Adjustments; Servo System Adjustments - YASKAWA SGM Series User Manual

Application

5.9.1 Servo System Adjustments

5.9 Adjustments

5.9.1 Servo System Adjustments
Speed
MECHATROLINK
command
5
Once the load moment of inertia constant (Cn−0003) has been specified, the following user
constants (parameters) are used to adjust the servo system.
D Cn-0004: Speed Loop Gain
D Cn-0005: Speed Loop Integration Time Constant
D Cn-0017: Torque Reference Filter Time Constant
D Cn-001A: Position Loop Gain
A simple block diagram of the servo system is shown below.
Speed pattern
Error
counter
Time
Position loop
Figure 5.10 Servo System Block Diagram
J Basic Rules for Gain Adjustment
The servo system is equipped with the following feedback systems.
D Position loop
D Speed loop
D Current loop
The inner loops require better response. Failure to follow this principle will result in poor re-
sponse and vibration.
The current loop already provides adequate response and cannot be adjusted by the user. The
user can adjust the position loop and speed loop gains. The speed loop integration time constant
and torque reference filter time constant can also be adjusted by the user.
The responses of the position loop and speed loop must be kept in balance. Increasing the posi-
tion loop gain alone to improve response will cause the speed reference in the SERVOPACK
to vibrate, producing slow or inconsistent positioning times. If the position loop gain is in-
creased, the speed loop gain must be similarly increased.
K
V
K
Speed
P
control
T
i
Speed loop
Kp: Position loop gain
Kv: Speed loop gain
Ti: Integration time constant
5 -20
Motor
Power
Current
Con-
control
vertion
Current loop
Encoder