Question

The ramp input is applied to a unity feedback system with type number 1 and zero frequency 20. What is the percentage of steady state error?

(a) 1%

(b) 2%

(c) 5%

(d) 9%

I got this question at a job interview.

My question is from Steady State Error in division Error Analysis of Control Systems

Answer 1

The correct option is (c) 5%

To explain I would say: Steady state error is the error calculated between the final output and desired output and the error must be less and this steady state error is inversely proportional to gain. Here unity feedback system is given with zero frequency 20 so we take 1/20^th part and the answer comes as 5%.