Optical fiber sensor-based inertial measurement system

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.

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.

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 unit, calculate the acceleration of the object based on the calculated strain, calculate rotational speed information of the object based on a phase shift represented in the electrical signal of the second detection unit, and calculate the angular velocity of the object based on the calculated rotational speed information.