Cooperative control of multiple autonomous marine vehicles: theoretical foundations and practical issues

This chapter gives a brief overview of some of the theoretical and practical issues that arise in the process of developing advanced motion control systems for cooperative multiple AMVs. Many of the problems addressed were motivated by challenging scientific mission scenarios defined in the course of the EU GREX and Co3-AUVs projects. A general architecture for cooperative AMV control in the presence of timevarying communication topologies and communication losses was developed. The architecture implementation relies on a number of SVPs and MVPs, the development of which was rooted in solid control theory. For simulation purposes, a proprietary Networked Marine Systems Simulator (NetMarSyS) was developed at ISR/IST. The simulator allows for the study of the performance that can be achieved with the algorithms developed for cooperative motion control, with due account for full vehicle dynamics, external disturbances and sensor noise, as well as inter-vehicle communication losses. NetMarSyS allows also for seamless distributed software and hardware-in-the-loop (HIL) simulations, prior to systems deployment at sea. The results of two test series carried out in the Azores and in Sesimbra, Portugal have shown the efficacy of the methods developed for cooperative motion control, as well as the reliability of the software and hardware structures that are currently being used to control the Medusa class of ASVs. Future work will address testing other MVPs (including the Go-To-Formation and Cooperative Target Tracking) and performing missions whereby a number of surface vehicles are used to track multiple targets underwater. From a theoretical standpoint, two main lines of research are envisioned: (1) cooperative navigation exploiting non-conventional geophysical-based navigation systems, and (2) in-depth study of the constraints imposed by the underwater channel and underwater communication protocols.