Research On Optimum Structural Design And Pointing Error Correction In Space-borne Solar X-EUV Imager

Changes in the solar activity are closely related to human life,and light and heat of the sun brings energy for life on Earth and is the source of changes in space weather.When the sun erupts a violent activity,it rapidly ejects large amounts of material into space,including magnetic fields,high-energy particles and electromagnetic waves.These substances will have a serious impact on the near-earth space environment,space weather and spacecraft safety,as well as a disastrous impact on human living environment.Therefore,it is of great significance to observe the state and activity of the solar surface and to predict space weather.In this dissertation,based on background of FY-3(05)solar X-EUV imager mission,an imaging observation equipment loaded on satellite applied to solar X-EUV band is developed.The working wavelength of the equipment is 19.5nm in normal incidence and 0.6nm～8.0nm in grazing incidence.The optical resolution is 2.5 arcsec in normal incidence and 5 arcsec in grazing incidence.The main content of this dissertation includes the five parts as follows.The whole system design and structural design of solar X-EUV imager are introduced,and the functional requirements and performance indexes of the imager are described.Described is the whole scheme design of the imager,including the twodimensional tracking turntable and the imaging telescope.At last,introduced in this dissertation are two key contents of the imager structure design,which is also the main research content of this dissertation.All the work aforementioned lays a foundation for the theoretical research and experimental verification in the following.This dissertation introduces the constitutive equation of transversely isotropic materials and laminates,including the function relationship between the laminates’ anisotropic properties and the fiber orientation angle.Then the mathematical model of optimal design of fiber orientation of carbon fiber reinforced polymer(CFRP)structural components is introduced.Furthermore,the optimization variables,optimization constraints and optimization objective function are defined.Moreover,the strain of the laminate is calculated by numerical method given that a fiber orientation is determined.Finally,the above theoretical calculation results are verified by finite element analysis,and the accuracy and validity of the laminate constitutive equation and theoretical calculation results are verified.Finally,provided are the layout molding process and the process flow of the CFRP structures of solar X-EUV imager.Topology optimization,size optimization and their applications in solar X-EUV imager are introduced.Firstly,the theoretical basis and optimization algorithm of topology optimization are described,and the optimal structure is given qualitatively which provides a reference for the detailed design.Secondly,ISIGHT optimization platform is used to describe the size optimization technology based on secondary development of UG and Hypermesh in detail.On the basis of meeting the requirement of constraints and objective functions,the final design results of key dimensions are obtained.Finally,the structural style and sizes of the main frame of the solar X-EUV imager are determined by the aforementioned structural optimization design technology,which provides a basis for the subsequent performance analysis and verification of mechanical resistance.The mechanical resistance performance of solar X-EUV imager is simulated and verified by vibration tests.The simulation and calculation work consists of modal analysis,sinusoidal vibration analysis,acceleration overload,impact response spectrum and half sine wave impact analysis.The test includes sinusoidal vibration test,random vibration test and characteristic frequency sweep test.The experimental results show that the fundamental frequency of solar X-EUV is respectively 55.53 Hz,75.37 Hz and76.55 Hz in X,Y and Z directions.The maximum amplification of sine acceleration at acceptance level is 6.537 times,and the maximum amplification of ESS random acceleration is 3.21 times.After the test,the structure of solar X-EUV imager is not damaged,and the stiffness and strength of the imager meet the design requirements.The calibration and correction of pointing error of solar X-EUV imager are studied.Firstly,the local coordinate system of each component of the X-EUV imager is established,and the mathematical model between pointing error and assembly error is set up.Secondly,the calculation and simulation of pointing error before and after correction is carried out by Monte-Carlo method,and the necessity and effectiveness of pointing error correction to enhancing the pointing accuracy is confirmed.Then,the mathematical model of coordinate transformation matrix calibration in pointing error correction experiment is given,and pointing error calibration and correction test is accomplished.Lastly,the results of the calibration test are analyzed and it comes to a conclusion that the corrected pointing error can meet the system performance requirements of solar X-EUV imager.In conclusion,FY-3(05)solar X-EUV imager is taken as the research background in this dissertation,and engineering requirements are taken into consideration.Research content include structural optimization design,resistance characteristics and pointing error analysis of solar X-EUV imager,and corresponding theoretical calculation,simulation analysis and test verification are carried out.The final design and the onorbit working condition of the solar X-EUV imager meet the design requirements.