为获取光学平台多自由度微振动信息, 设计了一种基于平面镜双频激光干涉的三自由度动态微振动测量系统。该系统利用激光多普勒效应, 采用三个测量轴获得测量反射镜的三点位移信息, 计算出测量镜平动、扭转角、俯仰角信息, 实时检测三自由度的微振动情况, 从而为光学系统的微振动补偿控制提供基础。对微振动测量系统进行了不确定度分析, 建立了不确定度模型, 为进一步提高系统精度提供理论依据, 也为系统在校准和计量领域的应用奠定基础。实验过程中, 采用高精度地震计对待测平台进行同步测量, 与系统平动测量结果进行对比, 验证了系统的测量准确性。该系统的平动分辨率可达到5 nm, 扭转角分辨率为5.05 μrad, 俯仰角分辨率为4.69 μrad, 具有多自由度、非接触、高分辨、可溯源的优点。

To obtain multi-degree-of-freedom micro-vibration information of an optical platform, a three-degree-of-freedom dynamic micro-vibration measurement system based on plane mirror dual-frequency laser interference is designed. The system utilizes the laser Doppler effect to obtain the three-point displacement information of the measuring mirror by using three measuring axes; calculates the overall displacement, torsion angle, and pitch angle information of the measuring mirror; and detects the three-degree-of-freedom micro-vibration in real time, thereby providing a basis for micro-vibration compensation control of the optical system. The uncertainty of the micro-angular vibration measurement system is analyzed, and an uncertainty model is established, which provides a theoretical basis for further improving the accuracy of the system and also lays a solid foundation for application of the system in the field of calibration and metrology. During the experiment, a high-precision seismometer was used to measure the platform simultaneously and, by comparison with the system translation measurement results, the measurement accuracy of the system was verified. The displacement resolution of the system is 5 nm, the torsion resolution is 5.05 rad, and the pitch resolution is 4.69 rad. The system has the advantages of multiple degrees of freedom, noncontact operability, high resolution, and traceability.