Representative architectures

Representative architectures
In order to implement a reactive system, the designer must identify the set
of behaviors necessary for the task. The behaviors can either be new or use
existing behaviors. The overall action of the robot emerges from multiple,
concurrent behaviors. Therefore a reactive architecture must providemechanisms
for 1) triggering behaviors and 2) for determining what happens when
multiple behaviors are active at the same time. Another distinguishing feature
between reactive architectures is how they define a behavior and any
special use of terminology. Keep in mind that the definitions presented in
Sec. 4.2 are a generalization of the trends in reactive systems, and do not
necessarily have counterparts in all architectures.
There are many architectures which fit in the Reactive Paradigm. The two
best known and most formalized are the subsumption and potential field
methodologies. Subsumption refers to how behaviors are combined. Potential
Field Methodologies require behaviors to be implemented as potential
fields, and the behaviors are combined by summation of the fields. A third
style of reactive architecture RULE ENCODING which is popular in Europe and Japan is rule
encoding, where the motor schema component of behaviors and the combination
mechanism are implemented as logical rules. The rules for combining
behaviors are often ad hoc, and so will not be covered in this book.
Other methods for combining behaviors exist, including fuzzy methods and
winner-take-all voting, but these tend to be implementation details rather
than an over-arching architecture.