Generation of energy-optimal trajectories for an autonomous underwater vehicle

Energy-optimal trajectories for an autonomous underwater vehicle can be computed using a numerical solution of the optimal control problem. The vehicle is modeled with the six-dimensional nonlinear and coupled equations of motion, controlled with DC-motors in all degrees of freedom. The actuators are modeled and controlled with velocity loops. The dissipated energy is expressed in terms of the control variables as a nonquadratic function. Two different numerical methods are used in this study, a function space conjugate gradient (CG) method, and a control vector parameterization (CVP) method. Energy-optimal trajectories were computed in simulation experiments. Good results were achieved with the CVP method, which was superior to the CG method