RoboCup Logistics League Referee Box

The RoboCup Logistics League Sponsored by Festo (LLSF) focuses on the logistics aspect of an industrial production workflow, using coordinated teams of autonomous mobile robots building on technologies also developed in robot soccer leagues like self-localization, navigation, or perception. The task is to complete variable production chains as efficiently as possible, which means moving semi-finished products through several production steps on machines on factory floor and finally delivering it to the customer.

The LLSF game comprises a rather constrained task for now. Yet overseeing the game requires tracking of more than 20 pucks and their respective states, watching machine areas of 10 machines to detect pucks that are moved out of bounds, placing late order pucks for visual triggering at speci ed places at certain times, and overseeing completion of the production chain awarding points and keeping a score. This can easily overwhelm a human referee and make the competition hard to understand for a visitor. In fact, in 2012 we needed to review a camera recording of a game to award points in hindsight because a situation was overseen by the two human referees. Therefore, we strive for the implementation of a (semi-)autonomous referee box (refbox). The refbox shall control, monitor, and score the overall game. The human referees instruct the refbox (e.g., to start or pause the game), which then communicates with the robots on the eld. The humans act as a second tier referee correcting for misjudgment of yet unforeseen situations. Additionally, full autonomy cannot be achieved, yet, because there is no sensor to detect pucks moved out of a machine area.

The core of the referee box is a knowledge-based system based on the CLIPS rule-base production system. It was built on ideas from our CLIPS-based task coordination project.

The refbox was implemented by the Technical Committee of the LLSF, in particular by members of the Carologistics RoboCup Team. It was used successfully in the RoboCup 2013 competitions throughout all games with only minor issues.

Publication

In the paper "RoboCup Logistics League Sponsored by Festo: A Competitive Factory Automation Testbed" (Niemueller, Ewert, Reuter, Ferrein, Jeschke, Lakemeyer) we proposed several ideas for the advancements of the LLSF — including the referee box — most of which have been implemented in the 2013 competitions.

Android Apps

To monitor and instruct the refbox from an Android smartphone or tablet we have created the Android app LLSF RefBox Viewer. It allows to connect to this referee box and visualize the most crucial bits of its internal state information published by broadcast messages on the local network. If connected directly to the referee box as a privileged client it allows to instruct the referee box to control the game. It is primarily intended for LLSF participants.

Another app, the LLSF Puck Manager, has been written to read and write RFID tags on the pucks with an NFS-enabled Android device.

Download

The Git repository is available at http://git.fawkesrobotics.org/llsf-refbox.git. The official release packages and documentation is available on the RoboCup Logistics refbox page.

Future Work

The project is ongoing adapting it to rule changes as they are introduced by the LLSF TC. If you are interested in this work and want to get in touch please contact Tim Niemueller

Acknowledgements

The project was supported and endorsed by the LLSF TC. Hardware for testing the system was generously provided by Festo Didactic, the sponsor of the league. Extensions like an overhead camera system was funded by the RoboCup Federation with a RoboCup Project grant. The Carologistics RoboCup Team was the guinea pig for testing the refbox prior to the actual competitions — thanks guys!