In this paper, we provide an overview of our on-going work using
spatial relations for mobile robot navigation. Using the histogram of
forces, we show how linguistic expressions can be generated to describe
a qualitative view of the robot with respect to its environment. The
linguistic expressions provide a symbolic link between the robot and a
human user, thus facilitating two-way, human-like communication. In
this paper, we present two ways in which spatial relations can be used
for robot navigation. First, egocentric spatial relations provide a
robot-centered view of the environment (e.g., "there is an object on
the left"). Navigation can be described in terms of spatial relations
(e.g., "move forward while there is an object on the left, then turn
right"), such that a complete navigation task is generated as a
sequence of navigation states with corresponding behaviors. Second,
spatial relations can be used to analyze maps and facilitate their use
in communicating navigation tasks. For example, the user can draw an
approximate map on a PDA and then draw the desired robot trajectory
also on the PDA, relative to the map. Spatial relations can then be
used to convert the relative trajectory to a corresponding navigation
behavior sequence. Examples are included using a comparable scene from
both a robot environment and a PDA-sketched trajectory showing the
corresponding generated linguistic spatial expressions.
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