Servotronix CDHD2S User Manual page 190

Operations
Please refer to VarComVELCONTROLMODE1.
The figure below shows the PDFF controller. Like the PI controller, the PDFF controller has an
integral gain (KVI) and a proportional gain (KVP), plus a feedforward KVFR.
When the application requires maximum responsiveness, less integral gain is required and
KVFR can be set to a high value. When the application requires maximum low-frequency stiffness,
KVFR is set to a low value, allowing high integral gain without causing overshoot. This will also
cause the system to respond to commands slowly. Moderate KVFR values are generally suitable for
motion control applications.
PDFF is a generalized controller. The control parameters KVP, KVI and KVFR are tuned through
trial and error.
Standard pole placement (PP) controller
Please refer to VarComVELCONTROLMODE2.
For pole placement (PP) controller tuning, only two parameters are required: load inertia ratio
(LMJR) and closed loop system bandwidth (BW).
Figure 7-4 Velocity control loop PDFF controller
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