View source for Control theory

'''Control theory''' is an interdisciplinary branch of [[engineering]] and [[mathematics]] that deals with the behavior of dynamical systems with inputs, and how their behavior is modified by feedback.

== Description ==

The usual objective of control theory is to control a system, often called the plant, so its output follows a desired control signal, called the reference, which may be a fixed or changing value.

To do this a controller is designed, which monitors the output and compares it with the reference. The difference between actual and desired output, called the error signal, is applied as feedback to the input of the system, to bring the actual output closer to the reference.

== Topics ==

Topics studied in control theory include:

* [[Stability]] (whether the output will converge to the reference value or oscillate about it)
* [[Controllability]]
* [[Observability]]

== Block diagrams ==

Extensive use is usually made of a [[Diagram|diagrammatic]] style known as the [[block diagram]].

The transfer function, also known as the system function or network function, is a mathematical representation of the relation between the [[input]] and [[output]] based on the [[Differential equation|differential equations]] describing the system.

== Applications ==

As the general theory of feedback systems, control theory is useful wherever [[feedback]] occurs.

Control theory has applications in a wide range of fields, including:

* [[Physiology]]
* [[Electronics]]
* [[Climate modeling]]
* [[Machine design]]
* [[Ecosystems]]
* [[Navigation]]
* [[Neural networks]]
* [[Predator-prey interaction]]
* [[Gene expression]]
* [[Production theory]]

== See also ==

* [[Block diagram]]
* [[Differential equation]]
* [[Engineering]]
* [[Feedback]]
* [[Input]]
* [[Mathematics]]
* [[Model]]
* [[Output]]
* [[Simulation]]

== External links ==

* [https://en.wikipedia.org/wiki/Control_theory Control theory]


[[Category:Control theory]]
[[Category:Engineering]]
[[Category:Mathematics]]