Mitsubishi Electric MR-J2S-CP Instruction Manual page 215

8. GENERAL GAIN ADJUSTMENT
(c) Adjustment description
1) Speed control gain 2 (parameter No. 37)
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)
2) Speed integral compensation (VIC: parameter No. 38)
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 inertia
moment 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)
(2) For position control
(a) Parameters
The following parameters are used for gain adjustment.
Parameter No.
7
34
37
38
(b) Adjustment procedure
Step
Set an estimated value to the ratio of load inertia moment to servo motor
1
inertia moment (parameter No. 34).
Set a slightly smaller value to the position control gain 1 (parameter No.
2
7).
Increase the speed control gain 2 (parameter No. 37) within the vibration-
3
and unusual noise-free range, and return slightly if vibration takes place.
Decrease the speed integral compensation (parameter No. 38) within the
4
vibration-free range, and return slightly if vibration takes place.
5 Increase the position control gain 1 (parameter No. 7).
If the gains cannot be increased due to mechanical system resonance or
the like and the desired response cannot be achieved, response may be
6 increased by suppressing resonance with adaptive vibration suppression
control or machine resonance suppression filter and then executing steps
3 to 5.
While checking the settling characteristic and rotational status, fine-
7
adjust each gain.
Speed control gain 2 setting
(1 ratio of load inertia moment to servo motor inertia moment) 2
Speed control gain 2 setting/
Abbreviation
PG1 Position control gain 1
GD2 Ratio of load inertia moment to servo motor inertia moment
VG2 Speed control gain 2
VIC Speed integral compensation
Operation
8 - 8
2000 to 3000
(1 ratio of load inertia moment to
servo motor inertia moment setting 0.1)
Name
Increase the speed control gain.
Decrease the time constant of the speed
integral compensation.
Increase the position control gain.
Suppression of machine resonance.
Refer to section 9.2, 9.3.
Fine adjustment
Description