Question

For a unity feedback system, the open loop transfer function is G(s) = K(s+2)/s^2 (s^2+7s+12). What is the type of system?

(a) One

(b) Two

(c) Three

(d) Four

I got this question at a job interview.

My question is based upon Steady State Error in section Error Analysis of Control Systems

Answer 1

Right choice is (b) Two

Explanation: As in the numerator it is mentioned K(s+2) so we got two poles in the open loop transfer function at the origin. For a given transfer function we calculate poles and zeros and the number of poles determine the type of the system.