Fractional-order finite-time attitude control for underactuated quadrotors with dynamic event-triggered mechanism

This paper addresses the finite-time attitude tracking control problem for under-actuated quadrotors, utilizing a dynamic event-triggered mechanism (dynamic-ETM) and fractional-order recursive sliding mode control (FORSMC) to handle model uncertainties and external disturbances. Firstly, a high-order sliding mode observer (HOSMO) is introduced to estimate and compensate for disturbances within finite time, effectively reducing the instantaneous changes in the controller and the actuator burden. Secondly, a FORSMC is designed to enhance robustness by leveraging fractional-order differentiation, which improves the accuracy of control inputs without amplifying measurement noise. Thirdly, a dynamic-ETM is employed to update the control inputs only when event-triggered conditions are met, reducing communication and control update frequency while maintaining acceptable performance. Additionally, the minimum inter-event time of the dynamic-ETM is proven to be strictly positive, ensuring the absence of Zeno behavior and the finite-time convergence of the control scheme is rigorously proven. Eventually, the effectiveness of the proposed control scheme is verified by numerical simulation and experimental results, and the control characteristics of the dynamic-ETM are analyzed.