GATE EC 2024 Set 1 — Question 38
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MCQ+2 / -0.67MediumRoot Locus DesignCompensators & ControllersControl Systems
Control Systems → Compensators & Controllers → Root Locus Design
Last updated
Question
A satellite attitude control system, as shown below, has a plant with transfer function cascaded with a compensator , where and are positive real constants.

In order for the closed-loop system to have poles at , the value of must be __________.

In order for the closed-loop system to have poles at , the value of must be __________.
Correct answer
(B) 1
Solution
The open-loop transfer function of the cascaded system is .
Given and .
So, .For a unity negative feedback system, the characteristic equation is .
We are given that the closed-loop system has poles at .
These two poles form a quadratic factor:
Since is a factor of the characteristic equation, we can perform polynomial division or compare coefficients. Let the third pole be .
Then the characteristic equation can be written as .
Expanding this, we get:
Comparing the coefficients with :
Both and are positive real constants, as required by the problem statement.The final answer is
Given and .
So, .For a unity negative feedback system, the characteristic equation is .
We are given that the closed-loop system has poles at .
These two poles form a quadratic factor:
Since is a factor of the characteristic equation, we can perform polynomial division or compare coefficients. Let the third pole be .
Then the characteristic equation can be written as .
Expanding this, we get:
Comparing the coefficients with :
1.Coefficient of : .
2.Coefficient of : .
3.Constant term: .
Since , we have , which implies .Both and are positive real constants, as required by the problem statement.The final answer is
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE EC question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Compensators & Controllers
2026 Set 1 Q11Consider the differential equation , with…2026 Set 1 Q19A control system is shown in the Figure. Which option represents the correct transfer function of…2026 Set 1 Q40For the control system shown in the Figure, the transfer function of a plant,…2026 Set 1 Q41The state and output equations for a control system are:…2026 Set 1 Q59Consider the unity negative feedback control system shown in the Figure. The value of gain …