High Sensitivity Fiber Bragg Grating Acceleration Sensor Based on Rigid Hinge

In order to break through low sensitivity limitation of the existing fiber Bragg grating (FBG) acceleration sensor, a new high sensitivity FBG acceleration sensor based on rigid hinge is proposed. The working principle innovation is that the sensor uses the rigid body rotation motion instead of the existing elastic deformation. The novel structure is that the pendulum rotates around the rigid hinge and the structure is symmetrically designed, which increases the elongation of the fiber grating by twice. The resonance frequency and sensitivity formula of FBG acceleration sensor is theoretically obtained by analysis. The influence of size parameters of the structure on sensor sensitivity and resonance frequency is further analyzed by MATLAB, and finally the structural parameters are optimized. On the basis, the first-order natural frequency of the sensor is simulated by ANSYS Workbench17.0. Experimental studies show that the natural frequency of the acceleration sensor designed in this paper is 39 Hz, the sensitivity of the sensor is 949.2 pm/g at 15 Hz, and the cross-interference is less than 6.49%, which is suitable for precision measurement under low frequency micro-vibration.