大型离轴三反空间相机前框架优化设计与试验

为了保证某离轴三反光学系统空间相机光机结构的高稳定性与高准确度,针对该光学系统中次镜、折叠镜组件轴向空间位置接近的特点,设计了次镜、折叠镜组件一体化的前框架结构,并提出了一种结合了自由模态与约束模态的拓扑优化方法来优化相机的前框架结构.将优化后的前框架模型带入整个相机,并对整机进行有限元分析.结果表明,光轴呈水平状态,次镜、折叠镜相对主镜的倾斜分别为9″与22.4″,次镜相对于主镜的偏心为0.021mm,均在光学系统公差要求范围内.此外,对前框架结构进行自由模态分析与试验,结果验证了优化方法的正确性.所提出的拓扑优化方法可以有效避免基于约束模态拓扑优化方法约束点之间不存在联系的缺陷,能够为高分辨、宽视场空间相机光机结构的设计提供参考.

Optimization Design and Test for the Front Frame of a Large Off-axis TMA Space Camera

To guarantee the high stability and high precision of an off-axis thee-mirror optical system space camera,a integration front frame structure was designed to support the second mirror and folded mirror according to the characteristics of the same height of second mirror and folded mirror in optical axis direction,and a topology optimization method based on constraint mode and free mode was proposed to optimize the front frame structure.Then,the integrated structure was assembled into the entire camera after optimization,and the finite element analysis of static was carried out.The results show that the camera maintains excellent static performance with the optical tilt between the primary mirror and secondary mirror being less than 9" and the optical tilt between the primary mirror and fold mirror being less than 22.4",the optical eccentricity between the primary mirror and secondary mirror being less than 0.021 mm,meeting the tolerance requirement of system.By free modal analysis and test to the integrated front frame structure,the results verify the correctness of the design method.The proposed topology optimization method can efficient avoid the defect of topology optimization based on constraint modal frequency that there is no relationship between the constraint points.It can provide reference for design the space camera with high-resolution and wide field.