Aerial robotic cooperative manipulation of cable-suspended loads exploiting cable slackness

MSc assignment

Aerial robotic cooperative manipulation of cable-suspended loads has become an important branch of aerial manipulation research also thanks to its many potential applications (e.g., in the delivery and construction fields). Cooperation allows for overcoming payload limitations and cables confer cost-effectiveness and hardware simplicity to the system.

When transporting a suspended load with aerial robots, the typical assumption made in the literature is that cables’ inertia properties are negligible. Hence, cables are modelled as massless rigid or elastic links.  As, at the equilibrium, cables are typically taut under the effect of gravity; many works assume that holds by hypothesis. However, during motion, tautness may not always be guaranteed, so planning and control laws to keep cables taut have been designed.

The hypothesis or the target of taut cables may be limiting. Cables that become slack during object manipulation can enhance the system’s possibilities, e.g., allowing for obstacle avoidance or for an augmented configuration space of the object.

Some work has addressed slack cables when demonstrating the fundamental properties of the manipulation systems, where one cable is attached to each aerial robot [2]. Others have considered the transition between slack and taut cables in particular circumstances, such as load lifting from the ground [3].

The topic of the thesis is to mathematically study cooperative aerial manipulation of cable-suspended loads to highlight the consequences and the potential of cables becoming slack. Control methods exploiting slack cables will be designed. A simulator should be used/designed to test the system model and the control methods.


[1] Sanalitro, D., Savino, H. J., Tognon, M., Cortés, J., & Franchi, A. (2020). Full pose manipulation control of a cable-suspended load with multiple UAVs under uncertainties. IEEE Robotics and Automation Letters, 5(2), 2185-2191.

[2] Sreenath, K., & Kumar, V. (2013). Dynamics, control and planning for cooperative manipulation of payloads suspended by cables from multiple quadrotor robots. r n 1 (r2), r3

[3] Cruz, P. J., & Fierro, R. (2017). Cable-suspended load lifting by a quadrotor UAV: hybrid model, trajectory generation, and control. Autonomous Robots, 41, 1629-1643.