Fractional-order nonlinear systems with fault tolerance

In this work, a fault-tolerant control methodology is proposed for a class of fractional-order nonlinear systems. First, the faults are diagnosed by means of a fractional PI reduced-order observer. Then, it is constructed a fractional canonical form, from where a fractional high-gain observer is proposed. A fractional dynamical controller is designed, which performs output tracking to achieve fault tolerance. It is proved that the origin of the system in closed-loop is Mittag-Leffler stable. This scheme is applied on the fractional model of the Van der Pol oscillator.