| Aimed at solving the problems of mirror reflection,arc interference and spatter existing in automatic welding seam tracking of aluminum alloy components,this paper has carried out four technical researches,including the design of automatic seam tracking system,the analysis and preprocessing of the factors affecting the visual image quality of seam groove,deviation extraction and online tracking control,the integration of tracking system and test verification.Four key difficulties,such as the elimination of arc light and mirror reflection interference in aluminum alloy welding,the extraction of groove image feature points,the influence of aluminum alloy welding deformation on tracking accuracy,and the algorithm of deviation extraction,are overcome.In this project,the laser seam tracking welding system is developed,and the laser seam tracking algorithm and control software are developed and passed the realtime tracking test of high-strength aluminum alloy automatic welding.In this paper,the influence of various interference factors on the visual image of the joint groove is analyzed and studied.The " separated arc baffle " is designed as the first anti arc interference measure."Cut-off narrow band filter light reduction system" is designed as the core anti-interference sensing technology measure.The sensor shell blackened inner wall and other anti-interference measures are designed to solve the secondary reflection of aluminum alloy,and the laser CMOS sensing hardware device is developed.To solve the difficult problem of high specular reflection of aluminum alloy joint groove and arc reflection caused by welding deformation of car body,a filtering noise reduction,adaptive threshold processing and contour extraction algorithm of groove image are developed.The feature points on one side of the contour are scanned,and then the pixel coordinates of the feature points are calculated according to the contour difference of the undisturbed area.It is verified that the algorithm can detect the feature points accurately even under the condition of strong specular reflection and serious deformation.In order to reduce the oscillation of the system,the algorithm of fuzzy controller is designed.After fuzzification and fuzzy reasoning,by comparing the effects of different methods of fuzzy solution on the output,the barycenter method is used to solve the fuzzy problem,and a smoother output is obtained,which improves the stability of the system.In this paper,software programs such as image acquisition and preprocessing,image anti-interference calculation,feature point detection,groove judgment,deviation extraction algorithm and fuzzy control are integrated,and a special laser CMOS seam automatic tracking control system is developed,which has the function of self-adaptive seam tracking of aluminum alloy welding gun,parameter setting,groove feature parameter extraction output,process monitoring,etc,the database system interface is reserved.In this paper,6061 high-strength aluminum alloy components are used to test and verify the non arc tracking and actual welding tracking of V-groove,single V-groove and I-groove butt weld components.The test results show that when the speed is 80cm/min,the tracking accuracy of aluminum alloy components with straight and curved weld can reach ±0.7mm and when the speed is 20cm/min,the tracking accuracy can reach ±0.4mm,which can meet the requirements of auto welding seam tracking. |
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