Battery-free robots use origami to change shape in mid-air

Newswise — Researchers at the University of Washington have developed small robotic devices that can change their motion by “hanging” into a folded position while descending through the air.

When these “micro-fliers” are dropped from a drone, they use a Many times From switching origami folds and scattering in the air to falling straight to the ground. To distribute flyers, researchers monitor the transition time of each device using several methods: an on-board pressure sensor (altitude estimation), an on-board timer, or a Bluetooth signal.

Microfliers weigh about 400 milligrams — about half as heavy as a nail — and can travel the distance of a football field when dropped from 40 meters (about 131 feet) in a light breeze. Each device has an on-board battery-free drive, solar-harvesting circuitry and a controller to make these shape changes in mid-air. Microfliers also have the ability to carry onboard sensors to check temperature, humidity and other conditions during takeoff.

team published these results September 13 in Scientific Robotics.

“Using origami opens up new designs for microflyers,” said the co-author Vikram look, UW Assistant Professor Paul G. in the Allen School of Computer Science and Engineering. “We combine the Mura-ori fold, which is inspired by the geometric patterns found in leaves, with power harvesting and tiny actuators to make our flyers mimic the flight of different types of leaves through the air. In the unfolded flat position, our origami. The structure falls chaotically in the wind, like an elm leaf. But switching to the folded position changes the airflow around it and allows for a steady descent, much like a falling maple leaf. This very efficient method allows us to be battery free. Control over the landing of microflares, which was not possible before.”

These robotic systems overcome several design challenges. Devices:

  • They are rigid enough to prevent accidental transition to the folded state before signaling.
  • Quickly switch between states. The devices' on-board actuators only need 25 milliseconds to start folding.
  • Change shape when unplugged from power source. The microflyer's power harvesting circuit uses sunlight to provide power for the actuator.

Current microflyers can move in only one direction – from a falling state to a falling state. This switch allows the researchers to control the fall of several microflares at the same time, so that they diverge in different directions on their way down.

The researchers said that future devices will be able to switch in both directions. This added functionality will allow for more precise landings in turbulent wind conditions.

Additional co-authors of this paper are: Kyle Johnson and Vicente Arroyosboth UW doctoral students at the Allen School; Amelie FerranUW doctoral student in the Department of Mechanical Engineering; Raul VillanuevaDennis Yin and Tilbun Elberierwho completed this work as UW undergraduates studying electrical and computer engineering; Alberto AlicedaUW Professor of Mechanical Engineering; Sawyer Fuller, UW assistant professor of mechanical engineering; and Shyam GolakotaUW professor at the Allen School.

This research was funded by a Moore Foundation Fellowship, the National Science Foundation, the National GEM Consortium, the Google Scholars Program, the Cadence Fellowship Program, the Washington NASA Space Grant Program, and the SPEEA ACE Fellowship Program.