Light helps fly maple seed-like mini robot, could help in rescue ops

Researchers have developed a tiny robot which replicates the aerial movements of a falling maple seed. This robot can be used for environment monitoring or for dropping off small samples in inaccessible areas like deserts, mountains, or the open sea.

The team of researchers from Tampere University, Finland, and the University of Pittsburgh, US, collaborated to build this tiny robot inspired from the wind-dispersed seeds which are common among maple trees.

According to the team, the tiny robot could be a game changer for search-and-rescue missions, studying endangered species, and even infrastructure monitoring.

Light robots research

Professor Hao Zeng and Doctoral Researcher Jianfeng Yang from the Tampere University work at the interface between physics, soft mechanics and material engineering in their Light Robots research group.

The group draws inspiration from nature to come up with polymeric gliding structures that can be controlled through light.

Earlier in 2023, they had unveiled their first creation – a dandelion seed like mini robot which used passive flying tactics. The polymer-assembly robot used a soft actuator to induce opening or closing actions of the bristles upon visible light excitation.

Now, the duo joined hands with Professor M. Ravi Shankar , from the University of Pittsburgh Swanson School of Engineering. Together they utilized a light-activated smart material to control the gliding mode of an artificial maple seed.

According to a release from Tampere University, maple disperses to possible new growth sites with the help of flying wings in the dry fruit, also known as samara. The wings help the seed rotate as it falls, which also enables it to glide in the presence of a breeze.

This wing design was the inspiration behind the newest creation from the team.

The team states that the artificial maple seed robot can be actively controlled using light.

“In the future, it can also be equipped with various microsensors for environmental monitoring or be used to deliver, for example, small samples of soil,” the release says .

Tiny maple seed-inspired robots are more adaptable

Inspired by the maple samara, the team made azobenzene-based light-deformable liquid crystal elastomer that achieves reversible photochemical deformation to finely tune the aerodynamic properties.

“The artificial maple seeds outperform their natural counterparts in adjustable terminal velocity, rotation rate, and hovering positions, enhancing wind-assisted long-distance travel through self-rotation”, says Zeng.

The tiny robots are equipped with GPS and other sensors which can help meet various research needs.

“The tiny light-controlled robots are designed to be released into the atmosphere, utilizing passive flight to disperse widely through interactions with surrounding airflows. Equipped with GPS and various sensors, they can provide real-time monitoring of local environmental indicators like pH levels and heavy metal concentrations” explains Yang.

The article was first published in the journal Nature Communications earlier this month.

Abstract

Miniaturized passive fliers based on smart materials face challenges in precise control of shape-morphing for aerodynamics and contactless modulation of diverse gliding modes. Here, we present the optical control of gliding performances in azobenzene-crosslinked liquid crystal networks films through photochemical actuation, enabling reversible and bistable shape-morphing. First, an actuator film is integrated with additive constructs to form a rotating glider, inspired by the natural maple samara, surpassing natural counterparts in reversibly optical tuning of terminal velocity, rotational rate, and circling position. We demonstrate optical modulation dispersion of landing points for the photo-responsive microfliers indoors and outdoors. Secondly, we show the scalability of polymer film geometry for miniature gliders with similar light tunability. Thirdly, we extend the material platform to other three gliding modes: Javan cucumber seed-like glider, parachute and artificial dandelion seed. The findings pave the way for distributed microflier with contactless flight dynamics control.