Cubli Wheelbot: Take a Look at How This One-wheel Cube Stunningly Balances Itself Like Magic

Sometimes engineers have great value and new ideas, and sometimes they are just creative. So, they came up with Cubli, a robotic cube that isn't very useful but is unique because it only needs to balance on a single point.

A group of engineers at ETH in Zürich, Switzerland, came up with the idea for the robot. The university has also made a wide range of moving systems, such as juggling machines and a unique drone that moves with the help of electric jets. According to Interesting Engineering, the name comes from the Swiss word for "cube," so "Cubli" comes from that.

The idea for the Cubli robot was simple at first. The engineers came up with the idea of making a 15cm cube that can jump up, stand on its corner, and walk across our desks using motors, batteries, and electronic parts already on the market. The educational article Cubli - A cube that can jump up, balance, and walk across your desk shows all the design principles and prototypes that went into making the robot.

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One-Wheel Cubli Balances Its Own Self

Spectrum IEEE said the One-Wheel Cubli (OWC) controls its pitch and roll with its single reaction wheel. The degree of yaw is not controlled so that the OWC can spin around on its pivot point, but it doesn't because of friction. The OWC is underactuated if it has more degrees of freedom than actuators, which are reaction wheels. But you need complete control over two axes to pull off this balancing act. So how does it work?

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NEW YORK - JANUARY 28: The new Honda robot ASIMO walks upstairs during a North American educational tour designed to introduce the public to ASIMO and to encourage students to study robotics science on January 28, 2003, in New York City. ASIMO (Advanced Step in Innovative Mobility) is a product of over 15 years of robotic development at Honda and was created to help people in need. (Photo by Spencer Platt/Getty Images)

The One-Wheel Cubli's designer, Matthias Hofer, says it's like balancing a pen and a broomstick vertically on your palm. Still, you only have to worry about balancing them on one axis. That is, they'll only tip toward or away from you, and you can move your palm underneath them to compensate for it. The shorter pen will be more challenging to balance and will need your palm to move quickly and in small steps.

On the other hand, the longer broomstick is much easier to keep in balance, and you can do it with slower steps. This is basically how the OWC works: you may only have one control input, but the small, fast movements and the large slow movements are separated enough that one actuator can handle them both independently by making the small quick movements inside the large slow movements. The long beam with the weights at the end makes the One-Wheel Cubli different from the original Cubli. It's there to make the difference in inertia between the two axes you're trying to control separately as big as possible.