Photo courtesy of UGOBE, Inc Pleo

For many years, people have been trying to create the perfect robotic pet. Something like a puppy maybe, but a puppy with a twist. The creators of Pleo are taking a shot at this challenge, and what they've come up with is definitely unique! By looking at the process they went through, and the decisions they made, you can learn a whole lot about robots.

To create any robot, your first step is to decide what you want the robot to do. This part is important because robots do all kinds of things. Some robots assemble cars or computers in factories. Some, like the Mars Rovers, explore distant planets. Some, like ASIMO and QRIO, entertain people. In the case of Pleo, the designers decided that they wanted to create a small, realistic robot pet. They want lots of people to be able to own this pet. Keeping Pleo small helps with that. If Pleo was as big as a horse and weighed 500 pounds, it would be hard to keep him inexpensive.

So Pleo is small. He weighs a little over three pounds. And the designers decided to make Pleo "look" like a baby dinosaur. The decision to make Pleo look like a dinosaur led to many other decisions. For example, dinosaurs have legs. This meant that Pleo would have legs for moving around. That's a big decision because making legs that move is a lot harder than using something like wheels or tank treads. To keep Pleo small and light while still having legs is a challenge with today's technology.

Photo courtesy of UGOBE, Inc Pleo playing tug

The small size of Pleo means that the legs must be powered by electric motors. Bigger robots can use pressurized air or even hydraulic cylinders (like a giant bulldozer or excavator does). But electric motors are the only thing light enough to fit into a small 3-pound package.

If Pleo were using wheels to move around, it would only take two motors. One motor would control the wheels on the left side, and the other would control the wheels on the right. Or you could have one motor to spin the two back wheels and a second steering motor to control the front wheels. Almost every radio-controlled car is set up in one of these ways.

Photo courtesy of UGOBE, Inc

What kind of dinosaur is Pleo? To create Pleo, its designers started with the fossils of a Camarasaurus dinosaur. According to his designers, Pleo has a, "height and weight consistent with that of a one-week old infant Camarasaurus."

But legs are different. To move a leg with any kind or realism, you need at least two motors, and a leg with full motion needs three. Usually the foot would need at least one motor too, although Pleo gets around that by making the feet act more like hooves.

Pleo also can move his neck, blink his eyes and wag his tail. So, altogether, Pleo has 14 small electric motors. The motors that Pleo uses are called servomotors. You find servos in things like model airplanes. Servos are small motors with built-in gears, and a control signal tells the motor to go to a certain position and stop. A servomotor is perfect for a small robot like Pleo.