What are the challenges in applying the results from [1] on aerial cooperative manipulation of suspended loads using non-stopping trajectories to a real robotic system? Especially:
- What happens if optimisation fails to find a solution at certain iterations?
- How to modify the method to guarantee safety?
- Does the performance improve if a receding-horizon optimisation is used?
Methodology:
This thesis focuses on the implementation of existing control algorithms for the manipulation of a cable-suspended load using non-stopping aerial robots. The thesis will use three Crazyflies 2.1 quadrotors as if they were unable to hover but must keep loitering during the task execution. The software will be implemented on a ground machine in MATLAB Simulink, and ROS will be used to send commands to the robots and to read the robots’ position and orientation online.
Background:
The majority of existing works on aerial robotic manipulation focus on multirotor platforms, exploiting their hovering capabilities. Despite their versatility, multirotors are inherently constrained by a limited endurance. By contrast, fixed-wing UAVs offer superior endurance but pose a fundamental challenge: unlike multirotors, they must maintain a strictly positive forward velocity. This constraint complicates the coordinated stabilisation of suspended loads. [1] and [2] establish the feasibility of maintaining a static equilibrium of a suspended load with any number of non-stopping robots greater than or equal to 3. A recently completed MSc thesis by Sofia Girardello developed an algorithm to track load trajectories with non-stopping carriers, too.
However, a thorough experimental validation is still needed to assess the applicability of the theoretical findings.
References:
[1] Trajectory control of a suspended load with non-stopping flying carriers Girardello, S., Michieletto, G., Cenedese, A., Franchi, A., and Gabellieri, C. https://arxiv.org/pdf/2510.11413
[2] Gabellieri, C., & Franchi, A. (2024, June). On the Existence of Static Equilibria of a Cable-suspended Load with Non-stopping Flying Carriers. In 2024 International Conference on Unmanned Aircraft Systems (ICUAS) (pp. 638-644).
IEEE. https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10556930
[3] Gabellieri, C., & Franchi, A. (2025). Coordinated Trajectories for Non-stop Flying Carriers Holding a Cable-Suspended Load. arXiv preprint
arXiv:2503.03481. https://arxiv.org/pdf/2503.03481