Dynamic modeling of high-speed elastic vehicles with inertial coupling

For high-speed flight, flat symmetric lifting-body configuration has much higher lift-to-drag ratios, compared to slender body axisymmetric configuration. However, it operates in a complex multi-field coupling environment involving aerodynamics and structures during high-speed flight, exhibiting significant bending-torsion coupling and inertial coupling effects. The classical inertial decoupling dynamic models cannot fully describe their motion characteristics. To address this problem, this study establishes an inertial coupling dynamic model in the transient coordinate system based on the Lagrange equation, which retains the coupling terms between rigid-body motion and elastic deformation. On this basis, different simplifying assumptions are introduced to derive the corresponding simplified inertial coupling model and inertial decoupling model. Subsequently, the influence of inertial coupling on the dynamic response is investigated through time-frequency domain comparisons of the coupling and decoupling models, modal truncation order analysis, and parameter sensitivity analysis. The results indicate that the inertial coupling model can capture the amplitude-frequency response characteristics of elastic modes and reveal the multi-peak coupling spectrum phenomenon induced by the coupling effect. This study provides a model foundation for the dynamic analysis and control-oriented modeling of flat symmetric lifting-body high-speed vehicles.