应用于FAST反射面闭环控制的实时仿真系统

The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is supported by a cable-net structure. By controlling 2225 actuators on the ground, the positions of the cross nodes can be adjusted to form an illuminated aperture having a diameter up to 300m. Actuators and cable-net structure compose a complex control system with multi-degree of freedom. Unlike conventional telescope, the surface of FAST reflector is spherical shape. So, active control is certainly necessary for FAST observation. However, measurement system would take about 10 minutes to complete a surface shape measuring. It is impossible to perform real-time and closed-loop control by only depending on the hardware system of this telescope. Therefore, the present topic, based on the mechanics simulation technology, would make an effort in development of a real-time simulation system. This system would enable FAST to sufficiently utilize the efficiency of the mechanics simulation method and the superior accuracy of the measurement system. In addition, this system can also provide the systematic evaluation of the fault conditions, which would be helpful to ensure the normal working hours of FAST. .Other giant radio telescopes in the world usually spend 2-5 years to realize the reliable and efficient operation, FAST would face the same situation. We just use this time to carry out the present research. The research result would provide the necessary technical reserves for future operation and maintenance of FAST, and also have important reference value for the other giant radio telescope in future.

五百米口径球面射电望远镜（FAST）通过2225台促动器进行索网的变位控制，是一个复杂耦合的控制系统。与传统望远镜不同，该望远镜反射面的基准面是球面，必须主动变位才能实现有科学意义的观测。但目前问题是，仅凭现有的测量设备不足以实现反射面的闭环控制，需要发展合适的模型方法。故本课题将致力于发展一种实时仿真系统，辅助反射面系统进行闭环控制。该系统不仅可以充分发挥力学方法的反馈效率，还可以充分利用测量系统在其最优时段的测量数据。此外，该系统兼备故障评估功能，可在少量促动器故障发生故障时，为主反射面继续观测运行提供数据支持，以保证望远镜的有效观测时间。.国际上类似巨型望远镜一般需要2-5年调试周期，FAST灵敏度及可靠性的提升也绝非一时之事。本课题正是在这种背景下展开研究，其研究成果不仅对FAST的调试、运行及维护有重要意义，还可以为其它巨型望远镜的设计及实施提供重要的参考价值。

与传统结构不同，FAST具有可主动变位的索网结构。FAST索网结构从球面到抛物面的连续变位过程是一个复杂的大规模数量促动器同步联动控制跟踪的过程。基于实时测量技术的闭环控制系统受天气、电磁干扰等因素的限制,不能满足FAST反射面控制的要求。因此，本项目开发了一种基于力学模型的索网节点控制方案，使FAST具有全天候运行和精确跟踪观测的能力。另外，为了评估少量促动器故障对整个索网结构安全的影响，项目组还开发了FAST索网结构实时评估系统，为FAST现场促动器的批量维护计划提供了依据，有效提高了FAST的观测时长。本项目的研究成果均已成功应用到了FAST的运行中，为FAST的正常、安全运行起到了至关重要的作用。