Multi-axis laser interferometer is generally employed in measuring multi-degree-of-freedom (M-DOF) displacement for many ultra-precision X-Y stages. In multi-axis measurement system, the installation deviation of interferometer laser beam is an important error source. In this paper, a novel calibration approach without other higher precision sensors has been presented, to calibrate the installation deviation in a 3-DOF displacement measurement system, with potential capability of calibrating 6-DOF measurement system. In the proposed method, one redundant measuring axis that is set as installation reference axis is added to the original 3-axis measurement system. Correspondingly, considering the installation deviations of 3-axis interferometer, a new displacement computational model with four equations is built. In this model, all installation deviations are constants and the displacement values are variable. Utilizing the redundant measurement information of three position points, the installation deviations are separated. The simulation results validate its feasibility. This approach can strictly ensure the parallelism and perpendicularity between measuring axes, and is easily applied to engineering.
Error Source Identification and Stability Test of a Precision Capacitance Measurement System
