The Research On Machine Vision Applied In Welding Robot

With the rapid development of computer science(large scale integrated circuit, application software and computing method),imagine processing, optoelectric technology and pattern recognition technology, the research and application of machine vision have been getting more and more concern and many primary achievements have been done. In this thesis,the welding robot in Huda Sanjia Mould corporation is taken as study object, welding automation is taken as studying purpose and automatic seam tracking in the help of machine vision is attached great importance. This thesis presents a novel method for vision tracking based on the finished electrical arc tracking.This method with simple structure can achieve high precision and intelligence.First, this thesis introduces the system structure of robot for welding, and designs the communication structure of serial ports for both welding robot and teaching box. In obtainment of image for welding seam, we obtain image for welding seam of the automobile mantle mould by line structure-light sensor in the help of structure-light triangulation principle, and according to vidicon imaging principle this thesis establishes the tracking model of the line structure-light sensor and its calibration technology.In the process of image for welding seam structure-light,this thesis presents a method for quick process and recognition of image. In filtering methods for image,we use LOG and median filter to improve real time of the system and presents a improvement method for rapid median filter.In edge detection and extracting straight lines, Roberts and Hough are taken.After extracting straight lines,we can obtain the center coordinate of welding seam easily.In the analysis of the whole process control system,fuzzy control is introduced in automatic seam tracking ,since welding process is a process with high nonlionliar, strong coupling and time-variation.This thesis presents a Fuzzy-P controller for vision tracking and finally the errors and its reason are analyzed through the experiment of the whole system.