Triangle codes and tracer lights based absolute positioning method for terminal visual docking of autonomous underwater vehicles
Author:
Zhang Zhuoyu,Zhong Lijia,Lin Mingwei,Lin Ri,Li Dejun
Abstract
Purpose
Docking technology plays a crucial role in enabling long-duration operations of autonomous underwater vehicles (AUVs). Visual positioning solutions alone are susceptible to abnormal drift values due to the challenging underwater optical imaging environment. When an AUV approaches the docking station, the absolute positioning method fails if the AUV captures an insufficient number of tracers. This study aims to to provide a more stable absolute position visual positioning method for underwater terminal visual docking.
Design/methodology/approach
This paper presents a six-degree-of-freedom positioning method for AUV terminal visual docking, which uses lights and triangle codes. The authors use an extended Kalman filter to fuse the visual calculation results with inertial measurement unit data. Moreover, this paper proposes a triangle code recognition and positioning algorithm.
Findings
The authors conducted a simulation experiment to compare the underwater positioning performance of triangle codes, AprilTag and Aruco. The results demonstrate that the implemented triangular code reduces the running time by over 70% compared to the other two codes, and also exhibits a longer recognition distance in turbid environments. Subsequent experiments were carried out in Qingjiang Lake, Hubei Province, China, which further confirmed the effectiveness of the proposed positioning algorithm.
Originality/value
This fusion approach effectively mitigates abnormal drift errors stemming from visual positioning and cumulative errors resulting from inertial navigation. The authors also propose a triangle code recognition and positioning algorithm as a supplementary approach to overcome the limitations of tracer light positioning beacons.
Subject
Industrial and Manufacturing Engineering,Computer Science Applications,Control and Systems Engineering
Reference48 articles.
1. Autonomous docking demonstrations with enhanced REMUS technology,2006
2. Underwater augmented reality for improving the diving experience in submerged archaeological sites;Ocean Engineering,2019
3. Development and test of a subsea docking system applied to an autonomous underwater helicopter,2022
4. Robust SVSF-SLAM for unmanned vehicle in unknown environment;IFAC-PapersOnLine,2016
5. Simultaneous localisation and mapping for autonomous underwater vehicle using a combined smooth variable structure filter and extended Kalman filter;Journal of Experimental & Theoretical Artificial Intelligence,2021