Optical axis calibration method using a 4-DOFM system for linear guide detection

In laser measurement, geometric error detection of long-travel linear guides is challenging because of air disturbances. This Letter proposes an optical axis calibration approach for long-travel linear guide detection using a four-degree-of-freedom measurement (4-DOFM) system. The 4-DOFM system can measure two straightness errors and two angular errors (pitch and yaw). The measured long-travel guide rail is divided into numerous sections for separate detection. The difference of optical axis between each section can be measured through the 4-DOFM system without additional equipment. The optical axis calibration algorithm is derived to achieve the synthesis of measurement results. A series of experiments were organized, and the effectiveness of the proposed method was verified on a linear guide with 2 m travel. The proposed method provides a practical solution for the geometric error detection of long-travel guide rails.