Hydrodynamic Analysis-Based Modeling and Experimental Verification of a New Water-Jet Thruster for an Amphibious Spherical Robot.

Xihuan Hou,Zan Li,Shuxiang Guo,Yao Hu,Debin Xia,Liwei Shi,Yu Liu,Huikang Liu,Huiming Xing

doi:10.3390/s19020259

Abstract

Thrusters are the bottom actuators of the amphibious spherical robot, and play an important role in the motion control of these robots. To realize accurate motion control, a thrust model for a new water-jet thruster based on hydrodynamic analyses is proposed in this paper. First, the hydrodynamic characteristics of the new thruster were numerically analyzed using computational fluid dynamics (CFD) commercial software CFX. The moving reference frame (MRF) technique was utilized to simulate propeller rotation. In particular, the hydrodynamics of the thruster were studied not only in the axial flow but also in oblique flow. Then, the basic framework of the thrust model was built according to hydromechanics theory. Parameters in the basic framework were identified through the results of the hydrodynamic simulation. Finally, a series of relevant experiments were conducted to verify the accuracy of the thrust model. These proved that the thrust model-based simulation results agreed well with the experimental results. The maximum error between the experimental results and simulation results was only 7%, which indicates that the thrust model is precise enough to be utilized in the motion control of amphibious spherical robots.

Highlights

Amphibious robots have attracted increasing attention from researchers for various applications in complex environments [1]
Motivated by the aforementioned discussion, this paper aims at combining hydrodynamic simulations and the theory of hydromechanics to establish an accurate thrust model of a new thruster
The propulsion mechanism of the amphibious spherical robot plays a vital role in achieving mechanism

Summary

Introduction

Amphibious robots have attracted increasing attention from researchers for various applications in complex environments [1]. With the development of amphibious robots, many kinds of propulsive devices have been proposed and developed, for instance, wheel-propeller-fins [6], wheel-propeller-legs [7,8], and curved flipper legs [9]. A propulsion mechanism with vectored water-jet thrusters was developed for the amphibious spherical robots by our team [10,11,12,13] This kind of water-jet thruster ingests water from the inlet and ejects water from the nozzle to generate a reaction (thrust) force for the robot

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Conclusion