Fractional order controller design for desired response

This article presents a design method for a fractional order controller based on using fractional order systems with time delay as the desired transfer function response. The method is applied to various typical stable processes. Obtained fractional controllers may be considered as a special case of fractional proportional-integral-derivatives. Analytical expressions are derived to determine the fractional controller parameters. Diffusive representation is used to achieve the fractional systems by a rational transfer function. Illustrative examples are considered to show the effectiveness of the proposed method. The desired specifications are fulfilled with a good accuracy using fractional controllers, in comparison with the conventional controllers.