Using origami techniques, a battery-free robot can automatically transform in mid-air

Researchers at the University of Washington in the United States have developed a small robotic device that can change the way it flies in the air by folding during descent. The research results were published in the latest issue of Science Robotics.

Screenshot of the paper

The micro-aircraft weighs about 400 milligrams, about half the weight of a nail. When dropped from a height of 40 meters in a light breeze, it can float the distance of a football field. Each device is battery-free, with only solar-collecting circuits and controllers to trigger these shape changes in mid-air. They also carry onboard sensors to measure temperature, humidity and other conditions as they soar.

A micro air vehicle in its unfolded state.
Image credit: University of Washington

The researchers say origami technology opens up new design space for micro-aircraft. By combining inspiration from leaf geometry with energy harvesting and micro-actuators, the aircraft can mimic the flight of different leaves in mid-air. In its unfolded flat state, the origami structure tumbles chaotically in the wind, similar to an elm leaf; but switching to a folded state changes the airflow around it and enables a steady descent, similar to the way a maple leaf falls. This energy-efficient method allows for battery-free control of the descent of a micro-aircraft.

The team said that these aircraft systems have solved several design challenges, such as being strong enough to avoid accidentally transitioning to a folded state before sending a signal; they can quickly switch between states, and the device's onboard actuators can initiate folding in only about 25 milliseconds; they can also change shape when not bound by a power source, and the power harvesting circuit can provide energy using sunlight.

Currently, the micro-aircraft can only transition in one direction - from a tumbling state to a descending state, but it allows researchers to control the landing of multiple micro-aircraft at the same time. In the future, the device will be able to transition in two directions and will also support more precise landings in turbulent wind conditions.

Editor-in-Chief’s comments:

Robots are continuously improving! Their forms and functions are constantly being upgraded, and their application scenarios are also expanding rapidly. In terms of form, their appearance is not limited to manipulators, robotic arms, and humanoid robots, but has also developed a variety of new forms; in terms of function, they can not only chat and handle assembly line production tasks, but also learn to paint, dance, and perform surgery; in terms of application scenarios, they have penetrated into some more subdivided and professional scenarios, such as performing underground pipeline monitoring and in vivo drug delivery tasks. These changes also mean that robotics technology increasingly needs to be deeply cross-linked and integrated with professional technologies in other fields.