Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Design and Analysis of Planetary Super-maneuverable Spherical Underwater Vehicle
Yixin Gao, Shijie Xu, Xinyi Xie, Chaowu Sheng, Rendong Feng, and Haocai Huang*
Ocean College, Zhejiang University
Zhoushan, Zhejiang, China* Corresponding author

displacement of its center of mass. Kagawa University proposed a novel
spherical underwater robot (SUR-V) with hybrid propulsion devices that
divided into two parts- vectored water-jet and propeller thrusters (AnRuochen et al. 2020; Guo Shuxiang et al. 2011). Although many SUVs
have been studied and designed, most of them are not compact enoughand their propulsion systems are hard to control, so an integrated andeasily controlled SUV is needed.

ABSTRACTThe exploration of narrow and tortuous underwater caves requires aflexible underwater swivel vehicle. This paper proposes a small, lowpower, and super-maneuverable spherical underwater vehicle (SUV)
which is suitable for cave observation. The planetary propulsion systemof the SUV can rotate fast to realize rapid direction change. An attitude
regulation mechanism is used to ensure attitude stability and a buoyancy
adjustment mechanism is designed to enable the vehicle to dive andascend with low energy consumption. Finally, the excellent turning
performance of the SUV is proved by the Planar Motion Mechanism test
simulations.

KEY WORDS: Spherical underwater vehicle; planetary propulsion
system; planar motion mechanism; hydrodynamic analysis.
INTRODUCTIONUnderwater caves contain numerous objects of great biological,
historical, cultural, and/or paleontological significance (Fortin et al. 2021)
which is the meaning to observe them. However, the condition of theunderwater caves is usually complex and it makes human deep-diving
exploration difficult. An agile underwater robot can replace human toperform ocean observation tasks. Current unmanned underwater vehicles
are most torpedo shape with less resistance along the shell extension
direction, but large steering resistance, lateral movement, and gyration
radius. These characteristics help them do large-scale missions, but makethem difficult to perform observation tasks in narrow and tortuous caves.
There are several SUVs have been designed. University of Hawaii
proposed an omni-directional, intelligent navigator (ODIN) with eight
refurbished thrusters and a closed spherical frame (Choi, Yuh and Keevil
1993; Choi et al. 2003). The vehicle has dual (autonomous/remote)
operational modes and a mechanical manipulator. Sumantr, Karsiti andAgustiawan (2008) proposed a variable ballast to control the buoyancyof the body in an underwater vehicle. This variable ballast mechanism
can make the water always fulfill the variable tank with varying volume.
Kaznov and Seeman (2010) proposed a spherical amphibious robot.
Groundbot accomplishes its locomotion and steering by adjustingFig. 1 Conceptual design of the spherical underwater vehicle
In order to solve the above problems, a novel planetary supermaneuverable SUV is conceptually designed in this paper (Fig. 1). The
planetary propulsion system enables rapid direction change by rotating
propeller frame, the attitude regulation mechanism is used to ensure
attitude stability by displacement of its center of mass, and the buoyancy
adjustment mechanism enables the vehicle to dive and float with low
energy consumption by changing the position of the movable plate. In
the following sections, the structure and motion modeling of the vehicle
are introduced. Based on the SUV’s structure, the hydrodynamic analysisof the SUV is studied using ANSYS FLUENT and the hydrodynamic
coefficients are solved by planar motion mechanism (PMM) test. Thenthe motion stability is proved using Routh-Hurwitz criterion. Finally, weprovide a brief summary of the structure and simulation results.

SUV STRUCTURE

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