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4.4 Potential Fields Methodologies

Figure 4.13 Five primitive potential fields: a.) uniform, b.) perpendicular, c.) attrac-
tion, d.) repulsion, and e.) tangential.

tional to the length of the arrow. A uniform field is often used to capture the

behavior of “go in direction n .”
PERPENDICULAR FIELD Fig. 4.13b shows a perpendicular field, where the robot is oriented perpen-
dicular to some object or wall or border The field shown is directed away
from the gray wall, but a perpendicular field can be pointed towards an ob-
ject as well.
ATTRACTIVE FIELD Fig. 4.13c illustrates an attractive field. The circle at the center of the field
represents an object that is exerting an attraction on the robot. Wherever the
robot is, the robot will “feel” a force relative to the object. Attractive fields
are useful for representing a taxis or tropism, where the agent is literally
attracted to light or food or a goal. The opposite of an attractive field is a re-
pulsive field, shown in Fig. 4.13d. Repulsive fields are commonly associated
with obstacles, or things the agent should avoid. The closer the robot is to
the object, the stronger the repulsive force 180 away from it.
TANGENTIAL FIELD The final primitive field is the tangential field in Fig. 4.13e. The field is a
tangent around the object (think of a tangent vector as being perpendicular to