DE-based tuning of PI(λ)D(μ) controllers

A new method that relies on evolutionary computation concepts is proposed in this paper to tune the parameters of fractional order PI(λ)D(μ) controllers, in which the orders of the integral and derivative parts, λ and μ, respectively, are fractional. The main advantage of the fractional order controllers is that the increase in the number of parameters in the controller allows an increase in the number of control specifications that can be met. A Differential Evolution (DE) algorithm is proposed to make the controlled system fulfill different design specifications in time and frequency domains. This method is based on the minimization of a fitness function. Experiments have been carried out in simulation and in a real DC motor platform. The results illustrate the effectiveness of this method.