航空叶片非接触光学测量的转轴精密标定方法

Research on accurate calibration of shaft in non-contact optical measurement of aviation blades

航空叶片为薄壁复杂扭曲件,转轴标定是获得完整叶片型面数据的前提条件,标定精度直接决定着最终获得叶片数据的整体精度。针对锥光偏振全息干涉的非接触式测头未进行路径规划前只能测量部分球冠点云、球心拟合精度不稳定的问题,提出了一种带半径约束的最小二乘球心拟合方法,通过八个方位扫描数据拟合球心与法线方向,实现转轴的精密标定。实验结果表明,该方法减小多方位测量点云分层效果显著,精度完全满足航空叶片的测量需求。

The blades are complex components that are twisted and thin-walled. Axis calibration presupposes complete blade surface data measurement and the calibration accuracy directly determines the overall accuracy of the blade measuring data. This paper is aimed at eliminating center fitting accuracy in- stability due to the little sphere data obtained using the eonoscopic interference of non-contact probe before measurement path planning and presents a least squares fitting method with a spherical radius constraint. The research involves fitting sphere center and normal direction using eight azimuth scanning data to achieve accurate calibration of rotating shaft. The experimental results demonstrate that the method capable of a significant reduction in point cloud stratification provides the precision adequate for aviation blade measurement.