Simultaneous modeling and adaptive fuzzy sliding mode control scheme for underactuated USV formation based on real-time sailing state data

Abstract

An adaptive fuzzy sliding mode control scheme based on data feedback is proposed in this paper, in order to achieve the trajectory tracking control of underactuated unmanned surface vehicles (USVs) in the present of unknown model parameters and environmental disturbances. Considering the problem of unknown model parameters, based on the feedback of sailing data, an online identification algorithm is designed to obtain real-time model parameters of USVs, which are used to establish the real-time simultaneous models of USV formation. A fuzzy control algorithm is introduced into the sliding mode controller design process to reduce convergence time and eliminate the chattering of the controller. Furthermore, a first-order low-pass filter is proposed to overcome the "differential explosion" issue, and a second-order differential tracker is designed to mitigate the jitter effects caused by higher-order derivatives of the lateral velocity. In addition, a nonlinear disturbance observer is developed to estimate and compensate the composite disturbances caused by real-time modeling inaccuracies and ocean environment disturbances. Finally, the effectiveness and robustness of the proposed control scheme are verified by several simulation experiment cases.