Weilding Path Recognition And Trajectory Planning Based On Vision

China's manufacturing industry will be in the direction of automation and intelligence in the future ten years. Welding technology takes an important part in modern manufacturing industry. So automatic and intelligent welding process is the direction of welding technology in the future. At present, most of the welding robots are conducted by the way of teaching and reappearance. When external environment changed, robots must be conducted again. So the production efficiency is low and the level of welding automation can not meet the requirement. The visual technology is applied to welding. Weld path is identified by the visual sensor. Then the weld path for trajectory planning is implemented. To some extent, all these can improve the automation of welding robot."Eye-to-hand" relationship was formed with the CMOS camera and the six degrees of freedom robot. Experimental platform was set up for the acquisition of images of plane curve welding line. The model of visual identification system was built. The model and calibration method of camera and the hand-eye calibration principle were introduced. The camera calibration and the hand-eye calibration were experimented with a target of planar checkerboard, obtaining the inside and outside parameters of the camera and the hand-eye relation matrix. The image preprocessing and feature information extraction were conducted with the collected plane curve weld. A method of image binary-coding was proposed based on the local threshold segmentation. And the coordinates of the welding center line were obtained by using the method of average. Finally, after fitting, the equation of the weld path center line in the image coordinate system was obtained. And after coordinate transformation,its equation in the world coordinate system was got. A method of establishing characteristic coordinate system of weld was given and that of the plane curve weld was also built. The kinematic model of six degrees of freedom robot was presented and its forward kinematic equations and inverse kinematic equations were analyzed.The equal interval line-approaching method was proposed and the plane curve weld path trajectory was generated by this method and its kinematical simulation was carried on. The system software of welding path recognition and trajectory planning based on vision was developed, about which the weld test was conducted. And errors about the test results were analyzed.