某机载光电系统主镜的轻量化设计与分析

为了达到某新型机载光电系统的轻小型化要求,对共孔径组件中ΦΦ445 mm的主镜开展了轻量化设计。首先,对比分析了多种轻量化形式特点,确定了主镜材料和结构形式。然后,以主镜轻量化率和面形精度为目标,综合理论计算与有限元分析手段,对相关参数进行迭代优化,确定出镜厚为68 mm,面板厚度为6 mm,筋板厚度为4 mm,优化后轻量化率达62 %。接着,对主镜开展工程分析,在1 g重力作用下,单一主镜光轴竖直时RMS达1.13 nm,光轴水平时RMS达0.23 nm,冲击振动下最大局部应力为0.19 MPa,组件状态下主镜RMS达11.67 nm,各项指标均满足设计要求。最后,借助干涉仪对实物主镜进行光学检测,面形精度RMS实测值为15.19 nm,进而验证了轻量化设计分析的准确性。

The lightweight design and analysis of the primary mirror for a new airborne opto-electronic system

In order to meet the requirements of lightweight and miniaturization for a new airborne opto-electronic system,the lightweight design of the primary mirror with a diameter of 445 mm in the common aperture module was carried out.Firstly,the characteristics of various lightweight forms were compared and analyzed,and the material and structure of the primary mirror were determined.Then,the relevant parameters were iteratively optimized by means of theoretical calculation and the finite element analysis aiming at lightweight ratio and the precision of face shape of the primary mirror.The mirror thickness was 68 mm,the panel thickness was 6 mm,and the rib plate thickness was 4 mm.The lightweight ratio reached at 62 % after optimization.Then,the engineering analysis of the primary mirror was carried out.Under the action of 1 g gravity,the RMS of the primary mirror was 1.13 nm when the optical axis is vertical; the RMS of the primary mirror was 0.23 nm when the optical axis is horizontal.The maximum local stress was 0.19 MPa under impact vibration.The RMS of the primary mirror was 11.67 nm under the component state.All the indexes meet the design requirements.Finally,the real primary mirror is detected by optical interferometer,and the surface accuracy RMS was 15.19 nm by measured,which verified the accuracy of lightweight design and analysis.