Research On Deformation Reconstruction Of Rocket Based On Fiber Bragg Grating Sensing And Its Application In Attitude Control

With the rapid development of modern aerospace industry,people put forward higher requirements for the launch efficiency of rockets.Larger slenderness ratio and higher structural efficiency will become an important trend in the development of launch vehicles.However,with the decrease of the structural mass of the launch vehicle and the increase of the slenderness ratio,the flexibility characteristics of the launch vehicle become more and more obvious.Therefore,the deformation reconstruction and attitude control of flexible arrow are the core problems of this paper.In this paper,several existing deformation reconstruction theories are studied and analyzed,and a deformation reconstruction algorithm based on Legendre polynomial is proposed.Combined with fiber Bragg grating sensing measurement means,the proposed reconstruction algorithm is applied to the deformation monitoring of rocket beam model and the attitude control of flexible rocket,The main work of this paper is summarized as follows:1)The measurement principle and error source of fiber Bragg grating sensor are analyzed and studied.The strain transfer coefficient is deduced according to the types of fiber Bragg grating sensors,which lays a theoretical foundation for subsequent simulation and experiments.2)Based on the theoretical analysis and derivation of the current modal method and Ko reconstruction theory,a deformation reconstruction theory based on Legendre polynomial fitting is proposed,and the corresponding simulation examples are set to verify it.3)Taking the equivalent beam model as the experimental object,the arrow shape deformation reconstruction experimental system is built to verify the accuracy of Legendre deformation reconstruction method under the experimental conditions.4)A method of deformation reconstruction and high-precision attitude control of launch vehicle based on strain measurement is proposed.The control system is designed by combining vibration measurement information with incremental dynamic inverse control.At the same time,the modeling and error analysis of fiber Bragg grating measurement system in flight environment are carried out,and the effectiveness of the proposed control method is verified by simulation.