Event-Driven Fixed-Time Control for Underactuated Nonlinear Systems: Application to Quadrotor UAVs

This paper presents an event-driven implementation of fixed-time sliding mode control (FxT-SMC) strategy for underactuated nonlinear systems, with application to quadrotor unmanned aerial vehicles. The event-triggered (ET) mechanism is designed to reduce communication and computation burdens while preserving the fixed-time convergence properties of the continuous controller. A nonsingular fixed-time sliding manifold is employed to ensure global convergence within a predefined time and to avoid singularities near the origin. When the tracking error enters a small neighborhood of the equilibrium, the manifold transitions smoothly to a quadratic form, ensuring continuity and eliminating potential singular behavior. Lyapunovbased analysis establishes global fixed-time stability (FxTS) under the ET framework, and Zeno behavior is excluded by design. Simulation results on a quadrotor UAV demonstrate that the proposed event-triggered FxT-SMC achieves precise trajectory tracking with reduced control updates by 74.2% and improved robustness against disturbances and model uncertainties.