Types of Control Systems

Control Systems is classified into the following categories:

  • Linear & Non-Linear Systems
  • Static & Dynamic
  • Time invariant & Time variant
  • Causal & non-Causal

Difference between Linear and Non-linear systems

Linear

Non-Linear

The relationship of output with the input is linear.

The relationship of output with the input is non-linear.

Satisfy Homogeneity & Superposition theorems.

Doesn’t satisfy Homogeneity & Superposition

Example : Register R= V/I

Example: Diode: I = I0 ( ev/t-1)

 
 


Difference between Static system and Dynamic system

Static systems

Dynamic systems

At any time output of the systems depends only on the present input of the systems.

At any time output of the systems depends only on the present as well as the past input of the systems.

Memory less systems

Presence of Memory Element

Y(t) = f (u(t))

This function is just dependent on present time like mentioned before.

Y(t) = f (u(t), u(t-1), u(t-2), …..)

This function also possess effects of their past inputs.


 Difference between Time invariant and Time-varying

Time invariant

Time-varying

At any time the output of the systems depends only on the present input of the systems.

At any time output of the systems depends only on the present as well as the past input of the systems.

Memory less systems

Presence of Memory Element

Y(t) = f (u(t))

This function is just dependent on the present time like mentioned before.

Y(t) = f (u(t), u(t-1), u(t-2), …..)

This function also possess the effects of their past inputs.


 Difference between Causal Systems and Non-causal Systems

Causal Systems

Non-causal Systems

The output of any casual system depends only on past and present inputs.

At any time output of the non-causal system depends only on the present as well as the past input of the systems.

It does not take part in any thing which is future (Non-anticipating) eg: y(t) = f(x(t), x(t-1),.....)

System anticipates future inputs based on past. for Eg: y(t) = f(x(t), x(t+1),....)

Examples of practical systems include Motor, Generator, temperature control, Etc. 

Examples of practical systems are weather forecast, guided missile, etc.

 
Thanks for reading. Any suggestions are also welcomed.

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