Software Implementation of FOPID Controllers with Tuning Capability for Fractional FOPDT Plants

In the present paper, two software implementations of fractional-order proportional-integral-derivative (FOPID) controllers are presented. Both implementations are based on discrete time modeling. One of the implementations is also endowed with a FOPID controller gain tuning algorithm based on knowledge of the dynamics of plant under study, namely a fractional-order first-order plus dead time model. The presented implementations are intended to be used on embedded platforms, including Python-capable devices, but can easily be implemented in a distributed control system (DCS) environment that has C/C++ programming language support. In the paper we reflect on the main ideas behind the implementations and provide two examples produced in a software-in-the-loop (SIL) environment with MATLAB/Simulink implementing the controlled plant and also providing a simulation result for comparison. These examples indicate the validity of the proposed implementations.