为了实现空气质量的实时监测，设计了一种车载红外探测设备的光机结构。该结构采用大孔径、无焦反射式光学系统，即高精度扫描反射镜实现了方位和俯仰0~360°扫描。通过有限元方法对系统进行静力学分析，结果满足光机结构设计要求。用锤击法对样机进行了模态测试，并对车载环境下的设备进行了振动实验。结果表明，光机结构一阶频率为52 Hz，相对于车载环境的125 Hz具有足够的动态刚度及结构稳定性，可保证该设备正常工作。

In order to test the air quality in real-time, an optical and mechanical structure of on-truck infrared detection equipment is designed. Using large aperture optical system, high precision scanning structure and unfocus reflecting telescope, the system achieves 0-360° scanning in orientation and pitching. The structural static analysis of the system is performed using finite element method and the results meet the optical and mechanical design requirements. A modal test is done by hammer beat method and a vibration test is carried out under the on-truck environment. Comparing the two results above, the first-order frequency of the optical and mechanical structure is 52 Hz, which has sufficient dynamic stiffness corresponding to the 125 Hz in the on-truck environment and can ensure the stable operation of infrared detection devices.