Research On TIG Welding Seam Sensing And Tracking Technology Based On Transverse Alternating Magnetic Ar

Tungsten Inert Gas Welding(TIG)has the advantages of high reliability,good Welding quality and stable arc,and is widely used in the Welding of high-precision and small-size workpiece.In order to make up for the shortcomings of slow cladding speed and low production efficiency of TIG welding,welding seam tracking technology is very necessary.At present,the contact sensor used in weld seam tracking has low precision and large mechanical wear.The cost of visual sensor is high and the data processing process is complicated.Arc sensors are widely used in industry based on their strong ability to resist arc light and soot,high precision and low cost.However,the TIG tungsten electrode is close to the workpiece,and it is easy to interfere with the workpiece by using swing and rotating arc sensors.Therefore,this paper develops a set of magnetically controlled arc sensors for TIG welding seam tracking through the research of magnetically controlled arc technology,and realizes the arc reciprocating swing by externally applying transverse alternating magnetic field.Thus,problems such as interference collision and tungsten electrode burning are avoided effectively.First to design the structure of magnetic control arc sensor,a mathematic model of the magnetic control arc swing,with COMSOL for platform,on the device of horizontal magnetic field finite element analysis,found that the formation of magnetic circuit and increase the excitation current can effectively improve the magnetic induction intensity of arc starting position,and through to the striking position of the magnetic induction intensity measurement,verify the validity of the model;The device is applied to actual welding to observe the arc swing shape under different current parameters,which lays a foundation for follow-up welding seam tracking.Based on the above research,the hardware circuit of the weld tracking system was built,and the subprograms such as remote control,motor drive and 485 communication with STM32 as the core MCU were designed.For large problems arc pressure signal to noise,using the LMS adaptive filtering algorithm and the extended kalman filtering algorithm for original signal separately carried on the processing of arc voltage,found that the extended kalman filtering algorithm can retain maximum signal characteristics,get more smooth signal curve,convenient for subsequent analysis of characteristics of arc voltage signal.The relationship between the arc pressure change value and the height change value is obtained through the downhill experiment,and the high and low direction welding seam identification is realized.The linear relationship between the integral difference and the deviation Dev was obtained by left-right interval integration method through the left-right swing experiment,and the left-right direction weld identification was realized.The arc voltage acquisition subroutine and tracking control algorithm are designed.In the direction of height,outfield points are removed from the calculated results of the tracker,so that the height tracking accuracy of the inclined plate is controlled within 0.13 mm,and the height tracking accuracy of the S-shaped plate is controlled within 0.28 mm.In the left and right direction,the parameter fuzzy self-tuning PID control algorithm is used to optimize the integral difference,so that the left and right tracking accuracy in fillet weld is controlled within 0.25 mm.The ideal and stable tracking effect is obtained in the experiment.