Research On The Fiber Coil Winding Method Of High Precision FOG

Because of its many advantages,the fiber optic gyroscope(FOG)has been widely used in various carriers such as land,sea,and air.In practice,the FOG circuit and optical path components are easily affected by temperature interference,which reduces the accuracy of the FOG.Fiber coil is the most sensitive optical path component.Therefore,this paper mainly studies the winding method of high-precision FOG fiber coil.The purpose is to improve the fiber coil winding method to reduce the effect of temperature on the fiber coil,thereby improving the accuracy of the FOG.We start by analyzing the fiber coil temperature error caused by the fiber coil under thermal disturbance conditions,and analyze the influencing factors and error mechanism of this error.Based on the error mechanism,the thermal-induced rate error model of the fiber coil is derived.According to the influencing factors of the error,the effects of adjusting the fiber coil material and improving the fiber winding method on the temperature error of the fiber coil are specifically analyzed.This article first describes the development of inertial devices and the research status of the FOG and focuses on the research status of fiber coil suppression technology for thermal interference.After that,we summarize the main research content of this article.Then,we first introduce the basic composition and closed-loop detection principle of the FOG.Secondly,we take the fiber coil as the research object and analyze the cause of the fiber coil temperature error and the factors affecting the fiber coil.Finally,we focus on deriving the calculation formulas for Shupe error and thermal stress error and establish a thermal-induced rate error model for the FOG.Secondly,we use Comsol software to implement finite element thermal analysis of fiber coils and thermal insulation structures.And we extract the temperature value and thermal stress value of the fiber in the fiber coil.Combined with the thermal-induced rate error model,we simulate and calculate the axial,radial,and circumferential thermal stresses and thermally induced rate errors of fiber coils of different sizes under uniform thermal disturbances.Through research and analysis,selecting a narrow diameter fiber to wind the fiber coil or reducing the thickness of the solid glue in the fiber coil can effectively restrain the influence of the thermal disturbance on the circumferential thermal stress distribution and thermally-induced rate error.Third,a four-cylinder coil is designed.And we apply uniform,external radial and external axial thermal disturbances to the four-pole,sixteen-pole,double-cylinder,and four-cylinder coils with single-cavity thermal insulation structures,and perform thermal analysis on them.The rate error model simulates the Shupe error and thermal stress error generated by each fiber winding method.Through comparative analysis,it is found that the thermal stress error generated by each winding method exceeds the Shupe error,and the sixteen-pole winding method has the strongest ability to suppress thermal disturbance at different positions in the space.After that,we designe different thermal insulation structures in the cavity for the four-cylinder winding method to help it suppress external axial thermal disturbances.The simulation found that the strongest ability to suppress axial thermal disturbance is the design scheme of the four-cylinder fiber coil combined with the four-cavity thermal insulation structure.This scheme has two advantages which shown as follows.One is that this scheme reduces the thermal stress error of the four-cylinder winding method.Another one is that the ability of this scheme to suppress uniform and radial thermal disturbances greatly exceeds the sixteen pole ring with a single cavity insulation structure,and the ability of the shaft to suppress thermal interference exceeds that of a four pole ring with a single cavity insulation structure.At the same time,it is found that the thickness of the heat-insulating structure should not be less than 0.5mm,otherwise the heat-insulating structure would lose its ability to equalize heat.Finally,we teste the polarization coupling distribution of the four-pole coil and the double-cylinder coil at different temperature points,and proved the advantages of the doublecylinder coil in terms of symmetry and stress distribution.From the experimental results,we reason that the four-cylinder coil also has these advantages.Then,the FOG with integrated four-pole coil and with sixteen-pole coil are used as research objects to verify the ability of the sixteen-pole coil to suppress thermal disturbances.At the same time,we verify the correctness of the thermal analysis process of the fiber coil structure and the thermal-induced rate error model of the FOG.Based on this,we conclud that the four-cylinder coil and the four-cavity thermal insulation structure design proposed in this subject have theoretical reference value.