Robust control of Autonomous Underwater Vehicles (AUVs)

This paper presents a robust nonlinear method for controlling depth and head of Autonomous Underwater Vehicles. The control of autonomous underwater vehicles (AUV) presents a number of unique and formidable challenges. AUV dynamic is highly nonlinear, coupled, time varying and subject to hydrodynamic uncertainties and external disturbances. For trajectory tracking, the problem statement requires the design of a depth and head control system for the vehicle in order to achieve precise trajectory. This paper is presented an adaptive-sliding mode controller focused on self-tuning when the control performance degrades during the operation due to model uncertainties and change in the vehicle system and its environment. The adaptive-sliding mode controller combined advantages of sliding mode controllers and adaptive estimators. In the adaptive-sliding mode controller, robust controller is applied for tracking and rejecting disturbances and adaptive estimator is applied for estimating uncertain parameters. This controller is compared with other control methods such as sliding mode controller. To show the validity of the proposed algorithm, computer simulation results are presented.