Kollmorgen AKD PDMM series, User Manual

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AKD PDMM User Guide | 12.3.4.1 Tuning the Velocity Loop
When in velocity operation mode, only the velocity loop is tuned. When in position operation mode, both
the velocity and position loops must be tuned.
12.3.4.1 Tuning the Velocity Loop
The velocity loop on the AKD PDMM consists of a PI (proportional, integral) in series with two anti-res-
onance filters (ARF) in the forward path and two-anti resonance filters in series in the feedback path.
To perform basic tuning of the velocity loop, you can use just the PI block and set ARF1 and ARF2 to
unity (no effect) and set the observer to 0 (no effect). Using just the PI block simplifies the process of tun-
ing the velocity loop. To start tuning you can adjust the PI Controller block first. A simplified velocity loop
without anti-resonant filters and observer is shown below. This is how you can think of the loop before the
anti resonant filters and observer is used.
Procedure for simple velocity loop tuning:
1. Set DRV.OPMODE to velocity or position, as appropriate for your application. If DRV.O-
PMODE is set to position, set VL.KVFF to 1.0.
2. Set VL.KP to 0.
3. Set VL.KI to 0.
4. Set service motion to make a motion that is similar to the move speeds that will be used in the
real application. Do not set the service motion to a speed higher than ½ of the maximum motor
speed, to allow for safe overshoot during tuning. Set acceleration to an appropriate value for
your application. Set service motion to reversing. Set time1 and time2 equal to 3 times the
expected settling time for the system. 1.0 second is a reasonable value for time1 and time2, if
you don’t know the expected settling time.
5. Enable the drive and start the service motion. You should see no motion, as there are no veloc-
ity loop tuning gains at this point.
6. When adjusting VL.KP and VL.KI, below record VL.FB and VL.CMD. These are the traces that
are used to determine the performance of the velocit loop.
89 Kollmorgen™ | December 2012