正方配置逐次4点法のゼロ点誤差補正法への角度センサ導入による精度改善

抄録

Square layout four-point method with angle correction has been proposed as an on-machine profile measurement method of machined flat surfaces. In this method, it is possible to measure the planar shape without the influence of translational error, pitching, and rolling of a stage. However, a zero-adjustment error, which is a deviation of the origin height of the four displacement sensors, causes a large form error of twist shape when the planar shape is reconstructed. To solve this problem, a back calculation method of the zero-adjustment error was proposed: which calculate zero-adjustment error from the difference in the error cumulative amount of two different calculation paths for a square measurement region, the raster scanning path and the diagonal path. To improve the calculation accuracy of zero-adjustment error, the authors have proposed to apply two-point method with angle correction to the diagonal direction by measuring the posture change of the stage unit with the angle sensor newly added in the diagonal direction. Monte Carlo simulations of the square layout four-point method and back calculation of zero-adjustment error were carried out. As a result, it was confirmed that the proposed method is effective to improve correction accuracy of the zero-adjustment error.