Online Anti-Swing Trajectory Refinement for Variable-Length Cable-Suspended Aerial Transportation Robot

Abstract

Aerial robots have demonstrated significant potential in suspended cargo transportation, especially in industries such as logistics and food delivery. Due to the underactuated and nonlinear dynamics of the cable-suspended system, directly tracking a given trajectory with a multicopter without modifying its controller often leads to significant payload swing. This compromises the safety and stability of the cargo. To address the aforementioned issue, this paper proposes an online trajectory refinement method for a variable-length cable-suspended aerial transportation robot, independent from the control layer. By incorporating payload swing angle information, the reference trajectory is refined in real-time, effectively suppressing payload oscillations during transportation. Specially, Lyapunov techniques and LaSalle’s invariance theorem are employed to rigorously guarantee the feasibility of the designed trajectory refinement scheme. Finally, hardware experiments are conducted to validate the effectiveness and superiority of the proposed method. The results demonstrate that the refined trajectory not only enables precise positioning of the multicopter, but also effectively suppresses payload oscillations during transportation, significantly enhancing the safety and reliability of the aerial cargo delivery.