Harmonic Potential Field Method for Autonomous Ship Navigation

Autonomous ship navigation technology is a promising approach to reduce human errors in maritime accidents. Artificial Potential Field method has been successfully employed for path planning of autonomous mobile robot and it can also be effective for ship navigation at sea. The problem of local minima, however, should be properly tackled. Harmonic functions, by virtue of their extrema appearing only on the domain boundary, are novel approach for autonomous ship navigation. In this paper, harmonic functions are used in defining the potential field. A fluid dynamic analogy is introduced and proper boundary conditions are chosen to solve the navigation planning problem for ships. With harmonic potential field, ship navigation route can be generated automatically in constrained water areas and the tracks of the ships can follow the navigational regulations for the specific region as well. Computer simulations are conducted for two typical water areas such as Traffic Separation Scheme and narrow channel. The simulations illustrate satisfied results for path planning of ship navigation.