In a groundbreaking development at the University of Washington, researchers have created a tiny robotic device capable of altering its aerial movement by snapping into a folded position while falling. These innovative devices, known as “microfliers”, employ a Miura-ori origami fold to transition from an uncontrolled tumble to a straight drop towards the ground when released from a drone.
The microfliers, which weigh a mere 400 mg – approximately half the weight of a nail, are designed to cover the length of a football field when dropped from a height of 40 m (about 131 ft) in light wind conditions. Each microflier comprises an onboard, battery-free actuator, a solar power-harvesting circuit, and a controller that triggers these mid-air transformations. Furthermore, the microfliers can be equipped with sensors to monitor humidity, temperature, and other atmospheric conditions during flight. The team’s findings were published in the Science Robotics journal on September 13th, 2023.
The application of origami principles introduces a fresh perspective to the design of microfliers. By integrating the Miura-ori fold, inspired by geometric patterns found in leaves, with power harvesting and miniature actuators, the researchers have enabled the microfliers to mimic different types of leaf flight patterns.
“When in its unfolded flat state, our origami structure tumbles chaotically in the wind, similar to an elm leaf,” explains Vikram Iyer, Study Co-Senior Author and Assistant Professor at the Paul G. Allen School of Computer Science & Engineering at the University of Washington. “However, transitioning to the folded state alters the airflow around it and facilitates a stable descent, akin to how a maple leaf falls. This highly energy-efficient method provides us with battery-free control over the microflier’s descent, which wasn’t feasible before.”
These devices are designed to be extremely rigid to prevent premature transition to the folded state. The onboard actuators of the devices can initiate the folding process in just about 25 milliseconds, allowing for swift state transitions. Moreover, the microfliers can change shape while being untethered from a power source, thanks to their power-harvesting circuit that harnesses sunlight to energize the actuator.
While the current microfliers can only transition in one direction – from a tumbling to a falling state, this feature allows researchers to control the descent of multiple microfliers simultaneously, enabling them to scatter in different directions during descent. However, the researchers anticipate that future devices will have the capability to transition in both directions, facilitating highly accurate landings even in turbulent wind conditions.
The research team also includes Kyle Johnson and Vicente Arroyos, both UW doctoral students in the Allen School; Amélie Ferran, a UW doctoral student in the mechanical engineering department; Raul Villanueva, Dennis Yin, and Tilboon Elberier. Elberier contributed to this work as a UW undergraduate student studying electrical and computer engineering; Alberto Aliseda, UW professor of mechanical engineering; Sawyer Fuller, UW assistant professor of mechanical engineering; and Shyam Gollakota, UW professor in the Allen School.
This groundbreaking research has been financially supported by numerous sources, including a Moore Foundation fellowship, the National Science Foundation, the National GEM Consortium, the Google fellowship program, the Cadence fellowship program, the Washington NASA Space Grant fellowship Program, and the SPEEA ACE fellowship program. This development could potentially revolutionize aspects of electronics and computer programming languages related to robotics and automated systems.
