基于有限元分析的固有变形逆解析方法是一种获取焊接接头固有变形的新方法。但是，采用该方法计算固有变形时，必须已知焊接前后焊接接头上少数点的三维坐标值。为了提高固有变形逆解析结果的精度，提出利用接触式三维坐标测量仪准确地获得焊件中面上三维坐标的新算法。该算法是通过在被焊件上加工小孔，在每一个小孔附近测量八个点的三维坐标，利用测量得到的坐标值确定小孔的中心位置。以2 mm和3 mm薄板表面堆焊焊接接头为例，以计算得到的小孔中心三维坐标为已知参数，基于逆解析方法求得了各成分固有变形，并采用固有应变法预测了2 mm和3 mm薄板焊接变形。通过比较分析发现，尽管焊件板厚只相差1 mm，但焊接变形的特征和变形量却有显著的差别，采用该测量方法及算法能获得焊接接头中面上较精确的三维坐标，基于逆解析方法获得的固有变形各成分有效准确。

Inverse analysis method based on the elastic finite element method is a newly approach to estimate the inherent deformations in typical welded joints. However, when this approach is employed to obtain the inherent deformations, the 3-D coordinates before and after welding at a limited number of locations in the welded joints should be known. In order to improve the precision of inverse analysis results, a new algorithm is proposed to obtain the 3-D coordinates at the limited locations on neural plane of weldment by using a contact 3-D measurement system. In addition, two bead-on plate welded joints with 2 mm and 3 mm thickness are selected as research objectives to demonstrate the effectiveness of the new method. The calculated 3-D coordinates are used as known parameters and inherent deformation components are gained based on inverse analysis method, then deformations of the two thin-plate bead-on joints are predicted by the use of inherent strain method. The comparison shows that there are big differences between the two joints with different thickness. The proposed measurement method and algorithm can accurately obtain the 3-D coordinates on the neural plane and the inherent deformation components obtained by inverse analysis method are accurate and effective.