航空发动机叶片长期工作在高温高压的涵道中,容易发生断裂、划道、形变等损伤。损伤叶片增材修复的关键是对其进行三维数字建模,模型的精度直接影响到熔覆制造的质量。基于航空发动机叶片的空间扭转特征,提出了一种非接触式的激光交叠式三维重建方法。利用扫描策略中线激光测头与叶片相对位置的特征矩阵初始化点云配准参数,通过分配权值缩小源点云规模,对迭代最近点算法进行优化。最后对点云数据进行精简、网格化,建立了损伤叶片的三维模型。在配准过程中,分析了点云块的交叠率对模型精度的影响。实验结果表明,当交叠率为50%时,采集时间短、信息完整度高,通过标准量块阶梯验证了模型的测量精度为10 μm,满足损伤叶片重建模型的精度要求。

The aero engine blade works in the culvert of high temperature and pressure for a long time, which leads to the damage of fracture, scratch and deformation. Three-dimensional digital modeling of damaged blade is the key step of its additive manufacturing. The accuracy of the model directly affects the quality of cladding manufacturing. In view of the spatial torsional characteristics of the space engine blade, in this paper, a non-contact laser overlapping three-dimensional reconstruction method is proposed. Based on the feature matrix of the relative position between the laser probe and the blade in the scanning strategy. The registration parameters of the point cloud are initialized, and the size of the source point cloud is reduced by assigning the weight, and the iterative nearest point algorithm is optimized. Finally, the point cloud data is simplified and meshed to complete the three-dimensional model of damaged blade. In the registration process, the effect of point cloud block overlap rate on the model accuracy are analyzed. Experimental results show that when the overlap rate is 50%, the acquisition time is short, and the information integrity is high. The standard measurement block ladder verifies that the measurement accuracy of the model is 10 μm. The method meets the accuracy requirement of the damaged blade reconstruction model.