Research On System Of Seam Detection And Weld Parameter Control In Automatic Pipeline Welding

With the development of petroleum gas and petrochemical industry, the pipeline is built in the peak period. Welding seam position and weld parameter are important factors to influence pipeline quality, so the detection and control technology involved is concerned much and studied much. According to the characteristic and deficiency of the existing automatic pipeline welding technology, the dissertation introduces effective welding seam detection and weld parameter control system, which can real-time adjust the position and control the orbit of welding gun accurately. As the result, high quality seam is obtained. Based on the CCD optical sensing technology, the welding seam detection system can detect out the seam edge fast and accurately by means of algorithms such as median filter, image segmentation, contour tracking and Hough transformation. Then the offset parameter can be calculated and transmitted to the control system by certaininterface card. The system has such characteristic as real-time, non-contact. Experiments show that this system can work steadily and can obtain accurate detection results.Weld parameter is used to regulate the orbit of welding gun. Based on such technology as serial communication, angle sensing, and motor control, the weld parameter system can realize parameter transmission, pipeline positioning, parameter switch, and welding gun driving. The swing speed of welding gun can be changed from 30mm/s to 50mm/s. The system shows such performances as easy to operate, steady running status, good anti-jamming ability, which fit finely the welding requirements. The major innovations achieved in the dissertation are as follows:Certain kinds of algorithms are adopted according to the characteristic of welding seam image. The seam detection system realizes real-time image process with these algorithms. Serial communication and angle sensing technology is used in weld parameter control system with which transmission and switch of parameter can be realized.Welding gun can run accurately and reliably in term of weld parameter with special motor control card and control software.