Path following control of an underactuated unmanned marine vehicle with model asymmetry in the presence of ocean current disturbances

Zhang Lei,Zhuang Jiayuan,Wang Bo,Sun Yushan

doi:10.1177/1729881419871807

Abstract

Path following control system of an underactuated unmanned marine vehicle is an important guarantee for its successful operation, the path following control problem of an underactuated and asymmetrical unmanned marine vehicle sailing in the presence of ocean current disturbances is addressed. Asymmetry of the unmanned marine vehicle model and higher order velocity coupling terms of damping coefficients of the unmanned marine vehicle are discussed, which would improve the accuracy of the path following control system. A kind of global differential homeomorphism transformation design is proposed to solve the difficulty of nonzero term appearing in the non-diagonal elements of the system inertia coefficient matrix and damping coefficient matrix, which is caused by the model asymmetry of unmanned marine vehicle. An improved line-of-sight guidance algorithm is presented by introducing longitudinal position error and tracking error weight factor into traditional line-of-sight algorithm, which could speed up the path following process, meanwhile the method could be extended to the application of curve path following. Virtual velocity in the tangent direction of the path to be followed is designed for the control system, by increasing a virtual control input, the underactuated control system is simplified, and the higher order velocity coupling terms of damping coefficients are integrated considered in the virtual control law. Stability of the path following control algorithm proposed for unmanned marine vehicle is proved by Lyapunov theory, and some simulation experiments are carried out to verify the effectiveness of the path following control system designed.

Highlights

Path following control system is one of the most fundamental and critical control systems during the whole operation process of Unmanned marine vehicle (UMV); after the scheduled task is determined, the UMV needs to accurately sail on the specified path according to the requirements of mission planning, and inaccurate path following may lead to task failure.[14,15,16,17,18]
Accurate path following control plays an important role for UMV in the oceanic surveys and exploration, an adaptive nonlinear second-order sliding mode controller is proposed to eliminate the chattering motion through a sliding surface during the path following control by Zhang et al.,[23] and David et al proposed a novel improved proportional–integral–derivative control approach that enables variable ballast systems on an UMV to complement the underwater vehicle’s hydroplanes when altitude keeping over a variable seabed,[24] while subject to complex unknown nonlinearities including un-modeled dynamics, uncertainties, and unknown disturbances, a novel fuzzy uncertainty observerbased path following control scheme for an underactuated marine vehicle is proposed in the study by Wang et al.[25]
The cooperative path following problem of multiple underactuated UMVs involves two tasks,[26] which may be used to cooperative topographic survey, and the first one is to force each UMV to converge to the desired parameterized path, while the second one is to satisfy the requirement of a cooperative behavior along the paths

Summary

Introduction

Unmanned marine vehicle (UMV), usually contained unmanned/autonomous underwater vehicle (UUV/AUV) and unmanned/autonomous surface vehicle (USV/ASV), can be used to perform a multitude of different tasks, such as mineral resources sampling, offshore oil and gas operations, ocean engineering maintenance, and military reconnaissance, and it is attracting more and more interest from the scientific, commercial, and naval sectors.[1,2,3,4,5] much advancements have been realized in this area, the. As $2 converges to 0, as proved in the “Stability analysis of intermediate state variables $1, $2, $3” section, and the virtual control input a’e is proved to converge to 0, combing with the second equation of system (13), it is easy to obtain that the UMV path following heading error ’e would globally and asymptotically converge to 0 as t ! To verify and illustrate the effectiveness and reliability of the path following control system designed based on the control algorithm proposed in this article, several computer simulation experiments are carried out, for an underactuated UMV in a preplanned route with the disturbance of ocean current, on the semi-physical simulation platform in our laboratory.

Discussion

Conclusions