Design of fairings for an underwater robot

Abstract

Defence Research and Development Canada (DRDC) Atlantic is having a one-half scale prototype of a large 3 degree of freedom robot built, which is designed to be mounted on the hull of Victoria Class submarines. This robot has a manipulator arm to aid in the deployment and recovery of Autonomous Underwater Vehicles (AUVs). This report presents the complete design and construction procedures for the fairings for the underwater manipulator. The objective of this design is to reduce the drag on the robotic arm by implementing a fairing that covers both the retractable portion of the arm and the arm manipulator mechanism. A final design alone with manufacturing and construction procedures are presented so that the design may be built in the future. A CFD analysis of the self-aligning fairing was performed, in which preliminary results were obtained. The accuracy of these could be achieved through mesh refinement to improve the solution at the boundary layer. A nine time reduction in drag was achieved when the robotic arm is stationary versus the non-faired version of the robotic arm. The goal of zero net lift was not met. Recommendations are provided on how a version of this design could be built that would produce no net lift. Keywords: Fairing, Design, Autonomous Underwater Vehicle, Underwater Robot, Submarine, Self-aligning, Hydrofoil.