Event-Triggered Adaptive Fixed-Time Trajectory Tracking Control for Stratospheric Airship

This paper proposes a trajectory tracking controller to address the issue of the unmeasurable airspeed of a stratospheric airship. First, we propose a fixed-time extended state observer in solving the issues of unknown disturbances and unmeasurable airspeed. Utilizing the sliding mode control and backstepping framework, a fixed-time convergent controller is designed in this paper. Then, the fixed-time controller is integrated with the event-triggered mechanism to decrease the actuation frequency of the actuator during the tracking of the predetermined trajectory. After that, we provide a proof that the observer error converges to zero within a fixed time and the semi-global fixed-time uniform ultimate boundedness of the closed-loop output feedback control system is proved by Lyapunov stability analysis. The simulation results validate the efficacy of the algorithm.