Adaptive LOS Path Following based on Trajectory Linearization Control for Unmanned Surface Vehicle with Multiple Disturbances and Input Saturation

This paper develops an adaptive line-of-sight (LOS) path following control strategy for unmanned surface vehicle (USV) subject to unknown multiple disturbances. An adaptive LOS guidance strategy is adopted to compensate for the sideslip angle induced by wind, waves and ocean currents. On the basis of considering the saturation of the actuator, a practical path following controller based on linear extended state observer (LESO) is presented by trajectory linearization control (TLC) technology and nonlinear tracking differentiator. The greatest advantage of this article is that the TLC technology is first introduced into the field of USV motion control to design path following controller, which providesa new research field for the development of TLC. A feedback linearization control law is designed to enhance TLC technology in linear time-varying system, and a LESO is constructed to provide the estimates of the tracking error and unknown disturbances. Meanwhile, to avoid signal hopping and reduce the consumption of control, the nonlinear tracking differentiator (NTD) is constructed to realize the derivative of virtual control command, which can also provide command filtering. In addition, auxiliary dynamic system is designed to handle input saturation issue. The stability of the system can be guaranteed based on the Lyapunov stability method. At last, the simulation results confirm the superior performance of the proposed strategy.