Study On Model Modification Method Of Marine Radar Frequency Synthesizer Based On Modal Parameters

Marine radar is the key equipment in the course of naval operations.It can provide navigation avoidance,position measurement,guidance for shipborne aircraft to fly at sea and maintain real-time communication.Compared with the ground fixed radar,vibration stress is added to the mission profile of shipborne radar,which is one of the main reasons for the failure of shipborne radar.As a part of shipborne radar,frequency synthesizer provides the functions of high precision and high stability frequency for shipborne radar,which makes the component easily affected by vibration stress in the operating environment.This kind of influence can cause the frequency synthesizer to produce noise when it is working,and may cause the frequency synthesizer to lose its basic function.In order to ensure the high reliability and high stability of the frequency synthesizer components,it is necessary to analyze and study the impact of vibration stress on the components.In this paper,the frequency synthesizer component of a Marine radar is selected as the research object,and the dynamic characteristics of the component are analyzed and studied.The main work is as follows:1)The digital prototype model of frequency synthesizer was established based on the digital prototype modeling technology,and the effectiveness of the model was verified by dynamic analysis method.Firstly,the CAD digital prototype model and FEA digital prototype model of frequency synthesizer were constructed respectively.Secondly,the finite element analysis method is used to solve the digital prototype model,and the simulation modal parameters of frequency synthesizer are obtained.Finally,the dynamics analysis is completed based on the simulation modal parameters.The analysis results show that the frequency synthesizer component model constructed by digital prototype modeling technology is reasonable.2)Carry out modal test on frequency synthesizer components,and obtain the test modal parameters of components through the modal parameter identification process of frequency response function.Firstly,the modal test of frequency synthesizer was completed based on the hammer method,and the vibration data was collected.Secondly,the coherence of the collected data is checked to ensure the accuracy of the test data.Finally,the frequency response function is solved by preprocessing vibration data,and the modal parameter identification of frequency synthesizer is completed.The experimental results show that the extracted experimental modal parameters based on the modal test are accurate.3)By comparing the errors between the results of two types of modal parameters of the frequency synthesizer,the model modification target was determined,and the model modification was realized based on particle swarm optimization algorithm.Firstly,the two types of modal parameters were compared,and four objects for model modification were determined,which were second-order simulation modal natural frequency,secondorder simulation modal mode mode,third-order simulation modal natural frequency and third-order simulation modal mode.Secondly,considering that the learning factor parameter of particle swarm optimization algorithm will have dynamic influence on the optimization process,the S-type function is introduced to realize the dynamic adjustment of learning factor,and the optimal value of learning factor is obtained by using this method.Finally,to solve the problem that the solution set search space dimension is large(four dimensional)when the model is modified,an optimization acceleration strategy is proposed,which is combined with the SAPSO(adaptive particle swarm optimization algorithm based on S-type function)algorithm.On the basis of modifying the digital prototype model of frequency syntheses,the convergence rate of the algorithm is improved.