Robust sensing of arc length

Pengjiu Li, Yu Ming Zhang

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


During arc welding, the arc heats and melts the work-piece as heat flux. When the welding current is given, the distribution and the intensity of the heat flux are determined by the length of the arc. The measurement and control of the arc length are fundamental in robotic and automated welding operations. Length of welding arc determines the distribution of the arc energy and thus the heat input and width of the weld. This work aims at improving the measurement accuracy of arc length using the spectrum of arc light at a particular wavelength during gas tungsten arc welding (GTAW) with argon shield. To this end, effects of welding parameters on spectral distributions were studied. To verify the effects of base metal and arc length, the arc column was also sampled horizontally as layers for spectral analysis. Results show that spectral lines of argon atoms are determined by arc length, independent of welding parameters other than the current. Based on these findings, a compact arc light sensor has been designed to measure the arc length with adequate accuracy. A closed-loop arc length control system has been developed with the proposed sensor.

Original languageEnglish
Pages (from-to)697-704
Number of pages8
JournalIEEE Transactions on Instrumentation and Measurement
Issue number3
StatePublished - Jun 2001

Bibliographical note

Funding Information:
Manuscript received April 15, 2000; revised February 16, 2001. This work was supported in part by the National Science Foundation under Grant DMI-9812981 and the Center for Robotics and Manufacturing Systems, University of Kentucky.


  • Arc
  • Manufacturing
  • Radiation
  • Spectrum
  • Welding

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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