Composite Curve Path following an Underactuated AUV

Ben Li,Wenjin Wang,Guohua Xu,Zhen Su,Yingkai Xia

doi:10.1155/2021/6624893

Abstract

This paper addresses the problem of composite curve path following for an underactuated autonomous underwater vehicle by utilizing an adaptive integral line-of-sight (AILOS) guidance and nonlinear iterative sliding mode (NISM) controller. First, the composite curve path is parametrized by a common scalar variable in a continuous way. Then, the kinematics error of an underactuated vehicle is described based on the nonprojection Frenet–Serret frame with a virtual point, which can be eliminated by the virtual point control and AILOS guidance. Meanwhile, the subpath switching algorithm is studied to realize the global path following for the composite curve path. Besides, the NISM controller is cascaded with the AILOS guidance law, and the cascade structure proved to be globally κ -exponentially stable under the influence of slow time-varying currents. Finally, simulations are considered to demonstrate the effectiveness of the proposed composite curve path following control scheme.

Highlights

In recent years, much research has been done in the field of path following for autonomous underwater vehicles (AUVs)
The composite curve path is obtained by a path planning algorithm with two steps
Utilizing a path search algorithm, the given order of waypoints is obtained based on certain optimization objectives. en, considering the kinematics constraints of the vehicle, multiple curves can be used to connect all the waypoints to generate a flyable path [4]

Summary

Introduction

Much research has been done in the field of path following for autonomous underwater vehicles (AUVs). For better tracking of the composite curve path, it is necessary to choose an appropriate path description method To solve this problem, all the curve segments are parametrized in a continuous way in this paper. A new composite curve path following controller is proposed for an underactuated AUV, based on nonlinear iterative sliding mode (NISM) controller [16] and AILOS guidance. (2) Based on the AILOS guidance law and the subpath switching algorithm, the global path following of the composite curve path in the kinematics layer is realized with the unknown ocean currents. As the expressions of subpaths may vary, they will be inconvenient to calculate and hard to expand for the path following of composite curve path To handle this problem, the path parametrization method is adopted to describe the composite curve path. Where (x0, y0) is the starting point, (xend, yend) is the endpoint, θ is the polar angle, θend is the polar angle of the endpoint, χ0 and χend are the path-tangential angles of Fermat’s spiral at the starting and the endpoint, and ρ determines the direction of spiral rotation

Problem Statement

Path following Control Design

Simulation Results

Case 1

Case 2

Case 3