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

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.