Monarch butterflies inspired the design of 3D-printed robotic wings whose delicate movements depend on magnetic fields.
Scientists have designed robot wings that resemble butterfly wings. They move without bulky electronic components or batteries, using magnetic fields while imitating the natural movement of butterflies.
“The extraordinary migratory abilities of Monarch butterflies and their highly efficient and flexible wing design inspired our project,” said Muhammad Khan from the Technical University of Darmstadt in Germany.
Monarch butterflies are known for his or her incredible endurance. They cover hundreds of kilometers yearly, migrating from Canada to Mexico in the autumn, before heading north again within the spring. This is feasible because of the natural structure of their wings, which makes them light, flexible and in a position to fly perfectly – a novel combination that researchers desired to emulate of their robots.
This project could enable scientists to create much smaller flying robots, allowing them to maneuver with greater precision and reach narrow spaces, while maintaining low energy requirements.
“Magnetic butterflies can be used for environmental monitoring, such as pollination studies, or as educational tools,” Khan said. “Their lightweight and energy-efficient design will also make them promising for micro-aircraft used in search and rescue missions.”
Building magnetic butterflies
Despite its small size, the natural structure of the monarch butterfly’s wings could be very refined and has evolved to face up to extremely long journeys. One of the fundamental principles that make these wings so effective in flight is that they not only produce thrust by actively moving, but additionally by passively bending their natural shape, which allows them to “glide” without expending additional energy.
To recreate this, a team of researchers led by Oliver Gutfleisch from TU Darmstadt and Denys Makarov from Helmholtz Zentrum Dresden-Rossendorf built automatic butterfly wings by embedding magnetic particles in a versatile plastic material.
“The wings are made of a magnetic composite material that responds to external magnetic fields,” said Kilian Schäfer, co-author of the study. “When a magnetic field is applied, the embedded magnetic particles cause the wings to bend or deform, mimicking the movement of real butterfly wings.”
Using 3D printing, they created 12 different wing designs of various sizes to check their behavior using a mix of experimental tests and computer simulations. Some designs also recreated vein patterns that mimicked those found on monarch butterfly wings to see if these structures could improve their performance.
They found that larger wings – about 28 mm long – with vein patterns were less stiff and easier to bend, allowing them to evolve higher in flight.
In their tests, the researchers also found that butterflies 3D printed using higher energy laser settings were thinner and flexed higher. However, they were also more fragile and vulnerable to damage.
“The biggest challenge was to produce thin, flexible structures with embedded vein patterns” that were still functional while being lower than a millimeter thick, Schäfer said. “Ensuring that these features remain intact (…) required fine-tuning the 3D printing process, particularly the laser energy settings, to achieve the desired mechanical properties.”
Lighter, higher robots
The unique design of magnetic robots allows them to operate with none electronic components, which normally limit the scale and weight of flying robots.
“Compared to traditional flying robot designs (…) our approach provides flexibility, reduced weight and the ability to perform complex, naturalistic wing movements,” Khan said.
Butterfly-inspired robots couldn’t only function as micro-aircraft, but is also utilized in biomedical devices corresponding to remotely controlled surgical tools and environmental monitoring systems.
“Additionally, it could inspire new designs for artificial muscles and shape-changing components in other areas,” he said.
So far, researchers have focused on examining one variety of wing movement that is crucial for lift and thrust in monarch butterflies. Reproducing all different movements required for flight would require more work.
Next steps will involve examining how the wings operate when exposed to several types of magnetic fields, including fields that change direction over time to manage the forward and backward movements of the wings. Further research and development will allow them to optimize the wing design for real-world aviation applications.
“Currently, wings are limited by the necessity for external magnetic fields. Future work may concentrate on integrating more miniaturized magnetic field generators with feedback control to make sure autonomous operation, Khan said. This could ultimately enable robots to maneuver and act without human intervention.
“We are also interested in applying similar biologically inspired design principles to the development of other shape-changing robotic systems, particularly for applications requiring high adaptability and performance.”
