Oct 1999, M. HoneggerThe autonomous behaviour of a robot is often considered to be the ultimate goal of its design. However, the practical application of the robot as an intelligent tool for human users requires an interaction between robot and users.
The service robot MOPS is picking up boxes with incoming mail at the ground floor of our five floor building, delivering them to the secretaries' offices, subsequently bringing back the outgoing mail to the ground floor station. MOPS' navigation is based on the recognition of natural landmarks which are compared to data of the building layout stored on the robots processor. The system has a highly accurate localisation and position control system, which enables MOPS to dock onto the pigeon holes and to load/unload boxes of mail. MOPS is also capable of hot-swapping its own battery pack, thus ensuring 24h availability. A hybrid navigation scheme combining graph-searching with a situation based behaviour selector and appropriate behaviours is used. The generated paths are close to being optimal, and the tolerance towards obstacles is high.
The interaction with humans takes place on various levels. The robot can be addressed by the secretaries and the maintenance offices by wireless internet communication, giving the robot its mail orders. The robot is supervised from the maintenance office, dealing with exceptional situations. Locally, service personnel can interact with the robot, having direct access to various robot functions. The mobile robot has a distinctly visible status display, and humans crossing its way can interact with the machine which has to react to human given signals. The software is based on the object oriented real-time framework XOberon, fulfilling real-time requirements, and running on a PowerPC.
MOPS is being used at the Institute of Robotics, ETH Zurich, for internal mail distribution. The current application, mail distribution, is only one out of a range of potential applications, such as cleaning, surveillance, inspection, etc.
Mail distributor has been chosen for its high demands on the cooperation of the three engineering disciplines mechanics, electronics and computer sciences. However, due to its universal design, MOPS can easily be adapted to customer requirements by changing the payload module, the design or custom-made add-ons.
A good overview of our project can be found in our publication in Service Robot an International Journal Vol. 2 No. 2 from MCB University Press. You can get a copy of the postscript file if you like.
A more recent paper has been published in the proceedings of the Third European Workshop on Advanced Mobile Robots (Eurobot'99). You can get a copy of the pdf file if you like.
For further information please send an email to mops@ifr.mavt.ethz.ch
Felix Wullschleger (wullschl@ifr.mavt.ethz.ch)
Institute of Robotics Homepage
Oct 1999, M. Honegger