卫星激光测距中主镜柔性支撑结构设计及分析

Design and analysis of a flexible support structure for the primary mirror of SLR

为了降低卫星激光测距中主镜在大温差环境下的面形误差,设计了一种主镜柔性支撑结构,针对柔性铰链结构形式,推导了单边圆弧形柔铰的转角柔度方程,确定了影响柔铰支撑刚度和柔度最敏感的两个参数为柔性铰链的宽度和最薄处厚度,采用有限元法对主镜支撑结构进行了仿真分析,确定了柔性铰链的宽度、最薄处厚度,使主镜在60℃温差环境下具有良好的热尺寸稳定性,结构刚度在工作状态下满足使用要求。在力热耦合状态下,分析结果表明,主镜综合面形误差RMS小于20 nm,主镜刚体位移则控制在6μm以下,并通过主镜面形检测试验进一步验证了仿真分析的正确性。由此,在大温差环境下该柔性支撑结构做到了刚柔兼顾。

To reduce the surface deformation of the primary mirror in a satellite laser ranging,a flexible support structure is designed.Based on the structure of the flexure hinge,a compliance formulation of the half right circular flexure hinge is formulated,therefore,the width ＇b＇ and thickness ＇t＇ of the flexure hinge,which are two of the most sensitive parameters,are picked out.Then,the flexible support structure is analyzed with finite element method,by which the value of ＇b＇ and ＇t＇ are determined.The simulation results show that RMS and displacement values of the primary mirror is less than 20 nm and 6 μm,respectively,under the load case of gravity in z direction coupled with uniform temperature drop 60℃,which is validated by measured values of primary mirror surface shape.Finally,the balance between rigid and flexible of the flexible support structure is found under great variation temperature.