Disturbance/Uncertainty estimation based accurate trajectory tracking control of an unmanned surface vehicle with system uncertainties and external disturbances

Abstract

In this paper, disturbance/uncertainty estimation based approaches are developed to achieve high-accuracy tracking control (HTC) of an unmanned surface vehicle (USV) with system uncertainties and external disturbances. Main contributions are as follows: (1) A finite-time disturbance observer (FDO) based HTC (FDO-HTC) scheme is proposed to guarantee accurate trajectory tracking by exactly rejecting external disturbances and the integral sliding mode technique is further employed to achieve fast tracking performance; (2) To address complete unknowns including system uncertainties and external disturbances, a finite-time uncertainty estimator (FUE) based HTC (FUE-HTC) scheme is further proposed to achieve not only complicated uncertainty estimation but also precise tracking control even under harsh environments; (3) Theoretical analyses reveal that the entire closed-loop tracking system is finite-time stable, and thereby leading to fast and precise trajectory tracking control. Simulation studies and comprehensive comparisons demonstrate remarkable performance of the proposed FDO-HTC and FUE-HTC schemes.