Cooperative Multi-Robot
Systems for Vision-based 3-D Mapping
(Rui Rocha’s Ph.D.
thesis, Oct. 2005)
Research Issues
|
·
Cooperative Multi-robot Systems (MRS)
with an emphasis on efficient communication among robots ·
Applying MRS to volumetric mapping missions using stereo-vision
sensors ·
Bayesian probabilistic models of
3-D workspaces ·
Entropy-based
metric for assessing
information utility ·
Coordinated Exploration using
an information theoretic method based on mutual
information minimization |
|
Abstract
Building cooperatively 3-D maps of unknown environments is one of the
application fields of multi-robot systems. This on-going research addresses
that problem through a probabilistic approach based on information theory. A
distributed cooperative architecture model has been formulated whereby robots
exhibit cooperation through efficient information sharing and coordinated
exploration. A probabilistic model of a 3-D map and a statistical sensor model
are used to update the map upon range measurements, with an explicit
representation of uncertainty through the definition of map's entropy. Each
robot is able to build a 3-D map upon measurements from its own stereo-vision
sensor and is committed to cooperate with other robots by sharing useful
measurements. An entropy-based measure of information utility is used to define
a cooperation strategy for sharing useful information, without overwhelming
communication resources with redundant or unnecessary information. Each robot
reduces the map's uncertainty by exploring maximum information viewpoints,
while minimizing mutual information and interference with other robots, so that
maximum information gain is achieved in every sensing cycle. The proposed
framework was validated through experiments with a set of mobile robots
equipped with stereo-vision sensors.
(citation of the thesis and related publications)
(top
of the page)
Images
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Snapshots of volumetric maps
obtained with mobile robots equipped with stereo-vision sensors.
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Mobile Robots that we used within
3-D mapping experiments in our lab: (a) Scout mobile robots from Nomadic
Technologies (top), equipped with stereo-vision (bottom) and a modem radio
providing wireless TCP/IP communication; (b) a stereo image pair (top) and its
associated disparity (bottom-left) and depth map (bottom-right).
·
Block diagram showing
the relation between different parts of the 3-D mapping process and the
resources of a given robot of the fleet.
Videos
·
Video created on July
2005: presents the experimental setup and an example of a cooperative 3-D
mapping mission with two mobile robots
(download video, AVI format, 66.4 MB)
·
Video created on July
2004: presents the experimental setup and an example of a cooperative 3-D
mapping mission with two mobile robots
(download video, AVI format, 10.2 MB)
·
Live video showing a
short sequence of real robots’ operations within a 3-D mapping mission
(download video, AVI format, 15.1 MB)
Last
update:
Copyright ©
2006 Rui Rocha, Dep. of Electrical and Computer Engineering,