Rotational angle-positioning device for positioning pivot shaft of turning lathe spindle at predetermined angular position, has command value-correction unit correcting command value for angles to determine corrected command value

摘要

The device (6) has a rotational angle detector (7) comprising a detection target ring (8). An error pattern-storage unit (11a) stores a grating period-error pattern (F), which has deviations between rotational angles and actual rotational angles detected by an angle detecting sensor (9). The angles correspond to correction-division points of arbitrary grating period in the detection target ring. A command value-correction unit (11b) corrects a command value for the rotational angles based on the grating period-error pattern to determine the corrected command value for the rotational angles.