Optical fiber sensor-based inertial measurement system

Patent metadata

Field	Value
Publication number	US-12320644-B2
Application number	US-202218087542-A
Country	US
Kind code	B2
Filing date	Dec 22, 2022
Priority date	Dec 23, 2021
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

Embodiments relate to an Inertia Measurement Unit (IMU) sensor that generates strain information including a change in strain based on first output light of a first type of optical fiber sensing unit, calculates acceleration information of an object on which an IMU sensor ( 10 ) is mounted based on the strain information, generates angular velocity information based on output light of a second type of optical fiber sensing unit, and calculates angle information of the object based on the rotational speed information.

First claim

What is claimed is:

1. An optical fiber-based Inertia Measurement Unit (IMU) sensor for measuring an acceleration and an angular velocity of an object on which the IMU sensor is mounted, the IMU sensor comprising:
a sensor module including at least one first type of sensing sensor to detect a change in strain to generate first output light, and at least one second type of sensing sensor to detect a change in rotational speed to generate second output light;
a sensor circuit to generate strain information including the change in strain based on the first output light of the first type of optical fiber sensing sensor, calculate acceleration information of the object on which the IMU sensor is mounted based on the strain information, generate rotation information based on the output light of the second type of optical fiber sensing sensor, and calculate angular velocity information of the object based on the rotation information; and
a sensor case to protect the sensor module and the sensor circuit,
wherein the sensor module includes at least one cantilever configured to deform when an external force is applied,
wherein the at least one cantilever is one of a plurality of cantilevers,
wherein at least one of the plurality of cantilevers includes a groove on a surface, and
wherein at least one of a plurality of strain sensors is disposed on the groove.

2. The IMU sensor according to claim 1 , wherein the first type of sensing sensor is a Fiber Bragg grating (FBG) sensing unit including at least one grating node, and
wherein the second type of sensing sensor is a Fiber-Optic Gyro (FOG) sensing unit including an optical fiber coil.

3. The IMU sensor according to claim 2 ,
wherein the FBG sensing unit is disposed along the cantilever.

4. The IMU sensor according to claim 3 , wherein the sensor module further includes a core body, and
wherein an end of each cantilever is coupled to the core body.

5. The IMU sensor according to claim 4 , wherein the core body includes at least one lead, and
wherein each optical fiber coil is coupled to each lead.

6. An optical fiber-based Inertia Measurement Unit (IMU) sensor for measuring an acceleration and an angular velocity of an object on which the IMU sensor is mounted, the IMU sensor comprising:
a sensor module including at least one first type of sensing sensor to detect a change in strain to generate first output light, and at least one second type of sensing sensor to detect a change in rotational speed to generate second output light;
a sensor circuit to generate strain information including the change in strain based on the first output light of the first type of optical fiber sensing sensor, calculate acceleration information of the object on which the IMU sensor is mounted based on the strain information, generate rotation information based on the output light of the second type of optical fiber sensing sensor, and calculate angular velocity information of the object based on the rotation information; and
a sensor case to protect the sensor module and the sensor circuit,
wherein the first type of sensing sensor is a Fiber Bragg grating (FBG) sensing unit including at least one grating node,
wherein the sensor module includes at least one cantilever configured to deform when an external force is applied,
wherein the FBG sensing unit is disposed along the cantilever, and
wherein the at least one cantilever has a plurality of through-holes, and the grating node of the FBG sensing unit is disposed between the plurality of through-holes.

7. An optical fiber-based Inertia Measurement Unit (IMU) sensor for measuring an acceleration and an angular velocity of an object on which the IMU sensor is mounted, the IMU sensor comprising:
a sensor module including at least one first type of sensing sensor to detect a change in strain to generate first output light, and at least one second type of sensing sensor to detect a change in rotational speed to generate second output light;
a sensor circuit to generate strain information including the change in strain based on the first output light of the first type of optical fiber sensing sensor, calculate acceleration information of the object on which the IMU sensor is mounted based on the strain information, generate rotation information based on the output light of the second type of optical fiber sensing sensor, and calculate angular velocity information of the object based on the rotation information; and
a sensor case to protect the sensor module and the sensor circuit,
wherein the first type of sensing sensor is a Fiber Bragg grating (FBG) sensing unit including at least one grating node,
wherein the sensor module includes at least one cantilever configured to deform when an external force is applied,
wherein the FBG sensing unit is disposed along the cantilever, and
wherein the grating node of the FBG sensing unit is disposed closer to an unfixed opposite end than the end of the cantilever coupled to the core body on the cantilever.

8. The IMU sensor according to claim 4 , further comprising:
at least one support to position the core body at an inner center of the sensor case.

9. The IMU sensor according to claim 3 , wherein a plurality of FBG sensing units is installed to measure the acceleration information for each axis of x axis, y axis and z axis, and
wherein a plurality of FOG sensing units is installed to measure the angular velocity information for each axis of x axis, y axis and z axis.

10. An optical fiber-based Inertia Measurement Unit (IMU) sensor for measuring an acceleration and an angular velocity of an object on which the IMU sensor is mounted, the IMU sensor comprising:
a sensor module including at least one first type of sensing sensor to detect a change in strain to generate first output light, and at least one second type of sensing sensor to detect a change in rotational speed to generate second output light;
a sensor circuit to generate strain information including the change in strain based on the first output light of the first type of optical fiber sensing sensor, calculate acceleration information of the object on which the IMU sensor is mounted based on the strain information, generate rotation information based on the output light of the second type of optical fiber sensing sensor, and calculate angular velocity information of the object based on the rotation information; and
a sensor case to protect the sensor module and the sensor circuit,
wherein the sensor circuit includes a substrate, a light source, at least one first optical interconnect element, at least one filter, at least one first detection unit, at least one second optical interconnect element, at least one phase modulator, at least one second detection unit and a calculator,
wherein the light source supplies incident light to the first optical fiber sensing sensor and the second optical fiber sensing sensor,
wherein the first optical interconnect element and the second optical interconnect element are couplers or circulators,
wherein when an optical signal of a specific wavelength passes through the filter, the filter is configured to change an intensity depending on the wavelength,
wherein the phase modulator demodulates the second output light of the second optical fiber sensing sensor based on a modulation signal,
wherein the first detection unit and the second detection unit convert, into an electrical signal, the first output light and the second output light processed by the filter and the phase modulator, and
wherein the calculator is configured to calculate the strain applied to the cantilever based on a change in wavelength spectrum represented in the electrical signal of the first detection uni

Assignees

• Korea Inst Sci & Tech

Inventors

• Kim Jinseok
• Kim Byung Kook
• Jang Minsu
• Moon Hyowon

Classifications

• G01P15/18

  in two or more dimensions · CPC title

• G01P15/03

  by using non-electrical means · CPC title

• G01D5/353

  influencing the transmission properties of an optical fibre · CPC title

• G01D5/268

  using optical fibres (G01D5/28 - G01D5/38 take precedence) · CPC title

• G01C21/16

  by integrating acceleration or speed, i.e. inertial navigation · CPC title