Design And Optimization Of Mirror And Its' Support Structure Of Space Camera

The space mirror subassembly is an important part of space camera.Image quality of space camera is effected directly by the lightweight form,material and support mode of the mirror.In order to improve the lightweight ration of the mirror and to ensure the surface accuracy of the mirror,a ?350mm lightweight mirror was designed and analyzed by theoretical analysis,empirical design,finite element analysis.The supports of different mirrors were studied contrastively.In order to ensure sufficient dynamic stiffness of the mirror subassembly,the dynamic response analysis and test were done consequently.The specific research contents are as follows:Four kinds of lightweight holes of the back opening mirror were designed.The results show that the structure stiffness of triangular,hexagon,sector and square lightweight holes range from high to low.The structure stiffness of back closed mirror,back half-opening mirror and opening mirror range from high to low.The thicknesses of mirror blank,front plate of the mirror,thickness of supported hole and mirror ribs were optimized.According to the light weight analysis above,the ?350mm mirror was optimized.The mass of the mirror was reduced from 6.27 Kg to 3.39 Kg,the mass was reduced by 45.9%.The mirror surface accuracy was increased by 10.00%,6.67% and 35.53% respectively,compared with the initial structure in the X,Y,and Z direction with 1g acceleration.The results meet the design requirement RMS?12.66 nm,PV?63.28 nm.(RMS??/50,PV??/10,?=632.8nm)Research and analysis were carried out on the central support scheme for the mirror of different calibers and materials.The application scope of center support scheme for circular mirror was determined.Theoretical analysis,structural design,finite element analysis and parameter optimization were carried out for the flexible hinge structure in the three-point support scheme of the back.It was found that the thickness of the flexible hinge and the shortening of the flexible hinge were beneficial to the improvement of the surface figure accuracy.The application scope of back support scheme was studied by finite element analysis and test.Support scheme was suitable for the round mirror diameter up to?1.5 m.In order to explore the support effect of the back three-point support scheme in other shape mirror,the long strip mirror subassembly with back three-point support was designed.The results still met the design requirements.Dynamic response analysis and test of the long strip mirror subassembly were carriedout.The first order natural frequency of the mirror subassembly was 255 Hz.The error obtained by FEA was 1%.In the 0-100 Hz frequency range,the maximum stress response of flexible hinge was 171 MPa,the acceleration magnification factor of the mirror was far less than the standard of 10.In the 0-2000 Hz frequency range,random vibration analysis was performed on the mirror subassembly.The acceleration power spectrum density and input response ratio met the 3? criteria.Analysis and test results indicate that the dynamic stiffness of the long strip mirror subassembly was met completely.