设计了一套由三轴直角坐标机器人、线激光传感器和工业计算机组成的焊缝跟踪系统。研究了该系统所涉及的测量原理、特征点测量方法和基于模糊自适应的控制方法。通过高斯核相关算法(KCF)在焊接过程中实时检测焊缝特征点, 并根据测量原理计算获得特征点相对于相机坐标系的三维坐标值。设计了一种自适应模糊控制器, 通过自适应模糊控制器计算坐标的偏差值和偏差变化率得到焊枪末端运动轨迹的控制量, 同时对模糊控制器的输入输出论域、模糊规则和隶属函数进行实时动态更新。实施了焊缝跟踪实验。结果显示: 采用最大焊接电流为350 A的惰性气体保护焊(MIG), 在强烈弧光和飞溅的干扰下, 该系统能实时跟踪焊接工件, 跟踪精度为0.325 3 mm, 传感器测量频率为20 Hz。焊接过程中焊枪末端运行平稳, 焊缝轨迹跟踪准确, 且抗干扰能力, 能满足焊接应用要求。

A real-time seam tracking system consisting of a three-axis cartesian robot, a line laser sensor, and an industrial computer was designed and its measuring principle, feature point measuring method and adaptive fuzzy control were researched. The Guassian Kernelized Correlation Filter(KCF) was adopted to detect the weld feature points in real time in welding process and 3D coordinate values of industrial camera were obtained by 2D pixel coordinate values based on measuring principle. A adaptive fuzzy controller was designed. On the basis of the adaptive fuzzy controller, the deviation values and deviation rate of the coordinate system were calculated to obtain the control values of movement trajectory for torch end. Meanwhile, the inputs and outputs on the domain and fuzzy membership functions of fuzzy controller were updated in real time. The experiments on seam tracking were performed. The experimental results show that the system realizes accurate seam tracking in real-time under the conditions of strong arc light and splash when the largest welding current is 350 A in Metal-Inert Gas Welding (MIG). The tracking error is less than 0.325 3 mm and the metrical frequency of sensor is up to 20 Hz. In welding processing, the end of the torch runs smooth the weld trajectory can be tracked accurately and the system shows strong anti-interference ability, so it meets the requirements of welding applications.