Have you ever seen a robot that looks like a ball with a stick on the top? Well, that's a ballbot! It's called a ballbot because it moves around on one big ball that's located on the bottom, and that ball helps it balance.
So you know how when you ride a bike or a skateboard, you have to keep moving or you'll fall down? That's what the ballbot has to do too! It's always moving just a little bit to stay balanced. And when it moves, it uses motors and sensors to help it figure out where it is and where it should go.
The ballbot is really cool because it can move in all sorts of directions. It can move forward and backward just like you and me, but it can also go sideways and spin around in a circle without falling over. And because it's so good at balancing, it can go up and down stairs or over bumps without any trouble.
People are working on making ballbots even better and more useful. Sometimes they use them to help people in hospitals or jobs when it is hard to get around. Maybe one day they'll even have ballbots that you can ride like a big bouncy ball!