Definition: The transfer function of a control system is the ratio of Laplace transform of output to that of the input while taking the initial conditions, as 0. Basically it provides a relationship between input and output of the system. For a control system, T(s) generally represents the transfer function. The transfer of the system is given as: Transfer function is considered as an appropriate way of representing a linear time-invariant system. We know that in a control … [Read more...] about Transfer Function of Control System

# Control Systems

## Feedback System

A feedback system is the one which utilizes presently achieved output of the system for causing variation in the applied input signal in order to get the required output. More simply, we can say that the presence of a feedback system allows getting the desired output with continuous comparison from the reference input of the system. Generally, these systems are used to provide more corrective response, by comparing the achieved output with the applied input. By the use of feedback in a … [Read more...] about Feedback System

## Proportional Integral Derivative (PID) Controller

A type of controller in which the output of the controller varies in proportion with the error signal, integral of the error signal and derivative of the error signal is known as the proportional integral derivative controller. PID is the acronym used for this type of controller. Proportional plus integral plus derivative controller is sometimes referred as a 3-mode controller, as it combines the controlling action of proportional, integral as well as derivative controller altogether. The … [Read more...] about Proportional Integral Derivative (PID) Controller

## Proportional Derivative (PD) Controller

A type of controller in a control system whose output varies in proportion to the error signal as well as with the derivative of the error signal is known as the proportional derivative controller. It is also known as a proportional plus derivative controller or PI controllers. This type of controller provides combined action of both proportional and derivative control action. We know that the presence of controllers in any control system improves the performance of the overall system. So, … [Read more...] about Proportional Derivative (PD) Controller

## Proportional Integral (PI) Controller

Proportional Integral controller sometimes also known as proportional plus integral (PI) controllers. It is a type of controller formed by combining proportional and integral control action. Thus it is named as PI controller. In the proportional-integral controller, the control action of both proportional, as well as the integral controller, is utilized. This combination of two different controllers produces a more efficient controller which eliminates the disadvantages associated with each … [Read more...] about Proportional Integral (PI) Controller

## Types of Controllers

A controller is basically a unit present in a control system that generates control signals to reduce the deviation of the actual value from the desired value to almost zero or lowest possible value. It is responsible for the control action of the system so as to get accurate output. The method of producing a control signal by the controller is known as control action. The figure below represents the block diagram of an industrial controller: Basically the deviation of the achieved … [Read more...] about Types of Controllers

## Examples of Closed-Loop Control System

We all know that a control system manages or directs the operation of a system in order to provide a specific output. In a closed-loop system, the desired output is achieved by making a comparison between achieved output and provided input. And for this purpose, a part of the output is fed back to the input in order to have the difference in the input and output value. This is known as a feedback signal. Thus we can say the system whose operation is controlled by its output is known as a … [Read more...] about Examples of Closed-Loop Control System

## Closed-Loop Control System

Definition: A closed-loop control system is a type of control system in which the controlling action shows dependency on the generated output of the system. In simple words, in these systems, the output of the system controls the input applied to the system. The variation in input according to the output leads to produce more accurate system output. Thus controllability in the closed-loop system is achieved through the output generated by utilizing a feedback path. Closed-loop systems … [Read more...] about Closed-Loop Control System

## Open-loop Control System

Definition: An open-loop system is a type of control system in which the output of the system depends on the input but the input or the controller is independent of the output of the system. These systems do not contain any feedback loop and thus are also known as non-feedback system. In open-loop systems, the output is neither measured nor fed back to the input for further consideration. Open-loop System In our previous article, we have discussed about control system. We know that a … [Read more...] about Open-loop Control System

## Control System

Definition: A combination of various elements connected as a unit to direct or regulate itself or any other system in order to provide a specific output is known as a Control system. We know controlling is basically known as the act of regulating or directing. So control system is used to direct the functioning of a physical system to carry out the desired objective. For example, from a television system, refrigerator, air conditioner, to automobiles and satellites everything needs a … [Read more...] about Control System