spatial inference

Realator - experiments with navigation tasks in artificial worlds

Why simulation?

boring screenshot There will always be one disadvantage in using simulators: unrealistic enviroment. But on the other hand - working with real robots - one cannot simply abstract from any sub-problem (e.g. object identification, obstacle avoidance), which easily results in diversion from the key topic: navigation.
We are using simulation as a play- and testing-ground for navigation strategies, hoping to get ideas we just would not get by only working with real robots. One of these ideas is discussed in more detail below.

Why robots?

pioneer robot As mentioned above, unrealistic enviroment is the main problem of any simulation. It is not our goal to push forward the borderline of what can be simulated, moving only slightly towards reality. Instead, implementing the strategies for evaluation and veryfivation on robots is our aproach.


navigation in office-like enviroments

assumptions: how does an office look like?

an office Offices are two-dimensional worlds, only containing one-dimensional objects: walls. The unequivocal identification of walls is assumed to be a solved problem, which is quite strong restriction. Though, tests have shown that working with incorrect identification is also possible. Furthermore, the enviroment may not be cyclic.
Our virtual robot is equiped with a camera capable of recording a 360 degrees panorama view. As the world is two-dimensional, a scan results in a line of pixels. Camera recordings of a moving robot result in movies (as can be seen below), where the data is presented in each row from -360 to +360 degrees.
a movie

navigation

A cyclic ordering of the walls can be calculated given the scans of a moving robot, leading to a very simple navigation strategy.
The task:The algorithm:
Find the way back to a specific wall loop
  select two visible objects around goal object
  turn between selected objects
  advance
until goal object is visible
The advantages are: Since then, work has been put into:


Future plans

Right now, where working on a new simulator allowing us to easily test strategies on our real robots and the simulator. Therefore, we're moving towards an more realistic three-dimensional enviroment. The goal will be plugging the robot controlling computer either to the robot or to the simulator, but there is still a lot of work to do, leaving plenty of room for a Studien- or Diplomarbeit.
We are also working on a robot interface based on speech, adapting elsewhere developed components, see [1].

Literature:

[1] Moratz, R., Hildebrandt, B. Ableitung raumbezogener Handlungsziele aus sprachlichen Instruktionen (34KB gzipped Postscript)


For further information, please contact Reinhard Moratz.