Development of a mathematical model for harbor maneuvers to realize modeling automation

Abstract A simulation environment of harbor maneuvers is critical for developing automatic berthing. Mathematical models are widely used to estimate harbor maneuvers. However, user’s analysis and decision are necessary to derive, select, and identify the model because each actuator configuration needs an inherent mathematical expression. We proposed a new mathematical model for arbitrary configurations to overcome that issue. The new model is a hybrid model that combines the simplicity of the derivation of the Taylor expansion and the high degree of freedom of the MMG low-speed maneuvering model. We also developed a method to select mathematical expressions for the proposed model using system identification. Because the proposed model can easily derive mathematical expressions, we can generate multiple expressions simultaneously and choose the best one. This method can reduce the workload of model identification and selection. Furthermore, the proposed method will enable the automatic generation of mathematical models because it can reduce user’s decision-making and data analysis for the model generation due to its less dependency on the knowledge of ship hydrodynamics and captive model test. The proposed method was validated with free-running model tests and showed equivalent or better estimation performance than the conventional model generation method.