Maxsine EP3 E Series - Low Pass Filter; Notch Filter

4.6 Resonance suppressions
55
4.6.1 Low pass filter
Set by the parameter P007. The low pass filter is valid by default. Low pass filter has good
attenuation to high frequency and can suppress high frequency resonance and noise. For example,
the use of ball screw machinery to improve the gain of the driver, sometimes high frequency
resonance will occur, the use of low pass filter has a better effect. However, the response
bandwidth and phase margin of the system are also reduced, and the system may become
unstable. If the system is resonant at low and medium frequency, the low pass filter cannot
suppress it.
When high frequency vibration of the machine is caused by servo drive, the time constant
T
f
of the torque filter is adjusted. This may eliminate the vibration. The smaller the value is, the
more responsive the control can be, but it is limited by mechanical conditions. The higher the
value is, the more it can suppress the high frequency vibration, and the higher the value is, the
less the phase margin will be, and the oscillation will be caused. If the load moment of inertia
ratio G is set correctly (G=J
L
/J
M
), it shall meet the following requirements:
)(22
1000
)(
HzK
msT
v
f



4.6.2 Notch filter
Set by parameters P200 ~ P205, two notch filters can be used at the same time to suppress
the resonance of two different frequencies. By default both notch filters are turned off. If the
resonant frequency can be known, the notch device can eliminate the resonant amount directly.
In general, if the resonant frequency is determined, the notch filter is better than the low-pass
filter. When the resonance frequency is unknown, the suppression frequency can be gradually
reduced in order from high to low, and the suppression frequency at the minimum vibration
point is the optimal set value. However, if the resonance frequency deviates from time to time or
other factors, and the deviation is too large, it is not suitable for the use of notch device.
In addition to the frequency, you can also adjust the notch depth and quality factor, but pay
attention to the appropriate Settings. With the depth of the notch wave, the effect of mechanical
resonance suppression may be very good, but it will cause great phase change, and sometimes it
will strengthen the vibration. Small quality factor, wide notch width, the effect of mechanical
resonance suppression may be very good, but it will cause a large phase change area, sometimes
it will strengthen the vibration.