A novel scheme to measure 2D error motions of linear axes by regulating the direction of a laser interferometer

In the standardized accuracy test procedures for machine tools, error motions of a linear axis, i.e. the linear positioning, straightness, and angular error motions, are separately measured in a different setup with a different measuring instrument. This paper presents a novel scheme to measure all the two-dimensional (2D) error motions of two linear axes by using a laser interferometer only. The proposed test consists of (1) direct measurement of the linear positioning deviation of two linear axes, and (2) the distance measurement to the retroreflector, positioned by the two linear axes on a rectangular path, by continuously regulating the laser beam direction of a laser interferometer. It requires a laser interferometer only; lower implementation cost is its major practical advantage. As an experimental case study, the proposed scheme is applied to a large-sized machine tool. The uncertainty analysis is also presented