System Identification Determination of Ship Maneuvering Hydrodynamic Coefficients Based on Free-running Model Test Results

Ship maneuvering performance evaluation is essential for primary design stages. Ship maneuvering calculations، horizontal plane motion control and development of maneuvering simulators need a mathematical description of ship maneuvering. In the recent years، different mathematical models are suggested for maneuvering of displacement vessels that are capable of estimation of vessel maneuvers with acceptable precision. These mathematical models are based on determined hydrodynamic coefficients and their accuracy depends on the known coefficients used to solve the mathematical model. System identification methods are developed to calculate these coefficients utilizing input and output data obtained from different sources. In this paper different maneuvers are executed through free running model tests of a container ship. The hydrodynamic coefficients in the mathematical model are determined by the Extended Kalman filter method. Then the mathematical model is solved and different maneuvers are simulated by coefficients calculated from the experiments. Simulations are validated by model tests. Finally the influence of rudder angle and advance speed on turning circle is studied. The mathematical model and hydrodynamic coefficients presented in this paper can be applied for optimization of ship maneuvering performance and course control purposes.