差动式光纤Bragg光栅加速度计传感头设计与仿真

Design and simulation of sensor of differential fiber Bragg grating accelerometer

针对传统悬臂梁-质量块结构加速度计存在的灵敏度与固有频率不能兼顾的问题,设计一种差动式光纤Bragg光栅加速度计,建立系统模型,对测量精度等进行理论计算与分析.传感头设计采用主梁与微梁结合的结构,是悬臂梁-质量块结构的一种改进形式,并运用有限元方法对其静态特性和动态性能进行仿真分析.结果表明:该设计系统精度可以达到10.5×10-3g,固有频率为270Hz,固有频率是同等精度的传统悬臂梁结构光纤光栅加速度计的2.7倍;此结构的加速度计在不降低灵敏度的同时可以有效提高系统的固有频率.

A differential fiber Bragg grating （FBG） accelerometer was designed to solve the conflict of sensitivity and natural frequency for the conventional accelerometer with cantilever-mass structure. The system model was established and the measurement precision was theoretically calculated and analyzed. The sensor structure combined central beam and tiny beam was designed, which is an improved style of conventional cantilever-mass structure. The finite element simulation and analysis on static and dynamic characteristics proved that the system accuracy was 0. 0105 g and the natural frequency was 270 Hz, which was 2.7 times of the natural frequency of a conventional cantilever-mass FBG accelerometer under same precision. Results also proved that the natural frequency could be increased without decreasing the sensitivity in this new differential FBG accelerometer.