Accuracy analysis of diferent probes used in articulated arm coordinate measuring machines

A very important task in a normal measurement operation or in the procedure of identifying the parameters of a kinematic model of an articulated arm coordinate measuring machine (AACMM) is the process of capturing data. This paper analyzes the probing error when using different probing systems (self-centering passive probe and self-centering active probe) in both, the measurements of geometric primitives and data capture procedure for kinematic parameter identification. Moreover, the influence of the probing direction over the error is analyzed through its components in each of the axis-directions of the sixth reference system of the measurement arm. This influence is presumably attributable to the forces exerted during the probing process in different directions to the probe orientation. With this analysis it is possible to establish correlations between the probing error, the probing direction and the position of the AACMM to get that position and orientation. Furthermore, an analysis of the accuracy and repeatability of the captured points has been carried out by comparing these points to nominal points materialized by a ball-bar gauge distributed in several positions of the measurement volume. The results with each of the systems studied show the advantages and original accuracy obtained with the self-centering active probe, and thus its suitability in verification and kinematic parameter identification procedures.