Nematodes inspire multi-terrain jumping soft robot

The device, made up of a silicone rod with a carbon-fibre spine, was made after watching high-speed video of nematodes pressing themselves into odd shapes to propel themselves forward and backward. The team’s findings are detailed in Science Robotics.

“Nematodes are amazing creatures with bodies thinner than a human hair,” said Sunny Kumar, lead co-author of the paper and a postdoctoral researcher in the School of Chemical and Biomolecular Engineering (ChBE). “They don’t have legs but can jump up to 20 times their body length. That’s like me laying down and somehow leaping onto a three-story building.”

Nematodes live in the environment and within humans, insects, and animals. One way they latch onto their host before entering their bodies is by jumping. 

Using high-speed cameras, Victor Ortega-Jimenez — a former Georgia Tech research scientist who’s now a faculty member at the University of California, Berkeley — watched the creatures bend their bodies into different shapes based on where they wanted to go.

To hop backward, nematodes point their head up while tightening the midpoint of their body to create a kink. From there, the worm uses stored energy in its contorted shape to propel backward, end over end. To jump forward, the worm points its head straight and creates a kink on the opposite end of its body, pointed high in the air.

“Changing their centre of mass allows these creatures to control which way they jump. We’re not aware of any other organism at this tiny scale that can efficiently leap in both directions at the same height,” Kumar said in a statement.

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After watching their videos, the team created simulations of the jumping nematodes. Then they built soft robots to replicate the leaping worms’ behaviour, later reinforcing them with carbon fibres to accelerate the jumps

Kumar and Tiwari work in Associate Professor Saad Bhamla’s lab. They collaborated on the project with Ortega-Jimenez and researchers at the University of California, Riverside.

The group found that the kinks allow nematodes to store more energy with each jump. They release it in a tenth of a millisecond to leap, and they can repeat the process many times.

The study suggests that engineers could create simple elastic systems made of carbon fibre or other materials that could withstand and exploit kinks to jump across various terrain.

“A jumping robot was recently launched to the moon, and other leaping robots are being created to help with search and rescue missions, where they have to traverse unpredictable terrain and obstacles,” said Kumar. “Our lab continues to find interesting ways that creatures use their unique bodies to do interesting things, then build robots to mimic them.”