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Although fleas are annoying pests, credit must be given where it’s due. These tiny creatures that are just 3 millimeters long can leap as far as 330 millimeters in a single hop—a distance that is close to 100 times their own body length. Now, a similar feat has been achieved by a miniature robot. The results were published 24 March in IEEE Robotics and Automation Letters.

“We were inspired by fleas in nature, which despite their small size, can unleash tremendous potential and jump close to 100 times their body length. No one in the field of robotics has been able to achieve this feat yet,” says Ruide Yun, a third-year Ph.D. student at Beihang University in Beijing who was involved in the study.

To achieve similar jumping abilities as fleas, Yun and his colleagues needed their robot to be able to unleash a lot of energy at once, so they created a robot that works somewhat like a mini piston engine.

Mini flea-sized robot leaps on top of a coke can

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But instead of relying on the combustion of fuel, it releases a high-voltage electric discharge between the positive and negative electrodes inside the piston chamber, heating the air inside the piston and causing it to expand. After the discharge ends, the air inside the chamber cools, and the piston returns to its original position, waiting for the next discharge. “Through this cycle, a reciprocating motion can be obtained, driving the robot to crawl and jump,” explains Yun.

In a series of experiments, the robot—which is just 3.4 mm across—was able to jump distances of 296.25 mm in length and 156.28 mm in height. This is equivalent to jumping or 87 times farther and 45 times higher than its own body length and height, respectively.

The robot is also able to crawl thanks to asymmetric friction between its legs and the ground as its piston fires. In the present study, it achieved crawling speeds of more than 46 body lengths per second on a flat surface.

“Our initial experiment was only intended to verify the novel driving method, but we never expected the robot to jump so high like a natural flea, while also exhibiting good crawling performance,” says Yun.

Based on the robot’s millimeter size, fast crawling speed, and good environmental adaptability, Yun says it could be useful for a range of potential detection and reconnaissance applications in the future, or even as a means to study small insects such as fleas—the very inspiration behind the robots.

However, this work is still in its early stages and there are a number of limitations with the current prototype that need to be addressed before its real-world applications are realized. The current prototype must be hooked up using wires to achieve the high voltages for jumping and crawling, and it still lacks steering capabilities.

“Next, we will conduct research to help the robots to break free from the constraints of wires and achieve free jumping and crawling, and we will be combining multiple drivers to achieve controllable jumping and crawling of robots,” says Yun, noting that the team may explore the use of actuators to control the robot’s motion.

Source: IEEE Spectrum Robotics