Rigid–Elastic Coupling Dynamics of Morphing Wing Aircraft

This paper presents a rigid–elastic coupling dynamic model for a morphing aircraft with variable-sweep wings, developed using Kane’s method. The model accurately captures the interactions between flight dynamics and structural dynamics during morphing. To fully account for the coupling effects, we derive a morphing aircraft model consisting of a rigid fuselage and two elastic wings. Each wing is modeled as a straight beam undergoing small elastic deformations while experiencing large overall motions following the fuselage in space, along with variable-sweep rotations relative to the fuselage. These factors introduce uncertainties into the flight dynamics. To quantify the uncertainties caused by wing rotation, additional morphing forces and moments are introduced to describe morphing-induced uncertainties, while additional elastic forces and moments are defined to account for uncertainties arising from wing deformations. Numerical simulations are conducted across different models and morphing rates to analyze the dynamic characteristics. The results reveal that the elastic deformations of morphing wings significantly influence pitch angles, pitch rates, and wing vibrations, particularly during large-sweep transitions exceeding 45°. Additionally, slow morphing rates below 5°/s induce significant transient uncertainties due to elastic vibrations. These findings establish a quantitative relationship between morphing rate, vibration characteristics, and model uncertainties, providing valuable insights for trajectory tracking and attitude control in morphing aircraft.