Page 22 - Introduction to AI Robotics

Part I
What are Robotic Paradigms? 5
PARADIGM A paradigm is a philosophy or set of assumptions and/or techniques which charac-
terize an approach to a class of problems. It is both a way of looking at the world
and an implied set of tools for solving problems. No one paradigm is right;
rather, some problems seem better suited for different approaches. For ex-
ample, consider calculus problems. There are problems that could be solved
by differentiating in cartesian (X ; Y ; Zordinates, but are much easier to
co
)
solve if polar coordinates (r; ) are used. In the domain of calculus problems,

Cartesian and polar coordinates represent two different paradigms for view-
ing and manipulating a problem. Both produce the correct answer, but one
takes less work for certain problems.
Applying the right paradigm makes problem solving easier. Therefore,
knowing the paradigms of AI robotics is one key to being able to successfully
program a robot for a particular application. It is also interesting from a his-
torical perspective to work through the different paradigms, and to examine
the issues that spawned the shift from one paradigm to another.
ROBOTIC PARADIGMS There are currently three paradigms for organizing intelligence in robots:
hierarchical, reactive, and hybrid deliberative/reactive. The paradigms are
described in two ways.

1. By the relationship between the three commonly accepted primitives
ROBOT PARADIGM of robotics: SENSE, PLAN, ACT. The functions of a robot can be divided
PRIMITIVES into three very general categories. If a function is taking in information
from the robot’s sensors and producing an output useful by other func-
tions, then that function falls in the SENSE category. If the function is
taking in information (either from sensors or its own knowledge about
how the world works) and producing one or more tasks for the robot to
perform (go down the hall, turn left, proceed 3 meters and stop), that func-
tion is in the PLAN category. Functions which produce output commands

to motor actuators fall into ACT (turn 98 , clockwise, with a turning veloc-
ity of 0.2mps). Fig. I.2 attempts to define these three primitives in terms
of inputs and outputs; this figure will appear throughout the chapters in
Part I.

2. By the way sensory data is processed and distributed through the sys-
tem. How much a person or robot or animal is influenced by what it
senses. So it is often difficult to adequately describe a paradigm with just
a box labeled SENSE. In some paradigms, sensor information is restricted
to being used in a specific, or dedicated, way for each function of a robot;