Eric Mittelstadt's temporary office here has been the staging area for a Japanese-American invasion of the domestic robot industry.

The prize is big--with industry's growing reliance on automation expected to create a potential $2 billion to $5 billion market by 1990, according to analysts monitoring the fledgling robotics industry.

Mittelstadt is president and chief executive officer of GMFanuc Robotics Corp., an independent, privately held company created by General Motors Corp. and Fanuc Ltd. of Japan.

GM is America's largest automaker. Fanuc is one of the world's biggest producers of computer controls and other automated devices used in the manufacture of industrial robots.

A successful venture by the two giants could alter significantly the makeup of the domestic robot market, in which about 50 mostly small manufacturers are struggling for a share of the profits and glory in shaping the factory of the future.

GMFanuc's plan of attack is two-pronged. The first is to help GM expand its application of robot technology to car production, by far the largest field of robot use today. The second is to grab the biggest possible piece of the growing demand for robots in textile manufacturing, electronics and other industries.

"This is a pretty damned exciting job," Mittelstadt said, preparing to move to nearby Troy, a Detroit suburb where GMFanuc is setting up permanent headquarters. "We got all kinds of competitors in the robotics industry. But we ought to be able to make money. We ought to be able to become a significant force," he said.

It won't be easy.

Unimation (a subsidiary of New York-based Condec Corp.) and Cincinnati Milacron together have captured nearly 70 percent of the current U.S. robot market. General Electric and IBM, two domestic powers in electrical/electronics and computer manufacturing, hold less than 2 percent, but are working aggressively to expand their beachheads. GMFanuc entered the robot wars six months ago, and now has a tentative hold on about 0.8 percent of the domestic market for robots.

GMFanuc "right now is a weeny thing," said Laura Conigliaro, an analyst for New York-based Bache Halsey Stuart Shields Inc. She said the company could have growth problems in a recessionary economy that has hit hardest at the heavy-metal industries, particularly auto and steel.

But GMFanuc comes from parents with clout. GM, for example, has weathered the harsh economic climate better than the rest of its domestic competitors in the auto industry, and is pushing ahead with a $40 billion program to overhaul its plants and product lines.

Much of GM's plant modernization program involves automation, especially the use of computer-programmed robots to load and unload auto components, and to paint and weld auto bodies. The company is the nation's largest user of robots, with 1,800 now in place. Many of those robots were purchased from Unimation, General Electric, and other robot makers.

GM has slowed down its robot purchases during the recession. But company officials say they expect to have 14,000 robots working by 1990. GM is not contractually bound to purchase the units made by GMFanuc. But it's a safe bet that GMFanuc will fill a substantial share, if not most, of the parent company's orders.

About 90 percent of GMFanuc's estimated $2 million in sales this year have gone to GM.

"We don't have any contractual lock on the GM market, but we've got a lot of knowledge about it," Mittelstadt said. "A lot of our people are from General Motors; and we know the people at General Motors, and we know what it takes to be successful inside of General Motors."

GM and Fanuc each kicked in $5 million to get the robot company started. That does not sound like much compared with other big business investments. But, "It's enough to keep us going for well over a year and a half, even if we don't sell anything. And we do intend to sell something," Mittelstadt said.

Still, the parent companies probably will have to contribute more money to their child. Besides its Troy headquarters, GMFanuc wants a U.S.-based manufacturing plant. The company now produces its robots at Fanuc facilities in Japan and at various independent shops in the Detroit area, where GMFanuc's N/C (numerically controlled) Painter robots are assembled.

GMFanuc currently has 120 full-time employes, mostly technicians and administrators. Like Mittelstadt, a former executive assistant in the car company's overseas division, most of GMFanuc's people come from GM.

Mittelstadt said GMFanuc hopes to have $50 million in sales for 1983, but conceded that, in the face of the recession, that goal "is a very ambitious target."

"But I've gotten a good indication that both parents are going to be fairly tolerant. They know that we're a new businesss and that, as a new business, we're not going to be wildly profitable in the first year and a half," Mittelstadt said.

But he said the parents' patience is not based in altruism. "Fanuc is giving GM needed expertise" in computer controls and robot development "and we're giving them manufacturing competence and access to the U.S. market," Mittelstadt said.

He said Fanuc officials "knew that General Motors' motivation is to become a significant force in the robotics industry, and that's what they wanted."