Distributed MPC Formation Path Following for Acoustically Communicating Underwater Vehicles

TL;DR

This paper develops a distributed model predictive control strategy for underwater vehicles that maintains formation and follows a path using acoustic communication, addressing real-world challenges like packet loss and asynchronous data exchange.

Contribution

It extends existing control algorithms to handle broadcast asynchronous communication, packet losses, and data quantization, making them more practical for real underwater environments.

Findings

Simulation results show the impact of adaptations on control performance.

Sensitivity analysis quantifies how hyperparameters affect performance.

Data rate savings are achievable with minimal control performance loss.

Abstract

We propose and analyse a model predictive control (MPC) strategy tailored for networks of underwater agents tasked with maintaining formation while following a shared path and using acoustic communication channels. The strategy accommodates both time-division and frequency-division medium access schemes, and addresses the inherent challenges of lossy and broadcast communication over acoustic media. Our approach extends an existing distributed control algorithm originally assuming standard double precision in exchanged data, and designed for synchronous, bidirectional, and reliable communication. Here we introduce adaptations for handling broadcast asynchronous communication, for mitigating packet losses, and for quantising exchanged data. These modifications are general and intended to be applicable to other distributed control schemes that were developed under idealised assumptions. Our goal is thus to help facilitating deployment also of other control schemes in practical field conditions. We provide simulation results that quantify the impact of these adaptations on the performance of the original controller, along with sensitivity analyses on how performance losses are influenced by key hyperparameters. Additionally, we characterise the data rate savings vs. control performance losses that may be achieved through tuning such hyperparameters, showcasing the feasibility of implementing the proposed strategy for practical purposes using commercially available full-duplex or half-duplex modems.