Charakterisierung von hydrodynamischen Unsicherheiten und 3D-Bewegungsplanung als Basis geregelter Unterwasserfahrzeuge

Die Arbeit zeigt, wie tiefgehendes Systemverständnis von Unterwasserfahrzeugen (UUVs), zweckmäßige Bewegungsplanung und umfängliche Reglersynthese ineinander greifen können. Dazu wurde Unsicherheiten (u.a. Zähigkeits- und Trägheitskräfte sowie Fluiddichte) an diversen UUVs detailliert behandelt. Den Kern stellt aber ein entwickelter Algorithmus auf Basis der „Methode der elastischen Bänder“ zur Planung im 3D-Raum dar, mit dessen Hilfe unterschiedliche Aufgaben der UUVs modelliert werden können. Zu deren Realisierung wurde eine Zustandsregelung mit Polbereichsvorgabe beispielhaft vorgeführt.The thesis presents how in-depth system understanding of underwater vehicles (UUVs), proper motion planning and a comprehensive controller synthesis can intertwine. To this end, uncertainties on various UUVs (e.g. viscous and inertial loads as well as fluid density) were dealt with in detail. However, the core is a developed algorithm based on the ‚method of elastic bands’ for planning in a 3D space. It can be used to model the different tasks of UUVs. For their realisation a state control with pole range specification was exemplarily demonstrated

Robust Formation Control for Multiple Underwater Vehicles

This paper addresses the distance-based formation control problem for multiple Autonomous Underwater Vehicles (AUVs) in a leader-follower architecture. The leading AUV is assigned a task to track a desired trajectory and the following AUVs try to set up a predefined formation structure by attaining specific distances among their neighboring AUVs, while avoiding collisions and enabling at the same time relative localization. More specifically, a decentralized control protocol of minimal complexity is proposed that achieves prescribed, arbitrarily fast and accurate formation establishment. The control signal of each vehicle is calculated based on the relative position of its neighbors and its own velocity only, which can be easily acquired by the onboard sensors without necessitating for explicit network communication. Finally, a realistic simulation study with five AUVs performing seabed scanning was conducted to clarify the approach and verify the theoretical findings of this work. © Copyright © 2019 Bechlioulis, Giagkas, Karras and Kyriakopoulos