The autonomous underwater vehicle (AUV) was designed and simulated its hydrodynamic behavior in order to serve as shallow coral monitoring system for coastal area of Thailand. The torpedo shape was selected to be the main body of the vehicle due to high speed and maneuverability characteristic with the length of 800mm including nose and stern and 200mm diameter. Two fins (airfoil NACA0012) and one rudder were equipped at the stern of the AUV body in order to control its direction, and single thruster was used. The mathematic model was used to determine the hydrodynamic of the vehicle under various circumstances including different speed. The fin angles were fixed at 0°, ±10°, and ±20° for hydrodynamic investigation under 2 and 5 m/s velocity regimes.
The motion system of the vehicle was achieved by using three servos and one thruster. The 16 bits microcontroller was used as the control centre as well as communication, while three accelerometers were used as motion sensors providing feedback signal to microcontroller for accurate stability and maneuverability. The power system of the vehicle was supplied by two 12V lithium polymer batteries with power monitoring system. The navigation system was achieved by using global positioning system (GPS); this allowed the travelling course used for vehicle and the current position which was transmitted back to the station. The signal for communication between the vehicle and station was Zigbee wifi/controller unit responding for command and data transmission.
