CRI听力: Ballbot

Fluid movement is always a challenge for robotic engineers. Now, a group of Swiss students has created a robot that defies the law of gravity as it moves while balancing on a sphere.

Our reporter Li Dong has the details.



A gliding robot, you may also call it "ballbot," is a robot that spins on a ball, gliding over a smooth surface.

Designed by 13 students at the Swiss Federal Institute of Technology, the three-foot-tall Rezero ballbot is able to roll across the floor and glide gently, while sensors prevent it from toppling over.

The ball is guided in its rotation by three small wheels, which are in turn operated by electric motors.

The robot balances its 30-pound frame on a sphere the size of a basketball. Then, with a gentle push, it glides across the stone floor using small electric motors to roll the ball.

All the while sophisticated sensors measure the robot's position 160 times a second to ensure it doesn't fall and smash to the ground.

Simon Doessegger, a mechanical engineering student, says unlike droids with two legs or wheels, the device is stable even when it speeds around corners carrying heavy loads.

"The ballbot has a very unique potential in motion. It is able to lean into curves and, because it's omni-directional, it means it can head in any direction at any time. It has no turning radius, so it's very agile and very dynamic. The ball itself is driven by three "omni-wheels" which are propelled by three electrical motors. On the top, you see the body with all the computers on it and the battery, which is the heaviest part of all, is at the top, because it's easier to balance a long stick on your hand than a small pen."

The ballbot, which weighs around 30 pounds, can run smoothly on any kind of ground as long as it is flat. Doessegger says it has near-human reactions, and it can be programmed to follow people, keep a set distance, or respond to a prod.

"It can manage some minor obstacles and even minor slopes, but it can't go off road, for example, because it would lose contact with the floor."

The Zurich ballbot is not the only or even first robot to move this way, but Roland Siegwart, Professor and Vice President of Research and Corporate Relations at the Swiss Federal Institute of Technology, says this design is the fastest and most agile so far.

"The concept is not new. It was built on a similar inspiration from other work in Japan and in the United States, but what the students did is really to have a full system approach where the designed mechanical system is improved with the control, and all the sensor systems are equipped. And by doing it like this, they were able to have much higher performance, higher speed, higher acceleration, more agility of the system."

For CRI, I am Li Dong.