Ask a robot to show you around Japan's Expo '85

Be prepared to be greeted by a robot (he may even bow in the Japanese tradition) if you plan to visit Expo '85 three years hence in this new city built for scientific research.

Not only will a robot shake your hand and utter a word of welcome, but it will also be on hand to guide you to the pavilions of your choice and provide you with hamburgers - or sashimi if your tastes run to raw fish. It will even sign autographs for your children as well as insert a stamp or coin into their notebooks.

The presence of some 30 mobile robots at the world exposition to be held in 1985 some 40 miles north of Tokyo is enough for promoters of the fair to dub it the ''Robot Expo.''

That robots should play so conspicuous a role in a world fair hosted by Japan is not surprising. Japan outstrips all other countries in the manufacture and use of robots. According to the Robot Institute of America, Japan had 14,246 programmable robots or 59 percent of the world's total in 1981. Its nearest rival, the United States, lags well behind with 4,100.

More than half of Japan's robots are used by the automobile, electric machinery, and appliance manufacturing industries. But robots are also prominent in the plastics, metal products, steel, and metal-processing machinery industries.

A visit to the Mechanical Engineering Laboratory in Tsukuba, close to the site of Expo '85, gives a glimpse into the future of Japanese robotics.

A technician at this research laboratory run by the Agency of Industrial Science and Technology trundles out a squat-looking knee-high machine laced with electronic circuitry. He explains how it does practically everything but bark. It's a robot seeing-eye dog.

The model, still in the research stage, uses ultrasonic sound to detect the distance between the robot and an obstacle ahead. Within 45 milliseconds it can convey a vibrating sensation to the person signaling whether to start, stop, turn left, or turn right.

The visitor is also shown a robot arm that fully produces the function of the human arm. Even the fingers on the hand operate independently. Another robot is capable of lifting a severely handicapped patient and carrying this person to a chair or bed.

A movie illustrates the progress made on a six-legged machine with artificial hands and feet that has limited decision-making ability and can see and feel itself around a room. In another scene, a driverless automobile moves forward and weaves from side to side to avoid obstacles as though driven by an invisible hand. It is, in fact, a completely autonomous automobile run by artificial intelligence.

As robots march from the pages and screens of science fiction into the workplace and even into private homes, their ever-increasing presence has become a subject of scrutiny and debate.

Their advantages are well documented: A robot faithfully repeats actions it has been taught over and over again. It never makes mistakes. It never slows down. Never stops for a break. Never takes a vacation. Does hard, hazardous, dirty, and boring work without complaint. And it improves productivity because a robot ''is good for two shifts.'' At least this last attribute was stressed at the huge Mazda automobile plant, just outside Hiroshima.

At the same time Japanese workers who have been more willing to accept robots than their American or European counterparts are beginning to raise questions about their own futures in an industrial robot world.

For the time being though ''the workers don't view them as a friend, but they don't regard them as an enemy either,'' according to a management official at Mazda.

A labor union spokesman at the same automobile plant cautions: ''Up to now robots have been friends to our members. However with the prospect of lower production (in the event world recession deepens) the adoption of robots on a large scale will have an adverse impact on employment.''

Although no official stand on robots had been taken by his union ''we do see mechanical and potentially mental problems ahead.''

Physically, he said, he thought robots could be hazardous because they are always moving around. Of greater concern to him though was that the worker ''will be isolated from his fellow workers. There will be no instant rescue. If something happens, the worker will be left alone.'' Although it did not happen at Mazda, which ranks among the world's top 10 automobile producers, one worker has been crushed by a robot in Japan.

At Mazda some 385 robots are used for welding and painting. Unlike C3PO in ''Star Wars'' or the expo robots these robots are little more than working mechanical arms with no face, legs, or torso. A sign above a Mazda assembly line of welding robots shooting a spray of sparks across the floor notifies the visitor that each robot welds, on average, 19 different spots on a car as it rolls by.

This is dirty, dangerous work and most workers are glad to be free of it. Once the worker recognizes their need, robots are not only accepted, but also regarded sometimes as a friendly rival. The worker may feel sufficiently stimulated to increase his productivity to match that of the robot. In some cases, workers have bestowed affectionate nicknames on robots they work with.

Japan's apparent willingness to accept robots has left many union leaders in the United States and Europe scratching their heads in wonder.

But industry spokesmen in Japan attribute much of this acceptance to the ability of both plant managers and workers to put their heads together a decade ago to devise the best ways of using and improving the then primitive machines.

This coupled with what may be a natural curiosity in machines plus a low unemployment rate have made Japanese less suspicious of robots than their Western counterparts.

Another potent factor was that robots started making their mark at a time when Japanese industry was putting a freeze on hiring because of the adverse affects of the 1973 oil crisis. That freeze, coupled with an explosion in consumer-produced goods, encouraged the trend toward robots since they helped reduce work overloads.

The automation carried out in the 1960s and 1970s occurred mainly at large corporations while smaller companies picked up the extra workers. But robotization is now advancing at such a pace and in both large and small industries that extra workers have nowhere to go.