Modeling and Integrated Control Design for Folding-Wing Aircraft during Morphing Process

Abstract

This paper proposes a novel integrated robust control framework tailored for folding-wing aircraft during large-angle morphing maneuvers. The morphing process induces severe nonlinearities, strong coupling between wing kinematics and vehicle dynamics, and significant time-varying shifts in the center of gravity and aerodynamic characteristics, posing substantial challenges to flight stability. To address these issues, a two-time-scale hybrid control architecture is developed: a robust sliding mode controller (SMC) governs the fast inner-loop attitude dynamics to counteract model uncertainties and disturbances, while a well-tuned proportional-integral-derivative (PID) controller manages the slower outer-loop trajectory variables, such as altitude and velocity. A high-fidelity multi-body dynamic model is derived from first principles using Newtonian mechanics, fully accounting for morphing-induced inertial and aerodynamic variations. Extensive closed-loop simulations validate the approach, achieving stable transitions with altitude errors within ± 1.5 m, velocity errors below ± 1.8 m·s^-1, and settling times under 50 seconds – even under ± 20% perturbations in aerodynamic coefficients. To the best of the author’ knowledge, this is the first implementation of a hybrid SMC–PID strategy specifically designed for large-scale rigid-body wing reconfiguration, offering a practical and theoretically grounded pathway toward deployable morphing aircraft systems.