Stream-Function Based 3D Obstacle Avoidance Mechanism for Mobile AUVs in the Internet of Underwater Things

Wenyu Cai,Junyi Yang,Meiyan Zhang,Qinan Xie,Shuaishuai Lv

doi:10.1109/access.2021.3119594

Abstract

The mobility manager in the Internet of Underwater Things (IoUT) plays a major role in data acquisition. In this paper, one novel obstacle avoidance method based on fluid mechanics is discussed for autonomous underwater vehicle (AUV) in 3D IoUT. The proposed method utilizes ocean current characteristics simplified as stream-function to design an optimal 3D trajectory with an obstacle avoidance function. 3D stream-function is constructed for spherical and cylindrical obstructions in details. Theoretical analysis of 3D stream-function proves that traditional 2D stream-function can be extended to 3D IoUT space under specific conditions. One path deformation method based on virtual obstacle methodology is proposed to overcome the inherent hysteresis problem of the traditional stream-function based obstacle avoidance design. Moreover, we introduce an energy consumption model for AUV to prove that our obstacle avoidance algorithm can improve energy efficiency if actual ocean currents exist. Extensive simulation results verify that the proposed obstacle avoidance method has the characteristics of curve continuity and smoothness, enhanced obstacle avoidance effects, and high energy efficiency. Therefore, the proposed method meets the actual requirements of multi-obstacle avoidance path planning for AUV in IoUT.

Highlights

The Internet of Underwater Things (IoUT), such as underwater sensor networks, which is defined as the network of smart interconnected underwater objects, have played an important role in many underwater applications [1], e.g., seabed exploration, underwater resource exploitation, maritime rescue, and military strategic exercises
Many studies have been conducted on autonomous underwater vehicle (AUV) in the aspects of path planning, formation control, and obstacle avoidance [2, 3]
The main contributions of this paper are summarized as follows: (1) Traditional 2D stream-function based obstacle avoidance algorithms are extended to 3D obstacle avoidance path design for IoUT in the presence of multiple spherical and cylindrical obstructions; (2) The virtual obstacle-based path deformation method is discussed to overcome the hysteresis problem of traditional stream-function based path design method; (3) One novel energy consumption model for mobile AUV is proposed to verify the energy consumption efficiency of the proposed algorithm

Summary

INTRODUCTION

The Internet of Underwater Things (IoUT), such as underwater sensor networks, which is defined as the network of smart interconnected underwater objects, have played an important role in many underwater applications [1], e.g., seabed exploration, underwater resource exploitation, maritime rescue, and military strategic exercises. On the one hand, hysteresis problem of the traditional stream-function based obstacle avoidance method [23] exists; i.e., the mobile AUV will stagnate in a special position sometimes. With respect to the above mentioned issues, this paper proposes one novel obstacle avoidance-based path-planning algorithm for mobile AUVs in the 3D IoUT region. Extensive simulation results verify that the proposed obstacle avoidance method based on stream-function has good performance in the presence of spherical and cylindrical obstructions in a 3DIoUT region. (1) Traditional 2D stream-function based obstacle avoidance algorithms are extended to 3D obstacle avoidance path design for IoUT in the presence of multiple spherical and cylindrical obstructions;. Considering that the stream-function coming from fluid dynamics is suitable in the field of path planning, we apply it in our 3D obstacle avoidance through some 3D expansions

STREAM-FUNCTION PRELIMINARIES AND 3D EXTENSION TABLE I VARIABLE DEFINITION

POWER CONSUMPTION MODEL BASED ON STREAM-FUNCTION OBSTACLE AVIODANCE

PATH DEFORMATION METHOD TO OVERCOME

CONCLUSION