大口径SiC轻量化反射镜柔性带式支撑静摩擦影响

采用柔性带式支撑方式的大口径光学反射镜与支撑带之间的静摩擦力对反射镜面形精度影响较大,而且该影响难于直接定量测量。针对这一实际情况,考虑到温度变化将引起静摩擦力状态变化这一规律,建立了温度—静摩擦力间的关系表达式;接着,以反射镜所受静摩擦力与环境温度关系为基础,通过测量不同温度下的反射镜面形精度,间接推算出静摩擦力对反射镜面形精度的影响;以1.2米SiC轻量化反射镜为研究对象,利用干涉仪检测其柔性带式支撑机构在不同温度下的面形精度,并利用实测数据推导出温度—静摩擦关系的相应系数;最后借助ANSYS软件,对带式支撑机构的受力情况进行仿真分析。实测结果与仿真分析结果一致性较好,说明该研究方法可较为准确地推导出静摩擦力对大口径SiC轻量化反射镜面形影响。

Influence of static friction for large aperture SiC light-weight reflecting mirror with flexible strip support

For the large aperture reflecting mirror with flexible strip support ,static friction between large aperture optical reflecting mirror and support stripe has great influence on surface distortion of reflecting mirror .Moreover ,the influence is hard to measure in quantity directly .In consideration of the fact that ambient temperature fluctuation would lead to state change of static friction ,relational expression of temperature-static friction was established .On the basis of the relational expression , the influence of static friction on reflecting mirror surface distortion could be deduced though measuring reflecting mirror surface distortion at different temperatures .By taking a 1 .2 m SiC light-weight reflecting mirror with flexible strip support mechanism as research object , the surface distortion measurement of flexible strip support mechanism was conducted at different temperatures with a interferometer , and corresponding coefficients of temperature-static friction relation were calculated with measured data ;simulation analysis on force condition of stripe support mechanism was conducted with ANSYS software .The results indicate that measured result and simulation analysis result have good consistency ,thus influence of static friction on mirror distortion of large-aperture SiC light-weight reflecting mirror can be deducted accurately in this proposed method .