The Design Of Weld Visual Tracking System

With the development of modern welding technology, the welding automation upgrades rapidly. In order to ensure the accuracy of welding process and improve the welding quality of workpiece, new requirements on automation and intelligent welding is needed. The emergence and widespread application of the robot technology, electronic technology, computer network technology, and the successful application of fuzzy mathematics and neural network in the field of welding, provides the possibility to realize seam tracking technology.The seam tracking system is designed for straight flat butt weld. By area CCD camera collection of industrial welding torch near the image, and (transmit the image to)the image is transmission to the touch Industrial Panel PC. Through the C++ program development, industrial computer for proceeds with the collected image two values, Adding window, Hough transform and least squares fitting a straight line of image processing method, and finally determine the central position of welding seam. According to the distance from the center of welding torch and camera as well as welding speed to determine the image processing delay time to ensure the realization of "the real welding seam tracking". Detected by delay-time records for statistical linear position, linear position detector is fixed so that the final size of the deviation calculate in real time and then control actuator to achieve the purpose of the weld. Considering a long straight butt weld and in order to improve the production efficiency, two identical sets of tracking device has been designed and controlled to singly or simultaneously weld in one or both ends welders. It can greatly shorten welding cycle and enhance the flexibility of the system.In the design concept of industrial plate computer as the only core to control, this paper designs in several aspects in the seam tracking system of mechanical structure, electrical system, image processing, and executing mechanism control. In the mechanical design, use a LED lamp set in the end of the CCD camera external as the light source of image acquisition. In order to avoid arc light interference and splash on the industrial camera disturbance and damage, the protective device was designed. In the design of electrical system, this paper completed the design of peripheral circuit and expansion of PCI port control circuit. In image processing, this paper uses Single channel processing, two values, Adding window, Hough transform and least squares fitting a straight line to process the image of weld nearby. And extract the weld path to calculate the position deviation between torch and weld center line. Walking and tracking device in the actuating mechanism adopts the mode of RS485 serial driver to control stepper motor. Through the integrated "soft" button on the industrial computer that program have prepared and designed to manual or automatic control.Through the system design of mechanical structure, electrical system, and programming work, this paper has realized the experimental platform’s built of seam tracking system with industrial flat computer as the core, and a high automated to the welding of carbon steel sheet and aluminums sheet butt straight weld.