Adjustment Example - YASKAWA SGD7S series Product Manual

3.3 Adjusting Less-Deviation Control 2

3.3.2 Adjustment Example

3.3.2 Adjustment Example
Adjustment Example for Pn100, Pn101, Pn102, Pn11F,
Pn197, and Pn401
The effects of Pn100 (Speed Loop Gain), Pn101 (Speed Loop Integral Time Constant), Pn102
(Position Loop Gain), Pn11F (Position Integral Time Constant), Pn197 (Less-Deviation Control 2
Torque Feedforward Filter Time Constant), and Pn401 (First Stage First Torque Reference Filter
Time Constant) are shown below.
Position
reference
reference
Position
deviation
Adjustment Example for Less-Deviation Control 2 Torque
Feedforward Gains (Pn198 and Pn199)
The effects of Pn198 (Less-Deviation Control 2 Forward Torque Feedforward Gain) and Pn199
(Less-Deviation Control 2 Reverse Torque Feedforward Gain) are shown below.
Torque feedforward is used for less-deviation control. The torque feedforward operation takes
the differential of the input position reference, converts it to an acceleration rate, and multiplies
it by the setting of Pn103 (Moment of Inertia Ratio (Mass Ratio)). Therefore, if the setting of
Pn103 is smaller than the actual moment of inertia ratio (mass ratio), the effectiveness of reduc-
ing the position deviation will be diminished. On the other hand, if the setting of Pn103 is larger
than the actual moment of inertia ratio (mass ratio), the position deviation can easily result in
overshooting.
In this type of case, you can change the settings of Pn198 and Pn199 to effectively achieve the
same things as changing Pn103 only for torque feedback.
Information
3-6
Before Adjustment ： Pn100 = 40 (40.0 Hz)
speed
Torque
0 100 400 600
Time (ms)
It is best to correctly set Pn103 (Moment of Inertia Ratio) rather than to adjust the settings of
Pn198 and Pn199. However, Pn103 will affect the entire control loop, so changing only the
torque feedforward amounts (Pn198 and Pn199) after completing gain adjustment is useful
for fine-tuning.
After Adjustment ： Pn100 = 100 (100.0 Hz)
Position
reference
speed
Torque
reference
Position
deviation
800 1000
Position deviation
is reduced.
0 100 400 600 800
Time (ms)
1000