A six-degree-of -freedom measurement system for the motion accuracy of linear stages

摘要

This paper presents a new six-degree-of-freedom measurement system (6DMS) which has thecapability to measure simultaneously all six motion errors of a linear stage. This system employs threeparallel laser beams to detect three relative linear distances of a moving body by Doppler effect so thatthe positioning, yaw and pitch errors can be separated. With an additional beam splitter and twoquadrant photodetectors to detect the lateral shifts of the returned beams, the remaining twostraightness errors and roll error can be obtained at the same time. In comparison with the HP5528Asystem, the accuracy of the positioning error is about 0.01μm to the range of 10 m, the straightnesserror is about 1μm within the measuring range of±0.1 mm, and angular errors are all about 1arcsec within the range of±50 arcsecs. This system is simple in principle and can be easily equippedto any moving stages, such as linear stages, X-Y tables.