Motion control system and X ray measurement apparatus

摘要

A motion control system comprising a servo motor for moving a rotary stage; a scale provided on the rotary stage or on an object that moves integrally with the rotary stage; a plurality of reading heads for detecting the scale and outputting a signal; a data processing part for calculating an average value of rotation angle data based on each of the output signals from the reading heads and outputting the average value as a signal; and a servo amplifier for controlling the motor based on the signal representing the average value of the rotation angle. The motion control system can cause the rotary stage to rotate to a desired rotation angle to a high degree of accuracy using the reading heads.