Adaptive Proportional‐Derivative Sliding Mode Control for a Quadrotor With Suspended Double‐Pendulum Payload

ABSTRACT Precise quadrotor positioning and payload swing suppression play an important part in a quadrotor aerial transportation system. However, in most practical scenarios, existing control methods fail to achieve satisfactory performance, mainly because these methods often neglect the double‐pendulum effect caused by the relative rotational motion of the hook and the cargo. To address this characteristic of the suspended double‐pendulum payload, we first propose an estimator to online estimation uncertain system parameters without knowing exact system knowledge. Then, we develop an adaptive proportional‐derivative sliding mode control, where an additional term is introduced in the sliding surface to suppress payload swing and enhance coupling between states. Finally, based on the Lyapunov method and LaSalle's invariance principle, the asymptotic stability of the closed‐loop system is proven without linearizing the original nonlinear dynamics or neglecting certain coupling terms.