Tracking control of an underactuated unmanned underwater vehicle

In this paper, a robust position tracking controller is developed for an autonomous, underactuated, unmanned underwater vehicle (UUV). Specifically, the proposed controller forces the three dimensional (i.e., longitudinal, latitudinal, and depth) position tracking error to within an arbitrarily small region about zero (i.e., global exponential uniformly ultimately bounded tracking) through the utilization of one translational and three orientation actuators. Therefore, the proposed methodology may hold special appeal to such underactuated applications as the omni-directional intelligent navigators (ODINs) by extending capabilities to include changes in vehicle depth. In addition, uncertainty in such parameters as vehicle inertia and hydrodynamic damping forces are compensated through a robust control structure. Simulation results are provided to illustrate performance and details of the controller.