Matrix-Weighted Coupling-Enhanced Adaptive Tracking Control for a Quadrotor-Slung-Load System

This article addresses the adaptive tracking control problem for an underactuated quadrotor-slung-load system subject to parameter uncertainties, a challenging task due to the system’s inherent underactuation and the coupled swinging load dynamics. To improve tracking performance and suppress unactuated swing motions, we propose a novel matrix-weighted coupling-enhanced composite state signal that explicitly integrates both actuated and unactuated state variables into the feedback control. Based on smooth projection operators, an enhanced adaptive tracking controller is developed to guarantee bounded parameter estimates, preventing parameter drift and ensuring smooth control inputs. The closed-loop system is rigorously proven to achieve asymptotic stability and bounded parameter estimation using Lyapunov theory combined with Barbalat’s Lemma. Simulation and experimental results show that the coupling-enhanced structure affects the closed-loop response and helps reduce load swing.