离轴三反空间相机主支撑结构优化设计与试验

Optimization Design and Test of the Supporting Structure for the Off-axis Three-mirror Reflective Space Camera

为解决离轴三反空间相机随机响应过大的问题,提出了一种以降低加速度响应均方根值(RMS)为目标的空间相机主支撑结构拓扑优化设计方法。首先,在分析各种空间相机主支撑结构和某离轴三反光学系统特点的基础上,确定了次镜组件和折叠镜组件分开支撑的结构形式。其次,以离轴三反空间相机次镜的加速度响应均方根值为优化目标,以体积分数,X、Y、Z向重力载荷分别作用下次镜的刚体位移,主支撑结构的一阶频率为约束条件对初始主支撑结构有限元模型进行拓扑优化设计,得到了加速度响应满足设计要求的主支撑结构。最后,对该结构进行有限元分析和振动试验,表明了该离轴三反空间相机力学性能指标均满足设计要求,其中Z向2 g RMS量级的随机激励下次镜的加速度响应均方根值为5.08 g;主支撑结构质量仅为3.8 kg,一阶频率达到了291.4 Hz。该离轴三反相机主支撑结构的设计方法可以作为其他同型相机结构设计的参考。

A kind of method of topology optimization design for the supporting structure was presented, which aimed at decreasing the acceleration response RMS value of the space cameras. Firstly, after analyzing the common various forms of the space camera supporting structure, a supporting pattem with the secondary mirror and the folding mirror fixed separately was determined according to the characteristics of this optical system. Secondly, a trussed supporting structure met the requirements on the acceleration response was designed, which directed by objective function of acceleration response RMS and in the meanwhile restricted by the volume fraction, the displacements of the secondary mirror with the influence of axial gravity and the first-order frequency of the supporting structure. Finally, the finite element analysis and vibration experiments show that the supporting structure could satisfy the requirements on the whole mechanics performance index of this camera. The fundamental value is 5.08 g with 2 g RMS random load under the more than 4 kg. The design scheme of this trussed light-small space camera with the same type frequency reaches 291.4 Hz, and the acceleration response RMS condition that the mass of this trussed supporting structure is not supporting structure could provide some reference to the other