在极大望远镜宽视场光谱仪准直镜结构轻量化研究中, 实施多学科多目标优化的可行性设计。通过多目标遗传算法结合多学科协同对准直镜轻量化结构进行优化设计, 即以镜面形状要素为优化参数、镜面面型和质量为目标, 并借助遗传算法为优化算法获取Pareto最优解。对比研究了不同轻量化孔轻量化后综合性能和轻量化后准直镜的热稳定性, 三角型轻量化后准直镜轻量化率为70%, PV值为82.696 nm; 矩形轻量化孔准直镜轻量化率为75.3%, PV值约为107.03 nm; 准直镜环境温度变化为10 K时, 准直镜形变约增加一倍。研究结果表明: 三角形轻量化孔综合评价优于矩形孔; 准直镜结构轻量化多目标优化设计全面考虑了准直镜结构轻量化、轻量化孔形状要素和光学面型形变等多学科之间耦合问题, 设计者可按需选择全局范围内最满意的最优解, 这将大幅度降低开发成本和周期。

Multidisciplinary and multi-objective optimization design method was applied in the researches of collimator mirror lightweight of wide field spectrometer of extremely large telescope. Lightweight design was operated independently on the basis of collaborative optimization which is one of the best feasible multidisciplinary design optimization approaches combined with multi-objective genetic algorithm to carry out the optimization, and the Pareto optimal set was obtained. The lightweight performance with different lightweight holes and the thermal stability of light-weighting collimator mirrors were comparatively studied. With triangle lightweight hole of collimation mirror, the light weighting rate is about 70% and the peak-valley (PV) value is 82.696 nm. With rectangle lightweight hole of collimation mirror, the light weighting rate is about 75.3% and the PV value is 107.03 nm. When the temperature of the collimator mirror changes about 10 K, the deformation of the collimator mirror is added doubled. The results indicate that the comprehensive evaluation of triangle lightweight hole is better than rectangle holes; the coupling and interdisciplinary relationships among the lightweight, the lightweight hole shape parameter and the deformation of mirror are comprehensively considered during the multi-objective optimization of collimator mirror lightweight structure. Thus the designers can choose the satisfactory optimization results according to their demands, so as to significantly reduce the product development cycle and costs.