激光雷达主反射镜支撑结构设计与实现

Design and Implementation of Primary Mirror Support Structure of LiDAR

为避免机载测深激光雷达光机系统中反射镜在不同工况下的面形误差,提出反射镜间柔性支撑结构,通过柔性结构改变反射镜与支撑结构之间的力学关系,来减少反射镜的变形量。首先通过Zemax软件制作出光学系统并导出到Solid works制作光机三维模型,再根据实际使用工况通过Ansys对三种结构进行刚度测试和面形分析。根据分析结果可知:使用环形薄圆筒的支撑结构的一阶频率高达331.06 Hz;热力耦合作用下镜面变形峰谷值为37.25 nm,均方根值为14.52 nm。此外,对支撑结构进行了动力学分析,在1g加速度激励下,反射镜最大加速度响应为4.32g。在随机振动下,反射镜组件最大加速度均方根值达到4.7g_(rms),支撑结构柔性装置的最大应力为21.3 MPa,力学特性良好。最后,设计了最大接收视场验证实验、光学系统远距离回波接收实验和机载水深测量实验,该结构可以很好地完成回波接收。结果表明,本文设计的反射镜支撑结构柔性结构稳定可靠,能用于机载测深激光雷达系统。

This research presents a new“intermirror flexible support structure”to mitigate surface shape errors in the mirrors of airborne bathymetric laser radar(B-Li DAR)optical systems under various working conditions.The flexible structure changes the mechanical relationship between the mirrors and support structure,thereby reducing mirror deformation.In this study,an optical system was first developed using Zemax and exported to Solid works to create a 3D model of the optical system.Subsequently,Ansys was used to analyze the face shape and conduct three different types of structural stiffness tests based on the actual working conditions.The analysis results reveal that the intrinsic frequency of the support structure using a ring-shaped thin cylinder is 331.06 Hz,peak-to-valley(PV)value of mirror deformation under thermal coupling is 37.25 nm,and root mean square(RMS)value is 14.52 nm.Moreover,dynamics analysis was performed for the support structure,and the maximum acceleration response of the mirror under the applied 1g acceleration excitation is 4.32g.Under random vibration,the maximum acceleration RMS value of the mirror assembly reaches 4.7g_(rms)and maximum stress of the flexible device of the support structure is 21.3 MPa,implying good mechanical characteristics.The maximum receiving field of view verification,optical system long-distance echo reception,and onboard bathymetry experiments were designed,which can effectively complete the echo reception.The results indicate that the flexible structure of the reflector support designed in this article is stable and reliable,and can be used in airborne depth measurement lidar systems.