5.3. The Animats
We developed animats of two kinds: predators and preys. Predators chase, kill, and eat
preys, and preys run away from the predators. Our initial intention was not to reproduce the
behaviour of specific species of animals, but to model general properties found in animal
behaviour.
The internal structure of each animat can be described in terms of four basic
components: the perceptual system, the internal medium, the behaviours production system
(BeCA), and the motor system. Animats communicate and socialize using I&I.
5.3.1. The perceptual system
“The world is my representation”
—Artur Schopenhauer
The perceptual system first registers stimuli that are in the perceptual region (Rp) found
in the plane (z, x) of the space (x, y, z) defined by the half-circle of expression (19):
(19)
where (z , x ) is the position of the animat, 2 its orientation in radians, and r is the radius of
the half-circle (the radius of perception). After this, the perceptual system eliminates the
stimuli that are found behind obstacles, as shown in Figure 21, determining the “perceived
scenario”. The stimuli found in the perceived scenario are pondered as a ratio between the
magnitude of the stimulus and its distance from the animat. If a stimulus leaves the perceived
scenario, then the pondered value (Fe) decreases in terms of the parameter ! , as shown in
expression (20):
(20)
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