Self-tuning PID control of welding penetration in thin-walled cylinder based on rear molten pool image
基于熔池背面图像的薄壁筒体熔透自整定PID控制系统

The fluctuations of process parameters and groove dimensions lead to the variations of weld penetration of the girth welding for the thin-walled cylinder. In order to ensure a stable penetration, the penetrations are needed to be detected and controlled in real-time. A vision-based direct-sensing equipment is installed for the thin-walled cylinder TIG(tungsten inert gas) welding to obtain a clear rear pool image. The processed image gives the rear width-range of the melt pool for desired penetrations. A self-tuning PID controller controls the penetration by properly adjusting the welding speed. Experiment results show that the penetration signal obtained by this method is reliable, practically eliminating the insensitive zone in indirect sensing.