Speed Loop Delay Compensation - Mitsubishi MELDAS MDS-C1 Instruction Manual

4-4-2

Speed loop delay compensation

Generally, the tool end position follows the operation later than the motor end position. With full closed
loop position loop control, the tool end position is used for position feedback, so the motor end position
could advance too far and cause the tool end position to overshoot easily. Speed loop delay
compensation suppresses overshooting by weakening the speed loop PI control (weakening advance
compensation = delaying). If the compensation is too large and PI control is weakened too far, the
positioning time could increase, or the position droop will remain when the motor is stopped.
<Adjustment method>
1. Set the servo function selection 1 (SV027: SSF1) bit1, 0 to 10. (Select delay compensation
changeover type 2)
2. Set the axis unbalance torque to the torque offset (SV032: TOF). (Refer to "4-3-5 (2) Unbalance
torque compensation" for details on measuring the unbalance torque.)
3. Observe the position droop waveform, and confirm the overshooting. Increase SV007 (VIL) in
increments of 5, and adjust so that the overshooting is improved. If set too high, the position
droop will remain when the axis is stopped.
No. Abbrev. Parameter name
Speed loop delay
SV007 VIL
compensation
SV032 TOF Torque offset
SV027 SSF1 Servo function
selection 1
CAUTION
4. Servo Adjustment
Set this when the limit cycle occurs in the full-closed loop, or overshooting
occurs in positioning.
Select the control method with SV027 (SSF1)/bit1, 0 (vcnt).
Normally, use "Changeover type 2".
When you set this parameter, make sure to set the torque offset SV032
(TOF). When not using, set to "0".
Changeover type 2 When SV027 (SSF1)/ bit1, 0 (vcnt)=10
The delay compensation control works when the command from the
NC is "0" and the position droop is "0". Overshooting or the limit cycle
that occurs during pulse feeding or positioning can be suppressed.
Set the unbalance torque of vertical axis and inclined axis.
F E D C
aflt zrn2 afse
bit
Set the execution changeover type of the speed loop delay
0
compensation.
vcnt
1 00: Delay compensation changeover
invalid
01: Delay compensation changeover
type 1
The position droop will remain if SV007 is set too high.
Explanation
B A 9 8 7
ovs lmc omr zrn3
Meaning when "0" is set
4 - 30
Setting range
0 to 32767
-100 to 100
(Stall [rated]
current %)
6 5 4 3 2 1
vfct upc vcnt
Meaning when "1" is set
10: Delay compensation
changeover type 2
11: Setting prohibited
0