Improvement of Control Performances Using Fractional Pid Controllers

This paper deals with the tuning of fractional PID controllers, in which the orders of the integral and derivative parts, λ and μ, respectively, are fractional. The purpose is to take advantage of the introduction of these two parameters and fulfil additional specifications of design. A new method for tuning the fractional PID controller is proposed in this paper. The basic ideas of this new tuning method are based, in the first place, on the classical ZieglerNichols tuning method for setting the parameters of the fractional PID controller for λ=μ=1 which means setting the parameters of the classical PID controller, and on the minimum ISE criterion by using the Hall-Sartorius method for setting the fractional integration action order λ and the fractional differentiation action order μ. Illustrative examples and simulation results are presented to show the control quality enhancement of this proposed fractional PID controller conception method compared to the PID controller conception using the Ziegler-Nichols tuning method. It is shown that the fractional PID controller gives more robustness and good control behaviour in presence of noise.