Question

Which of the following statements is correct for any closed loop system?

(a) All the co-efficient can have zero value

(b) All the co-efficient are always non-zero

(c) Only one of the static error co-efficient has a finite non-zero value

(d) Only two of the static error co-efficient has a finite non-zero value

This question was posed to me by my college director while I was bunking the class.

This is a very interesting question from The Approximation of Higher-Order Systems by Lower-Order in portion Time Response Analysis, Design Specifications and Performance Indices of Control Systems

Answer 1

The correct answer is (c) Only one of the static error co-efficient has a finite non-zero value

Easy explanation: Closed loop system has one of the static error constant for any input that can be position, velocity or acceleration error constant.