Seeing Straight

Jan. 20, 2005
Alignment difficulties between shipping cartons are no problem for a robotic palletizing arm and smart camera.

An intelligent camera and companion light source helps a German company straighten out an alignment problem on incoming pallets. Palletizing robots efficiently stack boxes for shipping, but are seldom used to off-load those very same stacks. Palletized boxes have a way of shifting position during transit. Cartons just a few inches out of alignment with the robotic gripper can get dropped and perhaps damaged.

From its central distribution center in Friedberg, Germany, Fresenius Kabi Deutschland GmbH delivers dietetic and infusion therapy products to its customers within 24 hr. Over 70% of the products it ships arrive at the center the same day. Incoming products transfer immediately to customer pallets awaiting delivery. Only a high degree of automation — both packing and unpacking — keeps costs manageable.

A camera with built-in intelligence, the Pictor by Vision & Control GmbH, Suhl, Germany, has been programmed to identify a carton's true orientation and transmit that information to a robot controller for fine positioning. The robotic arm and the carton stay in alignment resulting in fewer dropped or damaged cartons. Viewing a carton's true position from above meant both camera and lighting had to reside within the head of the robotic arm. The Vicolux area lighting system by Vision & Control was chosen for its modular construction and simple installation. Illumination on the carton top let the Pictor camera easily ID edges and sealing tape. Once the system spotted the corner of the carton the built-in serial interface sent its XY coordinates to the controller which maneuvered the robotic arm as necessary. The process repeats until there are no further adjustments. Then the arm picks up the carton and places it on the right customer conveyor.

The current installation has operated successfully for over two years.

The robotic arm positions the vacuum pickup over a carton to be removed from the pallet. The Pictor camera looks down on the top of the box illuminated by the Vicolux light source and identifies the box edges and corners.


Box edges and the highly reflective adhesive tape are easy to spot in this view from the Pictor camera. The camera's internal algorithm can distinguish between the real edge and an edge formed by an incomplete box closure, visible at the right.

Final alignment with the carton complete, the robot arm activates its vacuum system and lifts the desired carton off the pallet in preparation for shipment.


Fresenius Kabi Deutschland GmbH,

Vision & Control GmbH,

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