Orlando, Fla. -- Humanoid robots seized the spotlight at the IEEE's International Conference on Robotics and Automation here last week. All told, more than 1,200 engineers explored all the angles and scales of robots in upwards of 750 sessions covering everything from nanobots to full-sized robotic automobiles.
But humanoid robots dominated a host of sessions at the Disney World Hilton, ranging from pure theoretical studies to end-user applications. In the latter category was a report by Waseda University (Tokyo) and Kanagawa University (Yokohama, Japan) that described a new robot designed to help senior citizens walk.
"Society is rapidly aging," said Atsuo Takanishi, a Waseda University professor, citing estimates by Japan's Health, Labor and Welfare Ministry that almost 1.75 million--more than half of the nation's disabled--suffer from limb disabilities. So he and fellow researchers Yu Ogura, Hiroyuki Aikawa, Kazushi Shimomura, Hideki Kondo and Akitoshi Morishima set out to help them. Professor Hun-ok Lim at Kanagawa University also contributed to the research. In the end, they built Wabian-2, "the first robot designed to help walking-assistance makers in testing their instruments," Takanishi said.
Most senior citizens suffering from lower-limb disabilities can often be helped by wheeled walkers, the researchers said. But no robotic platform exists to quantitatively establish a human walking model that can guide the design of walkers and other aids.
Walking the walk
To the rescue comes Wabian-2, with movement that mimics that of humans, including a trunk that rotates. The humanoid's robotic arms can can support its weight while pushing a walker, enabling walker designers to validate their equipment in the lab well before it's tested by people.
Others have built humanoid robots, Takanishi said, including Honda (P2, P3 and Asimo); the Japanese National Institute of Advanced Industrial Science and Technology and Kawada Industries Inc. (HRP-2P); the University of Tokyo (H6 and H7); the Technical University of Munich, Germany (Johnnie); and the Korea Advanced Institute of Science and Technology (KHR-2). "But all these designs, includ- ing our own Wabian-1, were just trying to achieve stable, dynamic walking," he said.
Indeed, walking is a prerequisite to qualify as a humanoid, and it preoccupied many at the conference, including researchers from South Korea who hope to craft a generic walking algorithm that could supplant today's custom-designed ones.
"We have proven the validity of a simple rolling-sphere model on a constrained surface, rather than include all the complexities and full dynamics for a bipedal walking robot," said Bum-Jae You, director of the Intelligent Robot Research Center at the Korea Institute of Science and Technology (Seoul). He worked with researchers Doik Kim and Youngjin Choi at Hanyang University (Ansan, South Korea).
You's model envisions a flat platform inside the robot, on which a rolling ball can freely move. By tilting the robot's body to keep the ball at the center of mass, any walking robot can remain stable and upright. For instance, when stepping forward the center of mass moves forward. To maintain zero momentum, the robot's body must tilt back by the exact amount that keeps the ball in a fixed position.
That's fine for simple walking, but if the robot bumps into something or is pushed from behind, say researchers at the University of Tokyo and City University of Hong Kong, they'll need a special algorithm to maintain stability. "For sudden and large perturbations, we propose a method that is based on observation of human reactions," said professor Katsushi Ikeuchi at the University of Tokyo. He worked with fellow researcher Shunsuke Kudoh and with professor Taku Komura at the City University of Hong Kong.
The researchers used video cameras and force plates to capture human responses to sudden disturbances, then extracted the parameters relevant to their solution. For instance, when pushed from behind, a human compensates by quickly sliding one foot forward, then continuing to walk. The researchers encapsulated the discovered parameters in an optimization calculation that walking-robot designers can engineer into their algorithms.
If all that "walking" worked up an appetite in Orlando, one of the more realistic humanoids, designed by the University of Tokyo, aims at conquering one of the most ubiquitous tasks facing any human: cooking meals. "We are designing a housekeeping robot that realizes one of the seminal dreams of robotics--a robot housekeeper that can cook simple dishes while cooperating with a human cook," said University of Tokyo professor Masayuki Inaba, who worked with fellow researchers Fabien Gravot, Atsushi Haneda and Kei Okada.
The cooking robot combined predefined kitchen tasks, such as slicing and dicing, with dialogs aimed at enabling a human cook to assign tasks to the robot. To accomplish its task, the robot incorporated motion-planning algorithms that enable it to execute its predefined tasks anywhere in the kitchen.
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