
H.DETAILS OF HIGH-SPEED AND HIGH-PRECISION ADJUSTMENT APPENDIX B-65270EN/05
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Fig. H (f) Specified path and actual path
ctual path
Specified path
When advanced preview feed-forward is disabled, a figure error of
hundreds µm occurs as shown in Fig. H (f), and therefore can be
viewed even in the XY mode. However, if advanced preview
feed-forward is enabled for figure error reduction, it is difficult to
evaluate a figure error correctly unless the error is enlarged.
In such a case, use the figure comparison mode (contour mode) for
enlarging errors only for display (Ctrl O).
In addition, set an error display magnification with F3 (scale change).
For Fig. H (g), a display magnification of 100 is set.
The figure display is 5 mm wide.
The error is 50 µm in size.
Protrusion and cut due to
a delay on the Y-axis
Protrusion and cut due to a
delay on the X-axis
Fig. H (g)
elocity feed-forward adjustment
Velocity loop gain: 100%
Advanced preview feed-forward coefficient: 99%
FAD time constant: 24 ms (linear type)
Velocity feed-forward: 0%
Fig. H (h)
elocity feed-forward adjustment
Velocity loop gain: 100%
Advanced preview feed-forward coefficient: 99%
FAD time constant: 24 ms (linear type)
elocit
feed-forward: X100%
In Fig. H (g), the velocity feed-forward coefficient is not specified, so
that the movement along each axis delays where acceleration changes
to a large extent. As the result, a protrusion occurs at the joint of a
straight line with an arc, and a cut occurs at the joint of an arc with a
straight line. In Fig. H (h), a velocity feed-forward coefficient is set
for the X-axis only. The response of the X-axis has improved, so that
a figure improvement can be seen in the areas where acceleration
changes to a large extent along the X-axis.