Watermerlon is grown in 90 countries with worldwide production
exceeding 50 billion pounds per year.
The United States is the world's fourth largest producer. According
to the Department of Agriculture 70% of American households buy
watermelon.
The essential 'robotic' blending of intelligent sensing with
mechanical actuation can be found in vision-guided tractors, product
grading systems, planters and harvesters, applicators for fertilizers
and pest control. Robot manipulators can divide plant material for
micropropagation in sterile conditions; others can skin fruit for
canning.
Harvesting melon is a labor-intensive activity. In the United States
manual labor is relatively expensive. Israel is a country short of
farm laborers. Taking these considerations into account researchers
in both countries have sought mechanized solutions for labor
intensive agricultural pursuits.
A team of Israeli and U.S. researchers has designed a vision-endowed,
melon-picking robot to do the job. The robot is the result of a
collaboration of three Israeli Institutes of higher learning
including Ben-Gurion University, the Weizmann Institute of Science,
the Agricultural Research Organization and the American Purdue
University. It is now being commercialized. The researchers took into
account the price issues whereby labor, both in Israel and the United
States, is relatively expensive.
The machine consists of a mobile platform on which are mounted an
image-processing system, air blowers and a mechanical arm with a
gripper attached. As a tractor slowly pulls the platform through the
field, cameras take pictures that the system analyzes. The air
blowers ruffle the foliage to expose the fruit. When the harvester
sights a melon bigger than a certain size and therefore presumed to
be ripe it extends the gripper to grab the fruit and lift it off the
ground. Onboard software evaluates the image's shape, brightness, and
texture to locate the melons. Knives connected to the gripper slash
the stalk and the gripper places the melon on a conveyor belt.
The harvester named VIP ROMPER a tractor and picker that guides
itself down rows of maturing melon plants with only occasional human
steering corrections. A chemical sniffer determines whether the fruit
is ripe. A basketlike gripper on the arm gently grabs the melon,
"like a hand folding around it and lifts it as a knife cuts the
stem," states Professor Yael Edan of Ben Gurion University of the
Negev, Israel.
In field tests, VIP ROMPER correctly identified melons ripe for
picking, 85 percent of the time. Prof. Edan estimates a two-armed
version could attain a picking rate of one and a half seconds per
melon.
While robots are commonly used in automobile factories doing such
jobs as painting and welding, they are rarely seen in agriculture.
Robotics is usually associated with the manufacturing industry, where
it has had a history which is checkered, to say the least. In
agriculture, the opportunities for robot-enhanced productivity are
immense - and the robots are appearing on farms in various guises and
in increasing numbers.