Trajectory Optimization of Morphing Aerial Vehicles Based on Mid-Fidelity Aeroservoelastic Models

Morphing aerial vehicles exhibit enhanced maneuverability compared to fixed-configuration counterparts. However, it remains an open question for the quantification of the trade-off between performance gains and control cost at the level of trajectories. To answer this question, this paper integrates a trajectory optimization framework with a mid-fidelity aeroservoelastic model, which couples nonlinear multi-body structural dynamics with an unsteady vortex lattice method. Furthermore, a physics-based control cost model is derived to accurately capture the control cost required to overcome instantaneous aerodynamic hinge moments, providing a metric superior to conventional quadratic cost functions. The framework is applied to an aircraft with flexible, high-aspect-ratio wings with morphing winglets to evaluate trim capabilities, maneuver performance, and obstacle avoidance. The results demonstrate that the morphing wings significantly expand the flight envelope by decoupling the lift and pitch requirements. In dynamic maneuvers, morphing yields distinct trade-offs: a pull-up maneuver achieved a 28.95% increase in altitude gain at the expense of higher control cost, while a banked turn improved lateral displacement by 8.62% while simultaneously reducing control cost by 13.40%. Furthermore, in a lateral obstacle avoidance scenario, the morphing configuration reduced total control cost by 65.65% compared to a fixed-wing baseline. This efficiency is achieved by exploiting aero-mechanical coupling, where control surfaces are coordinated to offload aerodynamic loads from the morphing mechanism. These findings underscore that high-authority morphing can be optimized not only for peak performance but also for superior energy efficiency.