Drive Configuration
Verification of the Setup
If the position error shows oscillations of a certain frequency, check the Bode plot for a reason of the
oscillation (see also Figure 63 and 64). Try to adjust the parameters to increase the damping (increase
phase margin) or reduce the amplitude. Consider applying filters to damp the oscillation.
If the position error increases when a certain velocity is reached, the limit for the voltage output might
have been reached (see also
OutputLimit
of the current controller in 5.2.8).
If the position error increases when a certain acceleration is reached, the limit for the current output
might have been reached (see also
OutputLimit
of the position controller in 5.2.4 ).
5.5.4 Acceleration and Velocity Feed forward.
The following setup is used to verify the acceleration feed forward (see also 5.4.6):
1. Prepare the scope
by loading the
Scope Configuration
named
Feed Forward Analysis
.
2. Prepare the
Axis Module
: Setup a reasonable move between A and B. Activate the
Loop After
check-box and set a wait time of about 500ms.
3. Start the scope and execute moves by pressing
Move AB
.
If the acceleration feed forward is correctly configured, the
FeedForwardCurrent
should match the ac-
celeration related part of
ActualCurrentQ
and the position error becomes much smaller compared to
without acceleration feed forward. In some cases also velocity feed forward has to be added to get a
good match.
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Figure 65: Feed forward signal with only acceleration feed forward (left) and with additional velocity feed forward
(right).