Controller design for underwater vehicle systems with communication constraints

Abstract

Real-time cooperation between autonomous vehicles can enable time-critical missions such as tracking and pursuit of a dynamic target or environmental feature, but relies on wireless communications. Underwater communication is almost exclusively accomplished through acoustics, which bring challenges such as delays, low data rates, packet loss, and scheduling constraints. To address these challenges, this thesis presents contributions towards multi-vehicle feedback control in the presence of severe communication constraints. The first major area of work considers the formulation and solution of new multi-vehicle tracking and pursuit problems using closed-loop control. We first describe field experiments in target pursuit at high tracking bandwidths in a challenging shallow-water environment. Next, we present a methodology for pursuit of dynamic ocean features such as fronts, which we validate using ocean model data. The primary innovation is a linearization of ocean model forecast dynamics and uncertainty directly in vehicle coordinates. The second area of work presents a unified formalism for multi-vehicle control and estimation with measurement, control, and acknowledgment packets all subject to scheduling, delays and packet loss. We develop a modular framework that includes a novel technique for estimation using delayed and lossy control acknowledgments. Simulations and field experiments demonstrate the effectiveness of our approach.