Body Structure Design And Hydrodynamic Simulation For Small Underwater Robot

At present, humanity is faced with three major problems of population, resources and environment. The underwater robot (Remotely Operated Vehicle) used in underwater is an operating equipment,which dive into water instead of completing certain operations. More and more ROV is used in resource exploration and underwater operations as the rich underwater resources. A few propeller thrusters are used in traditional ROV’s heading control, which need to use open-frame structure to install these propellers generally. Open-shelf ROV is difficult to increase speed and these propellers also greatly increase the ROV’s body weight and sailing resistance. In order to minimize the ROV’s volume and resistance and to improve the observation ROV’s mobility and flexibility, this paper will design a mobile ROV of observation (detection) type for this purpose, so ROV should have a excellent water dynamic performance, streamlined shape. Refering to the excellent hydrodynamic rudder which is used on the ship to control direction, this paper will use two horizontal wings and a vertical rudder to control ROV’s movement direction. The ROV’s mobility will be greatly enhanced,which may solve the difficult problem of increasing traditional open-frame ROV’s speed.According to technical specifications of the design task, a ROV prototype is desgined in this paper (Remotely Operated Vehicle). The major work involved is the body structure design including the pressure hull design, seal design, the camera device design about angle adjustment, the selection of material structure and the whole assembly design. Taking into account of ROV mobility and basing on the requirement that the navigation resistance is as small as possibly, the excellent shell appearance is the most effective way to reduce the resistance. Basing on sectional design idea proposed by myring and considering ROV space, this paper will draw a shape with excellent fluid properties to satisfy layout requirement through setting adjustable parameters (data points). Then the shell of resistance parameter in flight directly is analyzed by using the software Fluent, which provides a basis selection for main propulsion motor. In addition, because the work environment of ROV is complex, the design about the pressure hull of thickness plays a key role for the entire security. In this paper, the design about the pressure hull of thickness is very detailed. By using simulation software to carry out static analysis after determining the thickness, the safety factor obtained at maximum working depth is in line with regulatory requirements, which verifies pressure hull of safety and design reliability. Seal is a key issue, and the O-ring seal design especially the detailed dynamic seal is adopted in this paper because of its simple structure and wide use scope. In order to reduce the navigation resistance from maximum extent, traditional ROV usually has multiple propellers (also known as the possession) which greatly increase navigation resistance. Refering to the ship’s rudder wing structure, this paper adopts the rudder wing structure with lower resistance to control the movement direction. Conducting simulation analysis about hydrodynamic performance by using NACA0015airfoil, the rudder wing of lift and drag obtained under different speed and attack angle can forecast motion control of the ROV, which provides a basis for servo selection by calculating rudder wing of the maximum torsion moment.In the end, the ROV has a streamlined shape, and its hydrodynamic performance is excellent. Rudder wing structure can minimize the ROV’s navigation resistance. This ROV which is observed in the harbor and used in marine research will have broad application prospect.