Vision-Based Measurement of Two-Dimensional Positioning Errors of Machine Tools

Abstract

This paper presents vision-based measurement of two-dimensional positioning errors of machine tools. A pre-calibrated grid plate is used as an artefact. The position of a grid point is measured in an image captured by a charge coupled device (CCD) camera attached to a spindle. Unlike conventional two-dimensional digital scales, the vision-based measurement can target the artefact in any orientation, and thus can be also applied to error calibration of a rotary axis. A longer working distance between the lens and the target is also its potential advantage for safer measurement. The paper demonstrates experimental applications of the vision-based measurement to the measurement of 1) static and 2) dynamic error motions of 1) a linear axis and 2) a rotary axis of a machine tool.

Keywords

• vision-based measurement
• volumetric accuracy
• camera
• grid
• five-axis machining center.