AUV의 수중 도킹을 위한 비쥬얼-초음파 항법 시스템 설계

Abstract

Docking systems are required to increase the capability of the AUVs to recharge the batteries and to transmit data in real time for specific underwater works, such as repeated jobs at sea bed. This paper presents a visual-acoustic navigation system for an AUV to dock into an underwater station with a camera and acoustic sensor array mounted at the nose center of the AUV. To make the visual-acoustic navigation system, this paper introduces a scenario that the AUV approaches a way point with an acoustic navigation system, an ultra short base line (USBL), in far field, and it comes to a docking station with the camera in near field keeping the docking station to the center of the image plane of the camera. This paper proposes an acoustic sensor array to get wide viewing angle of the USBL and a switching logic for efficient operation of the acoustic sensors. This paper derives an state equation of the visual servoing AUV combined with optical flow model of the camera and AUV dynamics, where the projected motions of the image plane are described with the rotational and translational velocities of the AUV. A simulation was performed to demonstrates the effectiveness of the navigation system with visual-acoustic sensors.