Fractional-order PI controllers design based on IMC scheme for enhanced performance of dead-time processes

A unified method for the fractional-order proportional-integral controller based on IMC scheme (IMC-FOPI) is proposed. The analytical tuning rules are derived for achieving the performance improvement in terms of both disturbance rejection and set-point tracking. Many illustrative examples are considered to confirm the effectiveness of the proposed algorithm for both integer and fractional-order processes with time delays. In addition, the robust stability of fractional-order systems are also carried out in order to demonstrate that the proposed controller can hold well the robustness against perturbation uncertainty in the process models.