The influence of the strategy of acquisition on uncertainties of measurement of a machined surface
Keywords:Three-dimensional metrology, Coordinate meas-uring machines (CMM), optimization of associat-ed surfaces, modelling, uncertainties of measure-ment, propagation
In the last few years of many researchers tried to develop methods of determination of uncertainties in a data processing sequence of a CMM (Coordinate Measuring Machine). Measurement on a CMM is based on the association of an ideal surface to the set of palpated points via a mathematical calculation of the distances between the palpated points and itself surfaces. At the time of this stage of measurement, the results certainly are sullied with uncertainties, in this respect the step of quality fixed by the standard ISO 9000, requires with the metrologist to estimate the uncertainty with which, it obtained his measurement. During this article, we will present a data-processing model allows to estimate the parameters of surfaces associated with the set of points resulting from a coordinate measuring machine and their uncertainties, by holding account the method or the strategist of palpation. The method of conjugate gradient is used to evaluate the attributes which characterize associated surfaces, after having optimized quadratic equation ei (variation of form) within the meaning of nonlinear least squares. With an aim of being able to show the influence of these methods on uncertainties of measurement.