Error Influence Simulation of the 500 m Aperture Spherical Radio Telescope Cable-Net Structure Based on Random Combinations

Abstract

The reflector of a Chinese 500 m aperture spherical radio telescope is supported by a giant cable-net structure. In the actual operation process, active displacement observation is realized by connecting the actuators with the control cables to adjust the cable net, which requires high manufacturing and installation accuracy. In this study, an error sensitivity computing method based on a normal distribution is adopted to perform single-error computing and multi-error coupling computing and to investigate the effect of the length error of all the cables, tensioning force error of active surface cables, and installation error of external nodes on the cable force. The results show that the length error of the surface cables and the installation error of the external nodes are the main factors affecting the cable force, while the length error of the control cables is a secondary factor. The coupling effect of multiple errors is not the linear superposition of each error’s influence; therefore, all the error factors should be comprehensively considered for coupling computing to determine the control index. Through multi-error coupling computing, it is determined that the length error limits of the surface cables and control cables are ±1.5 mm and ±20 mm, respectively, the tensioning force error limit of the active surface cables is ±10%, and the installation error limit of the external nodes is ±50 mm.