基于“FAST”主动反射面形状调节问题的研究

Research of Shape Adjustment Problem Based on “FAST” Active Reflector

基于抛物面的旋转坐标变换,结合约束条件,利用粒子群优化算法,本文研究了观测天体位于不同方位角和仰角时,FAST主动反射面的天体形状调节问题.首先确定了被测天体S位于基准球面的正上方即α=0°,β=90°时,旋转抛物面和基准球面的曲面方程.进而利用促动器径向伸缩约束条件结合反射面板调节因素,对旋转抛物面进行修正,优化计算得到了旋转抛物面焦距的修正量d,以此确定待观测天体位于基准球面正上方时的理想抛物面.其次,当观测天体改变方向,位于任意方位角α,仰角β时,对观测天体S位于基准球面的正上方时所得到的理想抛物面作旋转变换,确定改变方向后的旋转理想抛物面,并取α=36.795°,β=78.169°进行计算,得到将反射面板调节为工作抛物面的调节参数,使得该工作抛物面贴近理想抛物面,让到达馈源舱的平行电磁波最强,以获得天体电磁波经反射面反射后的最佳接收效果.

Based on the parabolic rotation coordinate transformation and constraint condition,the celestial shape adjustment problem of the“FAST”active reflector surface is studied when the observation celestial body is located at different azimuth and elevation angles. In the course of this study,we employ particle swarm optimization algorithm.First,the surface equations for the rotating parabolic and the reference sphere are determined,where the measured object is located directly above the benchmark sphere([α=0°,β=90°]). Then,the radial scaling constraints of the actuator are used to correct the rotating parabola. The optimization calculation obtains the focal distance of the rotating parabola. So,the ideal parabola are determined when the object to be observed is located directly above the benchmark sphere. Secondly,when the observed object changes the direction and the azimuth selection is arbitrary,we calculate for[α=36.795°,β=78.169°]. The ordinal ideal parabola is transformed by rotating in order to determine the rotating ideal parabola after changing the direction. The reflective panel is adjusted to a working paraboloid. So,the working paraboloid close to the ideal paraboloid. At this time,the parallel electromagnetic waves reaching the feeder compartment are the strongest.,so that the best receiving effect of celestial electromagnetic waves reflected by the reflecting surface can be obtained. The best receiving effect of celestial electromagnetic waves after being reflected by the reflection surface is obtained. This method is suitable for the optimal calculation and mirror adjustment of any azimuth angle.