基于电弧传感和位置前馈的机器人焊缝跟踪算法

Algorithm of weld tracking for robot based on arc sensing and position feed-forward

关节机器人具有自动化程度高、运动精准等优点,被广泛应用于电弧焊接领域。但是,由于被焊接工件存在加工、装配以及安装定位误差。所以,在焊接质量要求较高、且被焊接工件一致性不好的情况下需要配套焊缝跟踪系统方能实现高质量的焊接作业。电弧传感作为焊缝跟踪的传感方式具有系统结构简单、传感位置与焊接位置重合等优点,但也具有信噪比小、精度差、跟踪参数调整困难等缺点。本研究利用电弧传感的优点,结合机器人焊接对焊缝形状位置的预知特性,利用电弧传感作为基础偏差传感器,机器人控制器根据电弧传感器测量的偏差信号,对当前焊接点进行调整的同时,还对焊缝曲线的空间方程进行调整,从而实现对焊缝曲线上未焊接点的偏移量进行预判,实现焊缝偏差的前馈调整。

Joint robot is widely used in arc welding because of its high automation and precise motion etc. However,due to the processing, assembly and installation positioning errors of the welded workpiece, it needs tracking system to achieve to the high quality welding. As a sensing method of weld tracking, arc sensor has the advantages of simple system structure, coincidence of sensing position and welding position, and the disadvantages of low signal-to-noise ratio, poor accuracy, and difficult to adjust tracking parameters and so on. The advantages of arc sensor was used in this study, combining prediction of weld shape and position in robot welding, taking arc sensor as basic deviation sensor, and the robot controller adjusted the current welding point according to the deviation signal measured by the arc sensor, and at the same time adjusted the spatial equation of the weld curve, so as to realize the prediction of the deviation of the unwelded points on the weld curve and the feed-forward adjustment of the weld deviation.