[Aleksei]

At this time FOMCON supports control of SISO plants only. While MIMO control is possible with cascades of FOPID controllers, this falls out of the current scope of the toolbox, hence I cannot provide support for it.

[Aleksei]

Dear Shefali,
Use the FOMCON FOPID tuning tool, it supports SISO state-space models as well.

[Aleksei]

Dear Smita,
ZN is an aggressive tuning rule (albeit frequently used).
I have no idea what you mean by “Duarte Valerio” tuning rules, as these are not implemented in FOMCON.

• This reply was modified 8 years, 11 months ago by Aleksei.

[Aleksei]

The latest version is 0.41-beta. The next version should be out by the end of the year.

[Aleksei]

At the moment, it is not possible to assess the stability of systems with delays.
The latest version is 0.41-beta, for which a patch has been released in April. See this post: https://fomcon.net/forums/topic/preliminary-releases-and-patches/#post-914

[Aleksei]

Please elaborate. If you use Simulink then you can use the fractional PID block from the FOMCON library.

[Aleksei]

Kindly provide more details about the issue. What are you trying to do?

[Aleksei]

The choice of min/max step size depends on the dynamics of the control system under study. In addition, the difference in the transient response with different step sizes may be related to the Simulink solver used. This is all I can say without further details about your simulation.

• This reply was modified 9 years, 3 months ago by Aleksei.

[Aleksei]

You can use the fotfid tool for this purpose.

[Aleksei]

Please check out this part of the online documentation.

[Aleksei]

FO lead/lag compensators are equivalent to band-limited FO PI/PD controllers implemented in a specific frequency range $(\omega_b,\omega_h)$. You can tune these in FOMCON.

• This reply was modified 9 years, 5 months ago by Aleksei.

[Aleksei]

This is a patch related to incompatibility of propertiesGUI used in FOMCON version 0.41-beta with MATLAB R2014a. Anyone using this version of MATLAB should download and apply the following patch: 0.41-beta-patch-2014_04_23.zip

Put the folder inside the patch into the fomcon root directory and overwrite the affected file.

• This reply was modified 9 years, 5 months ago by Aleksei.
• This reply was modified 9 years, 5 months ago by Aleksei.

[Aleksei]

Kindly elaborate.

[Aleksei]

There might be a problem with the implementation of the solver. This part of FOMCON code belongs to the unmodified fotf toolbox code base. The solver *may* have some numerical issues that need to be addressed. I will review the code shortly. Meanwhile, kindly see the following references that document the implementation of the solver:

[1] Y. Q. Chen, I. Petráš, and D. Xue, “Fractional order control – A tutorial,” in Proc. ACC ’09. American Control Conference, 2009, pp. 1397–1411.

[2] D. Xue, Y. Chen, and D. P. Atherton, Linear Feedback Control: Analysis and Design with MATLAB (Advances in Design and Control), 1st ed.. Philadelphia, PA, USA: Society for Industrial and Applied Mathematics, 2008.

[3] C. A. Monje, Y. Chen, B. Vinagre, D. Xue, and V. Feliu, Fractional-order Systems and Controls: Fundamentals and Applications, ser. Advances in Industrial Control. Springer Verlag, 2010.

If you identify an explicit problem with the implementation, do not hesitate to file a bug.

[Aleksei]

The underlying principles are the same. However, different approaches are used: the fractional-order PID may be seen as a generalization of the classical PID, while the CRONE controller is based on a novel control strategy specifically developed by leveraging the flexibility of fractional-order operators. In both cases frequency domain analysis plays an important role, in case of CRONE controllers even more so.

• This reply was modified 9 years, 6 months ago by Aleksei.
• This reply was modified 9 years, 6 months ago by Aleksei.

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