Abstract:

The flutter of a foil with aeroelastic and servo system dynamics is regarded as the continuous switchings of a series of models on the flight trajectory or specific flight actions, and the switched system is introduced to describe the dynamic characteristics within the flight envelope. Then a robust adaptive switching control scheme for active flutter suppression is presented based on multiple Lyapunov functions and the model reference adaptive control (MRAC) methodology. Fast switchings between the models of different speed points and their corresponding controllers are allowed to cover the system dynamics within the flight envelope, as well as effectively avoid the disadvantage of adaptive control for demanding slow-varying parameters. Furthermore, using the Lure-Postnikov Lyapunov function, a sufficient condition via linear matrix inequations is deduced, which guarantees that the closed-loop switched system is a bounded MRAC, and thereby ensures the global stability within the flight envelope.

Key words: active flutter suppression, switched systems, adaptive control systems, hyperstability, stability analysis