Good Fruit Grower

April 1

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34 APRIL 1, 2015 GOOD FRUIT GROWER C an a robot prune an apple tree? The short answer, it seems, is yes. Give it some simple pruning rules, and it can do 90 percent of the work, reducing the human labor of dormant pruning to some minor touch-up. In fact, a machine capable of pruning apple orchards may be commercially available within a few years. For a cost of about 50 cents a tree, it will be able to find the right branches and make the proper cuts without human assistance. It may even be self-propelled and self-guided, needing no human operator except to turn it around at the end of a row. All that was explained during a lengthy workshop during the Mid-Atlantic Fruit and Vegetable Convention in Hershey, Pennsylvania, in January. By way of background: In 2012 a group of horticul- turists and engineers were awarded $3 million from the Specialty Crop Research Initiative, to be matched with institutional and industry funds, to develop automated pruning of grapes and apples. The project landed at Purdue University in West Lafayette, Indiana, under the overall direction of horti- culturist Dr. Peter Hirst. He had assembled the team that includes horticulturists Jim Schupp and Tara Baugher at Penn State University; electrical and computer engineers Johnny Park, Avinash Kak, and Noha Elfiky at Purdue; economist Jayson Harper at Penn State; sociologists Leland Glenna and Anouk Patel-Campillo at Penn State; Tony Koselka and Bret Wallach at Vision Robotics; and Julie Tarara from the USDA's Agricultural Research Service in Washington State. "The overall goal," Hirst said, "is to develop a pruning machine that growers can buy." It was not to be "pie in the sky," he said. "It was supposed to be 'rubber meets the road.'" The intention was to reduce the art and elevate the science of pruning. Fruit growers spend about 20 percent of their labor on pruning vines and trees, Hirst said, and they rely on an ever-less-certain labor supply from the migrant work- force. Pruning is not as large a labor investment as har- vest, and timing is not as critical, but pruning rates high on a grower's list of time-consuming tasks. Some work done The people at Vision Robotics in San Diego, California, had already developed a prototype grapevine pruner, so much of the work had been done on imaging—using cameras and computers to locate canes—and on the actual robotic arms that move the clippers, Edward Scissorhands style. A tractor pulls the machine over a row of grape vines while cameras capture images of the vines and a com- puter remembers cane locations and tells robotic arms where they are. Pruning grapes is relatively simple, since each cane is cut back to one or two buds. The grape prototype needed perfecting—one of the goals of this project—but the basic technology was there and was applicable to apples, Hirst said. "Apple trees are more complex and will take more time," he said. "But once we have that, it should be much smaller steps to translating the work for other fruits such as plums, peaches, and cherries." Koselka, with Vision Robotics, said he thought the company would have a grape pruning machine ready for market in 18 to 24 months. "It's an amazing time for mechanization," he said. The robot arms, with the flexible shoulders, elbows, and wrists, move as effectively as a human arm, but they now cost about $45,000 each. "We want to get that down to $10,000," he said, and thought that would happen, par- ticularly since there is currently so much interest in the medical world in developing better artificial limbs for people. Automated PRUNING Orchard Equipment Robots can follow pruning rules as well as humans, but a key was writing the rules. by Richard Lehnert "The overall goal is to develop a pruning machine that growers can buy." —Peter Hirst A tractor pulls a prototype of a robotic vine pruner down the row.

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