空间最优投影平面的斜口圆截面管路端头位姿测量

Accurate measurement of end position of inclined pipe with optimal projection plane of space

船舶、飞机等发动机为减小体积,采用斜口管路焊接代替弯头连接,管路系统中端头位姿是焊接对齐的前提。针对斜口管路端头位姿的高效高精度测量难题,提出了一种通过重建管路轴线以及管路端面进行端头位姿精确测量的方法。通过获取种子圆柱并设计非线性寻优算法提高圆柱拟合精度,通过高精度种子圆柱扩散重建得到管路轴线。通过双曲率阈值搜索方法对管路边缘进行搜索,得到管路端面边缘点整像素坐标。通过对端面提取得到的整像素坐标进行椭圆拟合结合射线求交方法求解端面边缘亚像素坐标,从而避免插值方法计算亚像素坐标受环境光源影响大的问题。最后,使用逐点最小二乘法重建空间投影平面并在平面上得到残差最小空间椭圆,空间椭圆中心即为管路端点,该投影平面即为端面所在平面,实现了对端头位姿的精确测量。实验结果表明,该方法的测量精度达到0.05 mm,角度测量误差小于0.1°,基本满足斜口管路端头的位姿测量精度要求,对管路的装配具有良好的指导意义。

To reduce the volume of ships,aircraft,and other engines,oblique pipe welding is used instead of elbow connection,and the end position in the pipeline system plays an important role in the welding alignment.First,the pipe axis was obtained by determining the seed cylinder and designing a nonlinear op⁃timization algorithm.Then,the pipeline axis was obtained through diffusion reconstruction of the high-pre⁃cision seed cylinder.Following this,the pipe edge was searched using the double curvature threshold search method,and the whole pixel coordinates of the end-face edge point of the pipe were obtained.Next,the subpixel coordinates of the end-face edge were obtained via elliptic fitting of the whole pixel coordinates extracted from the end face combined with the ray intersection method,avoiding the effect of the ambient light source on the subpixel coordinates calculated using the interpolation method.Finally,the spatial projection plane was reconstructed using the point-by-point least squares method and the minimal re⁃sidual spatial ellipse was realized on the plane.The center of the elliptical circle of the space was the end of the pipe,and the projection plane was the plane where the end face was located,enabling accurate mea⁃surement of the head position.The experimental results show that the measurement accuracy of this meth⁃od reaches 0.05 mm,and the angle measurement error is less than 0.1°,basically meeting the accuracy re⁃quirements of the head position measurement of an inclined pipeline,and presenting good guiding signifi⁃cance for the assembly of such pipelines.