Fuzzy logic based nonlinear blending hybrid control of a kestrel-inspired ornithopter operating in sinusoidal and...

Persistent gust disturbances and unsteady atmospheric dynamics remain a critical barrier to the stable and efficient flight of ornithopters. However, in nature, millions of avian species exhibit extraordinary inherent stability and aerodynamic adaptability, even under highly turbulent atmospheric conditions. Experimental studies have shown that birds actively deploy their covert feathers to dynamically modulate airflow and suppress gust-induced disturbances. Inspired by this biological mechanism, this study proposes a biomimetic Gust Alleviation System (GAS) integrated with a hybrid control framework for a kestrel-inspired ornithopter. The GAS is modeled using a reduced-order bond graph representation and actively modulates feather-like surfaces for aerodynamic load mitigation. An optimal Linear Quadratic Regulator (LQR) governs nominal gusts, while a robust [Formula: see text] controller is engaged for stronger gusts. A nonlinear fuzzy Sugeno-type blending mechanism is introduced to ensure smooth and shock-free transition between controllers in the intermediate gust regime. In addition to step-gust testing, the proposed system is evaluated under sinusoidal disturbances and realistic Dryden wind turbulence models, where it consistently maintains bounded, well-damped, and stable responses. The results demonstrate up to 50% reduction in gust-induced forces, 36% improvement in control efficiency, and 24% enhancement in robustness compared to conventional methods, while remaining fully aligned with literature-reported ornithopter dynamics. This biologically inspired GAS with fuzzy-blended hybrid control offers a reliable, energy-efficient, and aerodynamically resilient solution for next-generation ornithopters operating in unsteady atmospheric environments.