Cooperative Transportation using Multiple Single-Rotor Robots and Decentralized Control for Unknown Payloads

TL;DR

This paper presents a decentralized control system for multiple single-rotor robots to cooperatively transport unknown payloads, demonstrating stability and robustness through simulations and real-world experiments.

Contribution

It introduces a novel decentralized controller for single-rotor robots that guarantees stability for unknown payloads and handles robot failures.

Findings

Successful cooperative transport of large, unknown payloads in simulations.

Robust real-world demonstration with eight robots carrying a 2.7 kg payload.

System maintains functionality even without shared attachment positions.

Abstract

Cooperative transportation via multiple aerial robots has the potential to support various payloads and reduce the chances of them being dropped. Furthermore, autonomously controlled robots render the system scalable with respect to the payload. In this study, a cooperative transportation system was developed using rigidly attached single-rotor robots, and a decentralized controller was proposed to guarantee asymptotic stability of the error dynamics for unknown strictly positive real systems. A feedback controller was used to transform unstable systems into strictly positive real ones considering the shared attachment positions. First, the cooperative transportation of unknown payloads with different shapes larger than the carrier robots was investigated via numerical simulations. Second, cooperative transportation of an unknown payload (with a weight of approximately 2.7 kg and maximum length of 1.6 m) was demonstrated using eight robots, even under robot failure. Finally, the proposed system was shown to be capable of carrying an unknown payload, even if the attachment positions were not shared, that is, even if asymptotic stability was not strictly guaranteed.