Research of Ship ACA Actions at Different Stages during Overtaking Situations Based on CRI and COLREGS
Published on Jul 13, 2015
· DOI :10.1061/9780784479292.014
In order to study the Automatic Collision-Avoidance (ACA) actions of vessels in overtaking situation accord with rules of International Regulation for Preventing Collision at Sea (COLREGS 72) and ordinary practice of seaman, stags of vessel’s encounter process were separated by Collision Risk Index (CRI) and Time to Immediate Danger (TID).The reason is correct Collision-Avoidance (CA) actions in different stages are different. CRI and TID are derived from defined Situation Elements (SE). Then computing models of them and ACA actions in different stages were presented. The basis of research is center moved ship’s ellipse domain theories and MMG three-free dimensional digital model that is calculated from ship’s hydrodynamic equations. The following were proved by simulations: The mathematic models presented ensured rapid and reliable convergence of SE computing; new CRI model is much more accord with the thinking process of navigators and practice at sea than before; ACA action accord with COLREGS rules and ordinary practice of seaman, can be produced by program. The research may make big advance to the final achievement of ACA of ship in overtaking situation.