Motion control of docking AUV in currents

While ocean vehicles often operate in nonuniform currents, the effects of flow gradients on vehicle dynamics are typically ignored in motion models used for control. As applications for autonomous underwater vehicles (AUVs) expand into more constrained, dynamic environments, such as underwater docking, the benefits of using more precise motion models for motion prediction and control become more compelling. This paper presents a dynamic model for a streamlined underwater vehicle in a nonuniform flow. To illustrate the nonuniform flow effects, numerical motion predictions using the full dynamic model are compared in the flow fields with and without flow gradients. Due to the remarkable flow effects, cross-track feedback corrections are developed for docking control. The controller performance is validated by numerical simulations.