对典型的光电跟踪系统进行结构分析，提出了改善机械结构谐振频率的方法， 以便提高光电跟踪系统的跟踪速度。研究了典型跟踪架的垂直轴系的结构， 认为单向止推轴系沿轴向的窜动限制了扭转刚度。提出了以双向止推密珠轴系结合定心轴系的结构形式设计垂直轴系，从而有效地提高了系统的刚度，改善了系统的机械谐振频率。对改进后的跟踪架进行了模态仿真分析，并通过振动及扫频试验获得了光电跟踪系统谐振频率特性曲线。实验结果表明，系统谐振频率达到114 Hz，为伺服系统实现高速跟踪时的稳定性和快速性提供了硬件基础。在舰面跟踪高速起降目标的试验中，该系统最大跟踪速度达到150(°)/s以上，加速度大于240( °)/s2，显示其光电跟踪能力显著提升。

The structure of a typical photoelectric tracking system was analyzed and a method to improve the resonant frequency of mechanical structure was proposed to improve the tracking speed of the photoelectric tracking system. The structure of the vertical bearing of a typical tracking frame was researched， and it pointed out that the torsional stiffness of the system was limited by the movement of a one-way thrust bearing along axial direction. Then， a structure of double thrust bearing combined with centering bearing was proposed to design of the vertical axis. By which the system stiffness was enhanced and the resonant frequency of mechanical structure was improved. A modal simulation on the improved tracking gimbal was analyzed， the resonance frequency curve of photoelectric tracking system was obtained through the experiments of vibration and sweep frequency. The results show that the resonant frequency of the system is up to 114 Hz，which provides a hardware support for the stability and higher speed of servo system. In the actual task， the maximum tracking speed and the acceleration of the system is above 150 (°)/s and greater than 240 (°)/s2， respectively， improving the tracking ability of the photoelectric tracking system significantly.