2m望远镜主轴交流伺服控制系统设计

为了满足2m口径望远镜低速跟踪精度的要求,本文主要介绍了基于永磁同步力矩电机的望远镜交流伺服控制系统设计方法,首先,辨识出了系统结构的频率特性曲线;其次,根据系统的频率特性曲线设计了结构滤波器,以减小结构模态引起的谐振幅值;然后,根据系统的控制性能指标要求,设计了位置回路控制器和前馈控制器,以提高系统的位置跟踪性能;最后,在设计的硬件平台上进行了望远镜转台的低速控制实验。实验结果显示,当望远镜跟踪斜率为0.36″/s的位置斜坡曲线时,速度平稳性较好,位置跟踪误差RMS为0.006 1″,实现了极低速度跟踪的效果;在速度为5°/s,加速度为2°/s2条件下的正弦引导最大误差值为0.3″,稳态误差RMS值为0.066″。实验结果表明,2m口径望远镜交流伺服系统的设计满足了系统跟踪精度的要求,为大型望远镜交流伺服控制系统的设计提供了一定的参考。

Main axes AC servo control system for 2 m telescope

A design method for telescope AC servo control system, based on high-power permanent magnet synchronous motor, was proposed to meet the requirement of low-speed tracking accuracy for 2 m telescope. Firstly, frequency characteristic curve of system structure was identified; secondly, a structure filter was designed according to frequency characteristic curve of the system so as to reduce the resonant amplitudes caused by structural mode; then, according to the requirements of the system control performance index, the position controller and feed forward controller were designed to improve the system position tracking performance; lastly, a low-speed control experiment on the telescope turntable was conducted based on the designed hardware platform. The experiment result shows that the telescope is in better stableness and its tracking error RMS is 0.006 1" when it tracks a slope 0.36"/s position curve, which achieves an extremely low-speed tracking effect; the maximum error value guided by the sine curve is 0.3" and the tracking error RMS is 0.066" on the condition of speed 5°/s and acceleration 2°/s². The experiment result indicates that the design of AC servo control system for 2 m telescope meets the requirements of system tracking accuracy and provides a reference for the design of AC servo control system for large-scale telescope to an extent.