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

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.

An inertial measurement system comprising:

• an inertial measurement unit (IMU) sensor comprising:
• a plurality of cantilevers each having a surface comprising a first axis and a second axis and configured to be deformable, wherein the plurality of cantilevers comprise six cantilevers,
• a core body coupled to the plurality of cantilevers,
• a plurality of strain sensors respectively located on the plurality of cantilevers and each configured to detect a bending strain of a corresponding cantilever, and
• a temperature sensor located in the core body, configured to correct a change due to a temperature in a spectrum change of at least one of the six strain sensors, and implemented as a fiber Bragg grating (FBG) sensor;
• a light source configured to emit light to a plurality of FBG sensors;
• and
• a measurement device configured to receive a wavelength spectrum set from the plurality of FBG sensors, wherein the wavelength spectrum set comprises a wavelength spectrum of reflected light output from each of the plurality of FBG sensors,
• 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 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,
• wherein the measurement device is configured to detect a change in a wavelength spectrum of reflected light caused by an interval change between gratings due to deformation of the each of the plurality of cantilevers caused by a movement of the object to which the IMU sensor is attached to calculate a strain corresponding to the movement of the object,
• wherein the measurement device is configured to:
• determine the each of the plurality of cantilevers deformed by the movement of the object by detecting the change in the wavelength spectrum of reflected light;
• determine a deformation direction of the each of the plurality of cantilevers based on a wavelength spectrum change sign corresponding to the deformed cantilever;
• and
• measure a linear acceleration of the object based on the deformation direction and the strain.