Trajectory design of an underwater glider considering depth constraints

Abstract

Underwater gliders have attracted much attention over the last decade because of their low cost and long mission range. However, they operate at low speeds by diving and climbing at a constant gliding angle, so they are strongly affected by ocean currents and the water depth. Thus, the design of efficient trajectories for an underwater glider is of great importance. This dissertation presents the formulation of the trajectory optimization for an underwater glider considering depth constraints to minimize the traversal time in the horizontal direction. The formulation leads to a nonlinear two-point boundary value problem with inequality constraints. The problem is solved numerically with the pseudospectral method. The validity and feasibility of the proposed approach were demonstrated through numerical simulations that compared the traversal time and energy consumption of different trajectories, and criteria for efficient operation settings with respect to the distance to the goal and water depth limit were investigated.