Study On Dual-beam Laser Welding Control And Seam Tracking Technology

Tee joint structure is usually applied to join reinforced plates in aviation, carmanufacturing and shipbuilding. The quality and efficiency of laser welding withinapplying Tee joint directly influences the development of these industries and theapplication and expansion of laser welding technology. The high-intensity lightenAl-alloy is easy to distort and produce voids and cracks when it is welded by the laser inunconstrained systems. While applying the dual-beam laser welding and its trackingcontrol system for Tee joint, the joint distorting problem can be solved well in the processof laser welding. In order to realize the dual-beam laser welding for Tee joint andaccording to build the systematic measuring platform for the dual-beam laser welding,this thesis researches the technology of tracking control in the process of dual-beam laserwelding. Main research contents are as following:The platform construction and control function of the process of dual-beam laserwelding for Tee joints was deeply analyzed. And then the measuring platform for weldingwas built according to the seams features during the process of dual-beam laser welding.According to transform the homogeneous coordinates, the kinematics model of themachine tool was built and then the trajectory planning was realized.According to open CNC technology, the measure and control system of dual-beamlaser welding for Tee joints was developed. The system was based on PC and NC Systemstructure, the motion control card was used to be the lower machine, the seam trackingcontrol system which is based on vision sensors is used to do the real-time compensationfor welding deviation in the process of welding. The IPC was used to be upper computerand the PC software of the Multi-axis control system was developed.The deformation compensation principle and process was established. The positionloop based on PID control was designed, thereby the accuracy of the tracking system wasimproved. The tracking algorithm in the process of a high-speed welding is designed onthe basis of a data analysis for the visual sensor feedback. A requirement is proposed forthe curve welding. At the end, the welding experience has testified the effectiveness of thehigh-speed welding of tracking control.