Path following of unmanned surface vessel under the effect of position measurement noise

Abstract

A manipulation system for unmanned surface vessels (USVs), as well as other unmanned vehicles and autonomous vehicles, are commonly built up by three vital components which are guidance system, a navigation system, and control system, regardless of the mechanical aspects. In which, the navigation system will first use sensors to measure and estimate parameters, then feedback to the guidance system and the control system as input data. Based on those data and assignments from the user, the guidance system calculates and outputs reference data for the control system. The control system will drive the vessel according to the reference data from the guidance system to achieve those assignments. However, the process of measuring and estimating, in fact, is always affected by disturbances, which cause input error for the guidance system. Consequently, the reference data provided by the guidance system will be skewed and confused the control system, thereby reducing the quality of control and may cause instability for the whole system. This paper examines the problem of controlling an unmanned surface vessel following straight paths created by the waypoints given by the user. To solve the path-following for straight line problem, the paper will build a guidance system using the Line of Sight (LOS) method with lookahead distance and design a controller using a Backstepping algorithm. In addition, this paper will also study, analyze, and propose a method to reduce the influence of position measurement noise on the process of calculating the reference data of the guidance system. Thereby, the quality of the built system will be guaranteed when operating under the influence of measurement noise. The results of the proposed method will be shown through simulation on MATLAB/SIMULINK software. These simulation results will demonstrate the effectiveness and feasibility of the proposed method.