Optimal calibration strategy for a five-axis machine tool accuracy improvement using the D-optimal approach

摘要

An optimisation process is proposed to design a measurement strategy for the indirect calibration of a five- axis machine tool using the SAMBA (Scale and Master Balls Artefact) method. The DETMAX algorithm is applied to select optimised artefact positions and lengths, and rotational machine axes angular positions, based on a comparison of maximised observability indices values. Simulation outcome produces probing sequences that offer a better estimation of axis location errors and error motions within a limited processing time. Different optimised calibration scenarios are then conducted simultaneously in a nested experimental test to ensure a fair selection of the probing strategy within the same operational conditions. Observability index results supported by uncertainty analysis suggest that a one master ball, for axis location errors, and four master balls, for axis location errors and error motions, probing sequences are the most efficient strategies for a number of measurement depending on the number of machine error model unknown parameters.