Crosstalk decoupling measurement method to determine the six degrees of freedom of motion error of linear stages

Abstract

The simultaneous measurement of all six degrees of freedom of motion error for a linear stage is significantly faster than methods that measure each degree of freedom separately. However, in current simultaneous measurement methods, error crosstalk issues significantly affect measurement accuracy. In this paper, a direct and simple crosstalk decoupling simultaneous measurement method to determine the six degrees of freedom of motion error of a linear stage is proposed. Based on the combination of single-frequency laser interferometry and laser self-collimation, a novel, to the best of our knowledge, optical configuration with a complete error decoupling relationship is designed, and a mathematical model is derived for error decoupling to address the crosstalk issue. A prototype system based on the new method is developed, and experiments are conducted to verify its effectiveness. Analysis shows that, compared with a commercial laser interferometer for linear stage measurement, the deviations of the positioning, horizontal straightness, vertical straightness, roll, pitch, and yaw errors are ± 0 . 50 µ m , ± 0 . 58 µ m , ± 0 . 50 µ m , ± 1 . 02 i n . , ± 0 . 72 i n . , and ± 0 . 87 i n . respectively, over a 200 mm measurement range.