SPIE Web's (International Society of Optical Engineering) OE Reports - September 1998
Robots hired in poultry packing plants
|
The Intelligent Integrated
Belt Manipulator (IIBM) robot tackles a common
food industry task by removing items from a conveyor
belt and transferring them into a packing carton
for shipping. It is undergoing field testing at
a ConAgra poultry plant in Gainesville, Georgia.
|
Many jobs in poultry processing consist of materials handling tasks, such
as moving a product from a conveyor belt into a box or onto another conveyor
belt. Gary McMurray, a senior researcher in Georgia Tech's Agricultural Technology
Research Program (ATRP) and a project director for the robotics initiative,
said that their goal was to develop a low-cost robot that could perform materials
handling tasks with the same speed and dexterity as a human. Although poultry
plants are using simple forms of fixed automation, these machines have very
limited capabilities and are expensive.
Georgia Tech researchers have been developing a new breed of robot
that will increase efficiency and competitiveness for the poultry industry.
The Intelligent Integrated Belt Manipulator (IIBM) tackles a common food
industry task by removing items from a conveyor belt and transferring them
into a packing carton.
Conceived in 1992, IIBM has gone through several redesigns and refinements
over the years. The first-generation robot was powered exclusively by pneumatics,
attractive because of its low costs and ease of use. Noting that the prototype
fluctuated up to an inch in position when picking up items, McMurray said
that the speed was good but that the accuracy rate did not meet expectations
-- the robot picked up the product, but sometimes misplaced it in the shipping
carton.
Poultry pieces differ considerably in size and shape, varying the contours
of the packages by up to two inches and causing a shift in weight and center
of gravity. This made grasping demands another challenge for the IIBM, and
its end effector had to be constructed with some flexibility. Suction cups
were made from bellows material (which compresses up to three-quarters of
an inch), and a spring mechanism was added to those suction cups providing
another inch of compliance. These changes allow the grippers to conform to
different contours of a product.
After four months of lab testing, the current IIBM prototype has been
sent to the factory floor in a ConAgra plant (producers of Butterball and
Country Pride poultry products) in Gainesville, GA to focus on speed and
accuracy testing. Early field test results have been encouraging. In lab
trials, the IIBM's average cycle time was clocked at 2.1 seconds -- comparable
to a human worker. This timing has been sustained in the plant as well. During
lab testing, the robot occasionally dropped a tray pack, but rarely missed
picking up the product.
The new IIBM is a hybrid of pneumatics and electro-servo drives. Two
pneumatic axes and two electro-servo axes allow motion in four directions
-- up and down, parallel to the conveyor belt, perpendicular to the conveyor
belt, and at a 90-degree rotational pivot.
Besides cutting costs, the IIBM is attractive because it is simple
both to install and to maintain. Only a few physical dimensions must be programmed
-- the size of the tray packs, the location of the packing cartons, and the
height of the conveyor belt.
J. Craig Wyvill, director of ATRP, hopes to have the technology commercialized
within the next two years. His next step is to enhance the system with a
vision system, which would develop hand/eye coordination for the robot and
allow it to operate by merely seeing a picture of the product, eliminating
the need for task-specific software and programming.
McMurray stresses that the IIBM wasn't created to perform just one
materials handling task, but rather to demonstrate the cost-effectiveness
and flexibility of automation for the poultry industry. He estimates that
final commercial costs will range between $30,000 and $40,000 -- about half
the price of existing industrial robotic systems. Preliminary discussions
are already being held with private companies.
|
