射电天文研究室知识库

以新疆天文台南山25米天线改造计划为背景,为达到通过副反射面补偿方法提高天线整体电性能以及自动换馈的目的,详细研究了基于模糊控制器的天线副反射面调节系统。以六自由度并联平台伺服系统为被控对象运用Simulink仿真软件对模糊控制器进行了在无噪声阶跃输入,有噪声阶跃输入,无噪声弦波输入和有噪声弦波输入条件下的系统仿真,并进行了详细的误差分析得到了性能最优的系统模型参数,同时得到了在模糊控制器作用下的副反射面调节系统的基本运行性能参数:在弦波信号作用下系统响应误差小于等于0.09mm,在阶跃信号作用下系统稳态误差为0.0011mm,且调节时间约为0.3s。实验结果表明基于模糊控制器的控制系统整体性能良好,能快速、稳定、准确地完成副反射面调节任务,进而提高天线的整体电性能,满足天文观测和深空探测对数据准确性和系统可靠性的要求,具有一定的应用价值。

In this paper we present a detailed study of the performance of the adjustment system of the sub-reflector of the 25m radio antenna at the Nanshan Station of the Xinjiang Astronomical Observatory． Our study is to fit the plan of transforming the 25m antenna，which is to improve overall electric performance of the antenna through real-time compensation from the sub-reflector and to realize auto-switch of feeds． A key component of the adjustment system is its control system based on a fuzzy controller． In our study we use the Simulink to simulate the performance of the fuzzy controller in controlling the servo system of the 6-DOF parallel platform for different settings． The settings consist of the combinations of two cases of input signals ( step signals and sinusoidal signals) with two cases of noise ( vanishing noise and non-vanishing noise) ． Our study includes a detailed error analysis to obtain optimal parameter values of the control system as well as key performance parameter values of the adjustment system of the sub-reflector，which is under the control of the fuzzy controller． We have found that in the cases of sinusoidal signals as input signals the errors of system response do not exceed 0. 09mm，and in the cases of step signals as input signals steady-state errors of the system do not exceed 0. 0011mm with the adjustment time at about 0. 3s． Our experimental results show that the overall performance of the control system based on the fuzzy controller is sufficient for it to accurately，reliably，and promptly adjust the sub-reflector． The control system based on the fuzzy controller is thus valuable in improving the electric performance of the 25m antenna，in the sense that it can meet the requirements of data accuracy and system reliability in astronomical observation and deep-space exploration．