A mechatronic approach for real-time process control to achieve a uniform bead shape of robotic welding

Abstract

Gas metal arc welding (GMAW) process is one of the most widespread welding processes in industries and using robots to manipulate the welding torch leads to excellent production quality, reliability, efficiency, and cost-effectiveness. In the previous researches, the automatic GMAW system including robotic arm, moving workpiece table and vision capability are developed for real-time seam tracking and welding of complex parts. Despite a precise tracking result achieved by the robotic methods, the welding metal deposit is uncontrolled and generates a varying bead shape on the seam. This problem comes from the variable relative speed between the torch and the curved seam and deteriorate the welded product mechanical properties. In this article, a novel approach is proposed to adjust the GMAW parameters in real-time according to the measured relative speed. Based on the process affecting parameters, a control algorithm is designed. Then some mechatronic elements are added to the system to accomplish the process control. The experimental results indicate the approach efficiency on the bead shape uniformity.