Gain Adjustment Of Position Control (Pr.422, Pr.423, Pr.427, Pr.446, Pr.463, Pr.698, Pr.877) - Mitsubishi Electric FR-E700EX Instruction Manual

Position control
4.5.3 Gain adjustment of position control
(Pr.422, Pr.423, Pr.427, Pr.446, Pr.463, Pr.698, Pr.877)
Parameter
number
422 Position control gain
423 Position feed forward gain
427 Excessive level error
446 Model position control gain
Position control rotation
463
direction selection
698 Speed control D gain
Feed forward control/model
877
adaptive control selection
 The above parameters can be set when Pr.160 Extended function display selection = "". (Refer to page 182)
(1) Position loop gain (Pr.422)
 Make adjustment when any of such phenomena as unusual vibration, noise and overcurrent of the motor/machine
occurs.
 Increasing the setting improves trackability for the position command and also improves servo rigidity at a stop, but
oppositely makes an overshoot and vibration more liable to occur. The droop pulse amount is determined according to
the following formula.
Droop pulse amount (pulse)
 With the actual speed response of 100 rad/s (sec
10 to 1/3 of the actual speed response. As a guideline, normally set the position control gain in a range between 5 to 50
-1
rad/s (sec ).
Example) With the actual speed response of 200 rad/s, when setting Pr.422 to 1/10 of the speed response
Pr.422 = 200rad/s(sec
Phenomenon/Condition
Slow response
Overshoot, stop-time vibration or
other instable phenomenon
occurs.
(2) Position feed forward gain (Pr.423, Pr.877 = "1")
 This function is designed to cancel a delay caused by the droop pulses.
 When the position response or speed response (trackability of the speed command) is low, adjust Pr.423.
 Set a small value in Pr.423 first, and then increase the value gradually until the target position response or speed
response is acquired. Set this parameter within the range where an overshoot or vibration will not occur. The guideline
value is approximately 90%.
 This function has no effects on servo rigidity at a stop.
92
Name Initial value
20sec
40K pulses
0sec
Rotation speed (r/min)
60
=
-1
)1/10 = 20rad/s(sec
Increase the setting value.
Increase the value 3rad/s(sec
vibration or other instable phenomenon occurs, and set about 0.8 to 0.9 of that value.
Decrease the setting value.
Decrease the value 3rad/s(sec
vibration or other instable phenomenon does not occur, and set about 0.8 to 0.9 of that value.
Setting
range
-1 -1
0 to 150sec
0% 0 to 100%
0 to 400K pulses
-1 -1
0 to 150sec
0
0
1
0% 0 to 100%
0
0 1
2
Motor internal command resolution

(5120 pulses/rev)
Pr.422 Position control gain (sec
-1 -1
) to 200 rad/s (sec ), set Pr.422 so that the position control gain is 1/
-1
)
Pr.422 Adjustment
-1 -1
) by 3rad/s(sec
-1
) by 3rad/s(sec
Description
Set the gain of the position control.
Function to cancel a delay caused by the
droop pulses.
If the droop pulse [after the electronic gear]
exceeds the set value, the excessive position
error (E.OD) occurs.
Set the gain for the model position controller.
The position pulse increases when the motor
rotates CCW.
The position pulse decreases when the motor
rotates CW.
The position pulse decreases when the motor
rotates CCW.
The position pulse increases when the motor
rotates CW.
Set the differential gain of speed control.
Valid only during positioning operation under
position control.
Normal position control is performed.
Feed forward control is performed.
Model adaptive speed control is performed.
-1
)
) until just before an overshoot, stop-time
-1
) until just before an overshoot, stop-time