Yaskawa Sigma II Series Servo System - Manual (Page 240)

Sigma II User’s Manual Chapter 6: Servo Adjustment
6 - 8
Notch Filter Function
The notch filter function decreases the response to the set frequency, and effective when
there are machine vibrations. Adjusting the parameter setting according to the machine
vibration frequency reduces the machine vibration.
Torque Reference Filtering and Frequency Characteristics
The torque reference filtering and frequency characteristics are shown in the following
diagrams.
Note: The frequency characteristics shown above indicate that no response of the speed proportional gain can be
obtained if the difference between the speed proportional gain and the vibration frequency is too small.
Setting a smaller Q value decreases the response in wider zone around the set frequency.
Setting a bigger Q value decreases the response in the limited zone at about the set frequency.
When vibration is suppressed but overshoot occurs, increase the Q value may correct the
overshoot.
Notch filtering
(fc = 1/Δt)
Δ t
Torque
reference
wavefor
m
Torque
reference
wavefor
m
Frequency Characteristics When Q is set to 0.7. Frequency Characteristics When Q is set to 2.0
・ｓ＋ω
ｃ
２
ω
ｃ
Ｑ
ｓ ２ ＋
ｓ ２ ＋ω
ｃ
２
（ω
ｃ
＝ 2πｆｃ）
After torque
reference
filtering
Before torque
reference
filtering
fc Frequency fc Frequency
To
rque
refer
ence
To
rque r
efere
nce