Safety-Critical Fixed-Time Trajectory Tracking of Quadrotor UAVs via Event-Triggered Prescribed Performance Sliding Mode Control

This paper proposes a safety-critical fixed-time sliding mode control (SMC) strategy for quadrotor unmanned aerial vehicles (UAVs) to achieve precise trajectory tracking under external disturbances and prescribed performance constraints. A fixed-time prescribed performance function is first introduced, and by incorporating the state transformation technique into the SMC design, the proposed method guarantees that the closed-loop systems converge to prescribed small neighborhoods of zero within fixed time. Simultaneously, the tracking errors are strictly confined within user-defined safety boundaries at all times, despite external disturbances. To mitigate communication bandwidth limitations, a dynamic event-triggered mechanism is further developed for electronic speed-data transmission. Fixed-time convergence to the sliding surfaces and overall system stability are rigorously established using Lyapunov stability theory. Moreover, a cascaded control architecture is devised, wherein the proposed controller determines the desired accelerations, which are then utilized to compute the corresponding orientation and angular rates. Compared with existing tracking control approaches, the proposed framework not only ensures rapid convergence and guaranteed tracking performance but also significantly reduces communication overhead. The effectiveness and advantages of the method are demonstrated through simulation results.