针对现场环境下的航空制孔垂直度检测问题,提出了一种基于激光测距的快速高精度测量方法。首先,利用膨胀芯轴在被测孔内稳定支撑并模拟孔的轴线,通过安装在芯轴上的激光测距传感器和角度编码器获取孔的端面点云数据,并拟合出端面法向量;最后,计算该法向量与被测孔轴线之间的夹角作为垂直度误差。为了提高装置测量精度,提出了基于RANSAC的三维点云重建算法,并通过向量合成法补偿由膨胀芯轴体现基准时所产生的系统误差。利用不同垂直度标准环规对所述装置进行了标定,并完成了平面样件及曲面样件的制孔垂直度测量实验。实验结果表明:该装置的测量重复性<0.01°,最大示值误差<±0.1°,单个孔的测量时间<1min,能够满足航空制孔垂直度的现场检测精度与速度要求。
Abstract
To solve the problem of verticality detection of aviation drilling holes on site, a fast and high-precision method is proposed based on laser ranging sensor. Firstly, an expansion mandrel is stably supported in the hole to simulate its axis. Then the point cloud data of the holes end face is obtained with the ranging sensor and an angle encoder, which are both installed on the mandrel. And the normal vector of the face is further fitted. Finally, the angle between the vector and the axis is calculated as the verticality. At the same time, a 3D point cloud reconstruction algorithm based on RANSAC is proposed to improve the measurement accuracy. The systematic error, caused by the reference reflected by the expansion mandrel, is compensated after the vectors are synthesized. The measuring device is calibrated by verticality gauges and the experiments of verticality detection are completed for both plane and curved parts. The result shows that the measurement repeatability is less than 0.01° and the maximum indication error is within ±0.1°. It takes less than one minute for each hole. So the requirements of the accuracy and efficiency for on-site detection can be met.
关键词
计量学 /
垂直度 /
航空制孔 /
激光测距 /
膨胀芯轴 /
点云重建 /
测量重复性
Key words
metrology /
verticality /
aviation drilling hole /
laser ranging /
expansion mandrel /
point cloud reconstruction /
measurement repeatability
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基金
直升机传动技术国家级重点实验室基金(HTL-0-21G10);江苏省大学生创新创业训练计划项目(2021cx005069);南京航空航天大学“实验技术研究与开发”重点项目(2020050500057871)