空间天文仪器中的铍镜结构优化设计分析

为了满足空间太阳望远镜的技术要求,进行了铍摆镜研制,掌握了高精度铍镜研制技术路线。光学检测面形精度RMS为0.012λ,满足技术要求。对铍摆镜结构进行优化设计改进。介绍了铍摆镜结构优化方法,用ANSYS中的APDL语言编译了摆镜结构优化程序,进行了铍摆镜结构优化。并利用Matlab软件编写了改进遗传算法组合优化程序,再次完成了铍镜结构优化,并进行了横向对比分析。结果表明:两结果都满足技术要求。以扇形孔铍摆镜为例,改进的遗传算法组合方法的优化结果(RMS,1.470E-6mm)比ANSYS零阶优化方法的优化结果(RMS,2.099E-6mm)降低了29.96%,优于铍镜检测结果,说明改进后的摆镜结构方案可行。铍镜的成功研制,为我国空间天文仪器大口径铍镜研究和应用奠定了基础。组合优化方法结合了改进遗传算法和ANSYS软件的优势,具有适应性高、优化能力强等特点,具有较好的鲁棒性,对类似工程结构或天文仪器结构优化具有一定的借鉴意义。

Optimization design and analysis of the structure of beryllium mirrors of astronomical instruments in space

In order to satisfy the technical requirements of Space Solar Telescope (SST), a tip-tilt beryllium mirror was manufactured and its fabrication technology was developed. Its measured surface profile RMS error was 0.012 λ and met its technical specification. Then its structure was optimized and improved. The optimization method was introduced where the optimization program was compiled with APDL language of ANSYS software. In addition, the combined optimization program based on improved genetic algorithm was compiled with Matlab software. The structure of the beryllium mirror was optimized again with the program. The two optimized results were compared and analyzed. It is shown that both satisfy technical requirements. As an example, for a beryllium mirror with sector holes, the surface profile RMS error optimized with the improved genetic algorithm was 1.470E-6 mm and was 29.96% lower than the result optimized with ANSYS zero order optimization, which was 2.099E-6. The analysis results were better than its test values. It is shown that the scheme of the improved beryllium mirror structure is feasible. Our successful manufacture of the beryllium mirror lays the foundations of its investigation and application in large aperture space astronomical instruments of our country. The combined optimization integrates the advantages of both improved genetic algorithm and ANSYS software and so it has the advantages of high adaptability, strong optimization ability, and good robustness. It has some reference significance for optimization of similar engineering structures and other astronomical instrumental structures.