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Malagasy giant chameleon, Furcifer oustaleti,sitting on the branch in forest habitat. Exotic beautifull endemic green reptile with long tail from Madagascar.

Chameleon’s tongue strike inspires fast-acting robot design

Image credit: Ondřej Prosický | Dreamstime.com

Researchers at Purdue University, Indiana, have developed soft robots and actuators capable of re-creating high-powered and high-speed motions using stored elastic energy – inspired by the tongue strike of a chameleon.

Chameleons, salamanders and many toads use stored elastic energy to launch their sticky tongues at unsuspecting insects located up to one-and-a-half body lengths away, catching them within a tenth of a second.

Ramses Martinez, an assistant professor in Purdue’s School of Industrial Engineering and in the Weldon School of Biomedical Engineering in Purdue University’s College of Engineering, and other Purdue researchers at the FlexiLab sought to investigate how lizards catch insects to develop the actuators.

The robots are fabricated using stretchable polymers similar to rubber bands, with internal pneumatic channels that expand upon pressurisation. The elastic energy of these robots is stored by stretching their body in one or multiple directions during the fabrication process following nature-inspired principles.

Similar to the chameleon’s tongue strike, a pre-stressed pneumatic soft robot is capable of expanding five times its own length, catch a live fly beetle and retrieve it in just 120 milliseconds.

“We believed that if we could fabricate robots capable of performing such large-amplitude motions at high speed like chameleons, then many automated tasks could be completed more accurately and in a much faster way,” Martinez said.

“Conventional robots are usually built using hard and heavy components that slow down their motion due to inertia. We wanted to overcome that challenge.”

Ramses V. Martinez, an assistant professor at Purdue University, and his students created this cover image. Chameleon tongue strikes inspired the team to create soft robots that catch live insects in the blink of an eye.

Ramses V Martinez, an assistant professor at Purdue University, and his students created this cover image. Chameleon tongue strikes inspired the team to create soft robots that catch live insects in the blink of an eye.

Image credit: Ramses V. Martinez/Purdue University

Martinez said these new pre-stressed soft robots have several significant advantages over existing soft robotic systems.

Firstly, Martinez said they excel at gripping, holding and manipulating a large variety of objects at high speed. Furthermore, they can use the elastic energy stored in their pre-stressed elastomeric layer to hold objects up to 100 times their weight without consuming any external power.

According to the team, their soft skin can also be easily patterned with anti-slip microspikes, which significantly increases their traction and enables them to perch upside down over prolonged periods of time and facilitates the capture of live prey.

“We envision that the design and fabrication strategies proposed here will pave the way toward a new generation of entirely soft robots capable of harnessing elastic energy to achieve speeds and motions currently inaccessible for existing robots,” Martinez said.

The technology has been published in Advanced Functional Materials.

In September, researchers from Imperial College London developed a bio-inspired bot that uses water from the environment to create a gas, which enables the system to launch itself from the water’s surface.

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