Drive Configuration
Controller Tuning
5.4.6 Acceleration Feed Forward
A proper setting of the value for
FeedForwardAcceleration
is very important to achieve small position
errors during high dynamic movements. The value for
FeedForwardAcceleration
can also be determined
based on the Bode Measurement:
1. Open the measured data with the
Bode Tuning
application. See section 4.4 on how to open the
measurement and how to use the application.
2. Select
Position 0
in the
Select Controller
panel if single loop controller is used.
3. Temporarily set Kr to 1 and all other controller parameters to zero within the Bode Tuning applica-
tion. Also set the filters to
Bypass
. Do not commit these parameters as this setting is only used to
determine the value for the acceleration feed forward.
4. At lower frequencies the amplitude in the Bode view of
Gopen
should show a linear section with
a drop of 40dB per frequency decade. Measure the amplitude
A
with the cursor at a frequency
f
within the linear section (see also Figure 61). The acceleration feed forward can be calculated
with the following equation.
FeedForwardAcceleration
=
1
10
A
20
(
2
π
f
)
2
5. Press the Revert button to reset the parameters.
6. Set and commit the calculated feed forward value in the register
Axis[]/Parameters/PositionCon-
troller/FeedForwardAcceleration
.
5.5 Verification of the Setup
This section describes how to use the
Axis Module
and the
Scope
to verify the setup (see also section
5.5.1 Motor Direction and Magnetic Pitch
To verify the motor direction and the magnetic pitch, the
TestGenerator
is used to apply a rotating cur-
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Figure 61: Calculation of the acceleration feed forward. With a measured amplitude of -65.3dB at 29.8Hz, the accel-
eration feed forward is set to 0.052.
