Now, the corporations are working closely with universities to break new ground. One team has brought in a concert flautist to teach a robot how to become a musician.
Some of Japan's most successful corporations are putting large amounts of money into robot research, and have high hopes of growing commercial applications for robots in the future.
Recent years have seen rapid advances in robot technology and Japanese inventors believe we could be about to enter a new robotic age.
This development has been made possible by a huge growth in computer power and progress in speech recognition technology and miniaturisation.
New ground
Sony has already scored a big hit with its metallic pet dog Aibo, the latest version of which can recognise as many as 50 words.
Now, the corporations are working closely with universities to break new ground. One team has brought in a concert flautist to teach a robot how to become a musician.
The cybernetic student has good lungs and does not get tired but he does have his difficulties.
"He doesn't have good enough lips - I mean lip material," says flautist Wakamatsu Kunimitsu, "He cannot move very smoothly - it's very difficult for him."
Practical robots
Not surprisingly in a country addicted to gadgets, the robot exhibition proved a big hit with the Japanese public.
Japan has long been a world leader in robot technology. But, so far, the focus has been largely on entertainment.
Now, some of the country's largest companies are turning their attention to more practical applications.
The Honda motor company is pioneering work in humanoid robots.
The latest prototype is being developed as a companion - someone who can fetch drinks and generally make himself useful about the house.
Companions and carers
Some believe robotic health and care workers may soon become commonplace, especially in a rapidly ageing society like Japan.
With this in mind, scientists at Tokyo university are now working on a robot with more human features to provide a more natural companion.
Their robot's face is equipped with video cameras for eyes and is programmed to mirror the expression of anyone who looks at her.
Robotic engineers are also working on more immediately practical ideas such as the robot muscle suit for the elderly and infirm.
Many elderly people went to the exhibition to catch a glimpse of their future carers.
And they may not have long to wait. One retirement home is planning to introduce a network of robot helpers as early as next year.