Integral Sliding Mode Adaptive Path-following of Unmanned Surface Vessels with Uncertain parameters and Time-varying Disturbances

Abstract

An improved line-of-sight(LOS)-based integral sliding mode adaptive methodology is presented for the path-following of underactuated unmanned surface vessels (USVs) with uncertain parameters and time-varying disturbances. The inertia and damping matrices of USV are maintaining asymmetry and remaining higher accuracy of USVs' model. Introducing the coordinate transformation to the system matrices such that turned it into skew-symmetric matrices. We separate the guidance-control design procedure into two stages, namely, guidance subsystem and control subsystem, respectively. At the first stage, considering improved LOS algorithm to ensure USV perfectly sufficient forwarding the predefined path with the approximately calculated method of sideslip. At the second stage, using the velocity dynamics to design the control force and moment in surge and yaw, respectively. Integral sliding mode and adaptive actions are adopted by the controller to compensate for uncertain parameters and time-varying bias caused by external disturbances. It is shown that the close-loop system is uniformly asymptotically stable by using Lyapunov and cascade stability theories. Simulation results illustrate the effectiveness and robustness of the proposed methodology.