Strain sensor-based IMU sensor, and inertial measurement system comprising same

Patent metadata

Field	Value
Publication number	US-12442833-B2
Application number	US-202118019930-A
Country	US
Kind code	B2
Filing date	Aug 4, 2021
Priority date	Aug 5, 2020
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

Embodiments relate to an IMU sensor and an inertial measurement system comprising same, wherein the IMU sensor comprises: a core body including at least three surfaces each having a surface direction parallel to any one of three axes; a plurality of cantilevers configured to be deformable, one side of each cantilever being coupled to the core body; and a plurality of strain sensors each disposed on the surface of each cantilever, the strain sensors extending along the direction of the other side from one fixed side of the cantilever.

First claim

The invention claimed is:

1. An inertial measurement unit (IMU) sensor for measuring inertia of an object, the IMU sensor comprising:
a plurality of cantilevers each having a surface comprising a first axis and a second axis and configured to be deformable;
a core body coupled to the plurality of cantilevers; and
a plurality of strain sensors respectively located on the plurality of cantilevers and each configured to detect a bending strain of a corresponding cantilever,
wherein at least one from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface of the at least one cantilever faces an x-axis with respect to the core body, at least one other cantilever from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface of the at least one other cantilever faces a y-axis, and at least one other cantilever from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface faces a z-axis,
wherein a linear acceleration or an angular acceleration for the object is measured based on a strain measurement result obtained from the plurality of strain sensors,
wherein the plurality of cantilevers comprise six cantilevers,
wherein each of the six cantilevers comprises a strain sensor aligned in a direction of the first axis on the surface,
wherein two cantilevers from among the six cantilevers are coupled so that an axis parallel to the x-axis is a normal direction of the surface of each of the two cantilevers among the six cantilevers, other two cantilevers are coupled so that an axis parallel to the y-axis is a normal direction of the surface of each of the other two cantilevers, and remaining two cantilevers among the six cantilevers are coupled so that an axis parallel the z-axis is a normal direction of the surface of each of the remaining two cantilevers.

2. The IMU sensor according to claim 1 , wherein the six strain sensors form three strain sensor pairs for measuring a linear acceleration of each of three axes or three strain sensor pairs for measuring an angular acceleration having a rotation axis of each of the three axes,
wherein each of the six strain sensors is shared by a strain sensor pair for measuring a linear acceleration of any one of the three axes and a strain sensor pair for measuring an angular acceleration having one same axis as a rotation axis.

3. The IMU sensor according to claim 1 , wherein, when an external force having a linear acceleration component or an angular acceleration component is applied to the object, at least two cantilever pairs from among the six cantilevers are deformed in response to the external force,
wherein, in the pair of cantilevers, axes corresponding to the first direction of one cantilever and the other cantilever are not parallel to each other.

4. The IMU sensor according to claim 3 , wherein a cantilever pair deformed when a linear acceleration is applied to the object is coupled to the core body to have a surface direction facing a direction of the linear acceleration.

5. The IMU sensor according to claim 3 , wherein a cantilever pair deformed when an angular acceleration is applied to the object is bent in a direction of the angular acceleration.

6. The IMU sensor according to claim 3 , wherein, in the strain sensor pair for measuring the linear acceleration of any one of the three axes, one strain sensor is used to measure an angular acceleration having another axis of the three axes as a rotation axis, and the other strain sensor is used to measure an angular acceleration having a remaining axis of the three axes as a rotation axis.

7. The IMU sensor according to claim 1 , wherein the core body has one surface with a larger area than other surfaces,
wherein at least one groove is formed in the one surface, and at least one of the plurality of cantilevers is coupled to the core body to be located in the at least one groove.

8. An inertial measurement unit (IMU) sensor for measuring inertia of an object, the IMU sensor comprising:
a plurality of cantilevers each having a surface comprising a first axis and a second axis and configured to be deformable;
a core body coupled to the plurality of cantilevers; and
a plurality of strain sensors respectively located on the plurality of cantilevers and each configured to detect a bending strain of a corresponding cantilever,
wherein at least one from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface of the at least one cantilever faces an x-axis with respect to the core body, at least one other cantilever from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface of the at least one other cantilever faces a y-axis, and at least one other cantilever from among the plurality of cantilevers is coupled so that a direction of the first axis of the surface faces a z-axis,
wherein a linear acceleration or an angular acceleration for the object is measured based on a strain measurement result obtained from the plurality of strain sensors,
wherein the plurality of cantilevers comprise six or more cantilevers,
wherein the core body has six surfaces having directions parallel to three axes as normal directions, and side surfaces of the six cantilevers are respectively fixed to the six surfaces of the core body.

9. The IMU sensor according to claim 1 , wherein at least one of the plurality of cantilevers comprises a groove formed in one surface,
wherein at least one of the plurality of strain sensors is located in the groove,
wherein the IMU sensor further comprises a polymer layer formed on the at least one strain sensor located in the groove of the at least one cantilever.

10. The IMU sensor according to claim 1 , further comprising a mass body fixed to a side surface opposite to one fixed side surface of the each of the plurality of cantilevers; and
a plurality of through-holes formed between a portion where the mass body is projected onto a surface of the each of the plurality of cantilevers and a portion where the each of the plurality of cantilevers is coupled and fixed to the core body,
wherein a sensing portion of the strain sensor located on the surface of the each of the plurality of cantilevers is located between the plurality of through-holes.

11. The IMU sensor according to claim 1 , wherein the each of the plurality of cantilevers has a planar structure in which a portion located between one side and the other side of the each of the plurality of cantilevers has a smaller width than one end portion and the other end portion.

12. The IMU sensor according to claim 1 , further comprising a temperature sensor located in the core body and configured to correct a change due to a temperature in a spectrum change of at least one of the six strain sensors.

13. The IMU sensor according to claim 12 , wherein the temperature sensor is implemented as a fiber Bragg grating (FBG) sensor,
wherein the FBG sensor of the temperature sensor is located in the core body in which a change in a wavelength spectrum of reflected light caused by an interval change between gratings due to a temperature change is greater than a change in a wavelength spectrum of reflected light caused by an interval change between gratings due to a deformation of the each of the plurality of cantilevers due to a movement of the object to which the IMU sensor is attached.

14. The IMU sensor according to claim 1 , wherein at least one of the plurality of cantilevers comprises: a first elastic layer; a viscoelastic layer; and a second elastic layer,
wherein th

Assignees

• Korea Inst Sci & Tech

Inventors

• Kim Jinseok
• Jang Minsu
• Kim Byung Kook
• Kang Kyumin

Classifications

• G01F15/02

  Compensating or correcting for variations in pressure, density or temperature · CPC title

• G01P15/093

  by photoelectric pick-up · CPC title

• G01P15/02 Primary

  by making use of inertia forces {using solid seismic masses}(G01P15/14 takes precedence) · CPC title

• G01P15/18

  in two or more dimensions · CPC title

• G01P15/0802

  Details · CPC title