“…The stabilizing control problem remains a challenging problem in the case of submarine systems, especially when the vehicle is reduced in sizes and weight. Even if an explicitly time-varying or a discontinuous laws solve the stabilizing control problem for a large underactuated autonomous systems (Coron and Rosier, 1994), (Morin and Samson, 1997), (Pettersen and Nijmeijer, 2001), a depth analysis of each vehicle's model is required to design a stabilizing controller. In this paper, we study an ultraportable submarine vehicle, called ROV, and is expected for observation and exploration insubsea historical sites.…”