Harvesting strawberries is tedious work for humans, but developing a robot that can distinguish which fruits are ripe and pick them without damaging them or requiring farmers to reconfigure their fields has been a challenge.

About $750 million is spent per year in the U.S. on strawberry picking, and finding labor has become increasingly difficult. For the past three years, growers have let millions of dollars’ worth of fruit rot on the vine because of a lack of workers. For instance, migrants from Mexico are aging, having fewer children who get more education, and finding work closer to home.

“There is a huge need for this [automated harvesting] because I know from personal experience that we have a shrinking workforce, said Gary Wishnatzki, owner of Wish Farms and co-founder of Harvest CROO Robotics in Plant City, Fla. “CROO” stands for Computerized Robotic Optimized Obtainer.

“I charged our engineers with the task of creating a picker that does not require growers to radically change the way they currently grow,” Wishnatzki said in a press release. “That is the major reason other robotic harvesters have not yet been commercialized.”

Although California is the largest producer of strawberries in the U.S., most winter strawberries are grown on about 11,000 acres around Plant City, according to The Tampa Tribune.

Bob Pitzer, chief technical officer and co-founder of Harvest CROO, studied human movement before designing the first prototype picker. Strawberries are smaller and more fragile than other fruit, requiring a more delicate touch.

“People don’t realize how efficient humans are at doing things,” he said. “With robotic manipulation, our biggest challenge is minimizing time. Based on our observations, our goal was to develop robots to pick as many berries as possible while utilizing conservation of motion.”

Strawberry picking is currently labor intensive, and workers are becoming harder to find.

Another requirement for an automatic harvester is a visual system that can differentiate between ripe and unripe strawberries, because the former are harvested every three days in season, unlike crops such as corn, which tend to ripen together. Harvest CROO’s picker uses commercially available vision sensors and software.

In addition, robots can pick at night and avoid the bruising that comes when strawberries are picked during the day, said Steve Howard, co-owner of Sweet Life Farms, which is among the investors in Harvest CROO.

A modular design should make it easier for Harvest CROO’s machinery to be repaired by swapping out parts, said Pitzer.

Ripening robotics
Harvest CROO Robotics has raised $1 million since 2012 for its first prototype automated picker. The company hopes to get another $1.5 million from investors and to test its alpha prototype through 2016. The alpha model is also expected to package the strawberries in plastic clamshells for retail sale.

Investors in automated picking machinery include farmers in Florida and California. Harvest CROO has filed a utility and a provisional patent and plans to provide its picking machines to growers would pay on a per-box basis.

Harvest CROO is only one of several companies pursuing robotic strawberry harvesting, which is no surprise because that crop is worth more than $1 billion to Florida, according to the Florida Strawberry Growers Association.

Robotic Harvesting LLC is testing a prototype strawberry harvester near Oxnard, Calif. It hopes to save $1.1 million over five years in labor costs with a commercial version that would cost around $300,000.

In addition, Spain-based Agrobot is developing an automated strawberry harvester with 14 arms for the California market. Agrobot’s machine, which is also still in prototype, would cost about $100,000.

The global agricultural robotics market is estimated to grow from $817 million in 2013 to $16.3 billion by 2020, according to “Agricultural Robots Market Shares, Strategies, and Forecasts, Worldwide, 2014-2020,” a report from Orbis Research. In addition to labor and cost savings, potential benefits include more consistent harvesting of produce and the need for fewer pesticides.