Bicycle Tripod Weld Seam Offset Measurement System Based On Image Processing

The paper takes the robot automatic welding bicycle tripod as the research object to improve the success rate of robot welding.Aiming at the problem of low welding pass rate caused by artificially placed workpiece error before welding,the paper designs and studies the weld offset measurement system based on the knowledge of image processing.The system can guide the worker to adjust the workpiece with large error to the correct position according to the measured weld offset,and improve the qualification rate of the robot welding.Firstly,according to the on-site environment of the welding factory,a complete welding offset measurement hardware platform was designed,including visual sensing system,light source,industrial computer,control switch and markers.It not only provides a good operating platform for software systems,but also facilitates worker operations and stable operation in a complex workshop environment.Based on the MFC environment,a software client is developed.The software is divided into camera control module,offset reminder module,post-weld qualification judgment module and query module.The corresponding image information and data information can be clearly displayed,which is convenient for manually adjusting the workpiece placement according to the above information,and storing relevant data of the welding process to facilitate subsequent research.The software has designed a better human-computer interaction interface.For the acquisition of weld seam information,the image is pre-processed to enhance the characteristics of the weld seam in the weld picture.Using the edge detection method based on Otsu and Canny operator,not only the weld edge is accurately found,but also the influence of the illumination change of the shop on the edge of the weld is overcome,and the adaptability of the weld information acquisition is improved.For the calculation of the weld seam offset distance,the identification point is first identified,and the welding image is converted from the oblique angle to the vertical angle according to the identified marker point and the ratio of the pixel distance to the actual distance is calculated.Then,using the straight line fitting method,the intermediate weld fitting straight line is obtained.Finally,the measured weld seam offset line is used to measure the weld seam offset distance.At the end of the paper,the designed weld offset measurement system was tested,and the actual welding site workpiece was tested.According to the weld offset distance information calculated by the system,the worker adjusted the position of the workpiece twice,and the welding qualification rate of the robot was greatly improved.At the same time,the software and hardware are perfectly compatible,the system is easy to operate,and it can run effectively and stably for a long time.It shows that the system can not only improve the qualified rate of robot welding,but also realize the application in industrial field.