Kinematic and Computational Fluid Dynamics Analysis of an Underwater Manipulator Arm in Streamline and Blunt Body Arrangement

Abstract

This paper presents the hydrodynamic modeling, simulation and analysis of kinematic, velocity vector and pressure distribution of an underwater manipulator arm designed for a remotely operated underwater vehicle. The focus is to improve the modeling accuracy of the arm, which is simulated in a streamline and blunt body arrangement, with extended and retracted position, in order to achieve better control for coordinated motion of the 5 degree of freedom manipulator arm. The arm is simulated in suspended and submerged scenario, above and underwater, respectively. Kinematic analysis of the manipulator has been studied in order to identify the workspace of the manipulator. The workspace is important as it will define the working area suitable to be developed on the test rig, in order to study the effectiveness of using the manipulator arm for underwater application. Velocity vector and pressure distribution analysis is conducted in a laminar flow condition with a velocity of 0.1 m/s, which is in the range for underwater cases. The manipulator arm model is defined as the static body in a moving fluid. For retracted and extended condition which have been set according to the streamlines of inlet velocity on z-axis direction, high pressure occur at the arm, the tips of the gripper holder and model base as it exposed to the fluid flow and velocity. In the blunt body arrangement, pressure build up is discovered in most of the body cross section that exposed to the flow.