A distributed model predictive control using virtual field force for multi-ship collision avoidance under COLREGs

A multi-ship collision avoidance decision support and path following control formulation is studied in a distributed way. This paper proposes a complete set of solutions for multi-ship collision avoidance in intelligent navigation, by using a top-to-bottom organization to structure the system. The system is designed with two layers: the decision-making layer for path planning and the control layer for path following. Under the general requirements from the International Regulations for Preventing Collisions at Sea (COLREGs), the performance of distributed path planning decision-making for anti-collision is analyzed for both give-way and stand-on ships situations, and the Virtual Field Force method(VFF) is used for the path planning in details. The developed VFF method combined with the model of ship domain takes the target ships' speed and course into account, so that it can judge the moving characteristics of obstacles more accurately. Furthermore, the distributed Model Predictive Control (MPC) method of path following is analyzed, which form the control layer. The MPC method has the advantages of dealing with the under-actuated nonlinear system like the surface vessel. Simulation results indicate that the system proposed can work effectiveness.