||I describe an architecture for linking perception and action
in a robot. It consists of three towers of layered components.
The perception tower contains rules that create increasingly
abstract descriptions of the current environmental situation starting with
the primitive predicates produced by the robots sensory apparatus.
These descriptions are deposited in a model tower thich is continuously
kept faithful to the current environmental situation by a truth-maintenance
system. The predicates in the model tower, in turn, evoke appropriate action-producing
programs in the action tower. It is proposed that the actions
be written as teleo-reactive programs ones that react
dynamically to changing situations in ways that lead inexorably toward their
goals. Programs in the the action tower are organized more-or-less hierarchially
bottoming out ni programs that cause the robot to take primitive
actions in its environment. The effects of the actions are sensed by the
robots sensory mechanism, completing a sense-model-act cycle that
is quiescent only at those times when the robots goal is perceived
to be satisfied. I illustrate the operation of the architecture using a
simple block-stacking task.