| 摘要 |
PURPOSE:To remove an error caused by pitching of a table, and to measure straightness with high accuracy, by providing 3 detectors for detecting a distance to an object, a distance to a guide surface and the extent of pitching of the table, on the table moving along the guide surface. CONSTITUTION:On a table 11 installed to a guide surface so as to be freely slidable, the first and second detectors A, B for measuring a distance to an object and a distance to the guide surface are placed at an intervals of a constant distance l along the moving direction. Also, a level meter E for measuring the upper and lower direction displacement of the detector B against the detector A, which is caused by pitching is installed. When a subscript in case of starting a measurement is set to ''0'', and measured values of the detectors A, B, and the level meter E, in case of the K-th measurement are denoted as DKA, DKB and RK, respectively, straightness XK of the object and straightness YK of the guide surface are decided with high accuracy after correction for pitching has been added, by XK=XK-1-DKA+D(K-1)B+l(RK-RO) and YK=DKD- DOA+YK. |
