Download GTU BE/B.Tech 2019 Summer 4th Sem Old 141701 Control Theory Question Paper

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Subject Code: 141701

GUJARAT TECHNOLOGICAL UNIVERSITY

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SEMESTER-IV(OLD) - EXAMINATION - SUMMER 2019

Subject Name: Control Theory

Date: 20/05/2019

Time: 02:30 PM TO 05:00 PM

Total Marks: 70

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Instructions:

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

1. (a) Explain Open Loop and Closed Loop Control System with suitable Example. Also list their advantages and disadvantages. (07)

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2. (a) Explain Force-Current (F-I) Analogy. (07)
3. (a) Obtain differential equations of mechanical system shown in figure 2 (a) and draw the electrical network using Force-Voltage (F-V) Analogy. (07)
   (b) Using Block Diagram reduction technique, find closed loop transfer function of system shown in figure 2 (b) (07)
   OR
   (b) Define Following: (1) Block Diagram (2) Summing Point (3) Take off Point (4) Feedback Path (5) Touching Path (6) Input node (7) Self loop (07)

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4. (a) For Signal Flow Graph shown in figure 3 (a), Find the transfer function using Mason’s gain formula. (07)
   (b) Derive the equation of steady state error for closed loop control system. (07)
   OR
   (b) Write short note on effect of input (step, ramp and parabolic) on steady state error. (07)
5. (a) A unity feedback system has G(s) = 10(S+6) / ((s+2)(s+4)). Determine: (1) Type of system (i1) All error coefficients (iii) Error when step input of magnitude 2 is given to the system. (07)
   

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   (b) Explain following terms of transient response with suitable diagram. (1) Delay Time (2) Rise Time (3) Peak-Time (4) Peak Overshoot (5) Settling Time (07)
6. (a) Using Routh Criterion, determine the stability of the system whose characteristic equation is S⁶+ 3S⁵+5S⁴+ 9S³+ 8S²+ 6S +4=0. Determine the number of roots lying in the right half of S-plane. (07)
   OR
   (b) Using Routh Criterion, find range of k for the closed loop control system to be stable for H(S)=1 and G(S) = k / (S²(S+2)(S+5)) (07)
7. (a) Sketch the root locus of a unity feedback control system with G(S) = k / (S(S+1)(S+3)) and determine the value of k for marginal stability. (07)
   

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   (b) Sketch Bode plot of a unity feedback control system having open loop transfer function as given below. Determine gain margin and phase margin. G(S) = 5 / (S(1+0.1S)(1+0.05S)) (07)
8. (a) Draw the polar plot of the given system G(S)H(S) = 1 / (S(S+2)) (07)
   (b) Write short note on effect of derivative control action on control system. (07)
9. (a) Write short note on standard test signals used in control system. (07)

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