Fractional Order Controllers Versus Integer Order Controllers

Most industrial applications are using classical, integer order type PID controllers due to the widely known characteristics such as: simplicity, the existence of tuning methods based on process model and the provided robustness performances. However, in recent years, academic and industrial world's attention has been focused on fractional order PID controllers.This paper presents the general approach of the calculation and the fractional order systems as they are documented in the literature, and the transfer functions for the fractional order PID controllers. In simulation experiments, conducted in Matlab, processes described by the first-order transfer functions and dead time, classical and fractional order PID controllers obtained by Zeigler-Nichols tuning method were considered.