• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2019, Vol. 55 ›› Issue (17): 14-21.doi: 10.3901/JME.2019.17.014

• 特邀专栏:焊接机器人 • 上一篇    

基于焊缝熔透检测的机器人深熔K-TIG焊接系统

张抱日1,2, 顾盛勇1,2, 石永华1,2   

  1. 1. 华南理工大学机械与汽车工程学院 广州 510641;
    2. 广东省特种焊接技术与装备工程技术研究中心 广州 510640
  • 收稿日期:2018-09-23 修回日期:2019-03-03 发布日期:2020-01-07
  • 通讯作者: 石永华(通信作者),男,1973年出生,博士,教授,博士研究生导师。主要研究方向为机器人焊接、水下焊接和高效深熔焊接技术。E-mail:yhuashi@scut.edu.cn
  • 作者简介:张抱日,男,1994年出生,博士研究生。主要研究方向为焊接自动化、焊缝跟踪、智能视觉检测。E-mail:mebrzhang@mail.scut.edu.cn
  • 基金资助:
    广东省科技计划(2015B010919005)、国家自然科学基金(51374111)和广州市科技规划(201604046026)资助项目。

Robotic Deep Penetration K-TIG Welding System Based on Weld Penetration Detection

ZHANG Baori1,2, GU Shengyong1,2, SHI Yonghua1,2   

  1. 1. School of Mechanical Engineering, South China University of Technology, Guangzhou 510641;
    2. Guangdong Provincial Engineering Research Center for Special Welding Technology and Equipment, Guangzhou 510640
  • Received:2018-09-23 Revised:2019-03-03 Published:2020-01-07

摘要: 开发了一套基于熔透检测的机器人深熔锁孔非熔化极惰性气体保护焊接(Keyhole tungsten inert gas,K-TIG)系统,实现焊接高度(Contact tip-to-work distance,CTWD)自动调节与熔透状态的在线检测。利用电弧电压与焊接高度的对应关系,通过弧压传感器实时采集电弧电压信号并换算成焊接高度值,然后将实际高度值与预设高度值之间的差值经由过程控制对象连接与嵌入协议(OLE for process control,OPC)通信系统反馈给机器人控制系统,从而控制机器人实现焊接高度的自动调节。同时,构建了熔透检测系统,使用电荷耦合器件(Charge coupled device,CCD)相机采集熔池与小孔图像,从中提取熔池-小孔特征,并建立熔池-小孔特征与熔透状态之间的相关性,在此基础上建立识别熔透状态的反向传播(Back propagation,BP)神经网络,实现不同焊接高度下熔透状态的间接检测,最后根据该检测结果得到最佳的焊接高度。经过试验验证,整个系统可靠稳定,能准确检测焊缝的熔透程度,并实现焊接高度自动调节,从而提高了焊接质量。

关键词: 机器人焊接, K-TIG焊, 焊接高度控制, 熔透检测

Abstract: A deep penetration K-TIG welding system based on penetration detection is developed to realize the automatic adjustment of the contact tip-to-work distance(CTWD) and the on-line detection of the penetration state. Based on the corresponding relationship between the arc voltage and the CTWD, the arc voltage signal collected by the arc voltage sensor in real time is converted into the welding height value. Then, the difference between the actual height value and the pre-set height value is fed back to the robot control system through the OLE for process control(OPC) communication system, so that the robot can realize the automatic adjustment of the welding height. Besides, a penetration detection system is constructed. A charge coupled device(CCD) camera is used to collect the images of the molten pool and key-hole, whose characteristics are extracted. Then the correlation between the pool-hole characteristics and the penetration state is established. Based on this, a back propagation(BP) neural network for identifying the penetration state is established to realize the indirect detection of the penetration state under different welding heights, and finally the optimal welding height is obtained according to the detection result. After testing, the whole system is proved to be reliable and stable, and can accurately detect the penetration state of the weld, realizing the automatic adjustment of the welding height which improves the welding quality.

Key words: robotic welding, K-TIG welding, welding height control, online welding penetration detection

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