Measurement and identification of geometric errors of translational axis based on sensitivity analysis for ultra-precision machine tools

Identification of geometric errors of translational axis is a key step to improve the accuracy of machine tools. However, during the procedure of measurement, installation errors of instruments are inevitable and should influence the measurement results. In order to avoid this and improve the reliability and accuracy of measurement, a novel identification measurement method is proposed. The errors of positioning and straightness of translational axis are measured by a laser interferometer in four installation positions. Twelve measured results are obtained, and then are used to identify six geometric errors of translation axis, based on the homogeneous transformation matrix and the least square method. Furthermore, an optimization method based on sensitivity analysis of the identification matrix is presented to obtain the optimum installation positions of the laser interferometer, to diminish the influence of the installation errors. Finally, simulations and experiments are conducted to validate the correctness and effectiveness of proposed method. The results indicate that the optimization identification method proposed is effective and accurate.