A springtail-like jumping robot

Inspired by these agile hexapods, researchers at Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have built a robot that not only walks but also jumps, redefining the capabilities of microrobots.

Their work, published in Science Robotics, envisions a future where small, versatile robots can navigate tight spaces, traverse hazardous terrain, and operate independently in challenging environments.

The robotic innovation emerged from the lab of Robert J. Wood, the Harry Lewis and Marlyn McGrath Professor of Engineering and Applied Sciences at SEAS. It builds upon the Harvard Ambulatory Microrobot (HAMR), a platform initially inspired by the cockroach’s resilience and dexterity. The new version features a robotic furcula – a forked, tail-like structure similar to that of the springtail – allowing it to propel itself into the air.

“Springtails are interesting as inspiration, given their ubiquity, both spatially and temporally across evolutionary scales,” Wood said. “They have this unique mechanism that involves rapid contact with the ground, like a quick punch, to transfer momentum and initiate the jump.”

To achieve this motion, the robot relies on latch-mediated spring actuation, a technique that stores potential energy in an elastic structure before releasing it in a burst, much like a catapult. This mechanism is widely observed in nature – not only in springtails but also in the striking limbs of mantis shrimp and the high-speed tongues of chameleons.

Having previously designed a mantis shrimp-inspired punching robot, Wood saw a natural progression in exploring a similar system for jumping microrobots. “It seemed natural to try to explore the use of a similar mechanism, along with insights from springtail jumps, for small jumping robots,” he said.

The simplicity of the springtail’s furcula – a structure composed of just two or three linked segments – was particularly appealing. “I think that simplicity is what initially charmed me into exploring this type of solution,” said Francisco Ramirez Serrano, the study’s first author and a former SEAS research fellow.

Using advanced microfabrication techniques developed in Wood’s lab, the team engineered a compact, ultra-lightweight robot that can perform a range of dynamic movements: walking, jumping, climbing, striking, and even grasping objects.

The robot’s agility is remarkable. It can jump up to 1.4 metres – 23 times its body length – making it one of the highest-jumping robots of its size. While some robots can achieve longer jumps, they are significantly heavier, making the Harvard design uniquely efficient.

“Existing microrobots that move on flat terrain and jump do not possess nearly the agility that our platform does,” Serrano said.

To optimise performance, the team incorporated detailed computer simulations, fine-tuning the robot’s linkages, energy storage, and takeoff angles to ensure controlled and efficient landings.

The fusion of walking and jumping capabilities could enable robots like this one to explore environments too dangerous or inaccessible for humans.

“Walking provides a precise and efficient locomotion mode but is limited in terms of obstacle traversal,” Wood explained. “Jumping can get over obstacles but is less controlled. The combination of the two modes can be effective for navigating natural and unstructured environments.”

With its innovative design and multi-functional movement, this microrobot hints at a future where small, autonomous machines play a vital role in exploration, environmental monitoring, and beyond.