In his mind's eye, Gov. William Milliken can see an army of robots helping to lead Michigan out of its deep industrial depression.

He raised those hopes again today at an exposition of robots sponsored by the Society of Manufacturing Engineers that the society says is the largest demonstration of industrial robots ever assembled.

Huge crowds of business officials, engineers and spectators are filing into a Detroit river-front exhibition hall this week to watch the tireless mechanoids go through their routines. Robotics can be a new growth industry for Michigan and a salvation for old industries like autos, whose future is threatened by quality and productivity problems, Milliken said. He noted industry estimates that the production of robots could grow from a $150 million business today to $2 billion by 1990.

George Devol, who patented the first industrial robotics technology some 35 years ago, observed that the growth of the robot industry never has kept up with the hopes of its supporters. But the size of the crowds and the array of manufacturers from the United States and foreign countries at the exhibit seem to confirm predictions of very rapid growth.

In addition to the companies that pioneered in robot development, led by Unimation and Cincinnati Milacron, three of the country's largest firms--International Business Machines Corp., General Electric Co. and Westinghouse Electric Corp.--are using the conference to show off new robots that mark their entry into the field.

IBM has introduced a $25,500 automatic assembly unit to produce automotive, electrical and other small-scale parts. It can be programmed by use of IBM's new personal computer. General Electric announced on Monday that it will sell five new heavy-duty robots capable of many industrial uses such as spot welding.

And Westinghouse unveiled three new welding and assembly robots today. The presence of these companies and other major manufacturers such as Bendix Corp. in the robot industry will "accelerate the broadening of the customer base," says industry analyst Laura Conigliaro of Bache Halsey Stuart Shields Inc.

But these moves by IBM, GE and Westinghouse also indicated the ground that these companies must make up in robotics and factory automation development. All had to borrow from foreign expertise. GE's five new robots will be made by Volkswagen of West Germany at least until 1984 or 1985 when GE may produce its own versions. The three new Westinghouse robots come from Mitsubishi Electrical Co. of Japan, and IBM's new small manufacturing system is also a Japanese model.