General Methods For Adjusting Parameters - INVT DA180-S2R8SG0 Operation Manual

DA180 series basic AC servo drive

7.2 General methods for adjusting parameters

DA180 servo drive parameters can be adjusted by two methods.
Automatic adjusting
You need to evaluate the load inertia ratio manually and set the servo system rigidity, which has 32
options from 0 to 31. Then different loop gains can be set automatically.
This method features quick adjusting servo system responsiveness.
Adjust the system rigidity based on the actual situation. The recommended rigidity settings are as
follows:
Large transfer or transmission equipment
A greater rigidity value indicates quicker response, but it increases the possibility to cause noise and
vibration. You need to check the mechanical device actions before the setting.
If the setting cannot meet your requirements, use manual adjusting.
Manual adjusting
If the servo system encounters vibration or control performance cannot meet requirements, you can
adjust speed loop and position loop parameters to eliminate vibration or improve performance.
You can adjust the following parameters manually:
 Speed loop gain: It determines the response speed of the speed loop. If the mechanical system has
no vibration, a greater speed loop gain indicates a quicker response speed.
 Speed loop integral time constant: The speed loop contains the integral component, which can
respond to minor input. The integral component may delay servo system jobs. A greater time
constant indicates slower response, increasing positioning time. If load inertia is heavy or servo
system has a great possibility to encounter vibration, this time constant must be great. Otherwise,
the servo system may encounter vibration.
 Torque command filtering: The mechanical system may encounter resonance, which causes sharp
vibration noise. At this time, you must use the notch filter to eliminate resonance.
 APS gain: It determines the servo system responsiveness. A greater APS gain indicates a quicker
response speed, reducing positioning time. If you need to set the gain to a great value, the rigidity
and natural frequency of the mechanical system must be high.
Generally, the speed loop gain must be greater than the position loop gain. If the position loop gain is
much greater than the speed loop, the system may be overshot with the function of step signals,
therefore deteriorating system performance. System parameters are restricted mutually. If only the
position loop gain is increased, the commands output from the position loop may be unstable, which
Mechanical structure
Belt drive mechanism
Ball screw + belt drive
Manipulator
Direct ball screw or rigid body
-231-
Commissioning
Rigidity
0–13
5–16
5–16
15–22
18–25