平面光栅支撑结构设计及其面形分析计算

Design of Supporting Structure for Plane Grating and Surface Deformation Calculation

为满足二氧化碳探测仪平面光栅高精度面形要求,对光栅及其支撑结构进行了设计和分析.首先,对光栅结构组件各材料的选取和支撑结构形式进行了研究;然后,以坐标变换法和最小二乘法为理论依据,对镜面刚体位移和畸变的计算求解进行了探讨;接着,采用有限元法对光栅结构组件在不同热力耦合状态下的面形精度和结构强度进行仿真分析.运用有限元软件本身提供的二次开发功能,开发了能内部调用MATLAB编写的面形误差计算程序.经计算,各工况下面形误差PV≤63nm,RMS≤12.6nm.最后,为了验证结构组件的动态特性,进行了模态分析和谐响应分析,三个方向的基频分别达到1 046.3Hz,1 640Hz,1 147.5Hz.这些结果表明,光栅结构组件设计合理可行,能够满足各项设计要求.

In order to meet the high profile accuracy requirements of plane grating for carbon dioxide detector,the grating and its support structure were designed and analyzed. Firstly, the principles of selecting material for grating sub-assembly and the supporting form for grating were investigated. Then, the calculation method for mirror rigid body motion and surface shape error were discussed, based on the Homogenous Coordinate transformation theory and least square method. Subsequently, the surface figure precision and structural strength were analyzed with finite element method subject to thermol-structural coupling loads. A program that can directly call the surface shape error calculation program written by MATLAB was compiled using the secondary development function provide by the finite element analysis software. Simulation results show that the PV≤63 nm, RMS≤12. 6 nm. To verify the sub-assembly＇s dynamitic character , the modal and harmonic response analysis were adopted. The results indicate that the fundamental frequencies of the component in three directions are 1 046. 3 Hz, 1 640 Hz, 1 147. 5 Hz, respectively. These results demonstrate that the rationality of the supporting structure and can meet the requirements.