Position Control Gain Adjustment - Mitsubishi Electric 800 Series Instruction Manual (Function

7.8

Position control gain adjustment

Vector Vector Vector
Adjust gain using the following parameters to achieve optimum machine performance or improve unfavorable conditions, such
as vibration and acoustic noise during operation with high load inertia or gear backlash.
Pr. Name
422
Position control gain
B003
423
Position feed forward gain
B004
425 Position feed forward
B006 command filter
446
Model position control gain
B012
698
Speed control D gain
G219
Speed feed forward control/
877
model adaptive speed
G220
control selection
828
Model speed control gain
G224
880
Load inertia ratio
C114
 Position loop gain (Pr.422)
• Adjust the gain when a phenomena such as unusual vibration, noise and overcurrent of the motor/machine occurs.
• Increasing the setting value improves traceability for the position command and also improves servo rigidity at a stop, but
oppositely may cause an overshoot and vibration.
• The setting range is normally 5 to 50.
Movement/ condition
Increase the setting value.
Increase the setting value by 3 s
Response is slow.
overshoot, stop-time vibration or other instable phenomenon, and set about
80% to 90% of that value.
Lower the setting value.
Overshoot, stop-time
Lower the setting value by 3 s
vibration or other instable
overshoot, stop-time vibration or other instable phenomenon, and set about
phenomenon occurs.
80% to 90% of that value.
 Position feed forward gain (Pr.423)
• This function is designed to cancel a delay caused by the droop pulses in the deviation counter. Set this parameter when
a sufficient position response cannot be obtained after setting Pr.422.
• When a tracking delay for command pulses poses a problem, increase the setting value gradually within the range where
an overshoot or vibration will not occur.
• This function has no effects on servo rigidity at a stop.
• Normally set this parameter to 0.
• To set Pr.423, set Pr.877 = "1" to enable position feed forward control.
 Model adaptive position control (Pr.446)
• Set each response for position commands and for load and external disturbances individually.
• Set this parameter when a sufficient position response cannot be obtained after setting Pr.422.
• When setting Pr.446, set Pr.877 = "2" to enable the model adaptive position control, and set a value other than "0" in Pr.828
Model speed control gain, and a load inertia ratio in Pr.880 Load inertia ratio.
• Set a small value in Pr.446 first, and then increase the setting value gradually within the range where an overshoot or
vibration will not occur.
Initial value Setting range
-1 -1
Set the gain for the position loop.
10 s 0 to 150 s
Enable the function to cancel a delay caused by the droop
0% 0% to 100%
pulses in the deviation counter.
0 s 0 to 5 s Input the primary delay filter for the feed forward command.
-1 -1
Set the gain for the model position controller.
25 s 0 to 150 s
0% 0% to 100% Set the differential gain of speed control.
0 Normal position control is performed.
0 1 Perform position feed forward control.
2 Enable Model adaptive position control.
100 rad/s 0 to 1000 rad/s Set the gain for the model speed controller.
7-fold 0 to 200-fold Set the load inertia ratio for the motor.
How to adjust Pr.422
-1
until immediately before occurrence of an
-1
until immediately before occurrence of an
Description
7. Position Control
7.8 Position control gain adjustment
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