University of Washington (UW) scientists have introduced a remarkable advancement in micro-robotics, crafting battery-free, tiny robots inspired by the folding patterns of leaves.
Researchers at the University of Washington have created compact robotic devices capable of altering their mid-air movement by rapidly transitioning into a folded position during their descent. These devices are equipped with an integrated battery-free actuator, a circuit for harvesting solar power, and a controller that initiates these shape changes while in-flight. In the image, a "microflier" is depicted in its unfolded state.
Tiny Robots Called 'Microfliers' Can 'Snap' Into a Folded Position
These innovative robotic devices called "microfliers" employ a Miura-ori origami fold when dropped from a drone, enabling them to alter their movement while in the air, the University of Washington News reported.
These microfliers are engineered to shift from tumbling and dispersing outward through the air to dropping straight to the ground. This transition is expertly orchestrated using various methods: an onboard pressure sensor estimating altitude, an internal timer, or a Bluetooth signal.
Remarkably lightweight at approximately 400 milligrams, equivalent to half the weight of a nail, these tiny robots can travel the span of a football field when released from a height of 40 meters (approximately 131 feet) in a light breeze.
Each device is equipped with a battery-free actuator, a solar power-harvesting system, and a controller to initiate mid-air shape changes. These microfliers also possess the capability to carry onboard sensors for monitoring temperature, humidity, and other environmental conditions while in flight.
Using Miura-Ori Origami Fold for Microfliers
Vikram Iyer, co-senior author and assistant professor at the Paul G. Allen School of Computer Science & Engineering at UW, explained the significance of integrating origami into the design.
He said: "Using origami opens up a new design space for microfliers. We combine the Miura-ori fold, which is inspired by geometric patterns found in leaves, with power harvesting and tiny actuators to allow our fliers to mimic the flight of different leaf types in mid-air."
He continued: "In its unfolded flat state, our origami structure tumbles chaotically in the wind, similar to an elm leaf. But switching to the folded state changes the airflow around it and enables a stable descent, similarly to how a maple leaf falls. This highly energy efficient method allows us to have battery-free control over microflier descent, which was not possible before."
According to the team, these micro-robots successfully address multiple design hurdles. They possess the requisite rigidity to prevent inadvertent folding before receiving the signal.
Moreover, their transition between states is swift, with onboard actuators necessitating a mere 25 milliseconds to initiate the folding process. Crucially, these tiny robots have the capacity to alter shape even when untethered from a power source, thanks to a power-harvesting circuit that utilizes sunlight to supply energy to the actuator.
While the current microfliers can transition solely from a tumbling state to a falling state, the researchers said future models will be able to transition in both directions.
According to the team, this will enhance precise landings in turbulent wind conditions. The research team's findings were recently published in the journal Science Robotics.
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