Inertia measurement module for unmanned aircraft

• US 10,591,504 B2
• Filed: 11/10/2017
• Issued: 03/17/2020
• 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:
  US15/809,952
• Publication Number:
  US 20180088143A1
• Time in Patent Office: 858 Days
• 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 circuit board with an inertia sensor; and

a weight block including a recess;

wherein;

the circuit board is embedded in the recess; and

the weight block is configured to have 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.

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

3. The inertia measurement module of claim 1, wherein the weight block has a cuboidal shape.

4. The inertia measurement module of claim 1, wherein the weight block has a weight in the range from 1 gram to 30 grams.

5. 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 circuit board.

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

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

8. The inertia measurement module of claim 1, further comprising:

a vibration damper configured to attenuate vibration of the circuit board.

9. The inertia measurement module of claim 8, further comprising:

a housing assembly accommodating the circuit board and the weight block;

wherein the vibration damper includes a vibration-attenuation cushion fixedly bonded to the circuit board and abutting against an inner wall of the housing assembly.

10. The inertia measurement module of claim 9, wherein the vibration-attenuation cushion has a hollow part.

11. The inertia measurement module of claim 10, wherein the hollow part has a cuboidal shape, an circular shape, an ellipsoidal shape, a rhombus shape, or a quincuncial shape.

12. The inertia measurement module of claim 9, wherein the vibration-attenuation cushion is fixedly bonded to the circuit board through an adhesive layer.

13. The inertia measurement module of claim 12, wherein a bonding area of the adhesive layer is in the range from about 3% to about 30% of an area of the vibration attenuation cushion.

14. The inertia measurement module of claim 1, wherein the inertia sensor includes at least one of a gyroscope or an accelerometer.

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

16. The inertia measurement module of claim 1,

wherein the circuit board is a second circuit board;

the inertia measurement module further comprising;

a first circuit board including at least one of a power source, a memory, a processor, or a circuit module, the first circuit board and the second circuit board being disposed at two opposite sides of the weight block.

17. The inertia measurement module of claim 16, further comprising:

a signal line coupling the second circuit board to the first circuit board.

18. The inertia measurement module of claim 17, wherein the signal line includes a flexible signal line.

19. The inertia measurement module of claim 1, wherein the operation frequency of the unmanned aircraft is in a range from 50 Hz to 200 Hz.

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