FFPDT_FID Frequency-domain identification of FO-FOPDT model
[K,L,T,ALPHA] = FFPDT_FID(W,K,KDC,L,H) identifies a
fratcional-order FOPDT model of the form
Kdc -L*s
G(s) = -------------- e
alpha
1 + T * s
to be used in auto-tuning. The user must supply a set of
identified points {(w1,k1), (w2,k2), ...} where each entry
corresponds to a single (frequency, gain) point on the
frequency response plot. The parameters T and alpha are then
determined. The delay value must also be supplied but is not
used in the computations at this point, so the same value will
be returned by the function. At least two points are needed.
H must be a set of strictly decreasing step values for
computation, e.g. H=[0.25 0.1 0.01] (default). ALPHA range is
permanently set to [0, 2] and cannot be changed.