Stabilization of an underactuated AUV with hydrodynamic damping in three-dimensional space

Abstract

This paper investigates stabilization of a relative equilibrium of an underactuated autonomous underwater vehicle(AUV) with three independent control inputs: moment of pitch, moment of yaw and thrust, in three-dimensional space while the hydrodynamic damping appears. The relative equilibrium we interest corresponds to a trim trajectory that can save power and that is naturally unstable. Controllers with the knowledge of the hydrodynamic damping were presented to handle this problem in considerable volume of literature. It's a drawback that controllers need the knowledge of the hydrodynamic damping terms, since the damping is notoriously difficult to model precisely even locally. Combining the interconnection and damping assignment(IDA) method and adaptive strategy together, dynamic control schemes without the information of the damping are provided to stabilize the relative equilibrium. Simulation results are included to verify the effectiveness of the proposed schemes.