Ship Straight-path Following Control Based On High-order Slide Mode

With the gradual recovery and development of the shipping industry,the demand for automation of ship control is increasing,and the requirements for various ship handling performance are also increasing.The design of the track control of the conventional surface ship is difficult,such as high nonlinearity,uncertainty and easy to be disturbed by wind and current.Therefore,it is significant to study the straight-path following control of ships.Among many control theories,sliding mode control has good anti-disturbance ability,strong robustness that is simple and easy to realize the control algorithm,which has been deeply applied in the research of ship movement.The high-order sliding mode extends the traditional sliding mode,and can obviously weaken the chattering phenomenon.In this paper,after reading a large number of the literatures and in view of the underactuated characteristic of ship track control and nonlinear characteristics of ship motion control,the ship straight-path following controller based on high-order sliding mode theory is designed.Because of the complexity of ship track control,using the sliding mode control algorithm to convert the control object successively in the process of designing.In the final,track control is switched to control the ship rudder angle.Combined with PI control algorithm and STA,and added integral to counteract the effect of interference,the control law with track keeping characteristics of the ideal model with no interference and in the environment of wind,current,wave and so on is designed respectively.The control algorithm designed in this paper has been proved through the stability analysis that the design can make the tracking error converge to zero finally.And the results of simulation in the Simulink module of MATLAB showed that the designed controller can guarantee the tracking error converges to zero in finite time,fast and stable tracking of the desired trajectory.The control track design showed better steady-state error and dynamic control performance,the whole change smoothly without chattering,good stability,good track control effect,with strong robustness in the interference of wind,current,wave and so on.The designed controller has a certain theoretical significance.