High-resolution three-degrees-of-freedom motion errors measuring system for a single-axis linear moving platform

In this study, a high-resolution three-degrees-of-freedom (3-DOF) motion error measuring system based on interference is described. It can simultaneously measure the linear displacement and two angular errors of a single-axis linear moving platform. The displacement is measured using a polarization interference technique and the two angular errors are also measured based on the geometry optical theorem. The verification results show that the resolution is about 20nm. The 3-DOF measurement system detected displacements relative to a measurement mirror move with an accuracy of about ±8μm for a measuring range of ± 50mm, and detected the angular errors with a related accuracy of about ± 2 arc sec for a measuring range of ± 100 arc sec. ? IMechE 2009.