UC Berkeley

This dissertation addresses fundamental aspects of re-configurable swarms of Unmanned Underwater Vehicles (UUVs) for Underwater Wireless Optical Networks (UWONs) at different scales. At the scale of the swarm, we propose Guidance, Navigation and Control (GNC) systems to enable permanent UWONs. At the scale of the UUV, we present the development of a man-portable hybrid UUV with high-bandwidth wireless communication. Finally, we investigate, at the scale of the Free-Space Optical (FSO) system, Pointing, Acquisition and Tracking (PAT) systems to enable free-space laser communication. This dissertation begins with the report of a demonstration of underwater laser beam relay with two UUVs to illustrate the concept of swarms of UUVs for UWONs. Specifically, two submarine models were modified, localized and controlled to reflect the laser beam stemming from a laser pointer at the bottom of a water tank to the desired location. In the second part of this dissertation, we show that a guidance system combining Decentralized Model Predictive Control with graph theory enables to steer UUVs such that there is continuously a path through the UUV network to relay the optical signal for an unlimited time by re-configuring successive subfleets where a UUV is always within communication range with the neighbouring subfleets. The guidance system forms the high-level block of a hierarchical control scheme with an Adaptive Feedback Linearization Controller (AFLC) and an Extended Kalman Filter (EKF) at the low-level. In the third part of this dissertation, we present a man-portable hybrid UUV equipped with a LED modem on a Pan-Tilt system enabling 3.5Mbps full-duplex wireless communication over a range of 7m in a wave tank despite the motion of the UUV. The hybrid capabilities of the UUV have been simulated with a Software in the Loop (SITL) simulator, which showed the good performance of the AFLC and EKF implemented in the UUV's autopilot. Finally, the fourth part of this dissertation investigates two PAT systems with different configurations. The first configuration enables full PAT capabilities but requires precise alignment and calibration of the opto-mechanical components while a second configuration enables only tracking but has lower manufacturing requirements.