Research On Automatic Tracking System Of Steel Tube Weld Seam Of Oil Well Heating Cable

The length of steel armor of electric heater in Oilfield studied in this paper is several kilometers.The longitudinal seam of electric heater is welded by TIG welding,and the continuous welding time can reach several days or even more.Because of the fluctuation of equipment mould and the error of steel strip,it is easy to cause the deviation of the longitudinal seam position.At present,the welding torch can only be adjusted manually,so the quality is difficult to guarantee and the labor intensity is high.In order to solve the above problems,a camera-based seam tracking system is designed.The deviation information is given by image processing method and transmitted to the lower computer,which corrects the deviation of the torch,so as to achieve the purpose of automatic seam tracking.HD1080P camera is used as the vision sensor in the project,equipped with 5-50mm long focus lens,which has strong anti-arc and anti-smoke interference ability,and ensures that clear images can be obtained in a suitable range.Based on the research of image processing algorithm,this paper uses Visual Basic 6.0 to design image processing program.In order to facilitate the research,the program can open the image,video and real-time video acquisition,with softening,sharpening,binarization,edge detection and other algorithms,at the same time with the basic algorithm combination function,so that the research efficiency is greatly improved.The recognition mode is determined through research:the deviation between the center of the torch and the center of the weld is used to detect the deviation of the weld.The image processing steps include image preprocessing,binarization,edge extraction and so on.According to the characteristics of the weld,a red light projection method is proposed to detect the position of the weld quickly,which improves the efficiency of the algorithm.The program also uses the method of reducing the processing area to reduce the processing capacity and greatly improve the processing speed.The final overall operation time is less than 200 ms,which can meet the needs of seam tracking.The interface of the program is friendly,the scope of processing can be saved conveniently by clicking on the selected area with the mouse and cooperating with the background notebook.In the program,the identified deviation is filtered by software,which makes the data stable and improves the anti-interference ability.In the design,the communication interface between VB and PLC is realized by means of MSComm communication control in VB.Modbus communication protocol is widely used in communication mode.Bit,double-byte and multi-byte transmission is completed,which meets the needs of data exchange and motor control.Welding process test is carried out by using the automatic tracking system of steel armour welding seam of oil well heating cable,and the longitudinal seam of steel armour of cable is inspected to verify the usage of the automatic tracking system of welding seam.The experiment proves that the automatic seam tracking system basically meets the needs of production and can greatly reduce the labor intensity of workers.The proposed method of red-light projection can accurately lock the center position of the weld.The designed algorithm can give the deviation of the weld seam efficiently and steadily,and achieve the desired goal.The software has strong practicability and can provide reference and help for image processing algorithm research in other fields.