Controlled Drift: An Investigation into the Controllability of Underwater Vehicles with Minimal Actuation

This paper is directed towards providing an answer to the question, ”Can you control the motion of a Lagrangian float?” By design, a float has minimal actuation (only buoyancy control), and their horizontal motion is dictated by ocean currents (Lagrangian). With the appropriate vertical actuation, and utilising spatiotemporal variations in water speed and direction, we show here that broad controllability results can be met, such as waypoint following to keep a float inside or outside of a designated region. This paper extends experimentally validated techniques for utilising ocean current models to control horizontally actuated autonomous underwater vehicles by presenting an initial investigation into the application of these methods on minimally-actuated drifting floats. Simulated results for an offshore coastal region and a region within a highly dynamic tidal bay illustrates two scenarios promising an affirmative answer to the initially posed question.