The Hierarchical Paradigm

The Hierarchical Paradigm is historically the oldestmethod of organizing intelligence
in mainstream robotics. It dominated robot implementations from
1967,with the inception of the first AI robot, Shakey (Fig. 2.1) at SRI, up until
the late 1980’s when the Reactive Paradigm burst onto the scene.
This chapter begins with a description of the Hierarchical Paradigm in
terms of the SENSE, PLAN, ACT primitives and by its sensing representation.
The chapter then covers the use of Strips in Shakey to reason and plan

a path. Strips will serve to motivate the reader as to the computer challenges
inherent in even as simple a task as walking across a room. However, Strips
is not an architecture, per se, just an interesting technique which emerged
from trying to build an architecture. Two representative architectures are
presented, NHC and RCS, that serve as examples of robot architectures popular
at the time. The chapter concludes with programming considerations.