Consider the following statements regarding Steady-State Error:1.Type of system determines steady-state error for standard inputs.2.Increasing system gain reduces steady-state error.3.Integral control eliminates steady-state error for step input.4.Steady-state error is independent of system type.Which of the above statements is/are correct?

Correct Answer: C - 1, 2 and 3 only

Quick Concept Explanation

It determines which standard polynomial inputs can be tracked with zero or finite steady-state error. Integral action increases low-frequency gain and improves steady-state accuracy, but it can also affect transient stability margins. Key relation: Kp=lim G(s), Kv=lim sG(s), Ka=lim s²G(s) as s→0 for unity feedback.

Exam focus: Type-0/1/2 classification comes from poles at the origin. Common trap: Do not infer stability from system type alone.

Statement-wise Verification

• Statement 1 - Correct.
  Type of system determines steady-state error for standard inputs.
  It determines which standard polynomial inputs can be tracked with zero or finite steady-state error.
• Statement 2 - Correct.
  Increasing system gain reduces steady-state error.
  Integral action increases low-frequency gain and improves steady-state accuracy
• Statement 3 - Correct.
  Integral control eliminates steady-state error for step input.
  Integral action increases low-frequency gain and improves steady-state accuracy
• Statement 4 - Incorrect.
  Steady-state error is independent of system type.
  The correct principle is: It determines which standard polynomial inputs can be tracked with zero or finite steady-state error.

Core Concept

In unity-feedback control, system type is the number of pure integrators in the open-loop transfer function. It determines which standard polynomial inputs can be tracked with zero or finite steady-state error. Integral action increases low-frequency gain and improves steady-state accuracy, but it can also affect transient stability margins.

Formula / Key Relationship

Kp=lim G(s), Kv=lim sG(s), Ka=lim s²G(s) as s→0 for unity feedback.

Why the Other Options Are Wrong

Option A is incorrect because it omits correct statement(s) 1. Option B is incorrect because it omits correct statement(s) 2. Option D is incorrect because it includes incorrect statement(s) 4.

Exam Shortcut / Approach

Type-0/1/2 classification comes from poles at the origin.

Common Mistake

Do not infer stability from system type alone.

Quick Revision

System Type Gain and Integral Action is linked with Steady-State Error, Steady-State Analysis and Control Systems. Type-0/1/2 classification comes from poles at the origin.