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9.2.4. Feed Forward Compensation: FF
l
Function of feed forward is to generate a velocity command by differentiating the position
command and then add it to the velocity loop in the forward direction. Parameter FF sets the feed
forward compensation gain. It requires the password for entry.
l
The shipping set of the parameter FF is FF0.
l
It improves following error during acceleration / deceleration.
l
Setting the FF parameter to a higher value improves the following error. However, overshoot
becomes more likely to occur. It is recommended that the parameter is set to 0.5 or below.
Figure 9-29: Feed Forward Compensation Block Diagram
+
+
Position
command
Velocity
c
–
+
–
Position data
Differentiation
Position
loop gain
Feed forward
compensation gain
Velocity data
FF
PG
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