Research On The Design And Modeling Of A Spherical Autonomous Underwater Vehicle

Ocean is a basic element of the life support system of earth and it is a treasure for sustainable development. Therefore, the development of autonomous underwater vehicle is becoming increasingly important for ocean exploitation. AUVs have been used broadly in the fields of oil exploit on the sea, salvage and military purposes. Since the 90s, researches of AUV have received intense attention by many nations and have become a hot spot of scientific research.In this thesis, author proposes a prototype of spherical AUV and focuses on the dynamics modeling of it. A PID control simulation of surge is done by using the dynamics model. This dynamics model can provides a theory foundation for the latter research.First, this thesis discusses and analyzes the structure of the spherical AUV and illuminates its motion characteristic which is caused by the combination of propel force and hydrodynamic force. Experiments and theory analysis are used together in the modeling and identification of propel motors. Meanwhile, by using a theoretic analysis, all of the hydrodynamic coefficients are calculated. Some linear simplifications are applied on this spherical AUV in the process of dynamics modeling and the dynamics equation is established on the basis of these simplifications. Also, this thesis discusses about the hardware design which is mainly focused on the control system. There are two main parts of control system—an ARM central control platform and an AVR platform working as a coprocessor on the propel motors control. Finally, the dynamics equation is solved using the method of Runge-Kutta, and a surge control simulation is completed using MATLAB/Simulink.There is one more thing should be noticed that all the results of this thesis are obtained by computer techniques especially the surge control simulation, so some errors may exist between the computation results and actual conditions.