1m红外太阳望远镜光电导行系统的反馈控制分析

Analysis of the Feedback-Control System of the Auto Guide System of the 1m Infrared Solar Telescope of the Yunnan Observatory

我国正在研制中的1m红外太阳望远镜是目前国内唯一的地平式真空太阳塔,主要用于活动区磁场的精细光谱分析和太阳活动区磁场的时空精细结构研究。要求望远镜必须长时间高精度跟踪太阳(0.3″/30s、1″/10min)才能实现它的科学目标。光电导行是实现望远镜高精度跟踪观测目标的关键控制技术,通过检测观测目标像在图像传感器上的移动量作为反馈控制信号对望远镜实行闭环控制。首先建立了光电导行系统的控制系统模型,然后分析了系统的稳定性能、暂态性能、时域特性、频域特性及跟踪性能,并采用PID控制器对系统进行优化设计,以提高光电导行反馈控制系统的稳定性和跟踪精度。通过计算机仿真设计,采用PID控制算法能实现1m红外太阳望远镜的跟踪要求。

The 1 m infrared solar telescope being developed now is the only altazimuth vacuum-tube solar telescope in China. Its scientific objective is to achieve fine spectral analysis （including the Stokes-parameter analysis） and spatial-temporal fine-structure study of magnetic fields solar activity regions. A long - running and high-precision tracking system （AGS） is thus needed （with an accuracy of 0. 3 arcsec/30 seconds, or 1 arcsec/10 minutes ）. The auto guide system is a key technological component for controlling a large or medium-sized telescope, such as the 1 m solar telescope. In order to implement a closed-loop control of the telescope, the AGS provides feedback control signals to a control system by detecting the offsets of observed targets in the image sensor. In this paper, the model of the control system of AGS is constructed, and then the stability, transient performance, time-domain characteristics, frequency-domain characteristics, and tracking performance of the system are analyzed. In order to enhance the stability and tracking accuracy of the AGS feedback control system, a PID controller is added. Finally, the paper gives computer simulation results showing that the PID controller which is designed with certain control algorithm improves the system tracking accuracy to meet the requirement for the 1 m telescope.