Study on Maneuvering Motion Modeling of Small AUV

The maneuvering motion equations of AUVs (Autonomous Underwater Vehicles) are mostly appropriated and constructed from the field measurement on maneuverability in marine engineering. The applicability of the equations of motions applied to the conventional AUVs was confirmed for the NMRI small cruising AUV “mini-AUV” with 1.8m length developed at National Maritime Research Institute (NMRI) in Japan. The motion model is redefined concerning the MMG model which is commonly used in the ship maneuvering modeling field. The model treats a main hull, rudders, and a thrust unit as components for obtaining hydrodynamics terms in the motion equation. Based on the modeled equations, towing tests, etc. were conducted in the test basin of our institute, and the parameters in the equations of motions were determined. Free-running tests of the mini-AUV were also carried out in the basin to confirm the maneuvering performance of the AUV. In this paper, the procedure of maneuvering modeling on the hydrodynamic forces and test results of the modeling forces are introduced. The results of the free-running tests and computational simulations are presented under the same conditions for comparisons. As a result, the simulated results correspond reasonably well with the tank test ones, and then it was shown that the equations of motions on the small AUV presented in this paper are useful for estimating the navigational performance.