Adaptive Iterative Sliding Mode Berthing Control for Underactuated Ship Based on Chaotic Particle Swarm

An iterative sliding mode control method based on chaotic particle swarm optimization is proposed for the problem of automatic berthing for ships with three degrees of freedom. This method constructs a scalar function based on the berthing state, and the hyperbolic tangent function is used to carry out the iterative sliding mode design for the scalar functions and the ship transverse coordinates. The incremental feedback is used to control the rudder angle and rotating speed of the ship without the need to estimate the system's uncertainties and external disturbances. In order to improve the performance of the controller, a chaotic particle swarm algorithm with shrinkage factor is introduced, and the controller parameters are optimized according to the berthing route performance indicators. The mathematical model of 5446 TEU container ship is used to control and simulation. The simulation results show that the designed controller can quickly berth under the disturbances of wind and wave. The conclusions indicates the obtained automatic berthing route has no overshoot and oscillation after adding chaotic particle swarm optimization algorithm, and the rudder angle rotating speed is reasonable. It meets the actual project requirements and safety requirements.