Return to Session A1 Next Abstract

Session A1: Inertial Measurement Units (IMU)

Analysis of Vibration Error of Resonant Fiber Optic Gyroscope
Weiqi Miao, Fei Yu, Guochen Wang, Wei Gao, Harbin Institute of Technology, China
Location: Pavilion Ballroom East
Date/Time: Tuesday, Apr. 21, 11:48 a.m.

As a second-generation fiber optic gyroscope, the fiber length of the resonant fiber optic gyroscope required is several hundredths of that of the interferometric fiber optic gyroscope, when they both theoretically achieve the same precision. The resonant fiber optic gyroscope has the advantages of high theoretical precision and large dynamic range, which provides a way for the miniaturization and low cost of fiber optic gyroscopes, and has therefore received the attention of many countries.
The fiber optic ring used to measure angular velocity in a resonant fiber optic gyroscope is very sensitive about the surrounding work environment. When mechanical vibration happens, since the optical fiber has an elastic effect, mutual stress acts between the optical fiber and the mechanical structure and between the optical fiber and the optical fiber during vibration, resulting in the refractive index and length of the optical fiber are changed. So the resonant frequency of two beams of light that are transmitted in opposite directions in the coil are different. That is drift bias. If the design of the mechanical structure of the fiber optic gyroscope is unreasonable or the selection of the structural material is unreasonable, resonance will occur in a certain frequency range, which will directly cause the gyroscope to fail to work normally. Therefore, it is very important to study the mechanism of the vibration error of the resonant fiber optic gyroscope and find a way to effectively suppress the vibration error.
To describe the vibration error, the cylindrical coordinate system is established first. When the vibration signal acts on the bottom of the gyro, the elastic force of each layer of the fiber coil is analyzed by establishing the dynamic equation of the fiber coil. Based on the elastic effect of the fiber, the error equation of the gyro drift caused by the vibration is obtained. The error equation consists of two parts: the gyro error caused by the length change and the gyro error caused by the bounce effect. The simulation is based on the obtained error equation. The simulation results show that the final vibration error of the resonant fiber optic gyroscope is proportional to the amplitude of the vibration signal. The greater the modulus of elasticity of the fiber optic ring, the smaller the gyro drift caused by the vibration. The larger the density of the fiber optic ring, the greater the gyro drift caused by the vibration. Therefore, when the length of the fiber loop is certain, the fiber gyro output error caused by the vibration can be effectively suppressed by increasing the elastic modulus of the fiber coil and reducing the density of the fiber coil.
The values of the elastic modulus of the optical fiber coil and the density of the optical fiber coil are obtained by volume-weighted averaging various materials constituting the optical fiber ring. In fact, when the coil is wound, the diameter of the polarization maintaining fiber and the kind of curing adhesive can be selected. The gyro error drift caused by vibration can be reduced by selecting a suitable polarization maintaining fiber and curing adhesive.



Return to Session A1 Next Abstract