Manual Gain Adjustment - Leadshine EL8-EC Series User Manual

6.5 Manual gain adjustment

Due to limitation of load conditions, automatic gain adjustment might not achieve expected
performance. Control can be improved through manual gain adjustment
The servo system is made up of 3 control loops. From outer to inner: position loop,
velocity loop, current loop as shown in the diagram below.
Command Command
input filter
Inner control loop demands higher responsiveness. In order to avoid system instability,
please tune in accordance to this principle. Current loop gain usually satisfies the
responsiveness demand without tuning. When gain adjustment is done under position
control mode, in order to keep the system stabile, position and velocity loop gain have to
be increased at the same time to make sure the responsiveness of the position loop is
lower than velocity loop.
Steps to tuning (Position and velocity control)
For servo gain, if any one of the parameters is changed, please modify other gain related
parameters accordingly. Make sure to the change at around 5% and follow the rules as
below.
1) Increase responsiveness
a) Reduce torque command filter time
b) Increase velocity loop gain
c) Decrease velocity loop integral time
d) Increase position loop gain
2) Decrease responsiveness, prevent vibration and over shoot
a) Reduce position loop gain
b) Increase velocity loop integral time
c) Reduce velocity loop gain
d) Increase torque filter time
Velocity
feedforward
+
+
Position
control
- -
Position
feedback
User manual of EL8-EC***F AC Servo
Torque
feedforward
+
+
Velocity
control
- -
Velocity
feedback
Current
Motor
control
Current
feedback
Encoder
240