1.2m望远镜跟踪架结构设计与分析

Structural Design and Analysis of the 1.2m Telescope Tracking Mount

为提高望远镜系统的响应速度,增加伺服系统的控制带宽,望远镜的结构刚度需要得到有效保证。首先,根据望远镜力的传递路径,选择双排角接触球轴承作为承载元件,设计了适用于1.2m望远镜的地平式结构。然后,在ANSYS中使用Matrix27单元模拟轴承结构,并建立了望远镜的详细有限元模型,以预测该系统的性能。最后,通过有限元分析、模态测试以及扫频实验获得系统的性能,并借助于流场分析,研究了风载对望远镜性能的影响。仿真结果表明,系统的一阶谐振频率可达21.3Hz,能够满足前期设计要求;模态试验结果显示,系统的一阶谐振频率约为18.5Hz;扫频实验结果显示,方位轴一阶谐振频率为20.8Hz,进而验证了前期分析的正确性。流场分析显示,风载对望远镜驱动电机的力矩输出能够产生影响,控制系统校正后扰动力矩大小约为3.4Nm RMS。仿真和实验结果证明1.2m望远镜轴系的设计方案合理,测试方法可行,能够达到预期效果。

In order to improve the response speed of the telescope system and increase the control bandwidth of the servo system,the structural rigidity of the telescope needed to be effectively ensured. Firstly,double rows of angular contact ball bearings based on the transmission path of telescope force was selected and a ground-based structure of1.2 m telescope was designed. Then the detailed finite element model of the telescope was built by using matrix 27 element of ANSYS to simulate the bearings in order to predict the performance of the system. Finally,the performance of the system was obtained through finite element analysis,modal testing and frequency sweep experiment. Moreover,the influence of wind load on telescope was still studied. The simulation results showed that the first-order resonant frequency of the system can reach 21.3 Hz,which can meet the requirements of the previous design. The modal testing showed that the first-order resonant frequency of the system is about 18.5 Hz,which verified the ANSYS analysis. The flow field analysis showed that wind load can affect the torque output of the drive motor;and the disturbance torque after correction by the control system was about 3.4 Nm rms. The simulation and experimental results showed that the design of the 1.2 m telescope shaft system was reasonable and could meet the expected effect.