空间相机大型长条形反射镜支撑结构设计

Design of Support Structure for Large Mirror of Space Camera

针对某空间相机1m口径主反射镜的设计要求,以反射镜组件材料、径厚比、轻量化形式、支撑点数量等为设计变量,以施加1gn重力载荷以及2℃温升时反射镜面形变化均方根误差为目标函数,提出了一种三段可装配式柔性支撑结构。与常用的球铰支撑和Bipod支撑相比,文章中的支撑结构没有相对运动、机械摩擦和间隙,可以使反射镜基频更高。当受到载荷作用时,背板会产生变形,支撑结构中的柔性环节能够隔离由于背板变形而产生的应力,从而保证反射镜的面形精度。文章采用有限元分析的方法对反射镜组件动态特性、静态特性和热特性进行分析。结果表明,反射镜组件基频足够高、光轴水平时,同时施加1g_n重力载荷和2℃温升时面形变化均方根值能够满足设计要求,反射镜支撑结构设计合理。

By taking the material, diameter-thickness ratio, lightweight form, and number of support point as design variables and the mirror shape change root mean square error（RMS）under 1g_n gravity load and 2℃temperature increment as objective function, a three-section assembled flexible support structure is proposed for a 1m diameter primary mirror of space camera is introduced. Compared with the commonly used spherical hinge support and bipod support, the support structure proposed in this paper has no relative motion, mechanical friction and clearance, and can make the mirror＇s frequency higher. The backboard would deform when subjected to loads. The flexible part of the support structure can isolate the stress caused by the deformation of the backboard so as to ensure the surface figure accuracy of the mirror. By using the finite element analysis method to analyze the mirror, the main parameters include mirror component dynamic, static and thermal characteristics. The results demonstrate that the fundamental frequency of the mirror component is high enough and the RMS value of surface shape change meets the design requirements under the conditions of 1g_n gravity load and 2℃ temperature increment when the optical axis is level. The design of the mirror support structure meets the design requirements.