基于数据驱动的FAST主动反射面调节优化模型

Data Driven Optimization Model for the Adjustment of FAST Reflector

针对500 m口径球面射电望远镜(five-hundred-meter aperture spherical radio telescope,FAST)的主动反射面调节问题,利用旋转抛物面在三维空间中的定义建立了一个对任意天体角度均适用的工作抛物面方程,该方法不同于以往的坐标旋转的方法。利用反射面板重心点作为反射点,将反射接收比定义为能把光线反射到馈源舱被其接收的面板数量与300 m口径工作抛物面下总面板数量的比值。结合主索节点径向伸缩距离、边界平稳过度和邻接距离变化幅度三个约束条件,以接收比最大化作为目标函数,建立了一个工作抛物面优化模型,并利用节点数据和模拟退火算法对其进行求解,得到了工作理想抛物面。选用两组天体角度进行实例分析,结果显示调节后的接收比增大12.82%,并给出了工作主索节点的部分径向调节方案。本研究为FAST对于任意天体角度的变形提供了一种新的建模方法,也对馈源舱反射接收比提出了一种新的计算方式。

At any celestial angle,For the adjustment of the active reflector of the Five-hundred-meter Aperture Spherical radio Telescope(FAST),a working paraboloid equation for arbitrary celestial angles is established using a rotating paraboloid equation.This is different from the previous coordinate rotation method.The center of gravity of the reflector used as the receiving point,the receiving ratio is defined as the ratio of the amount of light received by the feed chamber to the total amount of light under the 300-meter aperture working paraboloid.Subject to the constraints of radial change of main cable nodes,a smooth transition of borders and variation amplitude of adjacency distance,a working paraboloid optimization model is formulated with maximization of receiving ratio of the feed cabin as the objective function,and the working ideal paraboloid is obtained by simulated annealing algorithm according to the main cable nodes data.The numerical results show that the receiving ratio increases by 12.82%after adjustment,and the procedure of adjusting radial change of main cable nodes is provided.This work provides a new modeling method for FAST deformation at any celestial Angle,and presents a new calculation method for receiving ratio of feed cabin.