A palm-sized levitation device from Yokohama National University can dart in any direction without touching the surface beneath it. By combining acoustic levitation with a piezoelectric squeeze film, the untethered system sidesteps the drag of friction and the tangle of cables, moving small components at speeds up to 3 meters per second.
The work, published July 10, 2025, in Advanced Intelligent Systems, could reshape how delicate parts are handled in electronics, biomedical labs, and chemical processing.
Why Friction is a Problem in Miniature Transport
As devices shrink, so does the margin for error when moving parts like microchips or biomedical samples. Conveyor belts and wheeled robots are slowed by surface friction, which can limit precision. Technologies like magnetic and pneumatic levitation have been explored, but they require special materials or bulky support systems. Acoustic levitation, which uses sound waves to suspend objects in midair, offers a path to contactless transport — but until now, traditional setups have been hobbled by tethering cables that affect motion.
A Cable-Free Approach
“While acoustic levitation removes floor friction, conventional systems rely on cables that disturb positioning. We solved this by developing an untethered levitation device with a wireless drive circuit, enabling stable levitation height and high-speed, flexible transport,” said study author Ohmi Fuchiwaki, associate professor at Yokohama National University.
The team’s device, measuring 95 by 72 by 45 millimeters, integrates a lightweight onboard power and control system. A piezoelectric actuator generates a squeeze film — a thin layer of air trapped between the device and the surface — allowing it to hover and glide over common flat surfaces like desks, glass, and whiteboards.
Performance in Tests
- Reached horizontal speeds over 1.4 meters per second on a whiteboard
- Maintained frictionless motion above 3.0 meters per second on a 10° incline
- Carried payloads up to 43 grams in addition to its electronics
- Traversed small surface obstacles, such as 50-micron steps
When levitation was turned off, the device could not overcome gravity on the slope, underscoring the role of the squeeze film in eliminating friction. The payload capacity was about 0.4 times its own weight, enough to carry parts, small containers of liquid, or biomedical samples without contact.
Applications Beyond the Lab
Potential uses range from assembling miniature machines to transporting chemical samples or even mixing fluids in test tubes by spinning them without contact. The researchers envision linking multiple levitation units to form robots capable of complex, autonomous movements.
Future improvements will focus on increasing levitation efficiency, stabilizing performance on irregular surfaces, and scaling the design for heavier loads. For context on how such advances could impact robotics and materials handling, see the National Institute of Standards and Technology’s work on intelligent systems.
“While acoustic levitation removes floor friction, conventional systems rely on cables that disturb positioning. We solved this by developing an untethered levitation device with a wireless drive circuit, enabling stable levitation height and high-speed, flexible transport.”
Journal Reference
Sunohara, Y., Ueno, S., Minegishi, R., Sekine, C., Kitamura, Y., Sugiyama, Y., Ando, S., Torii, A., & Fuchiwaki, O. (2025). Ultrafast untethered levitation device utilizing squeeze film for omnidirectional transport. Advanced Intelligent Systems. DOI: 10.1002/aisy.202401098.
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