What is Control Theory?
Control theory is a branch of Applied Mathematics dealing with the use ofÌýfeedbackÌýto 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, namelyÌýman-made systemsÌý²¹²Ô»åÌýbiological systems.
A
simple
example
of
a
man-made
system
isÌýcruise
controlÌýfor
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
theÌýcontrollerÌýin
the
system.
More
information
on
cruise
control.
Control theory is thus closely linked toÌý±ð²Ô²µ¾±²Ô±ð±ð°ù¾±²Ô²µÌýandÌý³Ù±ð³¦³ó²Ô´Ç±ô´Ç²µ²â, which has been its traditional sphere of influence, dating back several centuries. For example, in the 18th century the invention of theÌýregulatorÌýfor 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,Ìýhowever, 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 manyÌýtechnological 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 inÌýbiology. Indeed many aspects of the human body illustrate the role of control in a biological system. For example, our sense of balanceÌýdepends 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 isÌývisual feedbackÌýthat enables you to remain balanced.
Feedback
control
also
enables
the
human
body
toÌýmaintain
its
temperatureÌýwithin
a
narrow
range.
More
generally,
theÌýhomeostasisÌýof
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.