Procedure
1. Set both
ARF0
and
ARF1
to 400 Hz and set
KVP
low enough
to prevent oscillation.
2. Increase
KVP
slowly until oscillation at the resonant
frequency just begins. Then, reduce
KVP
slightly until the
oscillation just stops. Compute the velocity loop bandwidth
using the formula given at the beginning of this section. If
the velocity loop bandwidth is less than .25 times the value
of
ARF0
and
ARF1
, then proceed to Step 3. Otherwise, go to
Step 4.
3. Decrease both
ARF0
and
ARF1
by 20% and go back to Step
2.
4. The velocity loop bandwidth should now be approximately
one quarter the value of
ARF0
and
ARF1
. For margin,
reduce
KVP
,
ARF0
, and
ARF1
by 20%.
Backlash
Some backlash may be unavoidable, especially when gear
reduction is used. If backlash is present, the inertia match must
be good (load inertia should be roughly equal to motor inertia) for
good servo performance. Gearing reduces the inertia reflected to
the motor by the square of the gear reduction from motor to load.
Therefore, select a gear ratio to give the required match.
4 - 6
MA950
