Dynamic event-triggered prescribed performance formation control for hypersonic morphing vehicles

Safe formation control for foldable hypersonic morphing vehicles is investigated in this paper. With actuator saturation, faults, and external disturbances, a two-layer cooperative formation control scheme is established. Firstly, based on consensus theory, the formation task is divided into a position outer loop and an attitude inner loop. In the outer loop, a prescribed-time prescribed-performance function is introduced to constrain the position error, which forces it to reach a preset boundary within the specified time without overshoot. Consequently, both transient and steady-state formation performance is enhanced. Secondly, in the inner loop, an anti-saturation compensator is proposed to mitigate input limits, and the minimum fault effectiveness factor together with the disturbance bound is treated as a composite disturbance. A tan-barrier type Lyapunov function is employed to derive an adaptive law that estimates the bound of composite disturbance online and bounded tracking of the outer-loop command is guaranteed. Furthermore, a dynamic event-triggered mechanism with an internal dynamic variable is proposed. The threshold is adjusted online, which preserves control accuracy while markedly reducing communication and computation loads. Thirdly, to accommodate aerodynamic variations caused by structural morphing, local controllers are allocated to each morphing subsystem, and overall stability of the resulting non-stationary switching system is rigorously proven through Lyapunov stability theory and the average dwell-time condition. The effectiveness of the proposed scheme is verified through numerical simulations.