A novel self-calibration scheme for on-machine measurement based on five-axis machine tool kinematic model

Abstract

When measuring a geometric profile of workpiece on a machine tool by using a touch-trigger probe, geometric errors of linear axes can be a major measurement uncertainty contributor. The self-calibration schemes, well established for circularity or straightness measurement, cannot be applied to a free-form geometry. This paper proposes a novel self-calibration scheme for on-machine measurement of arbitrary two-dimensional geometry, based on the five-axis machine tool kinematic model. As an experimental verification, a cross-shaped workpiece is measured in accordance with the proposed self-calibration scheme. As a result, the proposed scheme successfully separated the geometric error of the workpiece from the geometric errors of linear and rotary axes.