QFT loop shaping with fractional order complex pole-based terms

In this work we propose a new family of fractional order structures, composed of so-called Fractional order Complex pole-based Terms (FCTs), to be used for Quantitative Feedback Theory (QFT) loop shaping. The choice of this kind of structure is discussed, and its ability to approach the optimal solution (close-to-optimality) is shown by comparing the results obtained by FCT-based structures to other fractional structures introduced previously in the literature. The ability of FCT-based structures to solve QFT problems is shown by solving a benchmark robust control problem.