VFH Obstacle Avoidance Using Single-Beam Acoustic Ranging for a Multi-Thruster AUV in Unknown Environments

Abstract

Deep-sea operations impose demanding requirements on the flexibility and autonomy of underwater vehicles. Unlike traditional torpedo-shaped AUVs, the disk-shaped, multi-thruster Autonomous Underwater Vehicle (AUV) demonstrates enhanced agility, which is ideal for navigating uncharted and complex underwater terrains. This paper proposes a dedicated obstacle avoidance strategy tailored to the multi-thruster AUV's exceptional horizontal manoeuverability and fixed-point multi-directional distance measurement capability. Upon obstacle detection, the vehicle adjusts the thrust difference of its horizontal thrusters to achieve in-place rotation across different headings, enabling continuous collection of obstacle distance data via single-beam acoustic ranging. The collected data is then input into an optimised Vector Field Histogram (VFH) algorithm to generate the optimal real-time heading for obstacle avoidance. This integration of fixed-point multi-directional sensing and algorithm-adaptive decision-making enhances the vehicle's obstacle avoidance robustness and adaptability. Comprehensive simulations are conducted in MATLAB and on the MOOS-IvP autonomous marine vehicle platform under diverse uncharted underwater environments to validate the strategy. Simulation results confirm the feasibility and reliability of the proposed obstacle avoidance strategy and algorithm.