Estimation of Parameters of an Autonomous Underwater Vehicle using ANSYS-CFD

Abstract

Autonomous Underwater Vehicles find huge applications in defence organizations for underwater mine detection and region surveillance. These are also useful for oil and gas and paper industries in detection of leakage in the pipelines and also in many other marine industries. Underwater Robots are two type: Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV). A ROV is a remotely operated vehicle usually connected with the mother ship or base station through a tethered wire and controlled by remote. But AUV is an Autonomous Underwater Vehicle which traverses autonomously without any external involvement. There is a no human efforts As opposed to ROV, control of an AUV is difficult because it is an under actuated system (whose actuator inputs are less than the number of degrees of freedom to be controlled), also the dynamics of AUV is influenced by external disturbances such as ocean current and hydrodynamic effects. The motion control problems of an AUV can be of different types such as, waypoint tracking, and also path following, trajectory tracking, localization.
This thesis describes the development of a six degree of freedom, non-linear simulation model for the prototype AUV. In this model, all the forces which strongly affect the dynamic performance of an AUV such as the external forces and moments resulting from hydrostatics, hydrodynamics, lift and drag, added mass, and the control inputs of the AUV propeller and fins are all defined in terms of vehicle coefficients. Computational Fluid Dynamics (CFD) along with empirical formulas and design of AUV to determine the hydrodynamic coefficients of the AUV. The objective of our thesis is design the AUV using ANSYS-CFD. And we analysed the parameter which is affected by the Ocean disturbances. And these parameters are used for track the desired path while maintaining a desired constant velocity in the forward motion.