摘要 |
A scanner system includes a servo control unit. A rotation angle of a rotating shaft supporting a mirror is detected, and an error of the detected value with respect to a commanded value is integrated by an integral compensator so that the detected value is able to track the commanded value. A tracking error proportional compensator is disposed in parallel with the integral compensator so as to add a correction value proportional to the error to the integrated value of the error. A plurality of gains are prepared for each of the integral compensator, the tracking error proportional compensator, a detected value proportional compensator and a detected value differential compensator of the servo control unit. Each gain is changed in accordance with a travel angle of the commanded value. Thus, the mirror can be positioned quickly so that the machining speed can be improved.
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