ECCENTRICITY MEASUREMENT METHOD, ECCENTRICITY MEASUREMENT INSTRUMENT, CONTROL PROGRAM OF THE ECCENTRICITY MEASUREMENT INSTRUMENT, ROTATING DEVICE, AND METHOD FOR MANUFACTURING THE ROTATING DEVICE
摘要
<P>PROBLEM TO BE SOLVED: To reduce the degradation in precision of rotation phase control due to eccentricity of an identification code group relative to a revolving shaft of a rotary scale in a rotating device using the rotary scale. <P>SOLUTION: A control device 100 includes: means which calculates a maximum or minimum value of ratios of detection pulse widths of slits SL by a first detection sensor 22 and detection pulse widths of the slits SL by a second detection sensor 23; means which calculates a variation in width of the slits SL in accordance with the maximum or minimum value; means which calculates an eccentricity of the slit group relative to a revolving shaft of a rotary scale 2 in accordance with the variation in width of the slits SL; means which calculates an eccentricity phase of the slit group relative to the revolving shaft of the rotary scale 2 in accordance with a rotation phase of the rotary scale 2 when the ratio of detection pulse widths reaches the maximum or minimum value; and means which corrects rotation errors of a carrying drive roller 11 on the basis of the eccentricity and the eccentric phase of the slit group. <P>COPYRIGHT: (C)2012,JPO&INPIT
