Aggressive maneuvers for a quadrotor-slung-load system through fast trajectory generation and tracking

The ability for a quadrotor with a slung load to perform agile and accurate maneuvers expands the variety of scenarios where load transportation can be applied and enhances its efficiency. Due to the complexity of the system dynamics, slung-load transportation remains a challenging problem, which also causes trajectory generation a time-consuming task. We propose a framework to efficiently generate aggressive load-swing trajectories. Trajectory generation for the load aims to minimize the fifth order time derivative of the load position which, indirectly, minimizes the quadrotor angular velocity actuation. Aggressive load-swing trajectories are obtained by having the constraints for load cable direction embedded into the trajectory generation via constraints on the load acceleration. The trajectory generation, together with an accurate trajectory tracking controller, allows the aggressive maneuvers to be easily performed on the quadrotor with a slung-load. Simulation and experimental results of three dimensional aggressive maneuvers are presented to validate the proposed trajectory generation methodology, including the quadrotor slung-load traversing a window by tilting the cable, and also going through an environment with obstacles that must avoided.