Title: Fish, Robots, and the Space Between

Abstract: Fish-like robots may soon revolutionize the way we interact with our planet’s oceans. But first, they will need to swim a lot better. The latest fish-like robots have speeds and efficiencies approaching those of real fish, but they still trail fish in terms of maneuverability, versatility, and stealth. Closing this performance gap is challenging, because it requires a smooth transfer of information between robotics, hydrodynamics, and biology. These fields use vastly different ranges of realism and precision, making them hard to connect. Robotics-centered experiments (e.g. autonomous prototypes) offer realistic in situ conditions, but they may lack the precision needed to find physics-based patterns in the data. Hydrodynamics-centered experiments (e.g. tethered airfoils in water channels) can uncover high-precision models that are rooted in physics, but they may oversimplify dynamics. Here we present our efforts to use medium-fidelity experiments to build bridges between models and the fishes/robots they govern. We apply our approach to three ongoing areas of study in the world of fish-robots: fin-fin interactions, ground effect, and active stiffness control.