Derivative Term Normalization; Rolloff Term Normalization - National Instruments Xmath Interactive Control Design Module ICDM User Manual

Chapter 4 PID Synthesis
Xmath Interactive Control Design Module

Derivative Term Normalization

The derivative term is low-frequency normalized, which means that at low
frequencies (below 1/T
overall controller transfer function at low frequencies. In particular, the
loop transfer function at s = 0 is not affected by the derivative term at all,
so static tracking, static actuator effort, and so on are not affected by the
derivative term. You can start by making the T
gradually increasing it until you get a good balance between better stability
margins and excessive actuator effort.

Rolloff Term Normalization

The two HF rolloff terms are low-frequency normalized, so they have little
effect at frequencies below T
parameters, and then gradually increase them until you start to notice a
degradation in stability.
) it is nearly one, and so has little effect on the
diff
. You can start with small values for these
hf
4-6
term small and then
diff
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