Contact-Free Actuation Enabled by Acoustic Metasurfaces

This grant will fund fundamental research on the remote and contactless actuation of objects with acoustic waves. Motion control and manipulation of objects present universal challenges in science and engineering. Conventional actuation mechanisms often require physical tethers or onboard energy sources, which can be cumbersome in practical applications in robotics, materials assembly, bioengineering, and biomedicine. Actuation by the radiation pressure of waves, such as acoustic waves, can be entirely contactless, but current techniques are limited to small, subwavelength objects. To overcome these limitations, this project will exploit the interaction of acoustic waves with engineered structures known as metasurfaces. The main idea is to envelop objects with surface patterns that are deliberately designed to control the momentum change of the actuating wave, that is, to control the direction and intensity of actuation, enabling to remotely move, steer, and manipulate these objects. The scientific research will be tightly integrated with education and outreach activities including hands-on demonstrations designed to broaden participation and expose students to science and engineering at the intersection of metamaterials and robotics. The technical objective of this project is to develop a foundational understanding of metasurface-controlled contactless dynamics. By utilizing metasurface patterns, it is possible to control the radiation pressure with high fidelity and high resolution at each location along the object’s surface. The objective of this research is to develop a bidirectional, forward and inverse, models that map between the desired object dynamics and metasurface patterns. By combining wave-physics analysis and finite-element simulations, this project will identify new metasurface topologies that are suitable as building blocks for contactless actuation. Modeling efforts will be supported by the fabrication and characterization of metasurface structures and tabletop experiments to demonstrate their dynamical behavior. 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.