Uncertainty analysis and variation reduction of three-dimensional coordinate metrology. Part 2: uncertainty analysis

Abstract

In this part of the paper, the uncertainty analysis of coordinate estimation for the case in which the sampled geometric errors are dominated by the random component is investigated. In practice, the uncertainty analysis of coordinate estimation using high-precision datum surfaces often falls into this type. In this paper, a sensitivity matrix, which serves as the theoretical basis of the uncertainty analysis, is presented to establish a linearized relationship between the variations of the coordinate estimation and the geometric errors of the part surface at the measurement points. Based on the sensitivity matrix, quantitative measures are derived for the prediction of coordinate variation. Computer simulation and experiments are conducted to verify the theoretical predictions when the surface geometric errors are small and dominated by the random component.