Page 69 - Concise Encyclopedia of Robotics

Configuration Space (C-Space)
fast-scan video. In robotic vision systems, there are advantages to using
more lines per frame than is standard with television, in order to obtain
improved image resolution.
See also IMAGE ORTHICON, VIDICON, and VISION SYSTEM.
COMPUTER MAP
An autonomous robot must have a sense of where it is relative to sur-
rounding objects, so that it will not bump into things, and so that it can
find whatever it is seeking. For this to be possible, the robot controller
can make a computer map of its environment.
Computer maps can be generated using radar, sonar, or a vision system.
Such a map can exist in either two or three dimensions.A two-dimensional
(2-D) computer map of the objects in a room might be generated for a
flat plane 1 m above the floor. Several 2-D maps, representing various
altitudes above the floor, can be combined to create a composite three-
dimensional (3-D) map.
A more sophisticated method of generating a 3-D computer map
involves the use of spherical coordinates. The spherical coordinate system
defines azimuth (compass bearing), elevation (angle above the horizontal),
and range (radial distance). For such a map to serve its purpose, hundreds
or even thousands of individual soundings or observations must be made.
These soundings or observations should be distributed evenly around a
half-sphere above the horizontal for terrestrial robots, or around a full
sphere for submarine, airborne, or deep-space robots. In deep space, a
reference plane must be chosen to serve as the “horizontal.”The larger the
number of soundings, the better is the resolution of the map.
See also RADAR, SONAR, and VISION SYSTEM.
CONFIGURATION SPACE (C-SPACE)
A configuration space (abbreviated C-space) is a scheme in which the
location and orientation of a robot is determined relative to other
objects in its environment. Ideally, a C-space should use the mini-
mum number of coordinates necessary to accomplish this task. This
eliminates redundancy, which consumes controller memory and can
cause confusion.
Consider a mobile robot designed to function on a single floor of a
building. The total physical region in which this robot exists (the world
space) is three-dimensional (3-D).This constitutes three degrees of freedom,
which can be considered in terms of the Cartesian (rectangular) coordi-
nates x (north/south), y (east/west), and z (up/down). The orientation,
or attitude, of the robot, can require up to three additional degrees of
freedom: p (pitch), r (roll), and w (yaw).

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