Development of a DVD pickup-based four-degrees- of-freedom motion error measuring system for a single-axis linear moving platform

摘要

In this study, a simple and high-resolution four-degrees-of-freedom (4-DOF) motion error measuring system based on DVD pickup has been proposed. It can simultaneously measure the horizontal straightness error and three angular errors of a single-axis linear moving platform. The horizontal straightness error is measured based on the focus technique of DVD pickup and the inverse algorithm is used to solve pitch, yaw, and roll angular errors through the kinematic analysis. The grating is mounted on the moving axis of a single-axis linear moving platform and reflects incident laser beam into several diffractive rays. Photodiode IC (PDIC) of DVD pickup is set up for detecting the focus error signal (FES) of zero-order diffraction ray from grating and quadrant detectors are set up for detecting the position of ±1st-order diffraction rays from grating. The 4-DOF motion error measuring system detected the three angular errors with a related accuracy of about ±1 arc sec for a measuring range of ±100 arc sec, and detected horizontal straightness with a related accuracy of about ±2 μm for a measuring range of ±150 μm.