8.13 Manual Tuning
8.13.1 Tuning the Servo Gains
8
T
uning
8-77
Notch filter
The notch filter can eliminate specific frequency elements generated by the vibration of sources
such as resonance of the shaft of a ball screw.
The notch filter puts a notch in the gain curve at the specific vibration frequency (called the
notch frequency). The frequency components near the notch frequency can be reduced or
removed with a notch filter.
Notch filters are set with three parameters for the notch filter frequency, notch filter Q value,
and notch filter depth. This section describes the notch filter Q value and notch filter depth.
•
Notch Filter Q Value
The setting of the notch filter Q value determines the width of the frequencies that are filtered
for the notch filter frequency. The width of the notch changes with the notch filter Q value. The
larger the notch filter Q value is, the steeper the notch is and the narrower the width of frequen-
cies that are filtered is.
The notch filter frequency characteristics for different notch filter Q values are shown below.
Note: The above notch filter frequency characteristics are based on calculated values and may be different from
actual characteristics.
•
Notch Filter Depth
The setting of the notch filter depth determines the depth of the frequencies that are filtered for
the notch filter frequency. The depth of the notch changes with the notch filter depth. The
smaller the notch filter depth is, the deeper the notch is, increasing the effect of vibration sup-
pression. However, if the value is too small, vibration can actually increase.
The notch filter is disabled if the notch filter depth, d, is set to 1.0 (i.e., if Pn419 is set to 1,000).
The notch filter frequency characteristics for different notch filter depths are shown below.
Note: The above notch filter frequency characteristics are based on calculated values and may be different from
actual characteristics.
0
-5
-10
-20
-15
Q = 0.7
Q = 1.0
Q = 0.5
Attenuation [dB]
Frequency [Hz]
0
-10
-20
-
3
0
-50
-40
d = 0.7
d = 0.1
d = 0.
3
d = 0.5
d = 0 (default
s
etting)
Attenuation [dB]
Frequency [Hz]
d = 1.0 (notch filter di
s
abled)
