TOYONAKA, Japan -- Like one-legged, one-armed aerobic dancers, half a dozen welding robots stood in a row, flexing and twisting their way through thousands of "reps" of a test pattern.
At one end of the row, a young workman taught a robot to take its "point test." The machine silently picked up a ball-point pen, put down a sheet of paper, drew a horizontal line and then moved down the page a fraction of a centimeter at a time, drawing lines and deciding for itself when the page was filled and it was time to stop.
This small robot factory, in a faceless industrial suburb of Osaka, Japan's second-biggest city, is one of scores where, many analysts believe, Japan is working one step at a time toward dominance in a technology crucial to manufacturing industries in the next century.
Driven by an acute labor shortage, Japanese companies have embraced robotic technology more avidly than Western competitors. Japanese companies also have been more willing to experiment with the use of robots in factories. Robotic technology has even sparked a cottage industry of mini-factories, as some families take on overflow work from large manufacturers.
The result: Japan has six times as many working robots as the United States.
And that technology gap may grow wider.
"We cannot see any factors that limit the industrial use of robots inthe next 10 to 20 years," Takehiro Tsuzaki said as he guided a reporter through the 30-worker factory. Mr. Tsuzaki is general manager of the robot department of Matsushita Industrial Equipment Co. Ltd.
"New sensors and processors and control systems are being developed and will open up entirely new uses and create applications in industries that can't use robots today," he said.
Automobile factories dominated the use of industrial robots in Japan as recently as the mid-1980s, accounting for more than half the market, he said. Auto plants continue to robotize, but as new users joined in, the auto industry's share of Japan's robots in use dropped to 46 percent by late 1990.
It's too early, he said, to guess the eventual effect robotization will have on Japanese industry, because some trends that no one foresaw may develop.
In the last two years, he said, one of these unexpected trends has been a throwback to the "putting-out system" of pre-Industrial Revolution England. In areas where land is affordable, he explained, a couple may buy or lease one or a few robots, set up a small workshop and take on mini-contracts to do repetitive jobs or overflow work for nearby factories.
"The husband typically sets up the job, then goes off to work while the wife stays home and tends the robots during the day," he explained.
"Even robot-making itself," he added. "It gets harder and harder to find workers in our factory, even though we've doubled production and expanded our space by 30 percent in the past three years. Come back in a year or two and you'll see robots making robots."
Figures compiled by the Japan Industrial Robot Association and the British Robot Association show Japan's working robot population rising from 14,250 in 1980 to 219,700 in 1989, the last year for which figures are complete.
In the same time, the United States' total went from 4,700 to 37,000 and Western Europe's from 4,265 to 56,176.
The 280 Japanese companies that make industrial robots reached a total production of $3.85 billion in 1990, the third consecutive year of growth at a rate of about 20 percent. The Japan Industrial Robots Association estimates that this year's growth will be at least comparable.
About 18 percent of the robots made in Japan were exported in 1989, and about 60 percent of the robots now in use worldwide were made here, the association estimates.
Mr. Tsuzaki believes growth in Japan's working robot population has accelerated again since 1989.
Even those figures may not fully measure Japan's dominance, Mr. Tsuzaki said. "Many of our customers in the United States and Europe actually are Japanese companies expanding or modernizing their international operations," he explained.