Collaborative Research: Leveraging Fluid-Structure Interactions for Efficient Control in Geophysical Flows

Microvehicles provide a low-cost platform for a variety of robotics and automation applications. Their excellent maneuverability, agility, and ability to operate in truly three-dimensional environments have enabled ubiquitous, low-cost sensors for a range of data collection and monitoring tasks. Recent developments in micro-aerial, ground, and marine vehicles have advanced in many exciting and high-profile ways. However, because of the vehicles' low weight and limited computational and power capacities, controlling them is more challenging since the motion of the vehicles is significantly impacted by the environments in which they operate. This award supports fundamental research needed to understand fluid-structure interactions, that is, how small vehicles in water or air move and react within a surrounding flow. The investigators will use these insights to establish a new paradigm for the design and control of low-cost microvehicles, resulting in more power-efficient systems and, thus, extending their lifetimes. The work is an interdisciplinary effort combining knowledge in fluid dynamics, control theory, and reconfiguration planning. It will improve navigation and monitoring of dynamic and uncertain environments, and will contribute fundamental knowledge in the areas of weather and climate prediction, environmental monitoring, fisheries science, and shipping, to name just a few, thus benefiting the U.S. economy and society. It will also provide opportunities for training interdisciplinary undergraduate and graduate students at the intersection of robotics and fluid dynamics.

The main insight underlying this project is that small, resource-constrained vehicles can exploit their nearly limitless environmental forces to extend their own power budgets and operating lifetimes. In particular, by adjusting their morphologies, these vehicles can adapt their transport properties in a fluid environment and control their trajectories without active propulsion. Accomplishing this vision will require foundational science in dynamics and control to understand fluid-structure interactions in systems of vehicles that not only have volume and inertia, but can also reconfigure their shape. The project will make initial steps in this direction by: 1) characterizing the effect of aspect ratio and mass on a vehicle's passive transport properties and the inertial coherent structures underlying these complex dynamical systems; 2) synthesizing design and motion control strategies incorporating inertial effects and the underlying fluid-structure interactions; and 3) investigating the efficiency trade-offs between morphological reconfiguration and active propulsion in a variety of fluid flows. The knowledge and insights developed during the course of this program will expand the capabilities of micro-autonomous vehicles to perform long-term operations and will lay the groundwork for future innovations in the large-scale deployment of micro-machines.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.