Resonance frequency calculation of accelerometer based on equal strength cantilever beam by Rayleigh method has been proposed and experimentally demonstrated. The accelerometer is with a compact structure in which a short section of fiber stubs containing a fiber Bragg grating (FBG) is attached on the bisector of a equal strength cantilever beam. By comprehensive considering the mass of beam and the mass of the block together, resonance frequency of different accelerometer can be calculated more precisely, compared with the experimental results the maximum relative error is 7.2% over the low frequency range from 20 to 45 Hz.
The random error model for evaluating FBG dynamic sensing system is proposed and established by using Allan variance, and the error recognition is experimentally demonstrated. The composition of the FBG sensing system, the characteristic of random error and error source for FBG acceleration sensing system are analyzed. The random error theoretical model based on the FBG acceleration sensing system is proposed and analyzed. In order to experimentally perform stability characterization of the system, the static output signal is achieved, and Allan variance curve is obtained by data processing, and the main coefficients of the error source can be further obtained. The model based on the Allan variance adequately demonstrates that it is feasible to evaluate the FBG system, which provides the basis for further designing, improvements and developing.