Growing & Winemaking


Robot Pruner Shows Its Stuff

July 2009
by Jon Tourney
Vision Robotics' "Intelligent Robotic Vineyard Pruner" (seen approaching a vine) demonstrates precision cutting at Sutter Home's Delta Ranch.

Grower uncertainty about future vineyard labor sources and costs has motivated development of sophisticated vineyard mechanization tools and systems in recent years. About 70 vineyard professionals gathered this spring with avid interest at Sutter Home's Delta Ranch vineyard for a demonstration of the "Intelligent Robotic Vineyard Pruner." It's the latest version of a project under development by San Diego-based Vision Robotics Corp., with assistance from several California vineyard industry investors.

Vision Robotics (, founded in 1999, has developed proprietary vision-based mapping and navigation systems to create robotic devices and technologies for numerous of applications. In a presentation prior to the field demo, company CEO Derek Morikawa said, "We're experts at using stereoscopic vision, with two cameras that work like human eyes to see depth." Other current projects include military, health care and cleaning applications.

The company was first approached to design agricultural applications in 2004. It's working with the Washington state apple industry to develop a product for harvesting and crop estimation, and with the California citrus industry to develop harvesting technology. Vision Robotics introduced its vine pruning concept to the grape industry at the 2007 Unified Wine & Grape Symposium.

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Derek Morikawa explains the science behind his company's robotic vineyard pruner.

Industry investors in the vine pruning development project include Sutter Home/Trinchero Family Estates, Vino Farms of Lodi, Lange Twins Vineyard Management of Acampo and Sunview Vineyards, which grows table grapes in Delano. Ag Industrial Manufacturing (AIM) of Lodi is a design partner.

Morikawa said $1.1 million has been invested to date, with Vision Robotics contributing more than $400,000 of its own money. The company is seeking $2.5 million for Phase 2 of development, likely to take two years, and is looking for as many as 20 industry investors to contribute $125,000 each, some of which will be tax deductible. Investors will gain rights to purchase all the available units for the first three years of production.

Morikawa listed the following features and goals for the robotic pruner:

  • Precision cuts with the quality of hand pruning.
  • Day and night operation.
  • Options to be towed by a tractor or be self-propelled.
  • Two pruning heads per row, with an over-the-row design to prune two rows at once.
  • Prune at speeds of 8 feet/minute.
  • Prune 1 acre in 4.4 hours (depending on vine density).
  • Save 40% to 50% over hand labor, with payback of 2.4 years.
  • Costs $125/acre (17.3 cents/vine), compared with hand labor at $257/acre (35.3 cents/vine).

The technology

Key to the Intelligent Robotic Vineyard Pruner are stereoscopic scanning cameras that take 15 frames per second, scanning the entire vine and working a full vine length ahead of the pruning shears. As Morikawa explained, "This 'vision' is the key sense the machine needs; otherwise it can't understand the vine and prune intelligently." An onboard computer uses the multiple overlapping photos to build a three-dimensional model of the vine, then applies "pruning rules" that were programmed into the software. The pruning rules guide and tell robotic arms with hydraulic pruning shears which canes to cut and which to leave, and where to make the cuts for the desired lengths and desired density of buds/vine.

This clean-cut vine was pruned by robotic shears.

Phase 1 represents about one-third of the total project, and Morikawa believes it accomplished its objective to show that the concept will work from end to end. "We feel the toughest parts of the technology have been done in Phase 1, and Phase 2 will help refine things in the field to improve overall quality, field ruggedness, the ability to prune more types of vines, and make it more operator-friendly with maintenance and support features," Morikawa said.

The earliest a commercial robotic vine pruner could be put into the field would be 2011. Morikawa estimated that a commercial unit will cost $150,000 and have at least a 10-year life cycle. The first machines will be designed for VSP and bilateral trellis and training systems, but later products could be modified for quadrilateral and other trellis systems. The machine is expected to be usable on sites with reasonable slopes, and in light rain, but not heavy rain conditions.

The technology can potentially be adapted to other practices such as suckering, leaf removal, shoot thinning and crop estimation, and the onboard camera and computer technology could be used for data collection and management to incorporate into GIS mapping systems. After observing the unit in action, some viticulturists were more interested in its potential application for crop estimation, believing the cameras could be used to count clusters during the growing season. Others, based on past experiences with new machine technologies, expressed the belief that successful field application may take longer than anticipated.

Lodi grapegrower Brad Lange, an investor who attended the demonstration, commented, "Mechanization is a way we can stay competitive . The cost of labor here is greater than in other parts of the world. The potential for technology like this is huge, and we look forward to using it in the future."

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