What is Control Theory?
Control theory is a branch of Applied Mathematics dealing with the use of feedback to influence the behaviour of a system in order to achieve a desired goal. One can distinguish two classes of systems for which control theory plays an indispensable role, namely man-made systems and biological systems.
A
simple
example
of
a
man-made
system
is cruise
control for
a
car.
The
actual
speed
is
recorded
by
the
speedometer
and
is
"fed-back"
and
compared
to
the
speed
setting
on
the
cruise
control,
which
causes
the
engine
to
accelerate
if
the
speed
is
too
low.
The
cruise
control
device
is
referred
to
as
the controller in
the
system.
More
information
on
cruise
control.
Control theory is thus closely linked to engineering and technology, which has been its traditional sphere of influence, dating back several centuries. For example, in the 18th century the invention of the regulator for a steam engine, a type of control mechanism, had a significant impact on industrial development in Europe. The development of the mathematical theory of control, however, began much later and has taken place mainly during the past 60 years.
In the second half of the 20th century, control theory played a major role in many technological advances, for example:
- Control of spacecraft
- CANADARM, the Space Shuttle's robotic arm
- Robot technology
- Antilock braking systems
- Smart fluid technology
More information on man-made systems.
On the other hand, it is being increasingly recognized that control theory plays an important role in biology. Indeed many aspects of the human body illustrate the role of control in a biological system. For example, our sense of balance depends on feedback. Most people can remain balanced while standing on one foot. If you close your eyes in this situation, however, you will quickly start wobbling. This simple experiment shows that it is visual feedback that enables you to remain balanced.
Feedback
control
also
enables
the
human
body
to maintain
its
temperature within
a
narrow
range.
More
generally,
the homeostasis of
a
living
organism,
i.e.
the
state
of
balance
between
its
interdependent
elements,
is
maintained
through
the
use
of
feedback
control.
More
information
on
niological
systems.