Contribution à l’estimation des incertitudes de mesure dans la chaine de traitement d’une machine a mesurer tridimensionnelle

Abstract

The measurement on a coordinate measuring machine (CMM) is based on the technique of association an ideal surface to the set of palpated points via a mathematical optimization calculus in the sense of least squares. This calculation minimizes the distances between the probed points and the ideal surface. When the probe touches the part, the actual point of contact is unknown; it substitutes an estimated point from the center and radius of the probe and the normal docking. This creates a doubt about the actual position of the palpated point. This doubt is spreading even on the parameters of the associated surface, as well as the geometric construction for the technical verification specifications. Within this framework, standard ISO 9000 requires with the metrologist to estimate the uncertainty with which, it obtained his measurement. In this context, the current work, consists in establishing a program in Visual basic-6 serving on the one hand to determine the parameters characterizing surfaces to be measured and on the other hand, one to estimate uncertainties on these parameters to emphasize the impact of the latter on the checking of the geometrical specifications.