| In recent years,with the coordinated development of various technologies such as robotics and information technology,manual welding processing methods with many disadvantages are gradually no longer suitable for large-scale container welding manufacturing occasions.Instead,the automatic welding processing system with welding automation special equipment and welding robots becomes a mainstream model.Special welding automation equipment is mainly used in the welding of corrugated plates on both sides of the container(the welding length of corrugated plate usually exceeds the working space of industrial robots),and its trajectory planning algorithm is the core technology in the control system of welding automation special equipment.Welding robots are mainly used for welding parts such as lock seats and hinges on containers,however,due to the current intelligent level of robots,most robots still stay in the fixed mode of "manual teaching-memory reproduction" while performing welding operations.Due to the influence of parts clamping error and other factors,there is inevitably a deviation between the actual trajectory of the welding seam and the teaching trajectory.The welding robot in this working mode cannot make corresponding corrective actions according to the change of the trajectory,so that the welding quality and precision of the workpiece is affected.Based on the above application background,this thesis mainly studies the welding trajectory planning and welding trajectory correction of the container automated welding processing system.This research was funded by the Southern CIMC Eastern Logistics Equipment Manufacturing Co.,Ltd.(project of automatic assembly and welding robot application for container back-end production lines).The main content of the paper includes:(1)Based on the analysis of the overall framework,working mechanism and design requirements of the container automated welding processing system,a special welding automation equipment control system based on the Ether CAT real-time bus protocol was developed.(2)In view of the characteristic that the welding trajectory of corrugated plate was composed of a space straight line and a space arc forming a complex curve,the S-shapedspeed planning curve was used to design the space straight line trajectory planning algorithm and the space arc trajectory planning algorithm to realize the uniform,steady and precise control for welding motion trajectory.(3)On the basis of image preprocessing,filtering out noise,and enhancing target information,the characteristics of the welding workpiece were analyzed and extracted,combined with these characteristics,a template matching method based on gray value,shape,and correlation was designed to locate the welding workpiece.Based on the translation matrix and rotation matrix of the pixel,the actual trajectory was calculated according to the offset and rotation angle detected by template matching,thereby correcting the welding trajectory.(4)In order to verify the feasibility of the proposed algorithm,two experimental platforms were constructed to verify the welding trajectory planning algorithm and welding trajectory correction algorithm designed in this paper.Experimental platform 1 was an experimental platform for trajectory planning of special equipment for corrugated plate welding,which was composed of lead screws,servo controllers,servo motors,and industrial computers.The software platform was developed based on the integrated environment of Microsoft Visual Studio 2015,and the control system was constructed based on the Ethercat real-time control bus,which integrates linear and circular interpolation algorithms.The selected groups of motion trajectories were texted to verify the accuracy of the interpolation trajectory and the stationarity of motion.Experimental platform 2 was an experimental platform for workpiece welding trajectory correction,which was composed of an ABB welding robot,an industrial computer,a Basler industrial camera and a light source.The software platform was developed based on the HALCON machine vision integrated development environment,which integrates image preprocessing,template matching,and welding seam trajectory correction algorithms,and conducts research and analysis of welding trajectory correction methods for locks and hinges of two major parts on the container,and the validity of algorithm were verified by experimental results.The final experimental results show that the research results of the trajectory planning algorithm and the correction method of workpiece welding trajectory in this thesis meet the actual production requirements. |
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