Speed Feedforward - YASKAWA SGMJV User Manual

6 Adjustments

6.9.3 Speed Feedforward

6.9.3 Speed Feedforward

The speed feedforward function is used to shorten positioning time.
The speed feedforward function is valid only in position control.
The host controller differentiates the position reference to generate the speed feedforward reference, and
inputs the speed feedforward reference together with the position reference to the SERVOPACK.
(1) Connection Example
Connect a position reference signal line to PULS and SIGN (CN1-7, -8, -11, and -12) and a speed feedforward
reference signal line to V-REF (CN1-5 and -6) from the host controller.
Host controller
Position
reference
Kp: Position loop gain
K : Feedforward gain
FF
(2) Related Parameters
Speed feedforward value is set using the parameters Pn207 and Pn300.
The factory setting is Pn300 = 6.00 V/rated speed. If, for example, the speed feedforward value is ±6V, then
the speed is limited to the rated speed.
Pn207
Pn300
Note: Too high a speed feedforward value will result in overshooting or undershooting. To prevent such troubles, set the
optimum value while observing the system responsiveness.
6-66
Model following control is used to set the optimum feedforward value in the servo. There-
fore, the speed feedforward (V-REF) and the torque feedforward (T-REF) cannot be
used together.
If the optimum values for the speed feedforward (V-REF) and torque feedforward
(T-REF) are not set, overshooting may occur.
SERVOPACK
V-REF
Differ-
Speed reference
K
FF
input gain
ential
+
PULS
SIGN
Parameter
n. 0 Disabled [Factory setting]
n. 1 Uses V-REF terminal for speed feedforward input.
Speed Reference Input Gain
Setting Range
150 to 3000 0.01 V/rated speed
Pn300
Pn100
Pn102
+
+
Speed loop
Position loop
gain
gain
- -
Pn101
Speed loop integral
time constant
Speed
calculation
Function
Speed
Setting Unit Factory Setting
Servomotor
+
Current loop
M
+
Enc
Encoder
When Enabled
After restart
Torque
Position
When Enabled
600 Immediately
Classification
Setup
Classification
Setup