Saturated Robust Nonlinear Control for Double-Pendulum Quadrotor Transportation Systems

Unknown external disturbances and dynamic/parameter uncertainties are usually existing when the quadrotor transportation system performs cargo delivery missions in the actual environment. Additionally, in most researches, the hook and the payload are regarded as a single point of mass which ignore the double-pendulum effect. To address the aforementioned issues, this paper proposed a saturated robust nonlinear controller for the quadrotor transportation system with double-pendulum effect, which has the ability to handle the lumped disturbance and suppress the payload and hook swing angles. On the basis of Lyapunov techniques and LaSalle's Invariance Theorem, the asymptotic convergence of the closed-loop system is guaranteed. Simulation results are presented to verify the performance of the designed control scheme.