
B-65270EN/05 4.SERVO FUNCTION DETAILS
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4.5 MACHINE RESONANCE ELIMINATION FUNCTION
4.5.1 Torque Command Filter (Middle-Frequency Resonance
Elimination Filter)
(1) Overview
The torque command filter applies a primary low-pass filter to the
torque command.
If the machine resonates at one hundred Hz or over, this function
eliminates resonance at such high frequencies.
(2) Series and editions of applicable servo software
(Series 30i,31i,32i)
Series 90D0/A(01) and subsequent editions
Series 90E0/A(01) and subsequent editions
(Series 15i-B,16i-B,18i-B,21i-B,0i-B,0i Mate-B, Power Mate i)
Series 9096/A(01) and subsequent editions
Series 90B0/A(01) and subsequent editions
Series 90B1/A(01) and subsequent editions
Series 90B6/A(01) and subsequent editions
(Series 0i-C,0i Mate-C,20i-B)
Series 90B5/A(01) and subsequent editions
(3) Explanation
Fig. 4.5.1 shows the configuration of a velocity loop including the
torque command filter.
VCMD
Motor
TCMD
Velocity feedback
+
−
PK1V/s + PK2V
Kt/Jm • s
Torque command filter
Fig. 4.5.1 Configuration of velocity loop including torque command filter
As shown in Fig. 4.5.1, the torque command filter applies a low–pass
filter to the torque command. When a mechanical system contains a
high resonant frequency of more than 100Hz, the resonant frequency
component is also contained in the velocity feedback shown in Fig.
4.5.1 and may be amplified by proportional term. However, the
resonance is prevented by interrupting the high–frequency component
of the torque command using the filter.
(4) Proper use of the observer and torque command filter
The torque command filter is set in the forward direction. Therefore,
there are fewer bad influences exerted upon the entire velocity control
system than the observer that filters a feedback signal. If the resonance
is very strong and it cannot be eliminated, use the observer.