A new approach to tune the two-degree-of-freedom (2DOF)

This paper proposes a new tuning method for PI controllers in two-degree-of-freedom (2DOF) structure. In design approach, first order plus dead time (FOPDT) model is used. The aim is to have good set-point response and disturbance rejection and also maximum robustness to model uncertainties. The tuning strategy is based on using Butterworth rules and genetic algorithm optimization. Simulation results demonstrate the effectiveness and validity of proposed method in coping with conflicting design objectives for a wide variety of processes including minimum phase and non-minimum phase and also integrating processes.