Pee Dee Precision, a local advanced agricultural robotics team, won 2nd place in the international Agbot competition. The award was for their work towards building a semi-automated watermelon harvester. The advantage the harvester had over its competitors was a unique way of combining a test for ripeness into the design of the harvest mechanism.
The design of the agbot started in November as soon as the contest criteria were released. The team assembled to take on the challenge was Robby Jowers, a Francis Marion graduate skilled in agriculture research; Smith Gaddy, a Citadel Graduate skilled in node.js development; and Jerry Martin, a Clemson and NC State graduate with 12 years of experience in agriculture engineering research. Prior to development an ATV donated by Yamaha Ventures in Silicon Valley, CA, was outfitted with basic teleoperation capability. The modified ATV was showcased along with its image processing capability at the SC Agribiz Expo. While at the expo over 20 full time watermelon producers were consulted about the basics of watermelon growing operations, as well as tricks of the trade to determine ripeness. All the ideas were collected then the watermelon harvester was designed.
The content of a watermelon resonates at a specific frequency when the melon is nearing ripeness.
As opposed to thumping the melon, ripeness was detected by sweeping harmonics through a speaker near the melon. A microphone was used to detect the frequency of oscillation. The oscillation of a ripe melon could be felt, and based on the sound and image was created. The created image was run through an image detection algorithm to determine ripeness.
The team from Virginia Tech placed first in the competition. Their guidance equipment and speed control was very good making for much more accurate navigation. Pee Dee Precision may compete again as another competition is scheduled for next year.