Measuring geometrical errors of linear axis of machine tools based on the laser tracker

Abstract

Linear axis is the fundamental part which is widely used in multi-axis machine tools. In order to refine the capability of multi-axis machine tools, efficient error compensation method should be developed, which necessitates effective error measurement method too. In this study, a simple method based on the laser tracker is proposed for measuring six geometrical error components of linear axis of multi-axis machine tools. Three noncollinear points are selected from the stage of linear axis under the test, and the spatial coordinates of these points are collected by a laser tracker. Then, the mathematical geometrical error model which is established by homogeneous transformation, comprehensively describing the relationship between the geometrical error components and the volumetric errors, is performed inversely to achieve a system of equations, and the six geometrical error components can be finally obtained by solving these equations. The effectiveness of laser-tracker-based geometrical error components measuring method is verified by various experiments. Furthermore, compared with some traditional methods, it is efficient and easy to implement because no any alignment of equipment is required and six geometrical error components can be determined synchronously.