Identification of 4-DoF maneuvering mathematical models for a combatant in intact and damaged conditions

Abstract

This article introduces the process of identifying the dynamics models of a combatant in intact and damaged condition based on the measured data from free running model tests. The applied system identification method is an Estimation-Before-Modeling approach, which estimates state variables and parameters separately. After estimating the states, the tendency of the hydrodynamic force acting on the combatant in intact and damaged conditions is compared. The modeling hydrodynamic force in intact and damaged conditions is performed based on the estimated hydrodynamic force tendency. Then, the process and results of identifying the hydrodynamic derivatives constituting the modeled hydrodynamic force are described. Differences of the hydrodynamic derivatives in intact and damaged conditions are analyzed, and maneuvering simulation is performed to verify them. The identified hydrodynamic derivatives are verified by performing maneuvering simulation and comparing the results with the measured data, and the asymmetric maneuvering characteristics of starboard and port maneuvering in the damaged condition are also confirmed.

Keywords

• Damaged combatant
• 4-Degrees of Freedom
• System identification
• Maneuvering simulation