Extended state observer design for autonomous surface vehicles using position-yaw measurements

Abstract

This paper is concerned with the disturbance estimation and state recovery of autonomous surface vehicles in the presence of uncertainty and unmeasured surge, sway, and yaw velocities by using the position-yaw measurements only. The uncertainty stems from parametric model uncertainty, unmodelled hydrodynamics, and external disturbance, which are induced by wind, waves and ocean currents. By using the output information of position-yaw measurements, a nonlinear extended state observer is developed to estimate the unmeasured surge, sway, and yaw velocities as well as the total uncertainty, simultaneously. The stability of the developed extended state observer is analyzed based on simultaneous Lyapunov inequalities. The proposed extended state observer can be used in target tracking, trajectory tracking, path following, formation control, and even sideslip angle identification, not only for fully-actuated marine vehicles but also for under-actuated marine vehicles. Simulation results are provided to validate the effectiveness of the proposed extended state observer for autonomous surface vehicles using the position-yaw measurements only.