Order & Poles: Basics of Control Engineering

[dhruv.tara]

Homework Statement

In control engg. we define the order of the system as (or atleast as far as I have understood as) Nu/s^m*(s+a)(s+b)...

I cannot understand the base for such classification? Why are we classifying systems based on the number of poles they have on origin?

Homework Equations

The Attempt at a Solution

 

[CEL]

No, the order of the system is the number of poles (at the origin and elsewhere).

 

[Ecthelion]

CEL is correct.

Something to add however is the way you have written the transfer function - it's done for a purpose. In controls seeing how many poles are at the origin, you're s^m part of the denomenator, has many ramifications that can be crucial when interpreting a system response or designing for one. So in seeing, and perhaps formatting a transfer function in this fashion, it is an aesthetic move but can make things easier.

 

[dhruv.tara]

thanks guys I was confusing myself with the order and type of the system... good I could get that clear just in time :)