Inertia measurement module for unmanned aircraft

• US 9,772,343 B2
• Filed: 09/15/2011
• Issued: 09/26/2017
• 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
• Application Number:
  US14/241,891
• Publication Number:
  US 20140224014A1
• Time in Patent Office: 2,203 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, comprising:

a sensing assembly comprising;

a first circuit board;

a second circuit board comprising at least one inertia sensor; and

a flexible signal line that connects the first circuit board to the second circuit board;

a weight block comprising a first surface and a second surface opposite the first surface, wherein a recess is (1) formed only on the second surface, and (2) configured to support the second circuit board that is embedded in the recess;

a first vibration-attenuation cushion and a second vibration-attenuation cushion arranged on opposite sides of the weight block, wherein the first vibration-attenuation cushion is provided as a sheet extending between the first surface of the weight block and the first circuit board, and wherein the second vibration-attenuation cushion abuts against the second circuit board via an adhesive layer; and

a housing assembly comprising a chamber configured to support the sensing assembly, the weight block, and the first vibration-attenuation cushion and second vibration-attenuation cushion therein.

2. The inertia measurement module of claim 1, wherein the second vibration-attenuation cushion is separated from the second circuit board via the adhesive layer.

3. The inertia measurement module of claim 1, wherein the adhesive layer is attached onto the second circuit board.

4. The inertia measurement module of claim 1, wherein the first and second vibration-attenuation cushions are arranged on the opposite sides of the weight block along a vertical axis extending longitudinally through the weight block.

5. The inertia measurement module of claim 1, wherein the first circuit board is rigidly affixed to an inner portion of the housing assembly, a first side of the second vibration-attenuation cushion abuts against the second circuit board, and a second side of the second vibration-attenuation cushion abuts against another inner portion of the housing assembly.

6. The inertia measurement module of claim 1, wherein the first circuit board is arranged outside of the recess of the weight block.

7. The inertia measurement module of claim 1, wherein the recess is dimensioned to match a shape of the second circuit board, and wherein a distance between the first surface and the first circuit board is less than a distance between the second surface and the first circuit board.

8. The inertia measurement module of claim 1, wherein at least one of the first and second vibration-attenuation cushions is made of a buffering material having a predefined elasticity.

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

10. The inertia measurement module of claim 1, wherein the weight block is dimensioned to take a shape of a cuboid.

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

12. The inertia measurement module of claim 1, wherein at least one of the first and second vibration-attenuation cushions is made of an elastic material comprising a plurality of cavities.

13. The inertia measurement module of claim 1, wherein the first vibration-attenuation cushion and the second vibration-attenuation cushion are adapted to absorb vibrations on opposite sides of the second circuit board.

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

15. The inertia measurement module of claim 1, wherein the inertia sensor comprises at least one of the following:

a gyroscope for obtaining an angular speed signal of the unmanned aircraft, and an accelerometer for obtaining an acceleration signal of the unmanned aircraft.

16. The inertia measurement module of claim 15, wherein the angular speed signal and the acceleration signal are transmitted from the second circuit board to the first circuit board via the flexible signal line.

17. The inertia measurement module of claim 1, wherein the second circuit board further comprises a power source.

18. The inertia measurement module of claim 1, wherein a size of the second circuit board is smaller than a size of the first circuit board.

19. The inertia measurement module of claim 1, wherein the sensing assembly further comprises a signal input interface terminal and a signal output interface terminal respectively operably coupled to opposing sides of the first circuit board.

20. The inertia measurement module of claim 1, wherein a shape of the first vibration-attenuation cushion is substantially the same as a shape of the second vibration-attenuation cushion.

21. The inertia measurement module of claim 1, wherein the first vibration-attenuation cushion is configured to absorb vibrations on a first side of the second circuit board, and wherein the second vibration-attenuation cushion is configured to absorb vibrations on a second side of the second circuit board that is opposite to the first side of the second circuit board.

22. The inertia measurement module of claim 1, wherein a contact area between the second vibration-attenuation cushion and the second circuit board ranges from about 12.6 mm² to 50.2 mm².

23. The inertia measurement module of claim 1, wherein a contact area between the second vibration-attenuation cushion and the second circuit board is about 28 mm².

24. The inertia measurement module of claim 1, wherein at least one of the first and second vibration-attenuation cushions has a length of about 13 mm to 20 mm, a width of about 13 mm to 20 mm, and a thickness of about 3 mm to 4 mm.

25. The inertia measurement module of claim 1, wherein the weight block has a weight of about 1 g to 30 g.

26. The inertia measurement module of claim 19, wherein the opposing sides of the first circuit board are different from a surface of the first circuit board that is rigidly affixed to an inner portion of the housing assembly.

27. The inertia measurement module of claim 1, wherein the sensing assembly, the weight block, and the first and second vibration-attenuation cushions are rigidly supported within and by the housing assembly.

37. 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, and wherein the first circuit board abuts against the weight block via at least the first vibration-attenuation cushion.

38. The inertia measurement module of claim 37, further comprising a signal input interface terminal and a signal output interface terminal respectively operably coupled to opposing sides of the first circuit board.

42. The inertia measurement module of claim 37, wherein the first circuit board is bonded to one side of the weight block via the first vibration-attenuation cushion and one or more adhesive layers, and wherein the second circuit board is attached to a supporting sheet that is bonded to the recess on an opposite side of the weight block, such that the first circuit board and the second circuit board are not permitted to move relative to the weight block during operation of the unmanned aircraft.

43. The inertia measurement module of claim 42, wherein the first circuit board and the second circuit board are not permitted to move relative to each other during the operation of the unmanned aircraft.

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

a sensing assembly comprising;

a first circuit board;

a second circuit board comprising at least one inertia sensor; and

a flexible signal line that connects the first circuit board to the second circuit board;

a weight block comprising a first surface and a second surface opposite the first surface, wherein a recess is (1) formed only on the second surface, and (2) configured to support the second circuit board such that the second circuit board is embedded in said recess;

a first vibration-attenuation cushion and a second vibration-attenuation cushion arranged on opposite sides of the weight block, wherein the first vibration-attenuation cushion is provided as a sheet extending between the first surface of the weight block and the first circuit board, and wherein the second vibration-attenuation cushion abuts against the second circuit board via an intermediate layer; and

a housing assembly comprising a chamber configured to support the sensing assembly, the weight block, and the first vibration-attenuation cushion and the second vibration-attenuation cushion therein.

29. The inertia measurement module of claim 28, wherein the intermediate layer is in direct contact with at least one of the second vibration-attenuation cushion and the second circuit board.

30. The inertia measurement module of claim 28, wherein the recess is dimensioned to take a shape and a size of the second circuit board, and wherein a distance between the first surface and the first circuit board is less than a distance between the second surface and the first circuit board.

31. The inertia measurement module of claim 28, wherein a portion of the intermediate layer is on the second circuit board and embedded in said recess.

32. The inertia measurement module of claim 28, wherein the first circuit board is rigidly affixed to an inner portion of the housing assembly, a first side of the second vibration-attenuation cushion abuts against the second circuit board, and a second side of the second vibration-attenuation cushion abuts against another inner portion of the housing assembly.

33. The inertia measurement module of claim 28, wherein the intermediate layer is bonded to at least one of the second circuit board or the second vibration-attenuation cushion.

34. The inertia measurement module of claim 33, wherein the intermediate layer is bonded to the second circuit board.

35. The inertia measurement module of claim 33, wherein a size of a bonding area occupied by the intermediate layer ranges from about 12.6 mm² to 50.2 mm².

36. The inertia measurement module of claim 33, wherein the intermediate layer is an adhesive layer that is provided in a sheet form designed for surface bonding to at least one of the second circuit board or the second vibration-attenuation cushion.

39. The inertia measurement module of claim 28, wherein the first circuit board is rigidly affixed to an inner top portion of the housing assembly, and one side of the second vibration-attenuation cushion abuts against a bottom inner portion of the housing assembly.

40. The inertia measurement module of claim 39, wherein the sensing assembly, the weight block, and the first and second vibration-attenuation cushions are rigidly supported within and by the housing assembly.

41. The inertia measurement module of claim 40, wherein at least the first circuit board or the second circuit board is not permitted to move relative to the housing assembly during operation of the unmanned aircraft.