IN the next few years, robots will begin vying with the dog and cat for the title of man's best friend. By the end of the decade, the domestic robot that vacuums, washes windows, and fetches things will put in an appearance. Sometime after the year 2000, the robot will evolve into a mobile companion and information base, similar to C3PO in the movie ''Star Wars.''
Of course, there is no guarantee that this scenario will come about in exactly such a fashion. Despite their sophistication, today's personal robots do little more than talk, move around, and pick up lightweight objects. To achieve even this much has taken 10 times the money and effort that pioneers in the field expected a few years ago.
Still, this timetable does reflect the current optimism of those working in personal robotics. Increasingly they feel that this dream, rooted in thousands of years of fiction and fantasy, is in their grasp. And if such is the case, it will usher in a whole new chapter in the relation of man to his mechanical creations.
Already, industrial robots have begun to make their mark in the factories of the world. Joseph F. Engleberger, the father of the industrial robot, says that to experience a state-of-the-art robot's-eye view of the world, you must smear a thick layer of petroleum jelly on a pair of glasses and put them on, tie one hand behind your back, put a mitten on your free hand, pick up a pair of chopsticks, and then try to assemble anything according to a detailed set of instructions.
In the last two years, industrial robots have been followed by the introduction of several robots designed for home and educational use. Compared with their $90,000 industrial brethren, the capabilities of today's personal robots, selling for less than $5,000, are even more modest. They are little more than expensive toys. But this was also true of the personal computer seven years ago. And pioneers in the field of personal robotics see their industry at a comparable stage: The necessary elements are in hand to transform personal robots into devices of increasing capability and sophistication. All that is lacking is the integration of the available technologies.
When these elements come together in two to three years, ''there will be an explosion that will make the personal computer look like just a warm-up,'' predicts Nelson B. Winkless III, the author of several books on robots and a 20 -year observer of the field.
This sense of anticipation and participation in matters of historic import was certainly in the air at the first annual meeting of the International Personal Robot Congress. The conclave, held here recently, attracted more than 700 people, including most of the pioneers in the field. It also served as a showcase for an assortment of mechanical contraptions, many resembling refugees from the set of ''Star Wars.''
A robot is essentially a computer with ''muscles'' and sensors that allow it to interact and modify its environment. Robots come in a wide variety. They can be nothing more than a mechanical arm hooked to a microprocessor that can be programmed to manipulate objects within reach. Or they can be mounted on wheels to move about a proscribed area under their own control.
Such a matter-of-fact description fails to reflect the fact that the idea of a robot taps deep roots. During the 2nd century BC, Hero of Alexandria wrote a book describing a theater with clockwork actors that move and dance.
''Unlike the personal computer, the concept of the robot has been presold by at least 200 years of mythology,'' comments Jean-Michel Gabet of Cosma International, a multinational consulting and marketing company. So people know what robots are supposed to do. This is quite different from the case of personal computers, whose functions remain a mystery to much of the public.
''However, people's expectations have a bad side as well: The (robot) technology is not yet able to fulfill them,'' Mr. Gabet adds.
Personal-robot makers generally agree that the public has an exaggerated view of the capabilities of their current offerings.
''Television has been very guilty of showing robots as sophisticated devices, which we know they are not,'' observes Peter Matthews, editor of Your Robot magazine in London.
THE personal robots currently being marketed have a very limited repertoire. They can talk and sing in tinny, electronic tones. (Because the song ''Daisy'' was the last thing the computer Hal in the movie ''2001'' sang before being shut off, it has become the theme song of personal robots.) They have arms and grippers that can pick up and move objects that weigh up to half a pound. They have an ultrasonic sonar to help them navigate without hitting things. They can also be equipped with sensors to detect different light and noise levels. Some can follow special tape strips around the floor. They come with limited memories , from 4,000 to 8,000 characters, which allow them to be programmed for several hours of continuous movement and 15 to 20 minutes of speech. Most models also come with a remote control that allows a human operator to direct their motions.
Still, the elements that can give the robots greater capabilities are clearly evident. Voice-recognition technology, which will allow robots to respond to verbal commands, is available but still too expensive. But the price is dropping steadily. Video-disk techniques are being applied to provide more than a 1 trillion characters of computer memory in a compact size that can fit on a mobile robot. Advances in the field of artificial intelligence are increasing the sophistication with which computers can mimic human behavior.
Aside from expanding a robot's capabilities, a problem for the embryonic industry is deciding just what a personal robot should be and do. Robot developers are divided into two camps on this issue. One camp argues that the personal robot should be the ultimate appliance. Utility, these developers argue , is more important than cost or personality.
''The personal robot industry will not go anyplace until it produces something really useful,'' asserts Mr. Engleberger.
In his view, the key to doing something useful is the mechanical arm. An armless robot, he gniffs, is nothing more than a computer on a cart.
In addition, Engleberger says he foresees the personal robot as a mechanical home repairman. By the time the robot servant is perfected, all major appliances will be manufactured and tested by factory robots. So it should be relatively easy to include basic repair skills in a domestic model, he argues. Tasks similar to those a domestic robot might perform are under serious study by industrial robot manufacturers, Engleberger says. These include garbage collection, fast-food preparation, pumping gasoline, sheep-shearing, tending nuclear reactors, and acting as hospital aides.
Representing the other camp is Nolan Bushnell, chairman of the board of Androbot Inc. in San Jose, Calif. He is trying to chart a different course for the personal robot: entertainment. Mr. Bushnell, who invented the home video game, asserts, ''In the next two to three years, the robot that tells the best joke will be the winner. Sure a robot must do something, but that doesn't mean it must have an opposing thumb. Fun sells. Personality is cheap.''
Fred D'Ignazio, who jokes he runs a robot flophouse, is another who sees entertainment as an appropriate role for today's robots. The Compute! magazine columnist and commentator on ABC's ''Good Morning America'' observes, ''Robots may not be the best way to do servant tasks. It may be better to automate the entire house. Besides, robots wouldn't have much appeal if they are viewed as appliances.''
His children love robots, Mr. D'Ignazio says. In the two months they had one of Androbot's robots, his son and daughter dressed it up in a number of fashions. He discovered that when awakened by the robot instead of a parent, the children got up cheerfully rather than grumpily. Also, the robot became the butt of family robot jokes, and they found themselves creating an imaginary life for their mechanical visitor.
''I don't much care for the fact that the press has been creating imaginary roles for robots as appliances. Frankly, they don't get very high marks in this regard. But they can do quite well as a pet or a teacher,'' D'Ignazio maintains.
Current robots, however, have about as much personality as a lawn mower. ''I don't see the kind of lovable, furry little guy with large, liquid eyes of the sort which people traditionally allow into their home,'' comments Mr. Winkless.
IF someone were to build a robot into a stuffed animal rather than a hard, plastic case, however, there are ways of programming it to allow it to learn from its experience. ''This makes something which continuously changes its behavior and so is constantly interesting,'' he suggests.
A backyard robot tinkerer, David L. Heiserman from Columbus, Ohio, has built some robots with just such a limited learning capability. ''After running for a while, the robot would develop a personality. It got so it was hard to turn it off,'' he admits ruefully. While intellectually he knows his robots are just machines, emotionally he relates to them as creatures, he confesses.
The human desire to personify robots is so strong, says Bushnell, that one of his serious worries is ''about the robot emancipation league which will form in about four years. I've seen how kids can develop a real affection for robots. So , inevitably, some jerk will want to give them their civil rights.''
It appears that toymakers have taken note of this susceptibility. At recent toy shows, robots are clearly in vogue. One of the most sophisticated of the robot toys that will soon be released is Maxx Steel from CBS Toys. This is a 20 -inch plastic robot with a remote control. It will sell for $300 to $400 and will be introduced soon with its own comic book, television special, and a number of ''RoboForce'' action figures.
Of course, there is no reason that robots with personality could not also perform useful tasks. Carl Helmers, editor of Robotics Age magazine, envisions a robot pet that doubles as a smart vacuum cleaner. And Winkless imagines a robot pet that would notice the unusual and bring it to attention of its owner, a sort of mechanical watchdog.
INDEED, many of those working in personal robots see home security as one of the first tasks that their devices can perform. The sensors built into today's home burglar alarms could be mounted on a mobile robot that could patrol the house or apartment.
''They should be good at frightening the unsophisticated burglar, and burglars are a pretty unsophisticated lot,'' Mr. Matthews says.
Another use being seriously pursued is that of automatic vacuum cleaner. RB Robots of Golden, Colo., has developed a prototype smart vacuum. But it doesn't work well enough yet to be released as a commercial product. The problem is in the state of the art in vacuum cleaners, rather than the robotics.
''The domestic robot will take its first hesitant steps in the next one to two years. It will become respectable in four to five years. And you will be able to buy it at Sears in six years,'' predicts Joseph Bosworth, the ex-aerospace salesman who founded RB Robots.
Once the mechanical domestic is developed, the future of the personal robot is ensured, Androbot's Bushnell argues, because ''the desire to have a slave is universal and the personal robot represents slavery without guilt.''
Well before this, small robots appear likely to help out the physically handicapped. ''The handicapped need very simple functions performed, but need a good strong arm,'' explains Mr. Bosworth. His company will soon announce a model specifically for this purpose, he says. Experiments at the Veterans Administration hospital in Palo Alto, Calif., have shown that a remotely controlled robot can greatly increase the independence of those with physical handicaps.
Currently, the major use for these small robots is education. Evidence of this is the fact that Hero 1, the robot produced by Heathkit/Zenith Education Systems, has become the largest-selling robot of any type in the world today. Hero was designed as an instructional aid for Heathkit's training courses in industrial electronics.
''Hero is not an ideal personal robot. We have kept insisting that this is an educational robot, but everyone keeps calling it a personal robot. Well, we're going to stop fighting the trend,'' says Douglas Bonham, who directs Hero's production.
Although he won't comment on the company's plans, there are indications that Heathkit will soon announce a more powerful model. ''We believe there is a personal robot market and we intend to go after it,'' Mr. Bonham says.
Equipping computers with arms and mobility not only opens up a market, it also raises a number of major legal problems. Who is to blame if a robot bumps a table and breaks the Ming vase? What if a bug in the robot's programming causes it to flail its arm around wildly and strike someone? At this point there is no answer to these questions.
The impact of the robot on human society is an increasingly controversial topic.
''The moral arguments are quite interesting,'' says Winkless. ''On the one hand, there is the question of whether it is right for robots to displace humans. On the other hand, there is the opposing moral drive that people should not be required to do meaningless work. And the definition of demeaning work appears to be whatever a machine can do better.''