Fachhochschule Köln (University of Applied Science of Cologne), founded in 1971, is the outcome of an amalgamation of renowned predecessor institutions. These included “factory schools” (Kölner Werkschulen), colleges of mechanical and construction engineering, the German Insurance Academy and schools of photography and social work. Later additions included the Gummersbach campus and the former colleges for library and documentation studies as well as completely new fields of study like restoration and conservation, design, along with an institute for technology in the tropics.
The Project: An Automatic Foosball Robot
Fun and science can definitely be combined. This was proven by the degree candidates at the Cologne University of Applied Sciences (FH Köln) with their project to automate a foosball table and thus demonstrate the capabilities of modern, freely programmable circuits – so-called FPGAs (Field Programmable Gate Arrays). Under the supervision of Prof. Dr. Jens Onno Krah, head of the Laboratory for Motion Control and Digital Signal Processing at FH Köln, students developed a foosball table on which people can play against a robot. The eye of the robot is a Pike digital camera from Allied Vision Technologies.
Here’s how the foosball robot works: The playing field is monitored by an AVT digital camera. It is located underneath the foosball table, where the green playing field has been replaced by translucent, impact-resistant, safety glass. Thanks to specially tuned lighting, the camera recognizes the shadow of the foosball from underneath. The images are analyzed in the “brain” of the robot – a computer – using algorithms, which calculate the position and speed of the foosball and transmit corresponding commands to the four “arms” of the robot. These “arms” consist of servo-motors, which are linked to the four handles on one side of the foosball table and operate the playing figures: For each handle one motor positions the players, while another is used to turn the figures, i.e. to kick.
Critical for the game experience is the reaction speed of the robot. This depends decisively on the speed of the camera, as shown by the experience of the development team: “The first prototype of the foosball robot was equipped with an analog camera and a comparably slow image processing speed of 20 images per second”, explains Prof. Dr. Krah. “So it was quite possible to win against the robot”.
With AVT Pike Nearly Unbeatable By Humans
The analog camera has since been replaced by a Pike F-032 high-speed camera from Allied Vision Technologies. Via its IEEE 1394b FireWire interface, up to 120 images per second are recorded and analyzed in VGA resolution (0.3 megapixels). Furthermore, the use of the AVT FirePackage software optimized the speed of image processing.
This six times faster version of the foosball robot was presented at the trade fair Embedded World in Nürnberg, Germany, in February 2007 and was tested thoroughly by users. The result: With the Pike camera, only experienced foosball players have a chance to win against the robot. “The robot won over 90% of the games and was able to kick five goals even against the two best foosball players”, says Prof. Dr. Krah. “No one expected the robot to kick such fast and hard shots”.