Dream Jobs 2004

Yoshihiro Kuroki: Dancing with Robots



What He Does:

Designs and builds humanoid entertainment robots

For Whom:

Sony Corp.

Where He Does It:

Shinagawa, Japan, a district of Tokyo

Fun Factors:

Teaches robots to dance

The dancers stand motionless at their positions and the room grows quiet. But as the music starts, they begin to move, bending, turning, and waving their fans gracefully as they perform a traditional Japanese dance. Yoshihiro Kuroki watches in silence, occasionally making notes. But as the dance ends, he beams with happiness. The performance has been flawless.

There have been many performances of traditional Japanese dances over the centuries, but this one is unique, because it is performed not by human dancers but by robots. And the performance takes place not in a dance studio but in a laboratory of Sony Corp.'s Entertainment Robot Co. in Shinagawa, Japan, where Kuroki is general manager. He is the mastermind behind a series of ever more capable humanoid entertainment robots, starting with the Sony Dream Robot, or SDR, in 1997, up to the current QRIO (pronounced "curio") in 2003.

These delightful machines are only 58 cm tall, about the size of a newborn infant, weigh about 7 kg, and move with 38 degrees of freedom, each with its own servomotor.

QRIO's predecessor, the SDR4X, announced in 2002, can walk, dance, sing, speak, recognize faces, and understand continuous speech. Each robot has two charge-coupled-device cameras to detect color and position and can locate a colored ball, move toward it, and kick it into a goal. It also has contact sensors in several joints to avoid pinching real human fingers. Seeing the robot perform, it is difficult to remember that there is no sentience behind those glass eyes.

Kuroki knew he wanted to work with robots ever since his second year of high school. His school was affiliated with Waseda University in Tokyo, and one day his class visited the lab of Professor Ichiro Kato. Kato had a vision, says Kuroki, that the 21st century would be the age of the personal robot. That vision was contagious.

Close Friends:

QRIO, Sony's entertainment robot, sees, hears, dances, and sings. Here, he shakes hands with Yoshihiro Kuroki, his creator.

In 1973, as soon as he was out of high school, Kuroki headed straight for Kato's lab, where Wabot 1, for Waseda robot, had just been developed. Kuroki, though, was not assigned to build humanoid robots but rather to develop prosthetic arms. Much of his work in graduate school was to analyze the electrical signals from real muscles and transfer the information to the prosthetic arm to make it move appropriately. "So it's similar to a robot," says Kuroki, "which also has artificial hands and limbs."

When he joined Sony Corp., Tokyo, in 1977, straight out of graduate school, there were no jobs for designers of humanoid robots. He started a project to develop robots for manufacturing television tubes, camcorders, and audiocassette players.

At the time, Sony's manufacturing lines were highly automated. But in 1990 the company did a complete about-face and redesigned its manufacturing lines to focus on human assembly--a decision that turned out to be a stroke of luck for Kuroki. "I was very disappointed and had to change my job," he says. "And then I decided it was time to develop a personal entertainment robot."

He and a colleague, Tatsuzo Ishida, started by researching the history of humanoid robots, including one developed in the 19th century by Hisashige Tanaka, the founder of Tokyo's Toshiba Corp. Kuroki laughs as he tells about the "karakuri doll," which could pick up one of four arrows, fix it in a bow, draw the bow, and shoot it at a target. "Three of them hit the target, and one of them is programmed to miss it."

It was while he was studying the field, in 1990, that Kuroki traveled to Hollywood to see No. Five, the robotic hero of the movie Short Circuit, along with No. Five's creator, Eric Allard. He was particularly impressed with the robot's ability to express emotion by moving its eyebrows and widening and narrowing its eyes.

Back in Japan, Kuroki set to work designing Sony's first entertainment robot. He knew he could not use the same servomotors that he had designed for the assembly robots in the 1980s, because this robot was much more complicated. All told, its torso, neck, and limbs had to have 28 degrees of freedom, compared with 4 degrees for the assembly robots. So he decided to develop special servomotors specifically for his small humanoid.

He and his team produced the first prototype in 1997. And the first time they switched it on, it made some weird motions and didn't behave very well. If the robot moved its arms one way, it fell over, because there was no countering movement to compensate for the shift in the center of gravity. Since then, engineers have designed a whole-body motion control system that knows what each joint is doing and calculates what other motions have to occur to keep the unit upright and stable.

Now that Kuroki's robots are famous, he spends a lot of his time writing papers and preparing presentations. But the best part of his job, he says, is developing new motion-control technologies for his robots.

As you might expect of a top engineer at the world's preeminent consumer electronics company, Kuroki surrounds himself with gadgets. In his Yokohama home, he's got a high-definition TV, a DVD player, a PlayStation, a Walkman, and a camcorder, but, unfortunately, no entertainment robot. Still, every summer he rents one and takes it home, he says, for evaluation. Or maybe he just does it for the fun of it.

--Linda Geppert

Photo: Bruce Osborne/Ozone