An Adaptive Correction System For MIG Pipeline Backing Welding Based On Multi-sensor

With the rapidly development of the oil industry and pipeline transportation, the pipelineengineering has a large quantities, multiple weld crater, apt to occur quality problem. Each problemwill lead to a serious consequence. The torch must always be positioned in the center of weld gap toguarantee high welding quality when the pipeline is affected by the machining precision and thermaldeformation effect. The backing welding directly affects the quality of pipeline welding. So theadaptive correction of welding torch is a key issue to be solved urgently in the process of pipelinebacking welding.Therefore, an adaptive correction system based on adaptive correction algorithm is developed.Firstly, the current development and research of welding automation is discussed. Secondly, the arcsensor and passive light vision sensor based on CCD(Charge-coupled Device) are detailed described.Thirdly, the design of this adaptive correction system is presented. The arc information processingsubsystem which uses filter algorithm to process the sampled current information and uses the linearrelation between the integral area of current information and height of the welding torch to get heightdeviation. In the visual information processing subsystem, which captures welding image in thecurrent base to eliminate the image noise, uses a visual attention model called Itti-Koch to preprocessthe image. Then Sobel transformation method to extract welding seam position is proposed. Theadaptive correction algorithm which is based on k-center is deeply researched. In the offline learningperiod, the reference welding seam is the mean value of a group welding seams which are clustered.In the online learning period, the weight of each welding seam is assigned by the distance betweenitself and the reference welding seam. Then the weighted mean of this group of welding seam positionis regarded as current seam position. The horizontal direction correction is realized by compensatingthe deviation between welding seam center and welding wire. The height direction deviation ofwelding torch is compensated at the same time.This research has completed the key technology of the correction system for MIG pipelinebacking welding and the correction software has been developed. The experiment results show thatthe multi-sensor adaptive correction system can obtain current information and welding pool imagestably, extract the deviation between welding seam and welding torch precisely, and realize thecorrection in horizontal and height direction. The welding results show a better seam shape.