At just under one and a half inches tall—about the height of a LEGO minifigure—Zippy is the world’s smallest self-powered bipedal robot.
Despite its tiny size, Zippy is surprisingly agile. It can start walking from a standstill, turn, skip, and even climb small steps.
What’s more, it can move faster than half a mile per hour, powered only by its onboard battery, actuator, and control system.
Zippy is the latest creation from researchers at Carnegie Mellon University, led by professors Aaron Johnson and Sarah Bergbreiter.
Their project focuses on understanding how small-scale robots can walk efficiently and navigate different terrains.
Johnson explains that bipedal robots—those that walk on two legs—are better at moving through uneven surfaces and avoiding obstacles compared to wheeled robots. This is especially useful in spaces designed for humans, like buildings and staircases.
Steven Man, one of the lead authors of the project, believes Zippy’s unique design could make it perfect for tasks like search and rescue, industrial inspections, and even scientific exploration in hard-to-reach areas.
“They can go into tight spaces that people and even other robots cannot manage,” he says.
Zippy was designed based on an earlier project called Mugatu, a steerable bipedal robot with rounded feet and a simple mechanism for movement. Undergraduate students Soma Narita and Josef Macera played key roles in developing Zippy, building on Mugatu’s design to create something even smaller and faster.
The secret to Zippy’s speed lies in its simple mechanics. It walks by lifting its front leg and shifting its weight forward.
This motion, combined with its rounded foot, allows the back leg to swing through and take the next step.
To keep things lightweight and efficient, Zippy uses a mechanical hard stop as a joint limit at its hip instead of a heavier servo. This clever design allows it to travel an astonishing 10 times its own body length per second.
To put that into perspective, if Zippy were the size of an average adult, it would be moving at 19 miles per hour. This makes it the fastest power-autonomous bipedal robot of any size based on body length.
The team at Carnegie Mellon has big plans for Zippy. Next, they want to add sensors like cameras to help it navigate and understand its surroundings on its own.
With these upgrades, Zippy could be deployed in groups to work together as a swarm, perfect for inspecting dangerous areas or helping in search and rescue missions. This tiny robot might just be the first step toward a new era of miniature machines that can walk, explore, and even save lives.
