Implementation of a two-stage algorithm for NG-GMAW seam tracking and oscillation width adaptation in pipeline welding

Seam tracking and oscillation width adaptation could effectively reduce the sidewall fusion defects in automatic narrow-gap gas metal arc welding (NG-GMAW). This study proposes a two-stage algorithm to realise seam tracking and oscillation width adaptation in NG-GMAW pipeline welding. The first stage involves using the principal component analysis (PCA) eigenvectors to adjust the oscillating centre, enabling seam tracking and oscillation width adaptation for the hot and fill layer. In the second stage, dataset was prepared based on the tracking data from the first stage, which can guide the welding torch trajectory for the cap layer. Experimental results show that the proposed scheme achieves seam tracking and oscillation width adaptation with an accuracy of 0.1 mm.