Ф620mm口径地基反射镜组件优化设计

Optimal design of Ф620 mm ground mirror assembly

为了获得Ф620 mm口径地基反射镜组件的最优设计方案,建立了反射镜及其支撑系统的参数化模型,并基于该模型对镜体厚度、支撑点位置和柔性支撑结构的设计参数进行多目标优化设计。首先,阐述了Ф620 mm口径地基主反射镜支撑系统的运动学约束设计原理。然后,从理论角度推导出柔性支撑的柔度矩阵和结构热变形的等效力,建立了便于优化迭代的反射镜组件参数化模型,对比了参数化模型与体单元组成的详尽有限元模型在多种静力学工况下的RMS值和系统的前6阶模态值,计算结果误差在10%以内,验证了参数化模型的有效性。最后,基于径向基函数的近似模型理论,在Isight环境下对参数化模型进行多目标优化处理。得到了多目标优化的Pareto front前沿,目标值权衡处理后得到系统的最优的设计方案。提出的优化设计方法具有较好的工程适用性,可为同类型的反射镜组件优化设计提供参考。

In order to obtain the optimal design of the Ф620 mm ground mirror assembly, the parametric model of mirror and its support system was established and the thickness of mirror, the support position and design parameters of flexible support structure were optimized based on the parametric model. Firstly,the kinematic restraint design principle of the Ф620 mm ground primary mirror support system was stated.Then, flexibility matrix and thermal equivalent force of flexible support was deduced from the theoretical perspective, a parametric model of mirror assembly was established to facilitate the optimization iteration,and the parametric model was compared with solid element detailed FEM model in multiple static loadcases in term of the RMS and the first six eigenvalues of the support system. The calculation error was less than 10% of the results to verify the validity of the parameters of the model. Finally, based on the theory of radial basis function approximation model, the multi-objective optimization of the parametric model was possessed in Isight environment. After obtaining the Pareto front of multi-objective optimization, the two objectives of optimal design system was weighed. The proposed optimum design method has better applicability in engineering and can provide reference for the optimization design of the same type of mirror assembly.