User manual of EL8-EC***F AC Servo
253
6.9 Model following control
Model following control is a type of closed loop control system. First, an ideal model is
constructed and acts as a reference for actual model in a closed loop control. Model
following control can be treated as a control mode with 2 flexibilities: Model reference can
be used to improve command responsiveness and closed loop control used to increase
responsiveness of the system towards interference. They don’t affect each other.
Model following control can be used in position loop control to increase responsiveness to
commands, reduce positioning time and following error. This function is only available in
position control mode.
+
Position
loop gain
Velocity
loop
gain
Velocity
feedforward
Torque
feedforward
Current
loop
control
Motor
Encoder
Velocity
feedback
Current
feedback
Position
Command
Position
filter
-
+
+
-
+
+
Position
feedback
+
Velocity
loop integral
time
constant
-
MFC
To adjust model following control
1. Automatic adjustment
Set model following bandwidth Pr0.00 = 1 for automatic adjustment. Now, Pr0.00 =
Pr1.01, model following bandwidth is adjusted automatically according to different
velocity loop gain.
3. Manual adjustment
Please used manual adjustment if
Automatic adjustment is not satisfactory.
Responsiveness needs further improvement in comparison with automatic
adjustment.
There is a need to set servo gain or model following control parameters
manually.
Steps to manually adjust
Step
Content
1
Set up vibration suppression.
2
Set up the right inertia ratio.
3
Manually adjust gain.
4
Increase Pr0.00 provided that ther
e is no overshoot and vibration. Usually Pr0.00 ≥
Pr1.01 is recommended.
