Spacing out

Application-specific robotics, in the form of Harvest Automation’s HV-100 robots, simplify spacing tasks for greenhouse growers. Metrolina in North Carolina is a prime example.

From rec rooms with iRobot vacuums (www.robot.com) roaming and cleaning the floors to operating rooms with such equipment systems as the da Vinci surgical system (www.davincisurgical.com) performing procedures as guided by consoles manned by skilled surgeons, robots are being used for a range of purposes.

So why not commercial greenhouses? Exactly.

Enter Harvest Automation’s HV-100 spacers. These miniature, mobile, autonomous high-tech helpers are being used to maximize labor efficiencies at a growing number of growers where the picking up and placing of plants is a considerable drain on manual labor resources. Furthermore, the bending over and picking up of plant containers makes this one of the least desirable tasks associated with commercial greenhouses.

With this in mind, mega-grower Metrolina Greenhouses in Huntersville, NC, which has 150 acres of greenhouse and production space, recently used the Harvest HV-100 robots during its busy poinsettia season. The poinsettia is the best-selling potted plant in North America, with annual volumes of approximately 65 million units in North America alone, 90 percent of which are sold during the six weeks before Christmas, according to www.flowers.about.com

Art VanWingerden, co-CEO of Metrolina Greenhouses, had been watching Harvest Automation’s progress since the commercial launch of the HV-100 at the beginning of 2013. The question he kept coming back to was simply, “Can Harvest Automation robots help us in our time of need? “
 

HV-100 robot
 

Before its usage of the HV-100 robots, spacing poinsettias at Metrolina had normally required a team of 9-10 workers per bay for a week in order to complete the task. “When it’s time to space our crop, it’s all hands on deck to see that our poinsettias are spaced on-time,” says VanWingerden. “We knew that Harvest Automation robots were doing great work at other sites, but we just weren’t sure they could keep up during our peak poinsettia spacing season.”

The robots were tasked with spacing more than 40,000 poinsettias in four days. Four HV-100 robots showed up for work ready and eager to get going first thing Monday morning. Metrolina’s bays were 41-feet wide and were divided into four beds of about 10-feet each. With one robot per bed, they were configured to space plants into a 26-inch center-to-center hexagonal pattern. The simplicity of setup and ease of use of the HV-100s allowed a single supervisor to easily set up and manage the robots on his own. Working 20 hour days with a single robot supervisor, each robot spaced an average of more than 2,500 plants per day. After four days of nearly nonstop operation, working night and day, the robots spaced the last of the poinsettias completing their task on-time, and ultimately moving over 40,000 plants.

“We could not have been happier with the results,” says Art VanWingerden. “Our poinsettia crop was spaced and ready to grow, and we did not have to impact shipping and production, authorize overtime, or hire additional workers to space plants.”

It’s likely that there will be more HV-100 successes in 2014 as Harvest Automation gained $11.75 million in Series C financing last October. The round was led by Mousse Partners Limited, based in New York, with existing investors – Life Sciences Partners, Cultivian, Founder Collective, Entrée Capital and MassVentures – participated in this third round of early stage financing. The funds will be used to further commercialize the HV-100.

“We are seeing strong product validation with first customers,” noted Harvest Automation CEO John Kawola.

“We are excited to continue our efforts to bring smart, mobile, adaptive robotics into agriculture, a market that is not only large in scale, but that could significantly benefit by deploying automation to work alongside people.”

 

How it works

When greenhouse workers perform the spacing task discussed in the article, they will often use a grid or other guide aligned with a cord stretched along the edge of the bed.  The guide, marked with tape or paint spots, helps workers position plants accurately in the desired pattern.  The guide is advanced down the bed as workers fill in the pattern.

When robots are used for spacing, a human “robot wrangler” first extends a special robot-detectable tape (called a boundary marker) along one edge of the bed.  The wrangler then places at least one container downfield; this establishes the row where the robot will begin placing plants. Next the wrangler dials in certain parameters via the robot’s user interface. Parameters include the spacing pattern (rectangular versus hexagonal), the desired center-to-center distance between plants, and the bed width. Finally, the wrangler points the robot toward the source of plants and presses the start button.

A planar laser range sensor mounted on the robot measures range every half degree throughout a 180°+ field of view. Containers appear as semicircles in the range data.  The robot uses this information to locate and approach the nearest accessible container. The robot grasps the container, picks it up, and then turns in the direction of the boundary marker. Special boundary sensors scan the ground as the robot moves forward.  When sensors locate the boundary marker, the robot turns to align with and then follows the tape. 

Soon the pattern of already-spaced plants comes into view. The robot locates the next empty position in the pattern, moves to that spot, and deposits the plant it carries.  Afterward, the robot drives back up the bed looking for the next container. The robot proceeds in this way until there are no more plants to move.

Obstacles – items that are neither plant containers nor other robots – present a challenge when they appear in the work area. Robots attempt to respond appropriately by stopping or avoiding the obstacle.  However, current limitations in both sensing and perception leave all robots with less than a human-level appreciation of their situation. For the HV-100, this means sometimes reaching for the pant leg of a stationary worker as though it were a container.

Beyond built-in programming protections, worker safety is ultimately assured by the robot’s small size. Errors, therefore, are annoyances rather than worker hazards.

Besides being an “application specific” technology, the HV-100s are also “collaborative.” While they do not communicate robot-to-robot per se, they recognize each other in the range sensor data.  When one robot encounters a teammate, the following robot waits for the lead robot to get out of the way before continuing with its task.


Source: www.robohub.org

 

 

For more information about Metrolina Greenhouses, www.metrolinagreenhouses.com.

For more about Harvest Automation and the HV-100, www.harvestai.com.

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