A Hybrid Propulsion Device for the Spherical Underwater Robot (SUR III)

The propulsion system as the main power for the underwater robot will extremely influence its hydrodynamic performance. This paper focuses on a novel hybrid propulsion device for the third-generation spherical underwater robot (SUR III) with both vectored water-jet thrusters and propeller thrusters. To the limited space and mechanism, the hybrid propulsion device not only reserves the symmetric structure to maintain balance underwater, but also enhances the better property. And the diversity of the movement is also proposed for the different target as remote or hover. In order to analyze the hydrodynamic characteristics of the propeller, we establish the flow field with the multi-reference frame method to calculate the pressure and thrust of the propeller in ANSYS CFX. Finally, we set up the experimental system with a 6-DOFs load cell to measure the thrust of the propeller. Comparing the simulation and experiment results, the simulation thrust error is less than 8.5%. Meanwhile the power of the propeller thruster is 22.5% better than the water-jet thruster.