Robust Event-Triggered Formation Tracking of Fixed-Wing UAVs Under Aperiodic Communication Outages

Reliable formation tracking of fixed-wing unmanned aerial vehicles (UAVs) is particularly challenging when external acceleration disturbances, command saturation, actuator-induced acceleration tracking errors, sampled communication, and recurrent common-mode outages occur simultaneously. This paper develops a predictor-based robust event-triggered leader–follower framework for a three-dimensional flight-path point-mass outer-loop model. A projected adaptive distributed observer estimates the leader state and is shown to achieve practical fixed-time stability over effective communication-available intervals. A constant-velocity state predictor and a dimensionless sampled-data triggering rule reduce inter-UAV transmissions, where the outage model accounts for physical outages, candidate-grid and dwell-time waiting, and network resynchronization. Prediction-error terms of the same order as the nominal signed-power feedback are retained explicitly to derive sampled-mode dissipation conditions and uniform ultimate boundedness for bounded outages followed by sufficiently long effective communication-available intervals. An adaptive robust controller separately addresses the matched acceleration-channel uncertainty and the unmatched observer-correction input; the virtual inertial acceleration is subsequently mapped to commands for thrust, normal load factor, and flight-path bank angle. Numerical comparisons, ablation studies, sensitivity analyses, and integration-step convergence tests illustrate finite-horizon formation recovery and a communication–accuracy–control-effort trade-off without numerically certifying the analytical recovery-interval condition.