Research On Nonlinear Gain Adaptive Sliding Mode Control Of Ship Trajectory Tracking Based On Disturbance Observer

Abstract

A nonlinear gain adaptive sliding mode control method based on disturbance observer is designed to solve the problem of ship modeling error and 3DOF fully driven ship trajectory tracking control disturbed by unknown external environment. In this method, the error between the current position and the expected position of the ship and the error between the current speed and the expected speed are comprehensively considered to design a nonlinear gain adaptive dynamic sliding mode surface. the nonlinear gain effectively weakens the chattering phenomenon of the traditional sliding mode control input, and a disturbance observer is introduced to estimate the uncertain disturbances caused by external unknown environmental disturbances and modeling errors. By selecting the appropriate Lyapunov function, the controller can ensure the ultimate uniform boundedness of all signals in the trajectory tracking system. Finally, the simulation verification is carried out based on a transport ship, and the results show that the designed controller can ensure that the transport ship can achieve effective trajectory tracking, and has high tracking accuracy and strong robustness to modeling errors and unknown disturbances caused by the external environment.