基于BP神经网络补偿卡尔曼滤波的激光-MIG复合焊缝熔宽在线检测  

Online Weld Width Detection of Laser-MIG Hybrid Welding Based on Kalman Filter Algorithm Compensated by BP Neural Network

作　　者：刘秀航 黄宇辉 张艳喜[1] 高向东[1] Liu Xiuhang;Huang Yuhui;Zhang Yanxi;Gao Xiangdong(Guangdong Provincial Welding Engineering Technology Research Center,Guangdong University of Technology,Guangzhou 510006,Guangdong,China)

机构地区：[1]广东工业大学广东省焊接工程技术研究中心,中国广州510006

出　　处：《中国激光》2022年第16期100-106,共7页Chinese Journal of Lasers

基　　金：广州市科技计划(202002020068,202002030147)。

摘　　要：焊缝熔宽是评估焊接质量和焊接稳定性的重要指标。针对强噪声环境下的激光-MIG复合焊接过程,本文研究了基于反向传播(BP)神经网络补偿色噪声卡尔曼滤波算法的熔宽检测方法。首先建立激光-MIG复合焊缝熔宽检测系统的状态方程和测量方程,通过视觉传感和色噪声卡尔曼滤波算法对焊缝熔宽进行估计;然后采用高精度激光扫描仪对焊缝的三维轮廓进行扫描,根据二阶差分法获得焊缝轮廓宽度,并将其作为熔宽的真实值;接着将卡尔曼滤波增益、新息值和预测值与卡尔曼滤波最优估计之差作为输入,利用BP神经网络对熔宽的卡尔曼滤波最优估计进行补偿。结果表明:BP神经网络补偿测量色噪声卡尔曼滤波算法能够有效降低焊缝熔宽检测的误差。与单独使用卡尔曼滤波算法相比,BP神经网络补偿卡尔曼滤波算法具有更好的非线性映射能力,可以提高卡尔曼滤波焊缝熔宽检测的准确度。Objective For decades,laser-are hybrid welding has gained remarkable attention as a reliable technology for material joint processing.It has been applied to various fields of the manufacturing industry due to several characteristics,such as deep penetration,high welding speed,and high-quality shaping.In the laser-arc hybrid welding process,the change in parameters may deeply influence the weld formation.To detect weld defects or monitor the quality of welding beads,several scholars have studied and explored the correlation between welding features and quality.Thus,numerous studies have investigated the relationship between metallic vapor features and molten pools.Among these features,weld width is a crucial evaluation criterion for welding quality and stability.It is commonly acknowledged that high-speed cameras are widely used to capture all types of features during laser-arc hybrid welding.This study presents an online detection of weld width based on the Kalman filter algorithm(BP-KF),which is compensated by a back-propagation neural network and can detect accurate weld width in a strong noise laser-MIG hybrid-welding environment.We assume that our innovative approach can provide the basis for online detection of a laser-arc hybrid-welding process.Methods The laser-MIG hybrid-welding detection system was established using a high-speed camera,arc welding machine,power fiber laser,and an image processing personal computer.During laser-arc hybrid welding,a high-speed camera was used to collect an image of a molten pool outline.Note that image processing is crucial for obtaining the width of the molten pool from an image.First,a molten pool area was defined and extracted by processing the sequential images emerging from the camera.Next,the end of the molten pool was identified by the difference of gray value in the image,and the keyhole was used to mark the position of the molten pool.After segmenting the image using a watershed algorithm,the width of the molten pool can be measured using the conversion from the p

关 键 词：激光技术 神经网络 激光-MIG复合焊接 熔宽预测 强噪声 卡尔曼滤波 

分 类 号：TG409[金属学及工艺—焊接]