title: A Precise Visual Method for Narrow Butt Detection in Specular Reflection Workpiece Welding.
abstract: During the complex path workpiece welding, it is important to keep the welding torch aligned with the groove center using a visual seam detection method, so that the deviation between the torch and the groove can be corrected automatically. However, when detecting the narrow butt of a specular reflection workpiece, the existing methods may fail because of the extremely small groove width and the poor imaging quality. This paper proposes a novel detection method to solve these issues. We design a uniform surface light source to get high signal-to-noise ratio images against the specular reflection effect, and a double-line laser light source is used to obtain the workpiece surface equation relative to the torch. Two light sources are switched on alternately and the camera is synchronized to capture images when each light is on; then the position and pose between the torch and the groove can be obtained nearly at the same time. Experimental results show that our method can detect the groove effectively and efficiently during the welding process. The image resolution is 12.5 μm and the processing time is less than 10 ms per frame. This indicates our method can be applied to real-time narrow butt detection during high-speed welding process.
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. zengjl12@mails.tsinghua.edu.cn.
authors.forename: Jinle
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. bhchang@tsinghua.edu.cn.
authors.forename: Baohua
authors.initials: B
authors.lastname: Chang
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. dudong@tsinghua.edu.cn.
authors.forename: Dong
authors.initials: D
authors.lastname: Du
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. hongyuxiang@tsinghua.edu.cn.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. changsh15@mails.tsinghua.edu.cn.
authors.forename: Shuhe
authors.initials: S
authors.lastname: Chang
authors.affiliation: Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanial Engineering, Tsinghua University, Beijing 100084, China. zouyr@tsinghua-tj.org.
authors.forename: Yirong
authors.initials: Y
authors.lastname: Zou
keywords: narrow butt; seam tracking; specular reflection workpiece welding; visual detection; welding process control