大型空间离轴三反相机分体支撑结构设计

针对某1 m分辨率、200 km幅宽的大尺度空间相机框架支撑结构轻质量、高刚度的设计要求,设计了一种轻型分体支撑结构。首先从大型空间离轴三反相机研制需求出发,综合比刚度、热稳定性及加工工艺等因素选择了性能良好的高体份SiCp/Al复合材料;然后以结构质量分数为约束条件,建立以基频为目标函数的拓扑优化数学模型,得到了拓扑结果清晰的各分体结构最优传力路径;进一步对主支撑结构各部分尺寸进行二次优化,得到了各分体结构的最佳构型和最优设计尺寸。设计后的分体支撑结构总重为227.8 kg,轻量化率达到93.9%,满足了高轻量化和高刚度要求。有限元分析结果及力学样机试验结果表明:分体支撑结构满足遥感相机整机基频大于50 Hz的刚度要求,在升温5℃工况下反射镜变形在公差范围之内,完全符合卫星平台对光学载荷的要求;力学样机在振动实验前后反射镜组件相对偏移角度均不超过22″,具有较好的稳定性,证明了拓扑优化和尺寸优化方法的合理性和可行性。本文提出的分体支撑结构设计对大型空间离轴相机支撑设计具有较高的工程实践价值。

Design of lightweight split support structure for large space off-axis three mirror camera

According to the design requirements of lightweight and high-stiffness large-scale space camera frame support structures with a 1-m resolution and 200-km width,a lightweight split support structure is designed.In this study,a high-volume SiCp/Al composite material with good performance is selected based on the development requirements of a large space off-axis three-mirror camera,including the specific stiffness,thermal stability,and processing technology.Then,with the structure mass fraction as the constraint condition,a topology optimization mathematical model is established with the fundamental frequen?cy as the objective function,and the optimal force transfer path of each split structure with clear topological results is obtained.The size of each part of the main support structure is optimized,and the optimal config?uration and design size of each split structure are obtained.After the design,the total weight of the split support structure was 227.8 kg,and the lightweight rate reached 93.9%,which meets the requirements of high lightweight and stiffness.The results of finite-element analysis and mechanical prototype test show that the split support structure meets the stiffness requirements of the whole remote sensing camera with the fundamental frequency greater than 50 Hz,and the deformation of the mirror is within the tolerance range under the working condition of 5°C,which fully satisfies the requirements of the satellite platform for optical loads.The mechanical prototype mirror assembly offset angle is less than 22°before and after the vibration test,showing its good stability,which proves the rationality and feasibility of the topology op?timization and size optimization methods.The design of the proposed split support structure has a high en?gineering practice value for the support design of large space off-axis cameras.