Trajectory Planning for Collaborative Transportation by Tethered Multi-UAVs

Collaborative transportation has been widely studied due to its high efficiency, and interesting research problems., specifically in trajectory planning. In this paper, a new trajectory planning scheme for collaborative transportation by tethered multi-UAVs is proposed to avoid obstacles. Firstly, the dynamics and configuration of the system is analyzed to derive the tethered force acting on each UAV, and define the angle between the rope and the vertical direction is calculated. Then the kinodynamic path search method is used to search an initial trajectory of the payload, and the initial trajectory of each UAV is solved. Finally, nonlinear optimization is used to optimize the trajectory of each UAV and the payload to achieve the effect of obstacle avoidance. Both numerical simulations and practical experiments are completed to verify the feasibility and effectiveness of the proposed planning scheme.