YASKAWA SGD7C-***AMAA*** Product Manual page 504

Model Following Control
You can use model following control to improve response characteristic and shorten position-
ing time. You can use model following control only with position control.
Normally, the parameters that are used for model following control are automatically set along
with the servo gains by executing autotuning or custom tuning. However, you must adjust them
manually in the following cases.
• When the tuning results for autotuning or custom tuning are not acceptable
• When you want to increase the response characteristic higher than that achieved by the tun-
ing results for autotuning or custom tuning
• When you want to determine the servo gains and model following control parameters yourself
The block diagram for model following control is provided below.
peed
peed pattern
Reference
Time
+
Deviation
-
counter
Po ition loop
VD Function Module in the Controller ection
(Operating program not provided by Ya kawa)
 Manual Tuning Procedure
Use the following tuning procedure for using model following control.
Step
Friction compensation must also be used. Set the friction compensation parameters. Refer to the
1 following section for the setting procedure.
8.12.2 Friction Compensation on page 8-68
Adjust the servo gains. Refer to the following section for an example procedure.
Tuning Procedure Example (for Position Control or Speed Control) on page 8-74
Note: 1. Set the moment of inertia ratio (Pn103) as accurately as possible.
2
2. Refer to the guidelines for manually tuning the servo gains and set a stable gain for the position loop gain
(Pn102).
Guidelines for Manually Tuning Servo Gains on page 8-79
Increase the model following control gain (Pn141) as much as possible within the range in which
3
overshooting and vibration do not occur.
If overshooting occurs or if the response is different for forward and reverse operation, fine-tune
model following control with the following settings: model following control bias in the forward direc-
4
tion (Pn143), model following control bias in the reverse direction (Pn144), and model following con-
trol speed feedforward compensation (Pn147).
Model following
control
mKp, mVFF, mTFF
peed feedforward
Po ition control loop
peed control loop
peed
+
Reference
peed control
Po ition
- ection Kv
loop gain Kp
and Ti
peed loop
ervo ection
Kp: Po ition loop gain (Pn102)
Kv: peed loop gain (Pn100)
Ti: peed loop integral time con tant (Pn101)
Tf: Fir t tage fir t torque reference filter time con tant (Pn401)
mKp: Model following control gain (Pn141)
mTFF: Model following control bia in the forward direction (Pn14 )
Model following control bia in the rever e direction (Pn144)
mVFF: Model following control peed feedforward compen ation (Pn147)
Description
8.13 Manual Tuning
8.13.1 Tuning the Servo Gains
Torque Feedforward
ervomotor
+
Current
Tf
Power
control
-
converter
ection
Current loop
PG
Encoder
M
8
8-81