
3. α SERIES PARAMETER ADJUSTMENT B-65150E/04
− 90 −
<2> Velocity feed-forward adjustment
When feed-forward is enabled, the time required for positioning
can be reduced, but a swell may occur due to insufficient velocity
loop response immediately before machining stops. A swell can
be reduced by an increased velocity loop gain, but there is an
upper limit on the velocity loop gain. So, adjust the velocity
feed-forward coefficient to reduce a swell for positioning time
reduction.
The default settings cause a swell immediately before machining
stops (Fig. 3.4.5 (f)). The swell can be reduced by increasing the
velocity feed-forward coefficient (Fig. 3.4.5 (g)).
Fig. 3.4.5 (g) After velocity feed-forward
adjustment
FAD: 64 ms
Feed-forward: 98.5%
Velocity feed-forward coefficient: 250%
Fig. 3.4.5 (f) Before velocity feed-forward
adjustment
FAD: 64 ms
Feed-forward: 98.5%
Velocity feed-forward coefficient: 100%
An optimum is
achieved
when the swell
here is
reduced.
A swell is
observed
immediately
before
machining stops.