Background
Modern control engineering is closely related to
electrical and computer engineering, as electronic circuits can often be
easily described using control theory techniques. At many universities, control
engineering courses are primarily taught by
electrical and computer engineering faculty members.
Previous to modern electronics, process control devices were devised by mechanical engineers using
mechanical feedback along with pneumatic and hydraulic control devices, some of
which are still in use today.
The field of control within
chemical engineering is often known as
process control. It deals primarily with the control of variables in a
chemical process in a plant. It is taught as part of the undergraduate
curriculum of any chemical engineering program, and employs many of the same
principles in control engineering.
Other engineering disciplines also overlap with control engineering, as it
can be applied to any system for which a suitable model can be derived.
Control engineering has diversified applications that include science,
finance management, and even human behaviour. Students of control engineering
may start with a linear control system course which requires elementary
mathematics and Laplace transforms (called classical control theory). In linear
control, the student does frequency and time domain analysis.
Digital control and
nonlinear control courses require
Z Transformations and algebra respectively, and could be said to complete a
basic control education. From here onwards there are several sub branches.
Control systems
Control engineering is the engineering
discipline
that focuses on the
modelling of a diverse range of
dynamic systems (e.g.
mechanical
systems) and
the design of
controllers that will cause these systems to behave in the desired manner.
Although such controllers need not be electrical many are and hence control
engineering is often viewed as a subfield of electrical engineering. However,
the falling price of microprocessors is making the actual implementation of a
control system essentially trivial[citation
needed]. As a result, focus is shifting back to the
mechanical engineering discipline, as intimate knowledge of the physical system
being controlled is often desired.
Electrical circuits,
digital signal processors and
microcontrollers can all be used to implement
Control systems. Control engineering has a wide range of applications from
the flight and propulsion systems of
commercial
airliners to the
cruise control present in many modern
automobiles.
Control engineers often utilize
feedback
when designing
control systems. For example, in an
automobile
with
cruise control the vehicle's
speed is
continuously monitored and fed back to the system which adjusts the
motor's torque
accordingly. Where there is regular feedback,
control theory can be used to determine how the system responds to such
feedback. In practically all such systems
stability is important and
control theory can help ensure stability is achieved.
Although feedback is an important aspect of control engineering, control
engineers may also work on the control of systems without feedback. This is
known as
open loop control. A classic example of
open loop control is a
washing machine that runs through a pre-determined cycle without the use of
sensors.
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