
1.AXIS CONTROL B-63943EN-1/02
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1.3.12 Cyclic Second Pitch Error Compensation
Overview
When a rotary table is rotated using a gear, there are two cycles of the
occurrence of pitch errors: One cycle is the same as that of the rotation
of the rotary table while the other is the same as that of the rotation of
the gear for rotating the rotary table. To compensate for pitch errors of
these types, the compensation for the pitch error due to the rotation of
the gear is superimposed on the compensation for the pitch error per
rotation of the rotary table.
Explanation
If the gear between the rotary table and the servo motor is of a single
stage, as shown in Fig. 1.3.9 (a), stored pitch error compensation is
used for the compensation for the pitch error of toothed wheel A and
cyclic second pitch error compensation is used for the pitch error of
toothed wheel B.
If there is a multiple-stage gear, as shown in Fig. 1.3.9 (b), stored
pitch error compensation is used for toothed wheel A and cyclic
second pitch error compensation is used for the cyclic pitch error that
occurs in each pitch error compensation interval of toothed wheel A.
Fig. 1.3.12 (a) Cyclic Second Pitch Error Compensation for a
Single-Stage Gear
Fig. 1.3.12 (b) Cyclic Second Pitch Error Compensation for a
Multiple-Stage Gear