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5-17 Speed Feed-forward
Operating Functions
5
5-17 Speed Feed-forward
Function
This function shortens positioning time by adding the amount of change in position command value
directly to the speed loop without passing it through the deviation counter.
Performing feed-forward compensation effectively increases the position loop gain and improves
responsiveness.
However, this function is not so effective in a system where the position loop gain is already
sufficiently high.
Parameters Requiring Settings
Adjust the feed-forward after completing the gain adjustment.
The Servomotor will overshoot if the feed-forward amount is too large. Increase the feed-forward
amount, but not so much that it causes overshooting.
The feed-forward filter is the first-order lag filter. Set this filter according to the acceleration and
deceleration time.
The figure above shows step response, but the positioning time will be delayed accordingly if
acceleration or deceleration occurs.
Parameter
No.
Parameter name Explanation Reference page
Pn015
Speed Feed-
forward Amount
Sets the speed feed-forward amount from the position
command. (Setting range: 0 to 100%)
5-68
Pn016
Feed-forward
Filter Time
Constant
Sets the time constant for the speed feed-forward first-order
lag filter. (Setting range: 0 to 64 ms)
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Speed
Command
Position Command
Encoder
Feedback
Deviation Counter
Pn010, Pn018
Filter
Pn016
Damping Control Filter
Pn02B, Pn02C
Pn02D, Pn02E
F/F
Pn015
Pn016
63.2%
Feed-forward amount
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