The Welding Seam Automatic Identifying And Tracking

Pressure vessels are main petrochemicals in petrochemical equipment manufacturing. Researchers attach importance to welding technology as a key working procedure during the course of pressure vessels manufacture that influences directly quality of them. With the development of the automation in the welding, the application of the welding seam tracking system becomes more necessary and more important, and the automatic real-time seam tracking system in the welding course has been recognized as an important problem in our country and in other foreign countries. At present, there are many methods on automatic identification and tracking of welding seams but a few of them can be put into action in the real environment.In this paper, I describe the present situation of welding seams' automatic identification and tracking technology. A welding seam tracking system controlled by SCM is designed with a CCD sensor and light apparatus of diode with GaAs as close infrared ray source of narrow band and a correcting an error and adjusting set with a perpendicular sliding track device moving to horizontal and vertical directions driven by two electric machineries. The system employs close infrared ray source of narrow band and forms some modal light strap by special design. This makes linear point lattice CCD obtaining two-dimensional tracking information at the same time and greatly lowers the requirement to environment conditions and improves the interference-free quality. After tracking information is magnified andsampled and transformed from A/D these put into computer. Horizontal errors between welding fire's position and welding track's center position and vertical errors relative to welding work piece obtained by computation and processes drive the executing electrical machineries. Having two freedoms, horizontal and vertical, the executing mechanism can fulfill the horizontal and vertical tracking of weld position.We have a test to use the tracking system. Approved by the testing consequence, this automatic seam tracking system can effectively track the joint and correctly adjust the height of the welding torch by controlling the welding head on the conditions of different welding speeds and error angles. The horizontal precision of the seam tracking was +0.4mm, and the vertical precision of the weld torch controlling was +1.0mm. So this system developed and designed in this paper is an automatic seam tracking system being implemented and utilized in the future.