On Cooperative Control of Two-Drones with a Slung Load

Increasing the load capacity of drones can be effectively achieved by utilizing two drones. This paper introduces a novel cooperative control strategy for the transport of a slung bar-shaped load using two drones. Our approach integrates differential flatness-based motion planning with filtering techniques to generate reference trajectories. This method does not require prior knowledge of the load mass or cable deflection angles, and ensuring compatibility with a wide range of flight controllers. The proposed control scheme employs a super-twisting controller as an internal stabilizer to ensure robustness against model inaccuracies and external disturbances, providing precise stabilization around the preplanned trajectories. This methodology is particularly well-suited for practical applications requiring the cooperative transport of complex loads, such as wind turbine blades, where precision, robustness, and simplicity are critical.