Reply To: Fractional PID Controller Design

[Aleksei]

Hi,
No, there is no overloading function `stepinfo()` for the fractional-order transfer function object yet, but the CST version can be employed as well. Consider an example:

loadsets
[y,t]=step(oustapp(G2));
stepinfo(y,t,1)

Here, I first load the example systems provided with FOMCON, then approximate a fractional-order system G2 by an integer-order one in the form of a refined Oustaloup recursive filter and obtain y and t vectors explicitly.

Note, however, that approximation parameters for a particular system need to be thoroughly selected to obtain a feasible result.