FAST主动反射面支承结构总体方案研究

Research on support structure scheme for active reflector of FAST

针对国家重大科学工程500m口径球面射电望远镜(FAST)主动反射面的工作特点,提出了整体索网与背架结构共同支承反射面的结构方案,对四边形及多种三角形球面索网网格划分方式进行分析和比较,确定了短程线型网格为优选划分方式;以反射面拟合精度及系统控制最易为综合目标,确定了球面索网的网格尺寸及背架结构最优半径等;对单根控制下拉索和3根控制下拉索两种方案从主动反射面的变位功能、索网结构的力学性能等方面进行了详细对比,确定了采用下端设置促动器的单根控制下拉索,实现反射面基准态的成型和工作态的变位。

FAST（Five-hundred-meter Aperture Spherical Telescope） is a major national scientific project.The support structure scheme for the active reflector was studied in this paper,including the integrated cable-net structure and the back-structure.The mesh modes of quadrangle and several types of triangles for the cable-net were compared,and the geodesic grid was determined as the optimal one.The grid size and the optimal radius of the back-structure were subsequently studied and determined with the fitting accuracy of the reflecting surface and the simplicity of the system control as the comprehensive goal.The schemes of one control cable and three control cables were compared in detail from aspects of the active shape-changing function of the reflector,mechanical properties of the cable-net structure and etc,the scheme of one control cable was determined and finally the forming of the benchmark state and the shape changing of the work state of the reflecting surface was realized.