25 m射电望远镜俯仰系统的全过程建模

最优控制可有效提高大射电望远镜的指向精度,但其控制器设计需要精确的被控对象模型。为此,文中依据其有限元模型,建立了俯仰系统从电机到副面运动的全过程模型。首先,应用模态坐标法建立了大齿轮和主反射面模型,体现了结构主体刚柔混合特性;然后,应用Euler-Bernoulli梁方程式推导了副面撑杆和副面模型,反映了结构末端柔性;最后,通过仿真分析验证了该建模方法的准确性和有效性。与目前已有的射电望远镜建模方法相比,该方法的优点在于在天线设计阶段就可模拟各部分的实际运转状况,可提前发现不足。

Modeling of the Whole Process of Elevation System for 25 m Radio Telescope

The optimal control can effectively improve the pointing accuracy of large radio telescopes, but design of its controller needs the precise model of controlled object. For this reason, in this paper the whole process model of the elevation system from the motor to the subreflector is established according to its finite element model. Firstly, the model of bull gear and main reflector is established by modal coordinate method, which embodies the mixing rigid and flexible characteristics of the main body of structure. Then, the model of subreflector struts and subreflector is derived by Euler-Bernoulli beam equation, which reflects the flexibility of structure end. Finally, the accuracy and effectiveness of this modeling method are verified by simulation analysis. Compared with the existing modeling methods for radio telescopes, the advantage of this method is that it can simulate the actual operation of each part at the antenna design stage so that the deficiency can be found in advance.