How Pleo Works

The idea for a baby dinosaur came from Caleb Chung, co-inventor of the Furby and one of the inventors behind Pleo. "[Chung had] created tons and tons of ... other kinds of products, and he had always wanted to do a dinosaur," Sosoka says. The next step was to determine the dinosaur's species. "We wanted to do a quadruped because they are more stable," Sosoka explains.

In addition to being stable, Pleo needed to be expressive. Sosoka continues:

The tail wasn't the only reason the designers chose to create a Camarasaurus. "It has a relatively long neck. A lot of dinosaurs don't have real long necks," says Sosoka. "And then it had a fairly large head. Pleo's head is bigger ... and it's not perfectly just scaled because there is a lot of stuff to put in there ... but the combination of wanting to have the tail, have a good-sized head, a long neck, the quadruped, led us to that particular dinosaur."

There also was plenty of research material on the Camarasaurus. They were abundant in North America, so there are lots of Camarasaurus fossils, including infant and juvenile fossils. "We could see that this would be the actual size the animal would be at somewhere around two weeks old," Sosoka says. "So they come out of this big, round egg ... then of course they grow to be huge, this gigantic thing. So by choosing this and picking this size, it's the real size that one of these would be if you could have one hatch and run around your table or living room."

Once the developers decided on a species, the next step was developing a prototype. We'll look at how Pleo went from idea to reality in the next section.

It takes a lot to get from the idea of a dinosaur to a walking model, especially when the goal is for the model to be particularly lifelike. "The first idea ... was an idea on how we could create much more natural and character-based animation," Sosoka says. "We were working on developing a prototype to see if this idea would really be effective ... Over the course of a couple of months, [that] resulted in a little walker. We had a blue walker and red walker, and they were little, almost like stick-figure robots made out of normal hobby servos and things like that. But when you saw them move, it was very expressive." You can see one of these walkers in our Pleo video.

The next step was to take that basic idea of a walking robot and transform it into a walking dinosaur. Doing this involved a team of experts, and not just experts in robotics. "A lot of the things we need are very, very specialized," Sosoka says. "We have a kind of extended family of contractors ... we have to fly different people [in] from different places to do that." The team working on Pleo could change from day to day. "We have special AI talents and sensor talents and all kinds of things ... You don't know exactly which kind of people you are going to run into when you are out there."

A lot of these experts worked to make Pleo look and sound real. Sosoka explains:

The sculptor created the physical texture and shape of Pleo's thermoplastic skin. "He made all these little patterns to bring out the little bumps on the skin, he made all these different pattern pieces," Sosoka says. A different expert created the patterns of color on Pleo's body. "Another person we had is a special-effects paint wizard," Sosoka explains.

Pleo's lifelike qualities also come from the way he moves. We'll look at the inspiration for Pleo's behavior next.

Pleo has lots of programming that controls his movements. He can also combine programmed movements to create new movements based on his environment. That way, he can appear to have an intent or a purpose for his actions and to express emotions. But these actions don't necessarily reflect what a real Camarasaurus would do. "Our goal with Pleo is not to be a model ... of that Camarasaurus, but we wanted to be as scientifically accurate as we could," says Sosoka.

So the Ugobe team worked with paleontologists, zoologists and other specialists to create a realistic foundation for Pleo's behavior while also making the dinosaur more personable and playful. "[Caleb Chung] worked with some scientists to try to understand more about this creature and how they lived and how they ... moved and ideas about what they might have sounded like and things like that." To that research, the team added the qualities people might like in a pet. "Sometimes the character is more like a dog than a dinosaur," says Sosoka, "We sprinkled in a little more character there, but wherever we could we tried to go with science and our understanding of that animal."

Whether it's acting like a dinosaur or a dog, Pleo's behavior comes from artificial intelligence. Sosoka explains. "We have a little memory, kind of like in classic AI, like a perceptron or a little neuron. And based on what happens in Pleo's world [the values in his memory] change."

These changing values allow different Pleos to behave differently, depending on their environment. Sosoka continues:

These changes to Pleo's behavior aren't necessarily permanent. As Sosoka explains, "In our design, Pleo doesn't really get to be fully grown up. He starts really young, where he can barely know where you are touching him, and he starts to understand his body and then move. Pleo doesn't get past the late teenage age, so he doesn't really get that set in his ways ... he is still plastic in that way. He is still able to change."

Along with Pleo's sounds, which are played through two speakers in his body, these movements help Pleo convey the appearance of emotions, from hunger to joy. Next, we'll look at some of the specifics of getting Pleo to move expressively.

It takes 14 motors to control Pleo's movements. But Pleo has to do more than just walk around aimlessly. His movements have to be purposeful, and he has to respond to people and objects. For this to happen, Pleo needs sensors -- lots of sensors.

Some of these sensors are touch sensors. "We didn't want you to feel like you were finding a sensor or pushing a button or something," Sosoka explains, "so one of the things that we did is we put eight capacitive sensors in ... capacitive touch sensors like sometimes [are] on lights ... or on your iPod." Finding a way to use these sensors was a challenge. "If you're snowboarding you go to press your iPod through your gloves, it doesn't work because it's not pressure that does it. It's actually the electrical coupling with the water in your body."

This meant that Pleo's skin -- while completely necessary to make him look real -- could get in the way of the sensors. Sosoka says:

These capacitive sensors look like thin, metal strips. They're located on Pleo's legs, back, shoulder, head and under his chin. In addition to these sensors are:

Interpreting and responding to all this input requires a network of processors and circuits. On the next page, we'll look at how Pleo handles all this data.

Getting Pleo to make purposeful movements and sounds starts with processing all of the input he receives. The eight touch sensors are a big source of information. Sosoka explains, "Each of [the touch sensors] has dedicated processing that they can do inside of a dedicated chip."

A separate processor in Pleo's head handles input from the area around that part of his body. Sosoka describes the processing power located there:

Other processors help turn all this input into movement. Sosoka explains:

Pleo's final microprocessor, another ARM7 23-bit processor, governs Pleo's connections to computer data from the outside world. "It handles the SD card, it handles the USB, it manages the flash data," Sosoka says. This processor also acts as Pleo's overall brain. "It manages the talking to the head, talking to the motor controllers, it deals with kind of all the other stuff that's going on in there. That's where Pleo's personality and behavior exist."

On the next page, we'll look at how Pleo's body carries out these instructions, and we'll explore some of the challenges the development team discovered when working on Pleo's physical structure.

Like most consumer robots, Pleo runs on batteries. These nickel metal hydride (NiMH) batteries are inflexible, and they take up a lot of room, so they have to go in the largest part of Pleo's body -- his abdomen. This made realistic movement a challenge. Sosoka explains:

The result was a removable battery pack that didn't interfere with the pivot in the middle of Pleo's back. The battery pack uses nickel metal hydride (NiMH) batteries and has a four-hour charge time for an hour of battery life.

Another challenge was Pleo's tail, which is central to the appearance of emotions. The trick was to make the tail movable while making it sturdy. Sosoka describes the tail's movement:

Motors move these wires in response to instructions from his processors. The motors also move Pleo's head, neck and legs. Clutches and force-feedback sensors in his legs help protect his components and provide responses to obstacles he encounters. "Pleo has clutches in all of his motors so that if he lands on his feet, his feet can give a little. They don't transmit all of the pressure. Those clutches also allow Pleo to know that you are messing with [his leg], and then he can cry out or limp," Sosoka says.

Out of the box, a Pleo has the ability to explore and learn from his environment. But Pleo also has the ability to be programmed and customized. We'll look at how this works on the next page.

Pleo's artificial intelligence works within the context of his operating system, Life OS. Because of the capabilities of Life OS -- some of which will be implemented in a Pleo software update -- people have the opportunity to change the way Pleo sounds and behaves. The overall goal, according to Sosoka, is "to allow lots of people to implement their vision and their dreams ... one of the things we spend a lot of time on is just finding ways to make it easy for people to express their idea of how a creature like Pleo should act or create their own experiences around it."

The basic idea is that educators, performers and hobbyists could customize Pleo using a digital memory device known as an SD card. With an SD card and a card reader, you could create programs and sounds and transfer them from a computer to a Pleo. Sosoka says:

Another forthcoming customization method for Pleo involves writing a simple computer program and saving it to an SD card. Using the Pawn scripting language, which is like a simpler version of the C programming language, people will be able to create their own Pleo controls. These abilities will be part of the Pleo developer's kit (PDK).

Many of these abilities will come as firmware upgrades to existing Pleos. Users will be able to download the upgrades from the Pleo site and transfer them to their Pleo using a USB connection. These upgrades will be transferred directly to Pleo's memory, but user modifications, like new programs and sounds, will be played from SD cards.

These are all part of the future of Pleo -- and the future of Ugobe. The company hasn't revealed its next robotics project, but according to Sosoka, "It will be a lot different from Pleo ... Pleo has a big space that we can explore and end users can explore, and so we can kind of let that space mature. We'll do something with the next life form will be in a very different space."