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Proceedings Paper

Uncertainty calculation of Ra based on information entropy principle
Author(s): Yan-ru Zhong; Yu-jin Zhao; De-wei Guo; Mei-fa Huang
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Paper Abstract

Uncertainty in verification results of Ra (arithmetic mean deviation specification) of surface roughness is usually not considered in actual measurement and evaluation processes. To overcome this problem, a new method for calculation of expanded uncertainty of Ra is proposed to assure the integrity and validity in verification results in terms of new generation of international GPS (geometrical product specifications and verification) standards. The method calculates basic verification results of Raof surface roughness by using principle of least-square. And the expanded uncertainty of verification results is computed by the relations between information entropy and uncertainty. With the measured result, the measured parts can be judged if it is acceptable by using the decision rules provided by standard ISO 14253-1. Finally, the comparison is given between expanded uncertainty and combined standard uncertainty through using a tested practical measured part. The combined standard uncertainty is computed according to the propagation formula given by standard ISO 14253-2. Experiment results indicate that expanded uncertainty can be immediately computed by Information Entropy Principle. Thus the decision can be made whether to accept or to reject the measured component by the result of Ra and uncertainty. Therefore, this method could reduce the probability both for mis-acceptance rate and the mis-rejection rate of the measured parts.

Paper Details

Date Published: 31 December 2008
PDF: 7 pages
Proc. SPIE 7130, Fourth International Symposium on Precision Mechanical Measurements, 71305C (31 December 2008); doi: 10.1117/12.819752
Show Author Affiliations
Yan-ru Zhong, Guilin Univ. of Electronic Technology (China)
Yu-jin Zhao, Guilin Univ. of Electronic Technology (China)
De-wei Guo, Guilin Univ. of Electronic Technology (China)
Mei-fa Huang, Guilin Univ. of Electronic Technology (China)

Published in SPIE Proceedings Vol. 7130:
Fourth International Symposium on Precision Mechanical Measurements
Yetai Fei; Kuang-Chao Fan; Rongsheng Lu, Editor(s)

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