Abstract: A model alignment method was proposed based on geometric features, and applied to a 3D model of integral impellers. First, centroid of the measured models was extracted. According to the symmetry features of the integral impeller, the least square algorithm was utilized to estimate the rotational axis and was modified by the more accurate data of shaft part. Therefore, the centroids and rotational axes of the measured models were aligned with those of the CAD models. Then, the aligning of the blade parts of the measured models with the CAD models was realized by using weighted least squares method according to the characteristics of manufacture precision. The maximum alignment deviation caused by the proposed method is as 0.2mm.

Key words: integral impeller, geometric feature, 3D measurement, alignment

摘要： 提出了基于几何特征的模型对齐方法，并应用于整体叶轮三维模型。提取了测量模型的质心。根据整体叶轮对称性，采用最小二乘法对其轴线进行了估算，并采用加工精度高的轴位置数据对轴线进行了修正，从而将测量模型的质心、轴线与CAD模型的质心及轴线对齐。根据整体叶轮的制造精度特征，采用加权最小二乘法，实现了叶片区域测量模型与CAD模型的对齐。经计算，采用上述方法的最大对齐误差为0.2mm。

关键词: 整体叶轮, 几何特征, 三维测量, 对齐