长焦距空间相机主次镜间桁架支撑结构设计

Truss support structure design between primary mirror and secondary mirror in long focal length space camera

为了满足长焦距空间相机主次镜间支撑结构高刚度、高强度、高热稳定性和轻量化的设计要求,从材料选择、结构形式、连接工艺和参数优化等方面分析了空间相机主次镜间支撑结构设计中需要考虑的问题。针对某7 m焦距,相对孔径1∶6,采用卡塞格林光学系统的空间相机,设计了一种采用碳纤维复合材料的3层27杆式主次镜间桁架支撑结构,并基于有限元法对其进行了优化设计。分析结果表明,设计的桁架结构质量减轻了38 kg,一阶固有频率可达80 Hz,在径向自重和5℃均匀温升载荷作用下,次镜最大倾角为4.6″,表明所设计的支撑桁架合理可行,能够满足长焦距空间相机的使用要求。

In order to satisfy the requirements of high stiffness,high strength and high thermal stability of support structure between primary mirror and secondary mirror,some problems about truss design such as materials selection,structural configuration,connection technology and parameter optimization are taken into account.As an example,a 7 m focal length and a relative aperture 1∶6,space camera with Cassegrain optical system has been developed.A 3-layer 27-strut made of carbon fiber composite is used in the main support structure between primary mirror and secondary mirror in the space camera,and the design is optimized by finite element method.The analysis results indicate that the weight of the support has been reduced by 38 kilograms,and the first-order eigen frequency is 80 Hz,the angle change between primary mirror and secondary mirror under radial self-weight and 5 ℃ uniform temperature rise loading is less than 4.6″.These researches verify that the support structure is rational and feasible and can meet the requirements of the design specifications.