Design and Analysis of a Surface Capture Device Under Moderate Sea State 4

Abstract

To address the limitations of poor adaptability and insufficient versatility of current surface capture technologies for autonomous underwater vehicles (AUVs) under high sea state conditions, this study proposes an ROV-based capture system equipped with guidance and clamping mechanisms for efficient and stable recovery of AUVs and similar floating targets in rough seas. This work is intended to provide technical support for solving AUV capture challenges in high sea states. Through a systematic investigation of capture methods and associated operational systems, the overall design of the dynamic surface AUV capture device is established. A three-dimensional model is developed to verify the feasibility of the overall operational sequence. Computational fluid dynamics (CFD) simulations are performed to analyze the hydrodynamic performance of the ROV carrier, with particular focus on the drag force and pressure distribution under flow velocities corresponding to Sea State 4 and below. The simulation results indicate that when the ROV inflow velocity reaches 3 m/s, the maximum drag force is approximately 5862 N and the maximum pressure on the frontal area is about 4570 Pa. Based on these data, the overall structural stability is verified, and the results confirm that the structure maintains adequate stability under the target operating conditions. Kinematic simulations are further conducted to investigate the collision force between the target AUV and the guidance/capture device under various initial attitudes and velocities in Sea State 4, thereby determining the overall capture tolerance envelope. Through design manual buffer parameter tuning and comparative improvement analysis, the collision force between the guidance device and the target is reduced by approximately 60%.