Research on the Trajectory Prediction of a Twin Screw AUV Based on an Accurate Dynamic Model

Twin screw AUVs can support unmanned operation in offshore engineering due to their good turning maneuverability. However, it is difficult to accurately predict the trajectory of AUVs because the hydrodynamic coefficients in their dynamic models are difficult to identify accurately. In this paper, a hybrid hydrodynamic coefficient identification method is proposed to support the model-based trajectory prediction of AUVs. First, some linear hydrodynamic coefficients are identified by the PMM test. Second, the remaining hydrodynamic coefficients are identified by the free-running test, using the identified hydrodynamic coefficients as prior knowledge. To verify the feasibility and effectiveness of the proposed method, turning simulations of a twin screw AUV are carried out using the CFD method. The results show that the trajectory prediction of the AUV based on the proposed method is accurate, verifying that the proposed method is effective.