Georgia Tech engineers have developed a 5-inch legless soft robot capable of jumping as high as a basketball hoop by mimicking the unique contortion technique of parasitic nematode worms.

The silicone rod with a carbon-fibre spine can leap 10 feet into the air and jump forward and backward, demonstrating how biological principles can inform innovative robotic designs for moving across rugged terrain.

Nematodes, also known as roundworms, are among the most abundant creatures on Earth. Their bodies are thinner than a human hair. Despite lacking legs, these tiny parasites can propel themselves up to 20 times their body length—equivalent to a human jumping onto a three-story building. Their jumping ability is critical in how they attach to hosts before entering their bodies.

“Nematodes are amazing creatures with bodies thinner than a human hair,” said Sunny Kumar, lead coauthor of the study published in Science Robotics. “They don’t have legs but can jump up to 20 times their body length.”

Victor Ortega-Jimenez, a lead author and former Georgia Tech research scientist now at UC Berkeley, spent over a year developing methods to capture the jumping motion of these microscopic creatures using high-speed cameras. The footage revealed how nematodes use body contortion to control their jumping direction and height.

The research team discovered that nematodes utilize a counterintuitive strategy to achieve impressive jumps–deliberately forming a kink in their bodies.

“Kinks are typically dealbreakers,” explained Ishant Tiwari, postdoctoral fellow and lead coauthor. “Kinked blood vessels can lead to strokes. Kinked straws are worthless. Kinked hoses cut off water. But a kinked nematode stores energy that is used to propel itself in the air.”

This kinking mechanism allows the nematodes to store energy rapidly and release it to execute powerful jumps in just a tenth of a millisecond. The researchers found that by adjusting the location of the kink and the orientation of their bodies, nematodes control their jumping direction with precision.

For backward jumps, they point their head upward while creating a kink at the midpoint of their body, similar to a person in a squatting position. For forward jumps, they point their head straight and form a kink at the opposite end of their body, angled upward.

“Changing their center 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 effectively leap in both directions at the same height,” Kumar noted.

After analyzing the high-speed footage, the team created computer simulations of the jumping nematodes. They then built physical prototypes – soft robots designed to replicate the worms’ behaviour. These early models were later enhanced with carbon fibre reinforcement to accelerate the jumps.

The researchers found that the key to the robot’s jumping performance was the ability to withstand and exploit the kink formation, which stores potential energy before release. The simple but effective design consists of a silicone rod with a carbon-fibre spine that can be bent into specific configurations for directional control.

The resulting soft robot can jump up to 25 times its body length, demonstrating how biological principles can translate into engineering solutions. The device can function on various surfaces, including sand, making it versatile for different environmental conditions.

Creating a robot that could mimic the nematode’s jumping mechanism presented several technical challenges. The team needed to determine the optimal materials to endure repeated kinking without structural failure. They also had to quantify the stiffness requirements to store and release energy efficiently.

Using atomic force microscopy measurements, the researchers analyzed the mechanical properties of the nematode cuticle and compared them with those of Caenorhabditis elegans, another well-studied nematode. These measurements informed the stiffness parameters for the robot design.

The engineers discovered that reinforcing the silicone rod with a carbon fibre backbone significantly improved the robot’s jumping performance. This modification allowed the robot to achieve heights comparable to those of the biological nematodes relative to body size.

The research team suggests their findings could lead to the development of robots capable of traversing challenging terrain without traditional locomotive systems like wheels or legs.

“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,” Kumar said. “Our lab continues to find interesting ways that creatures use their unique bodies to do interesting things, then build robots to mimic them.”

The ability to jump in multiple directions without complex mechanisms makes this design particularly valuable for applications requiring robots to navigate obstacles or uneven surfaces. The design’s simplicity could also be scaled for different applications and environments.

If the research advances, these soft robots could find applications in areas ranging from search and rescue operations to space exploration. The design principles demonstrated in this study—harnessing kink instabilities typically considered failures in engineering—open new possibilities for developing limbless robots capable of controlled jumping and locomotion.

The study suggests that engineers could create simple elastic systems using materials like carbon fibre that exploit kinks to hop across various terrain types. This could lead to new robotic mobility approaches without requiring complex mechanical joints or motors.

Integrating biological principles with engineering design demonstrates how studying nature’s solutions, even at the microscopic level, can lead to technological innovations that address complex engineering challenges in mobility and navigation.