German Sensor Application Prize 2006 - The Best Photoelectric Sensor Wins

The German Sensor Application Prize, first awarded in 2002, recognizes the most effective, economical, creative, or innovative solution for factory automation using industrial sensors. This year, Thorsten Knepper of Hauni Maschinenbau AG won the first prize. Working at Hauni's production site in Hamburg, Knepper specializes in designing and programming machine control systems and integrating sensors and actuators to control automatic processes.

Hauni is one of the world's leading system suppliers for the tobacco industry and the global market leader for cigarette making machines (commonly called makers). The award-winning application from Nuremberg is a robotic depalletizer designed to feed a bobbin loader for cigarette paper with long rolls of paper called bobbins. The problem was to determine the exact position of the bobbin delivered on a pallet to be able to position the gripper tool precisely.

To solve this application, Hauni employs an array of four diffuse mode photoelectric sensors mounted directly on the robotic arm. The sensors move across the bobbin on the pallet and detect the descending edge of each bobbin. If the sensors detect at least three edges, a vector analysis is used to calculate the exact center of the bobbin used to position the gripper.

The Hauni solution, equipped with Pepperl+Fuchs’ photoelectric sensors, can easily identify bobbins of different diameters and ensures exact positioning of the robotic palletizer without damaging the bobbins. Different materials do not affect the operation of diffuse mode sensors. Bobbin stacks located in close proximity to one another are clearly identified and the gripper is positioned safely.

For this application, Hauni uses high-precision ML6 series diffuse mode with background suppression sensors from Pepperl+Fuchs. These photoelectric sensors feature an extremely small, sharp light beam that provides high detection accuracy. They are also characterized by their excellent background suppression, which is essential to their reliability and repeat accuracy capabilities.

During extensive testing conducted by Hauni, the photoelectric sensors from Pepperl+Fuchs have clearly proven to be the best solution available. Even under critical operating conditions, the ML6 series provides reliable detection without switching errors. Reflective surfaces and ambient light have no negative effect on detection capabilities. The very small black-white differential offers reliable object detection, regardless of color and surface characteristics. The small, highly visible light beam allows precise edge and position detection. In addition, the sensors feature a short response time, efficient cross talk protection, and a compact, rugged design that ensures reliable functioning even in harsh environments.