By the early 1990s robots could be replacing farm workers in picking Florida oranges. That's the projection of researchers at the University of Florida and the Martin Marietta Corporation who are trying to adapt advanced military technology for civilian use in the state's orange groves.
''In very simplified terms, the same thing that helps a missile find a tank could help a robot arm find an orange,'' says Gerald Isaacs, chairman of the agricultural engineering department at the University of Florida.
As now envisioned, the machine's specially designed optical system would ''view'' a portion of a tree. The image is stored and processed in an onboard computer. This enables the robot to locate the fruit. Then the computer will guide an arm that has its own optical system for selecting individual pieces of fruit.
The United States is not the only country trying to apply robotics to agriculture: The Japanese are working on a robot that will pick tomatoes, and the French are studying the possibility of a robotic apple picker. Nor is Martin Marietta the only US company involved in such research. Honeywell Inc. is also trying to develop robots for use in harvesting oranges. But University of Florida researchers say that Martin Marietta's program is ahead of Honeywell's.
Economics appears to be the driving force behind the effort. ''With all the oranges we have in Florida, it's hard to think of anything else,'' Dr. Isaacs says, referring to the 46 million orange trees in the state. ''It's a 100 percent handpicked crop.
''We need something to make the pickers more efficient if Florida is going to compete with foreign countries. Here, farm workers get between $5 and $8 an hour for picking, compared with 50 cents an hour in Brazil.''
''It's very similar to the automotive industry,'' he says. ''We could say we won't mechanize, but then the crop will disappear. Do you think we'd still have people picking cotton even if we hadn't gone to synthetics?''
Edward Tutle, Martin Marietta's manager of technology evaluation and transfer , says the first robotic orange picker could be ready for testing within two years, but he says he doubts it would be commonly used in the groves until the 1990s.
''The machine is still in development, but we believe it has a high probability of working,'' he says. ''We have to work on the total concept, not just the machine. The trees will make the rules. We have to design a machine that can get around a tree.''
But he says the trees also have to be changed to fit the machine. The trees will have to be trimmed to a more uniform shape, which could make them grow taller and be more productive.
Harvesting would have to be primarily at night because the robots' circuits will work better under cooler temperatures.
And with a uniform amount of light that cannot be provided by daylight, the machines' vision system will have an easier time spotting the fruit.
But sending robots into the groves raises a question: What happens to the migrant workers who now have little other means of making a living other than picking fruit? About 25,000 workers are employed picking citrus fruit in Florida.
For Margaret Simmons, director of Farmworker's Self-Help in Dade City, Fla., the project's impact on farm labor may be mixed.
''If they had a robot, that would destroy us'' as a labor force, she says. ''I can't see it as helpful to farm workers at all.''
Ms. Simmons says only a ''superpicker'' could make between $5 and $8 an hour. Workers are paid by the number of tubs they fill with oranges, she says, and that varies with the amount of fruit on the tree. She questioned whether a robot could differentiate between a freeze-damaged orange and a good one.
But she adds that the possibility of robots should spur farm workers to train themselves for other kinds of jobs.
''If the prices paid for labor are never going to change, and if the conditions the farm workers now live in are not going to change, then maybe the robots will be good,'' she says. ''Maybe what we need to do is start educating the farm workers at a greater speed.''
The potential impact of robots on farm labor is not lost on scientists here. Isaacs says, ''We're concerned about the impact of this technology on farm workers. But we're looking ahead five or 10 years before you see anything in the grove.''
Mr. Tutle says the transition from farm workers to robots would come slowly: ''We will not replace people instantaneously. There are 46 million orange trees in Florida, and we're not going to get rid of good producing trees just because they won't meet the standards needed by the machines.''
''We're already losing harvesters,'' he says. ''By the time we have a critical harvester problem, we hope we will have a machine to take their place.''