ACE - The Autonomous City Explorer Project

As robots are gradually leaving highly structured factory environments and moving into human populated environments, they need to possess more complex cognitive abilities. Not only do they have to operate efficiently and safely in natural populated environments, but also be able to achieve higher levels of cooperation and interaction with humans. The Autonomous City Explorer (ACE) project  envisions to create a robot that will autonomously navigate in an unstructured urban environment and find its way through interaction with humans. To achieve this, research results from the fields of autonomous navigation, path planning, environment modeling, and human-robot interaction are combined.


ACE has its own channel on YouTube (, where there are videos about the project and experiment, a trailer, and the acceptance speech for the IJCAI-09 AI Video Competition "most innovative video" award.

Research Fields

Navigation and localization

  • Particle filter based SLAM and moving objects tracking
  • Bayesian framework for behavior selection under uncertainty in dynamic environments

Path planning

  • Path planning in dynamic environments

Human-robot interaction

  • Human-robot communication user-studies
  • Communication of map knowledge
  • Gesture based communication of navigational knowledge

Object classification/segmentation in 3D laser data

  • Efficient surface normal estimation for 3D point clouds obtained by a mobile robot
  • Segmentation of 3D laser data point clouds with graph-theoretic and template-based approach

Stereo Vision

  • Probabilistic mapping of human motion
  • Human detection with stereo vision
  • Gesture recognition using model-based human body pose estimation
  • Three-dimensional obstacle detection
  • Detection of salient points

The Evolution of ACE


Leading Researchers:

  • Kolja Kühnlenz
  • Dirk Wollherr

ACE Team:

  • Andrea Bauer
  • Klaas Klasing
  • Georgios Lidoris
  • Quirin Mühlbauer
  • Florian Rohrmüller
  • Stefan Sosnowski
  • Tingting Xu
  • Tianguang Zhang

Field Experiments

July 2007: Field experiment and user studies at the Stachus (Munich) collaboratively with the University of Salzburg.


July 2008: ACE went autonomously through the Munich


August 2008: ACE went autonomously from the lab to the Marienplatz in Munich. It did not use any map knowledge or GPS and found its way solely from information given from passers-by. (Everybody who gave directions to ACE: thank you.)


October 2008: ACE could be seen in the Deutsches Museum, during the "Long Night of Munich's Museums".

ACE at the Stachus in Munich, interacting with pedestrians
ACE is being interviewed
The route from the TUM to the Marienplatz