Table of Contents

Toggle**Important RGPV Question**

**EC-404 (Control System)**

**IV Sem, EC**

**UNIT-1 Introduction to Control System**

**Q.1** Define open loop and closed loop systems and describe effect of feedback on external disturbances.

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**Q.2** Write mathematical model of electrical and mechanical system shown in figure (i) and figure (ii).

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**Q.3** Construct signal flow graph for block diagram shown in figure (iii) and find out transfer function.

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**Q.4** Define terminologies used in control system and classify different types of control systems with suitable examples.

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**Q.5** For a unity feedback system having

Find error constants and error for ramp input with magnitude 5.

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**Q.6** What are effects of feedback? Classify different types of control systems with examples.

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**Q.7** Write mathematical model of mechanical system shown in figure (i) and write analogous electrical equations.

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**Q.8** Compare open loop and closed loop systems and find transfer function of block diagram shown in figure (ii) by reduction rules

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**Q.9** Determine transfer function of signal flow graph as shown in figure (iii) by using Mason’s gain formula.

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**Q.10** Explain the classification of control systems.

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**Q.11** Define transfer function and determine the transfer function of RLC series circuit if the voltage across the capacitor is a output variable and input is voltage source v(s).

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**Q.12** Discuss basis for framing the rules of block diagram reduction technique? What are drawbacks of the block diagram reduction technique?

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**Q.13** Find the transfer function for the block diagram shown as below.

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**Q.14** Find the transfer function C/R of the system for the given signal flow graph.

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**Q.15** What is closed loop system? Write its advantages and disadvantages with example.

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**Q.16** Β Give an introductory note on control system. Discuss about its terminology in brief.

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**Q.17** Write and explain any one practical example of control system which we can use in our day to day life.

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**Q.18** Write down the advantages and disadvantages of transfer function approach.

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**Q.19** What are the basic differences between open and closed loop control system and which one is preferred mostly and why?

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**UNIT β 2 Time Response Analysis**

**Q.1** Discuss time response of following:

i) 1stΒ order system ii) 2ndΒ order system

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**Q.2** Describe following in detail

i) Concept of stability of linear systems

ii) Routh Hurwitz stability criteria

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**Q.3** Describe standard test signals, steady state errors and error constants in detail.

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<strongclass=”has-text-color has-link-color” style=”color:#325ce8″>Q.4 Discuss effects of additions of poles and zeros to open loop and closed loop system.

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**Q.5** Apply Routh Hurwitz stability criteria to determine the stability and find the number of roots lying in the right half of the s-plane if characteristic equation of the two systems are given as follows:

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**Q.6** What is root locus? Describe steps involved in sketching root locus.

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**Q.7** Explain about various test signals used in control systems?

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**Q.8** The closed loop transfer function of a unity feedback control system is given by

C(s)/R(s) 20/(sΒ²+16s+25)

Determine:

i) Damping ratio

ii) Natural undammed resonance frequency

iii) Percentage peak overshoot

iv) Expression for error response

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**Q.9** Find stability of the system using Routh Hurwitz criterion s^{5}Β +2s^{4Β }+2s^{3}Β +4sΒ²+10s+20 = 0

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**Q.10** Sketch the root locus for the open loop transfer function of a unity feedback control system

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**Q.11** For a unity feedback control system the forward path gainΒ

then find the value of K for which the Root-locus crosses the imaginary axis and also find the value of angle of departure for complex roots.

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**Q.12** The limitation of root locus analysis is over come by Bode plot, this sentence is true or false, explain in details.

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**Q.13** Calculate the angle of asymptotes and the centroid for the system having.

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**Q.14** What are the necessary conditions to have all the roots of characteristics equation in the left half of s-plane?

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**Q.15** For the unity feedback system the open loop T.F.

Determine

a) Range of values of K

b) Marginal K

c) Frequency of sustained oscillations

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**Q.16** Open loop transfer function of a system is

Determine the gain ‘k’ so that the system has damping ratio of 0.5. For this value of ‘k’ also find rise time, peak time of the system for a unit step input.

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**Q.17** Explain system, control system, automatic control system, stability, response.

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**Q.18** Determine the phase margin of a system with the open loop transfer function.

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**UNIT β 3 Frequency Response AnalysisΒ **

**Q.1** Discuss following in brief

i) Polar plots Β Β Β Β Β ii) Bode plots

iii) Correlation between time and frequency response

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**Q.2** Write Nyquist stability criterion and draw the Nyquist plot 1 for G(s)H(s) = 1/ (s + 2) Also decide stability.

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**Q.3** State Nyquist stability criterion and describe procedure of assessment of relative stability using Nyquist plot.

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**Q.4** Establish correlation between time response and frequency response parameters.

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**Q.5** Define gain margin, phase margin and draw bode plot for the system having open loop transfer function.

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**Q.6** Write short notes on various frequency domain specifications.

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**Q.7** Derive expression for resonant peak and resonant frequency and hence establish correlation between time and frequency response.

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**Q.8** The open loop transfer function of a system is

Determine the value of K such that

i) Gain Margin=10dB

ii) Phase Margin = 50 degree

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**Q.9** Construct the Bode plot for the given system.

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**Q.10** The open loop transfer function of a system is

Determine phase margin.

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**Q.11** Write a short note on Mason’s Gain formula which is used for solving signal flow graph.

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**Q.12** The signal flow graph for a system is given below. Find the transfer function Y(s) / U(s)

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**Q.13** Β Explain the concept of Relative stability and Absolute stability.

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**Q.14 **Explain the term Gain margin. Write a short note on the advantages of Bode plot.

Draw the Nyquist plot forΒ

and make a comment on stability.

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**UNIT β 4 Approach to System Design**

Β **Q.1** Describe types of compensation techniques.

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**Q.2** Design compensators in time and frequency domain for following cases.

i) Phase lag ii) Phase lead lag

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**Q.3** Discuss types of compensation techniques and design of phase – lag and phase lead compensators.

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**Q.4 **Compare proportional, derivative, integral and composite controllers.

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**Q.5** What is lag-lead compensator? Under what conditions it is employed.

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**Q.6** Derive the relationship between ‘Ξ±’ and ‘Ξ¦m’ for a lead m compensator.

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**Q.7** Explain integral and derivative controller in detail.

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**Q.8** Write advantages and disadvantages of phase lead and phase lag compensator.

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**Q.9** Explain lead-lag compensator with diagram.

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**Q.10** Explain the relationship in between the state equation and transfer function.

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**Q.11** Explain the concept of Controllability and Observability in details.

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**Q.12** Write down the advantages of phase lead-lag compensation network.

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**Q.13 **Explain the different types of compensation network in details.

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**Q.14** Write notes on following:

i) Proportional and derivative controllers

ii) Integral controllers

iii) Composite controllers

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**Q.15** Write short notes on (any four):

a) Steady state response

b) Damping ratio

c) Root locus

d) Phase margin

e) Composite controllers

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**UNIT β 5 Noise**Β

**Q.1** Express the following transfer function in state space phase variable form.

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**Q.2** Evaluate the controllability and observability of the system with

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**Q.3** Discuss following in detail:

i) Transfer function decomposition

ii) State Transition Matrix (STM)

iii) Kalman’s Test

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**Q.4** Describe general state space representation and write state model for nthΒ order differential equation.

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**Q.5** Convert the following transfer function into state-space form:

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**Q.6** Write short note on following

i) Controllability and observability

ii) Transfer function decomposition

iii) Solution of state equation

iv) All-pass and minimum – phase systems

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**Q.7** Obtain the solution of state equation and list the properties of state transition matrix.

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**Q.8** Test the given system for Observability using Kalman’s test

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**Q.9** Find the controllability and observability of the system with the transfer function

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**Q.10** Define the following:

i) State vector

ii) State space

iii) State equations

iv) State variable representation

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**Q.11** What are the advantages of state space approach over transfer function as well as graphical approach for the analysis of control system? Explain with suitable example.

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**— Best of Luck for Exam —**