A team of researchers from Purdue University is taking cues from nature to inspire fast-acting robotics with chameleon-like reflexes capable of grabbing and maneuvering items with astonishing speed. With stretchable polymers, they say these soft robots could inform efficiency in future robot manufacturing.
High-powered and high-speed, the robots get their power from their elastic energy, or capability to expand to various degrees in order to move quickly. Internal pneumatic channels expand with pressure to snap and grab, yet are able to release their hold on an object by contracting. It all comes from biomimicry: the hyper-elastic tendons in woodpeckers, the snapping speed of Venus flytraps, and of course the quick-firing tongues of chameleons. One of the robots is capable of expanding up to five times its own length and can catch and retrieve a live flying beetle in just 120 milliseconds. (Tell that to the fruit flies haunting your kitchen.)
“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,” said study author Ramses Martinez in a statement. “Conventional robots are usually built using hard and heavy components that slow down their motion due to inertia. We wanted to overcome that challenge.”
Elastic energy is best summarized as a stretched rubber band. By slowly pulling the rubber band apart, stress is put on the material that, when released, quickly pops back to its original form. This same capability is seen in animals like the three-toed woodpecker whose elastic energy is stored in tendons at the back of its legs.
Publishing their work in Advanced Functional Materials, the researchers say that their biologically inspired robotic grippers are capable of holding up to 100 times their own weight while perching upside down from angles of 116 degrees – much like a woodpecker perches on a tree while sleeping or hunting for food. Robots that take their inspiration from three-toed woodpeckers are able to catch a ball moving at 10 millimeters per second in just 65 milliseconds.
But animals don’t deserve all of the credit. Martinez and his team were also inspired by the Venus flytrap’s ability to snap prey quickly and efficiently. They were able to similarly build a robot that can close in just 50 milliseconds with just a quick burst of pressurization.
Researchers believe that their soft robots are set apart from others currently available.
"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," said Martinez.
But whether they’re used to manufacture goods or catch kitchen fruit flies remains to be determined.