Resonances
Mechanical resonances are caused by springiness between motor
inertia and load inertia. This may result from belts, flexible
couplings, or the torsional stiffness of shafts. In general, the
stiffer the couplings, the higher the resonance frequency and
the easier it is to tune the system for good performance.
If the velocity loop breaks into an oscillation at a frequency well
above the calculated velocity loop bandwidth, a resonance
problem may well exist. A second symptom is that the frequency
of oscillation is relatively constant in the presence of changes to
ARF0
and
ARF1
.
ARF0 & ARF1
Two digital anti-resonant low-pass filters
ARF0
and
ARF1
are
included in the velocity loop. Their purpose is to lower the gain
above f
vc
and especially at any resonant frequency > f
vc
so that
oscillations do not occur. Default values, also a function of the
selected system response, are shown below:
Gentle
Medium
Stiff
ARF0 (Hz)
100
150
1500
ARF1 (Hz)
200
750
1x10
5
If the velocity loop bandwidth cannot be raised to an acceptable
value without encountering a resonant oscillation, the procedure
on the following page is recommended.
MA930 Manual
6 - 5
Содержание OC930
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