Torque Feedforward - YASKAWA SGMJV User Manual

6.9.2 Torque Feedforward

The torque feedforward function shortens positioning time.
The torque feedforward function is valid only in speed control and position control.
The host controller differentiates a speed reference to generate a torque feedforward reference, and inputs the
torque feedforward reference together with the speed or position reference to the SERVOPACK.
(1) Connection Example
Connect a speed reference signal line to V-REF (CN1-5 and -6) and a torque feedforward reference to T-REF
(CN1-9 and -10) from the host controller.
Host controller
+
Position
reference +
-
Kp: Position loop gain
K : Feedforward gain
FF
(2) Related Parameters
Torque feedforward is set using the parameters Pn002, Pn400 and Pn415.
The factory setting is Pn400 = 3.0 V/rated torque If, for example, the torque feedforward value is
the torque is limited to
Parameter
n.
Pn002
n.
Torque Reference Input Gain
Pn400
Setting Range
10 to 100
Note 1. Too high a torque feedforward value will result in overshooting. To prevent such troubles, set the optimum value
while observing the system responsiveness.
2. The torque feedforward function cannot be used with torque limiting by analog voltage reference.
T-REF Filter Time Constant
Pn415
Setting Range
0 to 65535
• The following settings are required if model following control is used together with the speed feedforward
(V-REF) input and torque feedforward (T-REF) input.
Parameter
n.0
Pn140
n.1
SERVOPACK
T-REF
Differe-
K
T-REF filter constant
FF
ntial
V-REF
Kp Speed reference input gain
±
100% of the rated torque.
0 Disabled [Factory setting]
2 Uses T-REF terminal for torque feedforward input.
Setting Unit
0.1V/rated torque
Setting Unit
0.01 ms
Function
Model following control is not used together with
speed/torque feedforward input.
Model following control is used together with speed/
torque feedforward input.
Pn400
Pn415
Torque reference input gain
+
Pn300 Pn100
Speed loop gain
-
Pn101
Speed loop integral
time constant
Speed calculation
Divider
Function
Speed
Position
Factory Setting
30
Speed
Position
Factory Setting
0
When Enabled
6.9 Compatible Adjustment Function
Servomotor
+
M
Current loop
+
ENC
Encoder
±
3V, then,
When Enabled Classification
After restart Setup
Torque
Classification
When Enabled
Immediately Setup
Torque
Classification
When Enabled
Immediately Setup
Classification
Immediately Tuning
6
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