Ship Path Following and Collision Avoidance Based on Vector Field Guidance Law and Model Predictive Control

Abstract

A model predictive control (MPC) method based on the vector field guidance law is proposed to improve the effectiveness of path following and collision avoidance for ships. First, the path following and collision-avoidance problems are transformed into heading-control problems by the vector field guidance law. Then, the first-order Nomoto response model is adopted as the ship dynamic model for the model predictive control. Considering the input limitation of the rudder angle, the disturbance observer is introduced to compensate the model error and the environmental disturbances. The stability of the designed path following control system is verified by the Lyapunov theory. Finally, a collision avoidance strategy based on the vector field guidance law is designed to enable the ship to avoid collision autonomously in the process of path following. The simulation results indicate that the proposed methods can make the ship track the target path accurately and realize collision avoidance under the impacts of wave disturbances.

Keywords

• ship path following
• collision avoidance
• model predictive control (mpc)
• vector field (vf) guidance law
• disturbance observer