Adaptive asymptotic tracking control of uncertain fractional-order nonlinear systems with unknown control coefficients and actuator faults.

For uncertain fractional-order nonlinear systems (UFONS) with unknown control coefficients and intermittent actuator faults, the asymptotic tracking control problem is investigated in this paper. Firstly, to weaken the influence of virtual control coefficients and intermittent actuator faults, a smooth fractional-order projection operator-based adaptive compensation mechanism is presented. Additionally, a fractional-order nonlinear filter is constructed to replace the fractional-order derivative of virtual control functions approximately, which not only avoids the issue of complexity explosion existed in backstepping control frame, but fully compensates the effects of boundary errors caused by the employed filter in spite of the unknown virtual control coefficient. By constructing a fractional Lyapunov function from the property of projection operator, it is proved that all signals in the closed-loop system are bounded, and the asymptotic tracking control object is achieved. Definitively, a simulation study is presented to verify the availability of the presented method. • This paper investigates the issue of asymptotic tracking control design for fractional-order nonlinear systems with unknown control coefficients and actuator faults. • Firstly, in order to weaken the influence of virtual control coefficient, an adaptive compensation mechanism based on the smooth fractional-order projection operator design method is proposed. • Additionally, a fractional-order nonlinear filter is constructed to approximately replace the virtual control functions as well as its fractional-order derivative, which not only avoids the inherent complexity explosion problem under the framework of backstepping, but also fully compensates the effect of boundary error caused by the introduced filter when the virtual control coefficient is unknown. [ABSTRACT FROM AUTHOR]