Visual welding process control in Pulsed GMAW using Otsu-thresholded features

Pulsed Gas metal arc welding (GMAW) technology is a commonly useful welding technology worldwide, and it’s still a difficult point to keep a safe and stable state in the welding process due to the complex variations. In this study, molten pools serve as a crucial indicator for evaluating welding states. In the pulsed GMAW process, metal transfer predominantly occurs through molten pools. To facilitate effective monitoring and control, a visual-sensor-based control system was developed. By analyzing the physical characteristics of the welding arc under varying welding speeds, real-time images are captured and processed using Otsu’s thresholding method to segment and extract key features. These extracted features are then fed into a closed-loop feedback control system, enabling dynamic adjustment of welding parameters in response to changes in the welding state. Compared with traditional approaches, this study improves welding process stability and reduces the probabilities of weld defects. The results demonstrate that under actively controlled welding conditions, a high-quality weld bead was achieved. The overall average deviation of the weld bead height remained within ± 0.03 mm, and the average variance within ± 0.31 mm², indicating robust control of the welding process. The results maintained 97% of the stability margin. This study provides a foundation for intelligent and adaptive control in automated welding applications.