Robust roll angular error measurement system for precision machines.

This paper presents a robust and low-cost roll angle measurement system (RAMS) on the basis of two parallel beams in association with two position detectors. The commonly occurring influences of beam drift, beam diameter, and intensity variations, and non-parallelism of dual-beam on the roll angular error measurement of precision linear stages are thoroughly considered and reduced. The effectiveness of the designed system and proposed methods were demonstrated by a series of experiments. It has been verified that the designed system's measurement accuracy is within ± 1.2 arcsec over a measurement range of 1 m. The designed system is easy to construct both in the laboratory environment and factory field.