User manual of EL8-EC***F AC Servo
258
Notch filter depth
The ratio between input and output of center frequency.
When depth = 0, center frequency output is totally off and when depth = 100,
Hence when notch filter depth is set at lower value, the depth is higher and better
at suppressing mechanical resonance but it might cause system instability.
If the ___ from mechanical properties analysis tool doesn’t show any obvious peak but
vibration did occur, it might not be due to mechanical resonance, it may be that servo gain
has reached its limit. This kind of vibration can’t be suppressed by using notch filter, only
by reducing gain and torque command filter time.
To use notch filter
Automatic notch filter
1. Set Pr2.00 = 1 for auto notch filter adjustment
2. If Pr0.03 stiffness increases, 3
rd
group of notch filter (Pr2.07/Pr2.08/Pr2.09)
updates automatically when driver is enabled. Pr2.00 = 0, auto adjustments stop.
If resonance is suppressed, it means self-adjusting notch filter is working. If
resonance occurs when mechanical stiffness increases, please use manual notch
filter, set filter frequency to actual resonant frequency.
Manual notch filter
There are 2 ways to use manual notch filter.
1.
After enabling self-adjusting notch filter, set the values from 3
rd
group of filters to
1
st
group of notch filter (Pr2.01/Pr2.02/Pr2.03), see if resonance is suppressed. If
there is other resonance, set Pr2.00 = 1, then set the values from 3
rd
group of filters to
2
nd
group of notch filter (Pr2.04/Pr2.05/Pr2.06)
2.
Get resonant frequency, notch filter bandwidth and depth and set it into the
corresponding parameters through Motion Studio.
