

3. The inertia measurement module of claim 1, wherein the vibration damper comprises a cushion between the second circuit board and a housing assembly of the unmanned aircraft on which the inertia measurement module is mounted.

4. The inertia measurement module of claim 1, wherein the weight block is made of a metal material.

5. The inertia measurement module of claim 1, wherein the weight block is a cuboidal metal block.

6. The inertia measurement module of claim 1, wherein the weight block has a weight of 1 gram to 30 grams.

7. The inertia measurement module of claim 1, wherein the second circuit board is disposed on a supporting sheet, which is bonded to the weight block.

8. The inertia measurement module of claim 1, further comprising an adhesive layer, which bonds the second circuit board with the weight block.

9. The inertia measurement module of claim 1, wherein the inertia sensor comprises a gyroscope, which senses an angular speed, and an accelerometer, which senses acceleration.

10. The inertia measurement module of claim 1, wherein the first circuit board comprises a memory, and a circuit module.

11. The inertia measurement module of claim 1, further comprising a signal input interface terminal and a signal output interface terminal connected to the first circuit board.

12. The inertia measurement module of claim 11, wherein the signal input interface terminal or the signal output interface terminal communicates with the first circuit board in an asynchronous serial manner.

13. The inertia measurement module of claim 1, wherein the recess of the weight block has a shape and dimensions substantially matching a shape and dimensions of the second circuit board.

14. The inertia measurement module of claim 1, wherein the vibration damper includes portions arranged on opposite sides of the weight block and the second circuit board.

15. The inertia measurement module of claim 1, wherein the second circuit board is a flexible circuit board.

16. The inertia measurement module of claim 3, wherein the cushion has a width of 13 mm to 20 mm.

17. The inertia measurement module of claim 3, wherein the cushion has a thickness of 3 mm to 4 mm.

18. The inertia measurement module of claim 1, wherein the signal line is a flexible signal line.

19. The inertia measurement module of claim 1, wherein the inherent frequency of the inertia measurement module is configured to be outside of an operation frequency range of the unmanned aircraft.

20. The inertia measurement module of claim 1, wherein the inherent frequency of the inertia measurement module is configured to be less than 50 hertz.

21. The inertia measurement module of claim 1, wherein the second circuit board, the weight block, and the first circuit board are bonded together in one piece.

22. The inertia measurement module of claim 1, wherein the vibration damper has an elastic coefficient that reduces the inherent frequency of the inertia measurement module to be less than the operation frequency of the unmanned aircraft.

23. The inertia measurement module of claim 6, wherein the weight block has a weight of 15 grams to 25 grams.

24. The inertia measurement module of claim 3, wherein the cushion abuts against an inner wall of a housing assembly, said housing assembly being configured to support the inertia measurement module.

25. The inertia measurement module of claim 19, wherein the operation frequency range of the unmanned aircraft ranges from 50 hertz to 200 hertz.

26. The inertia measurement module of claim 1, wherein the first circuit board is located further away from the weight block compared to the second circuit board.

27. The inertia measurement module of claim 24, wherein the inertia measurement module is rigidly affixed to the housing assembly.

28. The inertia measurement module of claim 1, wherein the recess is formed on only one side of the weight block.

29. The inertia measurement module of claim 1, wherein the recess does not form a through-hole extending through the weight block.

30. The inertia measurement module of claim 1, wherein the recess has an inner side surface extending along a perimeter of said recess, and wherein a side lateral surface of the second circuit board is in contact with the inner side surface of the recess when the second circuit board is embedded in said recess.