Fault Detection for Underwater Hexapod Robot Based on PI Observer

Abstract

Viscous flow analysis around a underwater robot was performed using the ANSYS-CFX package in order to estimate hydrodynamic force. The Reynolds-averaged Navier-Stokes equations were solved to determine the hydrodynamic coefficients for the body and legs of the multi-legged underwater robot Crabster. A turbulence closure model, k-ω Shear-stress transport(SST) was adopted. For the efficient CFD calculation, the unstructured grid was generated using ICEM-CFD. The comparison of the hydrodynamic forces between the previous robot geometry and the newly improved one was carried out. Furthermore the effect of viscous boundary layer on seabed was also assessed. The hydrodynamic forces acting on each part of leg and body were calculated separately to model the flow parameters for attitude control of the robot. Finally flow calculation was performed with the robot with multi-legs with various incident angles. The results of flow analysis is expected to be used as the base data in determining the geometry of the underwater robot and controlling the attitude.the body and legs of the multi-legged underwater robot Crabster. A turbulence closure model, k-ω Shear-stress transport(SST) was adopted. For the efficient CFD calculation, the unstructured grid was generated using ICEM-CFD. The comparison of the hydrodynamic forces between the previous robot geometry and the newly improved one was carried out. Furthermore the effect of viscous boundary layer on seabed was also assessed. The hydrodynamic forces acting on each part of leg and body were calculated separately to model the flow parameters for attitude control of the robot. Finally flow calculation was performed with the robot with multi-legs with various incident angles. The results of flow analysis is expected to be used as the base data in determining the geometry of the underwater robot and controlling the attitude.