Soft robot mimics plant tendrils to curl and climb

A curling, climbing soft robot inspired by plant tendrils could lead to flexible wearable devices or adaptable robotic arms for exploration, its creators have said.

Created by engineers at the Italian Institute of Technology, the robot is reportedly the first to make reversible movements based on the principle of osmosis – water transport – within plants.

Researchers, including Barbara Mazzolai, Edoardo Sinibaldi and Indrek Must, also took inspiration from plants’ movement in their surroundings. Unlike animals, plant movement is linked to growth, so they continuously adapt their shape to the external environment. Complex movements are possible, such as the Venus flytrap’s closing ‘mouth’, or tendrils in climbing plants coiling and uncoiling around external supports.

The team studied how osmosis allows plant cells, tissues and organs to move thanks to small particles in the intracellular plant fluid, and then replicated it in an artificial tendril.

The soft robot is made of a flexible PET tube, containing a liquid with electrically charged particles. A 1.3V battery is used to attract the particles to flexible electrodes at the bottom of the ‘tendril’, moving the liquid and therefore the robot. A video published online shows the small, light device coiling into a spiral before uncoiling.  

Applications could range from wearable technologies to the development of flexible robotic arms for exploration, and the team’s GrowBot project envisages the development of a robot that manages its growth and adapts to the environment, able to recognise the surfaces or supports it attaches to.

“The challenge of imitating plants' ability to move in changing and unstructured environments has just begun,” said a press release.

The research was published in Nature Communications.