Research Of Automatic Seam Tracking System For Laser Welding Based On Machine Vision

Laser welding has a variety of advantages, such as high energy density, small heatingzones, long distance welding, welding material variety and easy welding processautomation,so it has been increasingly widely used in machinery manufacturing,aerospace, energy, transportation, petrochemical and other industries. With the deepeningof its application, the corresponding process, welding process control and other aspectshave been extensively studied. As the laser welding has the features of nonlinear,time-varying confounders, it will appear seam deformation in welding process whichcauses welding torch deviation. Therefore, seam tracking system has become an importantresearch direction of welding automation.On the basis of absorbing mature technology at visual weld inspection, by means oflaser welding lathe，this paper designs a seam tracking system based on machine vision,and elaborates on its implementation.For two common aviation weld: butt welds and T-joint fillet welds,, this paper adoptstwo measurement methods respectively based on micro depth of field lens and linestructured light. Combined with the structural characteristics of laser welding special latheand the analysis of the two seam bias adjustment methods: decomposition and detached，establishes a detached mechanism for automatic seam tracking system.By using special welding lathe that has the features of good scalability and strongcompatibility, which based on the control structure of open CNC system, designs thehardware implementation of seam tracking system. Deduce the formula forforward-looking seam tracking process based on the model of welding trajectory andcomplete the design of control strategy for seam tracking. According to the characteristicsof the Dual-beam welding for T-joint fillet seam in aviation, this paper takes researches onweld seam tracking application analysis and path optimization. The results show that theseam tracking system designed by this paper can achieve accurate real-time adjustmentsfor welding process deviation, and meet the actual processing of the weldingrequirements.