Omron G5 Series User Manual page 331

Torque Feed-forward Operating Method
1
Set Inertia Ratio 1 (Pn004).
Set the inertia ratio as correctly as possible.
• If the inertia ratio is calculated for the selected motor, input the calculated value.
• If the inertia ratio is not known, perform autotuning and set the inertia ratio.
2
Set Torque Feed-forward Command Filter (Pn113).
Set this to approximately 50 (0.5 ms).
3
Adjust Torque Feed-forward Amount (Pn112).
Gradually increase the value of Torque Feed-forward Gain (Pn112).
Since the position error during acceleration/deceleration at a constant speed can be brought
close to 0, it can be controlled to almost 0 throughout the entire operation range during a
trapezoidal speed pattern under ideal conditions where no disturbance torque is working.
In reality, disturbance torque is always applied and, therefore, the position error cannot be
completely 0.
Position
error
Command
speed
Torque feed-forward can reduce the position error in the range of constant acceleration/
deceleration.
Precautions for Correct Use Precautions for Correct Use
If you increase the torque feed-forward filter time constant, operating noise will be reduced.
However, the position error at the acceleration change point will become larger.
OMNUC G5-series (Pulse-train Input Type) AC Servomotors and Servo Drives User's Manual
Motor speed
Speed Feed-forward Amount = 100 [%] (fixed)
Torque
Feed-forward Amount
0 [%]
50 [%]
100 [%]
6 Applied Functions
Time
6
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