Maneuverability measure of hovering-type underwater vehicles using robotic manipulability: A preliminary study

Abstract

Considering a mission involving the installation of seafloor instruments using an underwater vehicle, it is crucial to place the instrument at the desired location as accurately and safely as possible. However, a fixed thruster configuration may not provide sufficient performance for installing instruments of varying shapes and sizes, and modifying the thruster arrangement can compensate for this limitation. This paper applies robotic manipulability to evaluate the maneuverability of underwater vehicles when selecting a thruster arrangement suitable for accomplishing a given task. We first outline robotic manipulability and formulate the input–output velocity relationship of an underwater vehicle with n thrusters on a horizontal plane to apply the concept. We then examine the maneuverability of two thruster configurations: an equilateral-triangle arrangement composed of three thrusters and a square arrangement composed of four thrusters. Furthermore, the sum of the vector norms of the thruster speeds is computed while the vehicle tracks a straight-line path to investigate its relationship with the vehicle’s maneuverability. These results demonstrate that robotic manipulability can be effectively applied to evaluating the maneuverability of underwater vehicles and that a higher level of maneuverability contributes to reducing energy consumption.