基于重力补偿的立式三平板绝对检测（英文）

Absolute Three-flat Test in Vertical Direction with Gravity Deformation Compensation

为了实现高精度平面面形绝对检测,对传统的立式三平板绝对检测方法进行了重力变形补偿.通过有限元软件仿真了平板在水平放置于工装上的重力变形,并将其加入到平面绝对标定的计算中.把平面标定分成旋转对称项和旋转非对称项分别标定后进行综合,并与旋转平移绝对检测方法的测量结果进行了对比,去除离焦项对比结果均方根小于1nm.为了进一步验证离焦项的标定,对一平板在不同口径环形支撑下的形变量进行了检测和仿真,对比结果的峰谷值小于9nm,达到较高的离焦项测量精度.实验结果验证了基于重力变形补偿的立式三平板绝对检测方法能够实现立式下平面的高精度绝对检测.

In order to get lower uncertainty,a method was proposed to compensate the gravity deformation caused by flipping in vertical absolute three-flat test.The gravity deformation of the flat surface was simulated by finite-element software and added to the three-flat test calculation.The calibrated results were compared with shift-rotation absolute testing method,and the root mean square of the surface map difference was less than 1nm without power term.For power term verification,a flat supported on different rings was tested and subtracted.For power term verification,a flat supported on different rings is tested and the difference between the tests and the simulation was less than 9nm peak to vally,which was usually sufficient for flat power term testing.This experiment also proves the accuracy of the power simulation indirectly,the improved three-flat test can be applied in high precise flat absolute calibration including the power term in vertical direction.