Event-Triggered Adaptive Backstepping Dynamic Surface Control for Strict-feedback Fractional-Order Nonlinear Systems

This paper addresses an event-triggered adaptive dynamic surface control (DSC) problem for a class of strictfeedback uncertain fractional-order nonlinear systems (FONS) with external disturbances. An adaptive backstepping DSC approach combined with a serial-parallel estimation (SPE) model is introduced by designing a compensation signal. Specifically, the predicted errors of the system states and the estimated states are utilized for the control and adaptive laws design. A novel eventtriggered scheme with relative-threshold is introduced to reduce the triggering number. It is shown that with the proposed scheme, the semiglobally uniformly ultimate stability of the uncertain FONS is guaranteed, and all the signals of the closed-loop system are bounded. An example for Chua-Hartley's system are shown to demonstrate the effectiveness of the proposed method.