Online Fractional-Order PIα Controller Tuning Scheme

This paper proposes a new design of fractional order adaptive PI (PIα) controller for a class of first order plus time delay (FOPTD) plants. An offline tuning method is achieved to fix the fractional order α, to satisfy gain and phase margin specifications. Then, an adaptive control is used to adjust online the basic parameters Kp and Ki. The robustness of the proposed scheme is ensured by the property of the well-known Bode’s ideal transfer function. The resulting adaptive control ensures more robustness against gain variations, due to the use of fractional operators. Simulation results confirm much the effectiveness of the proposed tuning scheme.