Vibration Suppression Measures - Mitsubishi Electric MDS-E Series Instruction Manual

MDS-E/EH Series Instruction Manual
5 Servo Adjustment
(4) Adjusting the settling time
The settling time is the time required for the position
droop to enter the in-position width after the feed
command (FΔT) from the CNC reaches 0.
The settling time can be shortened by raising the
position loop gain or using SHG control. However, a
sufficient response (sufficiently large VGN1 setting)
for the speed loop is required to carry out stable
control.
The settling time during normal control when the
CNC is set to linear acceleration/ deceleration can
be calculated using the following equation. During
SHG control, estimate the settling time by multiplying
PGN1 by .
2
Settling time ( ms) =

5.3.2 Vibration Suppression Measures

If vibration (machine resonance) occurs, it can be suppressed by lowering the speed loop gain 1 (VGN1). However,
cutting precision and cycle time will be sacrificed. (Refer to "Speed Loop Gain".) Thus, try to maintain the VGN1 as high
as possible, and suppress the vibration using the vibration suppression functions.
If the VGN1 is lowered and adjusted because vibration cannot be sufficiently suppressed with the vibration suppression
functions, adjust the entire gain (including the position loop gain) again.
(Examples of vibration occurrence)
• A fine vibration is felt when the machine is touched, or a groaning sound is heard.
• Vibration or noise occurs during rapid traverse.
If machine resonance occurs, the resonance frequency can be confirmed at AFLT frequency on NC drive monitor
screen. Based on this frequency, the notch filter frequency can be set. When "0" is displayed, resonance is not occurring.
POINT
Suppress the vibration using the vibration suppression functions, and maintain the speed loop gain (SV005) as high as
possible.
F
Position
droop
F × 10
10 3
60 × G0tL × PGN1
ln
PGN1
PGN1 : Position loop gain1 (SV003)
F : Rapid traverse rate
G0tL : Rapid traverse linear acceleration/
deceleration time constant
INP : In-position width (SV024)
267
F
T
0
G0tL
0
6
PGN1×G0tL
1− exp
2 10
INP
(rad/s)
(mm/min)
(ms)
( m)
Setting time
Time
In -position
In -position width
3
IB-1501229-F