The Reactive Paradigm

The Reactive Paradigm

 Define what the reactive paradigm is in terms of i) the three primitives
SENSE, PLAN, and ACT, and ii) sensing organization.
 List the characteristics of a reactive robotic system, and discuss the connotations
surrounding the reactive paradigm.
 Describe the two dominant methods for combining behaviors in a reactive
architecture: subsumption and potential field summation.
 Evaluate subsumption and potential fields architectures in terms of: support
for modularity, niche targetability, ease of portability to other domains, robustness.
 Be able to program a behavior using a potential field methodology.
 Be able to construct a new potential field from primitive potential fields,
and sum potential fields to generate an emergent behavior.


This chapter will concentrate on an overview of the reactive paradigm and
two representative architectures. The Reactive Paradigm emerged in the late
1980’s. The Reactive Paradigmis important to study for at least two reasons.
First, robotic systems in limited task domains are still being constructed using
reactive architectures. Second, the Reactive Paradigm will form the basis
for the Hybrid Reactive-Deliberative Paradigm; everything covered herewill
be used (and expanded on) by the systems.

The major theme of this chapter is that all reactive systems are composed
of behaviors, though the meaning of a behavior may be slightly different in
each reactive architecture. Behaviors can execute concurrently and/or sequentially.
The two representative architectures, subsumption and potential
fields, are compared and contrasted using the same task as an example. This
chapter will concentrate on how architecture handles concurrent behaviors
to produce an emergent behavior, deferring sequencing to the next chapter.