Reconfigurable aerial load transportation by multiple agents: An adaptive sliding mode approach for robust tension control

In practical cooperative aerial transportation, the system is inevitably exposed to unmodeled and unpredictable disturbances, such as wind gusts, internal interaction forces arising from agent-load coupling, and inaccuracies in load mass information, making robustness and adaptive disturbance rejection essential for reliable real-world deployment. This paper presents an adaptive, robust trajectory-tracking control strategy for a team of unmanned aerial vehicles collaboratively transporting a cable-suspended load. To assess the method’s effectiveness, extensive real-world experiments were conducted across multiple scenarios, including conditions with unforeseen disturbances. Experiments involving up to five aerial agents, combined with external disturbances and load-parameter uncertainties, further demonstrate the robustness and scalability of the proposed approach, while a formation-reconfiguration experiment highlights its adaptability during task execution. The results demonstrate that the proposed controller ensures accurate trajectory tracking of the suspended load and consistently outperforms two benchmark controllers with distinct characteristics, achieving up to 83% of performance improvement in certain scenarios. These findings highlight the robustness and applicability of the method for practical deployment. • A squad of multirotors are used to carry a cable-suspended payload. • The squad is scalable to n-robots. • A robust controller for the framework and its stability analysis are provided. • The system is robust against environmental disturbances (e.g. wind gusts).