Full-Duplex Hybrid Underwater Networked Control System With Controller Optimization

This work introduces a novel full-duplex (FD) hybrid underwater networked control system (NCS) designed to enhance the precision and responsiveness of autonomous underwater vehicles (AUVs). Through streamlined communication and control, the proposed system enables high-performance execution of mission-critical operations, such as docking maneuvers. Unlike prior hybrid systems limited to half-duplex (HD) operation or optical/acoustic systems designed for stationary nodes, this work introduces the first unified framework that integrates FD capabilities into a hybrid acoustic/RF control loop, tuned explicitly for dynamic mobile underwater networks. This framework combines long-range acoustic and short-range RF links, leveraging FD technology to halve the communication latency and double the control update rate compared to conventional HD approaches. To address the variable time delays inherent in underwater networks, we implement and compare two controller optimization strategies: 1) a sequential model-based algorithm configuration (SMAC)-tuned proportional-integral-derivative (PID); and 2) a linear quadratic regulator (LQR) adapted for low-speed station-keeping. The system is evaluated in a high-fidelity cosimulation framework incorporating comprehensive underwater hydrodynamics and channel models. Results demonstrate that the FD hybrid system with LQR control significantly reduces docking time and exhibits superior robustness, maintaining stability under water currents up to 0.7 m/s, whereas SMAC-tuned PID approaches fail beyond 0.3 m/s. This establishes the proposed NCS as a resilient solution for time-critical underwater operations.