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92 I nnovations often emerge from a practitioner’s need to do a job more efficiently, hence the Global Unmanned Spray System (GUSS), the brainchild of Dave Crinklaw. Along with his father, Bob, he started an agricultural spraying business called Crinklaw Farm Services in 1982, beginning with a couple of tractors with towed sprayers, covering 20-40 acres of orchards and vineyards per day in California’s Central Valley. These days the company, renamed CFS, sprays 5000 acres per day on average at the peak of the season throughout California and into Arizona, treating a growing proportion of this acreage with the purpose-built GUSS autonomous UGV. CFS has been operating the GUSS commercially for two years, and is now selling it to other agricultural operators through spin-off company GUSS Automation. Always an inventor, Crinklaw and his team have designed and built agricultural tools such as sprayers that can cover three or four vineyard rows at once. They have also developed orchard sprayers using systems that detect young trees and the spaces between them, and switch the flow on and off as needed, as well as automated machines equipped with cameras, sickle-cutters and saw blades that can prune two rows of vines simultaneously. These and other developments have helped CFS to become the largest commercial spraying company in California. It now faces a labour shortage though, explains Gary Thompson, chief operating officer of GUSS Automation – a major motive for developing GUSS. He says, “One of the hardest positions to fill is that of tractor driver, because when you’re spraying trees you’re going at 2 mph. Most of our work is at night, especially in the summer, when it’s too hot during the day and the materials we spray with lose their effectiveness. “At times we’ll be sending crews three to four hours away from home, so they’d be spraying all night long and sleeping in a hotel during the day.” He says Crinklaw started to consider the idea of an autonomous spray system about 15 years ago, but at the time the technology wasn’t there and the labour shortage was not so acute. “About five years ago though it started getting really tough. We could easily have hired an extra 30 employees on any given day just to get the work done,” he says. “The technology was starting to come around, and at that point Dave walked out into the shop and drew on the floor what he thought the world’s first unmanned orchard sprayer should look like, and set a couple of his fabricators to start welding it up. He didn’t know at the time how he was going to automate it, but you have to have the platform to begin with.” Known as the Orchard GUSS, the vehicle is 24 ft long, 7 ft 6 in wide and 6 ft 4 in tall. It carries a 600 gallon stainless steel chemical tank with a ring Peter Donaldson explains the workings of this unmanned orchard sprayer, which is attracting international interest Fruits of February/March 2020 | Unmanned Systems Technology