Mitsubishi Electric MELSERVO-J4 Series Instruction Manual page 245

■Parameter adjustment
• [Pr. PB09 Speed loop gain]
This parameter determines the response level of the speed control loop. Increasing this value enhances response but a too
high value will make the mechanical system liable to vibrate. The actual response frequency of the speed loop is as indicated
in the following expression.
Speed loop response frequency [Hz] =
• [Pr. PB10 Speed integral compensation]
To eliminate stationary deviation against a command, the speed control loop is under proportional integral control. For the
speed integral compensation, set the time constant of this integral control. Increasing the setting lowers the response level.
However, if the load to motor inertia ratio is large or the mechanical system has any vibratory element, the mechanical system
is liable to vibrate unless the setting is increased to some degree. The guideline is as indicated in the following expression.
Speed integral compensation setting [ms] ≥
• [Pr. PB07 Model loop gain]
This parameter determines the response level to a speed command. Increasing the value improves trackability to a speed
command, but a too high value will make overshoot liable to occur at settling.
Model loop gain guideline ≤
For position control
■Parameter
The following parameters are used for gain adjustment.
Parameter
PB06
PB07
PB08
PB09
PB10
■Adjustment procedure
Step Operation
1 Brief-adjust with auto tuning. Refer to the following.
Page 239 Adjustment procedure by auto tuning
2 Change the setting of auto tuning to the manual mode ([Pr. PA08]: _ _ _ 3).
3 Set the estimated value to the load to motor inertia ratio/load to motor mass ratio. (If the estimate
value with auto tuning is correct, setting change is not required.)
4 Set a small value to the model loop gain and the position loop gain. Set a large value to the speed
integral compensation.
5 Increase the speed loop gain within the vibration- and unusual noise-free range, and return slightly if
vibration takes place.
6 Decrease the speed integral compensation within the vibration-free range, and return slightly if
vibration takes place.
7 Increase the position loop gain, and return slightly if vibration takes place.
8 Increase the model loop gain, and return slightly if overshoot takes place.
9 If the gains cannot be increased due to mechanical system resonance or the like and the desired
response cannot be achieved, response may be increased by suppressing resonance with the
adaptive tuning mode or machine resonance suppression filter and then executing steps 3 to 8.
10 While checking the settling characteristic and motor status, fine-adjust each gain.
Speed loop gain
(1 + Load to motor inertia ratio) × 2π
Speed loop gain/(1 + Load to motor inertia ratio)
Speed loop gain
(1 + Load to motor inertia ratio)
Symbol Name
GD2 Load to motor inertia ratio/load to motor mass ratio
PG1 Model loop gain
PG2 Position loop gain
VG2 Speed loop gain
VIC Speed integral compensation
2000 to 3000
1 1
× to
4 8
6 NORMAL GAIN ADJUSTMENT
Description




Increase the speed loop gain.
Decrease the time constant of the speed
integral compensation.
Increase the position loop gain.
Increase the model loop gain.
Suppression of machine resonance
Page 247 Machine resonance
suppression filter
Page 250 Adaptive filter II
Fine adjustment
6.4 Manual mode
6
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