Team Develops Touchless Tomato Transplanter

Lal Singh, professor emeritus in Agriculture; Joel Arthur, Civil Engineering; Ron Borge, Agricultural Engineering; and Ramesh Varahamurti, Mechatronics, have completed the development of a robot that will transplant tomatoes. Dr. Singh wrote the following account of their work.

Eighty-five percent of the world’s total processing tomatoes are produced in the central valley of California, the Mediterranean coast, and China’s Xinjiang province. Although California produces over one-third of the world’s and 90 percent of the United State’s production of tomatoes used for paste, the world’s attention has been transferred to China. China’s advantage, compared with Europe and the United States, is the low cost of production—especially labor cost. This, combined with government price supports and their agriculture export subsidy policy, gives China a tremendous competitive advantage. The export share of China’s tomato paste in the global market has increased from 7.7 percent in 1999 to 30 percent in 2007, and by 2010 it will account for 40 percent of the world trade share.

California farmers have remained competitive in the global market place by using technology to reduce their costs and expand production. However, California farmers still remain at a disadvantage. Labor cost in China compared to the United States is what makes Chinese tomato products a bargain for U.S. consumers. This threat from China has challenged the competitiveness of tomato production in California.

The Morning Star Company is the world’s leading tomato processor, and it farms significant tomato acreage in California. The company has identified planting operations as being labor intensive. At present the tomato seedlings are planted by hand, which accounts for significant labor cost. Because of Chico State’s record for applied research and previous innovative research in developing a “touchless” transplanter, the company asked Dr. Singh for help. A research project was launched to develop a “robot” to replace humans in the planting operation of tomatoes.

Four faculty members—Arthur, Borge, Varahamurti, and Singh—as well as senior engineering students formed the research team. The Morning Star Company and USDA/ARI funded the project.

The research was conducted in three phases. In phase one, a “robotic” machine was designed, fabricated, and tested in a mechatronics laboratory. This robot simulated human hand motion. The design accomplished certain performance and functional tasks. Phase one successfully demonstrated the proof of concept, that is, a robot can mimic the human hand. In phase two, the pick-and-place robot was improved by adding a conveyor motion to index the tray. A color sensor was added as well to detect a “live” or “dead” plant. This sensor increased the intelligence of the machine. The machine was field tested with simulated plants.

With the knowledge acquired from phase one and two, the research team launched a more challenging phase three of this research project. The automation of tomato transplanting required computer control and synchronization of 10 operations: move the seedling tray in position, pick the plant from the tray, move the plant to a conveyor belt, untangle the plants and drop a single plant onto conveyor, return the MT tray, use a color camera to recognize a dead plant, remove the dead plant, maintain spacing between plants, open a furrow, drop the plant in the furrow, and cover with soil. The field-scale prototype machine was briefly tested in the field. This research required knowledge of agribusiness, production agriculture, agricultural engineering, civil engineering, mechanical engineering, mechatronics engineering, control systems, and computer programming.

Singh is the research project director and principal investigator. He is hoping to acquire funding to test and collect data in field conditions. Along with research in California, Dr. Singh has research projects in India to introduce California tomato varieties.

—Lal Singh, professor emeritus, College of Agriculture