Station-keeping control of an unmanned surface vehicle exposed to current and wind disturbances

Abstract

Field trials of a 4 meter long, 180 kilogram, unmanned surface vehicle (USV) have been conducted to evaluate the performance of station-keeping heading and position controllers in an outdoor marine environment disturbed by wind and current. The USV has a twin hull configuration and a custom-designed propulsion system, which consists of two azimuthing thrusters, one for each hull. Nonlinear proportional derivative, backstepping and sliding mode feedback controllers were tested in winds of about 4-5 knots, with and without wind feedforward control. The controllers were tested when the longitudinal axis of the USV was aligned with the mean wind direction and when the longitudinal axis was perpendicular to the mean wind direction. It was found that the sliding mode controller performed best overall and that the addition of wind feedforward control did not significantly improve its effectiveness. However, wind feedforward control did substantially improve the performance of the proportional derivative and backstepping controllers when the mean wind direction was perpendicular to the longitudinal axis of the USV. An analysis of the length scales present in the power spectrum of the turbulent speed fluctuations in the wind suggests that a single anemometer is sufficient to characterize the speed and direction of the wind acting on the USV.

The review unmanned surface vehicle path planning: Based on multi-modality constraint

“…Partial functions have achieved (Yoo, B., & Kim, J., 2016;Sarda, E. I., et al, 2016;Song, R., et al, 2017;Ma, Y., et al, 2018;Singh, Y. et al, 2018;Wang, N., et al, 2019) Level six…”

Design of Ship Course Controller Based on Improved Adaptive Backstepping

“…In [7], an advanced adaptive observer based ship dynamic positioning backstepping is proposed, and the bias term is used to represent slow-varying disturbances and unmodeled dynamic. In [8], the backstepping is proposed to design station-keeping controllers of unmanned surface vehicle, and favorable results are obtained in the actual marine control system. In [9], the backstepping method is also adopted to design controller for under-actuated ships with input saturation, achieving global stability tracking.…”

A Strategy of Robust Control for the Dynamics of an Unmanned Surface Vehicle under Marine Waves and Currents

“…Works like [6] develop LQR controllers and observers for this station-keeping task. Other works like [7] present the implementation of various controllers for the station-keeping problem of a USV under environmental perturbations; the dynamic of the perturbations is not considered in the model of the USV; however, they include a wind feed-forward control for counteracting the effects. In [8] an antidisturbance controller based on a disturbance observer (DO) is developed and tested through simulations and comparisons; the proposed method can be used for different scenarios and control tasks.…”