Cooperative wing-lifting and T-tail attitude control based on normalized energy margin for narrow-gap traversal of flapping-wing aerial vehicles

Abstract To address the problems of redundant structural weight gain, strong morphing disturbance, and hard switching in segmented control of traditional folding-wing schemes in narrow gap traversal of flapping-wing aircraft, this paper proposes a narrow gap traversal control method with cooperative wing lifting and T-tail. The method constructs a unified trajectory planning and adaptive control framework centered on the normalized traversal energy margin, achieving multi-phase continuous regulation through energy-state-driven smooth soft switching. Only through stepless wing lifting from 0° to 90° does it simultaneously realize aerodynamic deceleration and compression of the lateral projection dimension from 1.2 m to 0.15 m, combined with decoupled T-tail active attitude compensation to suppress morphing disturbances. Experiments on a 160 g prototype show that: at the configuration level, the structural weight is reduced by 21.3% and the hover endurance is improved by 26.3%; at the traversal level, the success rate reaches 83.3% with an altitude deviation of ±6.5 cm; at the attitude level, the oscillation amplitude is significantly lower than that of traditional segmented control. This method provides a lightweight, highly reliable, and easy-to-implement flapping-wing flight solution for confined-space operations such as post-disaster search and rescue, pipeline inspection, and indoor reconnaissance.