Research On Attitude Adjustment And Positioning System Of Welding Gun In Ultra-narrow Gap Welding Of Rails

Rail welding has become an essential process in the construction and development of high-speed railway,whose welding quality directly affects the service life of the rail,the smooth and safety of the train,the passengers comfort,and so on.The ultra-narrow gap welding constrained by the flux sheet requires less heat,which can meet the low cost welding requirements of saving energy and saving material.The affected zone by heat is narrow during the welding process,and the processing efficiency is high.Therefore,the application of ultra narrow gap welding to seamless welding of railway construction is of great significance.However,in the ultra narrow gap arc welding,if welding wire offset the center line of the straight groove,the quality of the welding will be affected.In this situation,it is of great significance to improve the welding quality by adjusting the welding gun to the center line of the straight groove.With the rise of the fourth industrial revolution led by the Internet,intelligence and integration,the proposal of the intelligent manufacture strategy of German Industry 4.0,Made in China 2025,and integration of informatization and industrialization,provides a thinking for the intelligent adjustment and positioning of the welding gun in the ultra-narrow gap welding.Therefore,in this thesis,a welding gun intelligent adjustment and positioning system is designed,which combines the visual sensing system with the motion control syste.The designed system can automatically adjust the position to the straight groove center line,and improve the welding quality and welding automation.The main work is as follows:(1)Under the background of the ultra-narrow gap welding,the experimental platform of the welding gun attitude adjustment and positioning system is set up from the geometric structure characteristics of the rail and the structure characteristics of the special plate type welding gun,which mainly includes the walking mechanism of the welding gun and the visual sensing system.(2)The image recognition algorithm based on laser vision for the extraction of the center line and the position prediction of welding torch is studied in ultra-narrow gap rail welding.In the environment of Visual Studio 2010,the image processing function library of the Open CV is configured to process and analyze the captured image of the “#”.The welding gun attitude is predicted and extracted.(3)The four-degrees of freedom mechanical arm are controlled by the Advantech PCI-1245 motion control card,the movement control of the gun walking is realized,and the adjustment and positioning of the welding torch attitude is completed.The man-machine interface of image recognition system and motion control system is built by MFC.The operation is intuitive and convenient,and it also exhibits high stability.