Depth and Heading Control of a Two DOF Underwater System Using a Model-free High Order Sliding Controller with Transient Process

The main difficulties associated with underwater control are the parametric uncertainties and the significant disturbaces form underwater currents which can not be measured easily. In order to avoid this problem, a model-free high order sliding mode controller is proposed, and design a reasonable transient process which make the controller have a good performance for any initial error condition. Performance of the proposed controller is verified using numerical simulations and real time experiments, implemented in a two freedom nonlinear underwater vehicle model. Simulation and experiments results show that exponential fast convergence of depth and heading, overshooting is very small, for any initial condition. And the controller is proposed needs few parameters to adjust. Algorithm is very easy to complie, could meet the engineering needs.