Research on Tracking Strategy for Autonomous Underwater Vehicle in Constrained Tunnel Space

To address the challenges posed by spatial constraints and fluid perturbations in underwater tunnels, this study proposes an efficient Autonomous Underwater Vehicle (AUV) and introduces a tracking control strategy to tunnel conditions. First, the AUV integrates a modular buoyancy adjustment system, effectively mitigating the issues of large turning radii and loss of pitch control at low speeds typically encountered with conventional rudders. The Variable Look-Ahead Distance (VLAD) mechanism is integrated into the Adaptive Line-of-Sight (ALOS) guidance system to facilitate precise estimation of the angle of attack and ensure rapid convergence of tracking errors. In addition, a Hyperbolic Sliding Mode switching Controller (HSMC) is proposed, and its stability is rigorously analyzed. This approach dynamically adjusts the sliding mode surface based on the characteristics of the two hyperbolic functions, effectively reducing control buffering and improving the stability of wall tracking. Finally, the experimental results from both planar and curved wall tracking tests demonstrate that the proposed control strategy significantly reduces tracking errors while exhibiting superior resilience to interference.