Determination of ship maneuvering hydrodynamic coefficients using system identification technique based on free-running model test

In the recent years, different mathematical models have been 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 research, a 4.36-m model of kriso container ship (kcs) displacement vessel has been manufactured by fiberglass, and the maneuver turning tests have been carried by selfpropulsion method. a 3dm-gx1 sensor, together with a protractor and global positioning system (gps), has been used to measure the yaw and rudder angle, position, linear accelerations, and angular velocities of the vessel in different times. 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. the mathematical model and hydrodynamic coefficients presented in this paper can be applied for optimization of ship maneuvering performance and course control purposes.