Visual Servoing Algorithms and Coordination Latency for Docking Precision in Underwater Inspection Vehicles

Abstract

The deployment of autonomous underwater vehicles for the inspection and maintenance of subsea infrastructure has grown exponentially over the past decade. A critical requirement for the persistent operation of these vehicles is the ability to autonomously dock with submerged base stations for battery recharging and data offloading. Achieving the necessary terminal docking precision remains a formidable challenge due to the complex hydrodynamic forces, limited visibility, and inherent system delays present in the subsea environment. This paper provides a comprehensive examination of docking precision by analyzing the intersection of visual servoing algorithms and coordination latency within the control loops of underwater inspection vehicles. Visual servoing, particularly image-based visual servoing, offers high-resolution relative positioning for the terminal phase of docking but is highly susceptible to processing delays and thruster response lags. Through an extensive evaluation of latency sources including image acquisition, computational processing, and mechanical actuation, this study elucidates how coordination latency degrades the convergence stability of visual servoing controllers. Furthermore, the research investigates the dynamic coupling between visual tracking errors and hydrodynamic disturbances. The analysis demonstrates that uncompensated coordination latency fundamentally alters the error space, leading to terminal overshoot and docking failure. By systematically isolating the effects of algorithmic design and systemic delay, this paper establishes a foundational understanding of the constraints governing autonomous underwater docking, offering critical insights for the development of robust, delay-tolerant navigation strategies for next-generation marine robotics.