Robust Adaptive Tracking Control for Aerial Transporting a Cable-Suspended Payload Using Backstepping Sliding Mode Techniques

Aerial transportation technology is the lifeline of air disaster rescue. In this article, a robust adaptive tracking control scheme using backstepping sliding mode techniques is proposed for a quadrotor-based aerial transportation system with a cable-suspended payload in disaster rescue, where the payload is ensured to be driven to predefined trajectories in the presence of strong coupling, uncertainties, and external disturbances. The quadrotor and the payload are modeled as a rigid body and a point mass, respectively, and the two coupling terms between the virtual input of the payload position loop and the payload attitude error as well as between the input force and the quadrotor attitude error are analyzed owing to the underactuated of the quadrotor-based transportation system. Then, adaptive backstepping sliding mode control strategies are designed for the position and swing dynamics of the payload to guarantee payload trajectory tracking, and an observer-based geometric attitude control method is presented for the quadrotor attitude dynamics to ensure the global attitude stability of the system, where prior information about disturbances is not required. The closed-loop stability of the whole system is strictly proven. Finally, real-world experiments are conducted to verify the feasibility and robustness of the proposed control scheme. Note to Practitioners-The motivation of this article is to investigate a robust and adaptive control tracking scheme for aerial transportation systems with a cable-suspended payload in disaster rescue. In most of the existing aerial transportation control schemes with a cable-suspended payload, the payload is driven to follow a desired trajectory while only considering the coupling effect between the aerial platform and the payload. However, in practical disaster rescue applications, the aerial transportation system is inevitably affected by strong coupling, uncertainties, and external disturbances. Meanwhile, to the authors' best knowledge, there exist few studies that investigate payload following issues while considering strong coupling, uncertainties, and external disturbances simultaneously. Therefore, this article proposes a robust and adaptive tracking control scheme using backstepping sliding mode techniques for a quadrotor-based aerial transportation system with a cable-suspended payload to ensure the stable and accurate payload following control under strong coupling, uncertainties, and external disturbances, where prior information about disturbances is not required under the proposed scheme. The closed-loop stability of the whole system is strictly and mathematically analyzed as well as real-world experiments provide promising results. Moreover, the proposed scheme provides a more realistic setup for autonomous aerial transportation with cable-suspended supplies in disaster rescue.