An approach towards the control of underwater vehicles

Underwater vehicles present difficult control-system design problems due to their nonlinear dynamics, uncertain models, and the presence of disturbances that are difficult to measure or estimate. In this paper, one approach has been carried out for controlling voltage supplied to two horizontal propellers of an underwater vehicle with the objective of controlling the following variables, the yaw angle, the yaw rate and the sway speed. The design is based on the recursive procedure of the multivariable backstepping. The designed algorithm jointly with a simple optimization procedure, that minimizes the energy consumption, is capable of handling these problems with effectiveness. This method, as opposite to the input-feedback linearization, deals directly with nonlinearities and is highly robust to imprecise models. Simulation results are reported to demonstrate the effectiveness of the proposed approaches with an improvement on the precision manoeuvring.