Vision-based Weld Seam Feature Recognition And Automatic Tracking Research

Weld seam automatic tracking technology is the key and foundation to realize the welding automation.Welding sensing technology is the basic condition of weld automatic tracking,compared to the arc?contact?ultrasonic sensing technology,the structure-light vision sensing with access to large amount of information,high sensitivity and precision,strong ability to resist the interference of strong electric field and magnetic field,and is applicable to various forms of weld powerful advantage,become the heated focus of seam tracking researchers.This article first expounds the key role of weld automatic tracking,analyzes the principle,advantages and disadvantages of different sensors in welding applications,comprehensive visual weld automatic tracking technology research and application present situation,combining the characteristics of virtual instrument and application,design the camera as the sensor,as an auxiliary line laser light source,NI system for controller,walking mechanism for structure light vision weld automatic tracking system of the actuator.Among them,the high-speed camera and a laser line packaging together to form the visual part;NI system consists of image acquisition card,data acquisition card and the LabVIEW software,etc.;Walking mechanism by the host,control in the servo system and some transmission mechanism.Welding workpiece fixed placed in travel mechanism placed stage,the laser line is projected onto the weld of the workpiece,get the weld image through the visual system,and then transfer the image to the NI host.The image is processed on the LabVIEW software platform:gray scale conversion,median filtering,binarization,removal of isolated points.According to the template matching method to identify the weld feature,and then calculate the location of the weld and the location of the welding gun coordinate deviation,The deviation information is transmitted as a control signal from the NI system to the controller of the travel mechanism.The controller adjusts the torch position in real time according to the received control command,and finally realizes the real-time tracking of the weld.After the system is completed,firstly,use the system to do the real-time tracking verification test,using laser simulation welding torch,looking for some laser tracking path,the results show that the laser path is basically maintained in the weld center position.With this verification foundation,and the use of micro-plasma arc welding torch for the system of the weld tracking welding experiments,The results show that the system can clearly identify the weld and complete the automatic tracking welding during the welding process.