**5. Conclusions**

One should emphasize that the proposed solution of the VFOPID controller do not guarantee the absolute optimum of the closed-loop control system synthesis. It proves that the proposal of a physically realizable VFOPID controller by microcontroller (with finite memory) leads to better results due to the assumed performance criterion.

The main idea of the proposed method is to assume *a priori* the order functions with unknown parameters. In the VFOPID controller synthesis essential is an assumption that the summation order equals 1 One can express the action as the assumption of skeleton order functions with unknown parameters evaluated further in an SSE optimization algorithm.

Here, it is worth mentioning that there are still open problems of the VFOPID controllers tuning.


**Author details**

Piotr Ostalczyk<sup>1</sup>

Lodz, Poland

Lodz, Poland

**13**

\*† and Piotr Duch2†

*Variable, Fractional-Order PID Controller Synthesis Novelty Method*

*DOI: http://dx.doi.org/10.5772/intechopen.95232*

\*Address all correspondence to: postalcz@p.lodz.pl

† These authors contributed equally.

provided the original work is properly cited.

1 Institute of Applied Computer Sciences, Lodz University of Technology No. 1,

2 Institute of Applied Computer Sciences, Lodz University of Technology No. 2,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,
