Roundness Measurement with Software Datum Method —Comparison between Mixed Method and 3-point Method by Computer Simulations—

Wei Gao, Tadatoshi Nomura, Satoshi Kiyono

Research output: Contribution to journalArticlepeer-review


This paper presents a new software datum method for roundness measurement, which is called the mixed method. In this method, 2-point displacement and a tangent angle of either point are simultaneously measured using 2 probes. A differential operation of them cancels the vibrational eccentric motions due to the rotational error and a deconvoluting operation of the differential data gives the correct roundness. In this paper, the mixed method is compared with the 3-point method, the traditional method of roundness measurement, by analyzing their transfer functions, resolutions and sensitivities to some factors of errors, such as the drift, positioning error, etc. Differing from the 3-point method, the mixed method can measure high frequency components regardless of the probe distance. The mixed method can also improve its resolution in the whole frequency domain by widening the probe distance. The effectiveness and limitations of the mixed method for roundness measurement have been verified by simulations and some important information for the sensor-design of roundness measurement have been gotten by theoretical analyses.

Original languageEnglish
Pages (from-to)106-110
Number of pages5
JournalJournal of the Japan Society for Precision Engineering
Issue number1
Publication statusPublished - 1994
Externally publishedYes


  • 3-point method
  • metrology
  • mixed method
  • on-machine measurement
  • resolution
  • roundness
  • roundness measurement
  • software datum
  • transfer function

ASJC Scopus subject areas

  • Mechanical Engineering


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