Error separation technique of "two-point and two-setting method" and application in contactless automatic measurement

Combining with the characteristics of contactiess sensor and according to the Donaldson principle the paper puts forward the error separation technique of " two points and two setting method" . This technique can not only realize the separation for roundness error of intermediary from rotating error movement of spindle but also reduce the time of a measuring period and avoid the " drift" error which is brought by measuring system. Besides according to above error separation technique the authous of the paper develop a error separation system which can be used in ultra-high--precision contactless roundness measuring instrument. The maximal " drift" value of the system is less than 10 nm.