Title: Adaptive sampling strategies for measurement of freeform surfaces using coordinate measuring machines in continuous scanning mode

Authors: G. Rajamohan; M.S. Shunmugam

Addresses: Department of Manufacturing Engineering, National Institute of Foundry and Forge Technology, Ranchi – 834 003, India ' Manufacturing Engineering Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai – 600 036 India

Abstract: Freeform surfaces are complex surfaces without rotational symmetry. Their measurement and verification using the coordinate measuring machines (CMMs) require a suitable sampling strategy. Considering continuous scanning CMMs, the sampling strategy involves the estimation of number of isoparametric scan lines (sample size) and identification of their positions. It is often difficult to establish such information owing to the complex nature of freeform surfaces. Adaptive strategies, satisfying certain user-defined criteria, may be used for this purpose. This research attempts to develop an adaptive sampling strategy based on dominant isoparametric lines. This strategy iteratively identifies the number of isoparametric scan lines and their positions. The iterations are controlled by positional deviations and maximum number of scan lines, both are user-defined. On the basis of comparison with an existing sampling strategy, the proposed strategy has been found to yield better results with fewer isoparametric scan lines.

Keywords: adaptive sampling; continuous scanning; CMMs; coordinate measuring machines; freeform surfaces; isoparametric lines.

DOI: 10.1504/IJPTECH.2014.060613

International Journal of Precision Technology, 2014 Vol.4 No.1/2, pp.3 - 18

Published online: 30 Apr 2015 *

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