It looks like a washing machine on wheels, but the bulky contraption vacuuming the hallways of a Tokyo high-rise is a robot.
Japanese researchers hope that robots like this one will be the answer to a pressing question hanging over the country -- how to cope with an aging population and a declining labor force.
The vacuuming machine developed by Fuji Heavy Industries Ltd is already cleaning floors in about 10 buildings around the country, including a 54-floor skyscraper in central Tokyo.
The device operates at night after office workers have gone home. It takes elevators to move from one floor to another.
"The elevator is in cleaning mode. Please do not board," an automated message warns human passengers as the droid's wheels whir to life and the robot rolls inside.
Such robots capable of operating in homes, offices and other venues outside factories are still rare even in Japan, a powerhouse in the field of robotics and home to roughly 40 percent of the world's industrial robots.
Japanese researchers are racing against time to build robots smart enough to serve the needs of the elderly in a country in which 40 percent of the population will be over 65 by 2055.
As Japan's population grows older and its labor force shrinks, researchers say new types of robots will play a major role as there simply won't be enough people to do these jobs.
"In the type of aging society that we foresee, the situation will likely get to the point where there will be little choice but to get some help from them (robots)," said Isao Shimoyama, dean of the University of Tokyo's Graduate School of Information Science and Technology.
Shimoyama is among a group of University of Tokyo researchers who are working with counterparts from seven leading Japanese firms -- including Toyota Motor Corp, Fujitsu Laboratories Ltd and Mitsubishi Heavy Industries Ltd -- to develop robotic and information technology that will lead to a new generation of robots in the next 15 years.
"If you leave clothes lying around, a robot might pick them up for you and put them in the washing machine," Shimoyama said. "Once they are dry it might fold them up and put them away."
Prototypes of new robots capable of performing mundane tasks will be unveiled in 18 months.
Such machines do not need to be humanoid, although robots that resemble people have some advantages, said Shimoyama, who researched humanoid droids earlier in his career.
Two-legged, humanoid robots such as Honda Motor Co Ltd's ASIMO would likely have an easier time climbing up stairs inside homes than a robot that moves on wheels, developers say.
But it will be some time before such devices make their way into people's homes.
"They may look smart, but they are still quite stupid," Shimoyama said. "I don't think they will ever be as smart as humans."
While safety is an obvious concern, robots also need to be sensitive to people's needs.
Researchers at Fujitsu Frontech Ltd and Fujitsu Laboratories responsible for developing "enon," a guide and patrol robot designed for use in shopping malls and corporate facilities, are working on this.
Enon, which has a humanoid upper body but no legs, is equipped with a touch screen on its chest and space in its belly to carry loads weighing up to 10 kg.
In guide mode, it will detect a newcomer and approach the person with a nod and a greeting: "Are you a visitor? Hello."
Visitors requiring directions can point to icons displayed on enon's chest screen. If the restroom icon is pressed, the screen will display a map that shows the way.
The robot will then face and point in the direction of the restroom, although it won't actually walk the visitor there.
Enon is now in use at four locations in Japan, including a shopping mall near Tokyo. One goal might be to make it more helpful for the elderly.
"People who work in the transportation sector often ask whether we can build a robot that will find elderly people who look lost in train stations, and ask them if they are all right," said Toshihiko Morita, director of Fujitsu Laboratories Ltd's autonomous system laboratory.
"Actually that is hard to do, very hard," he said.