Research On Vibration Characteristics Of Fiber Optical Gyroscope

At present,fiber optic gyroscope(FOG) has become the mainstream and new-type instrument in the inertial technology field,which is different from the traditional electromechanical instrument in its principle and key technology.There are many advantages such as high reliability,long-lifetime,quick start-up,wide dynamic range and so on.The study has entered into practical stage-at abroad, while in the domestic it is still in engineering and applied research stage.On account of its sensitivity is in motion and the changing of working environment is tempestuously,then we should ensure that FOG can work normally in any environment.For this reason,vibration is an important performance index to realize the practical utilization and engineering application.According to the vibration mode and the analysis of test method of FOG,a conclusion is drawn:FOG do forced vibration which is uncertain in general condition.On the basis of the finite element theory in ANSYS,the analytical method of FOG's mechanical structure is modeled and analyzed.Additionally,the thesis in this paper does lots of researches on the theory of mechanical vibration and the addition modulation effect produced by mechanical vibration acted on FOG's sensitive elements which is called fiber loop.Concluded that the irreplaceable error will be generated by vibration once the winding symmetry of fiber loop is poor,when the disturbance to FOG is the frequency vibration that modulate the light intensity signal.Both of these two cases above will affect the precision of FOG's output.Improve the firmness and symmetrical of fiber loop by improving the winding method,and adopting coating adhesive packaging technology,so as to reduce the modulation effect due to the vibration of the fiber loop.Finally,mechanical resonance under the vibration condition is the key factor to augment gyro drift which related to the drift of gyro-stabilized platform,and then put forward the design proposal of FOG's mechanical structure and packaging mode.With the parameters which determine the mechanical structure, according to the vibration theory and finite element analysis(FEA) theory,in the paper it used the finite element software ANSYS to research on modal analysis and harmonic response on different structures,then compared the vibration performance of different structures and deduced the reasonable mechanical structure,which has improved the harmonic frequency of the whole system much larger than the detection bandwidth,reduced the influence of the vibration to FOG and provided the appropriate direction of FOG's design structure under various environments for the further research.