星敏感器支架的结构/热稳定性分析及验证

为明确星敏感器支架受空间环境影响产生的变形对星敏感器定姿精度的影响,对星敏感器支架的结构/热稳定性进行了研究。通过有限元法对星敏感器支架进行刚度分析,将热分析获得的在轨极端工况下的温度数据映射至结构模型上计算得到热变形,利用最小二乘法得到各星敏感器光轴矢量,最后进行试验验证。结果表明:星敏感器组件的结构基频为429 Hz,与分析结果相差不超过2%,试验前后星敏感器光轴与基准坐标系各轴夹角最大变化不超过5;在轨期间星敏感器支架最大温度波动小于2 ℃,星敏感器光轴变化最大为4~5,与分析结果一致。星敏感器支架的结构/热稳定性良好,能够满足星敏感器定姿精度要求。

Analysis and verification of structure stability and thermal stability of a bracket of star sensors

To verify the effect on accuracy of star sensors by deformation of the bracket of star sensors in space, structure stability and thermal stability of the bracket were investigated. Structural properties of the bracket were analyzed by FEM and then the temperature data in worst case on orbit were mapped to the structure model. Based on the temperature data, the thermal deformation of bracket was figured out and vectors of optic axes of star sensors were obtained by least square method. Finally experiment was conducted to verify the analysis. Results indicated that fundamental frequency of star sensors and the bracket was 429 Hz with the difference less than 2% from the analysis and the max variety of the optical axes after vibration test was no more than 5. The max temperature change of the bracket in orbit was less than 2 ℃ and the max variety of the optical axes was about 4-5 which was similar to the analysis. Both the ground test data and orbit data demonstrate that the bracket of star sensors has good structure stability and thermal stability which can meet the requirement.