Design of Robust Nonlinear Optimal Controller for Underwater Vehicle to Move in Depth Channel Using Gradient Descent Method with Systematic Step Selection

This paper proposes the design of a robust nonlinear optimal controller to move the underwater vehicle in the depth channel using gradient descent method. A nonlinear model with six degrees of freedom (6-DOF) has been extracted for the underwater vehicle. To selection of the model and design of controller, conventional assumptions used for other controllers have not been considered and the developed controller can be implemented via at least assumptions. In presented control method, systematic step selection for solving of the algorithm has increased the rate of convergence significantly. The performances of the proposed robust controller for moving in depth channel with considering of parametric uncertainty for the model have been confirmed via some simulations. The results show the desirable performance of developed controller.