Design optimization of an AUV for performing depth control maneuver

Abstract

A methodology for optimizing the inertial characteristics, propeller, battery capacity and PID (Proportional Integral Derivative) controller for propeller of an Autonomous Underwater Vehicle (AUV) is proposed in this paper. The AUV is launched at high speed in horizontal orientation, thereafter it pitches bow down and finally hovers at a particular desired water depth. The study involves both positively and negatively buoyant AUV. Four quadrant propeller open water model and quaternion are incorporated in the Maneuvering Modeling Group (MMG) type maneuvering model to make it suitable for 7 degree of freedom (DoF) dynamics. The bow down orientation is performed due to the inertial characteristics of the AUV, while the depth control maneuvering of the AUV is carried out by using PID controller for propeller revolutions. A cost function is proposed in terms of energy consumed and the distance traveled by AUV during the desired maneuver. The numeral value of cost function can be computed by carrying out numerical simulations. The numerical simulations can estimate when the AUV's propeller works in turbine mode. This information is useful for protecting the electric/electronic components of the AUV.