control syst test i

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4 th Semester – B.E. / B.Tech. First Internal Assessment Test – Jan/Feb 2015 Sub. Title : CONTROL SYSTEM ENGINEERING Date : 30-01-2015 Sub. Code : Branch : ECE Duration : 3 Hours Max. Marks: 100 Answer all questions Part A - (10 x 2 = 20) 1. Write the properties of signal flow graph. 2. Give the mathematical model of the given mass-spring-dashpot system in fig. 3. Compare open loop control system with closed loop control systems 4. How a control system is classified depending on the value of damping? 5. What are transient and steady state responses of a control system? 6. Write Masons Gain formula. 7. Why negative feedback is invariably preferred in closed loop system? 8. Write the analogous electrical elements in force current analogy for the elements of mechanical translational system. 9. What are time domain specifications? 10. What is the effect of PD controller on the system performance? Part B - (5 x 16 = 80Marks) 11. a) i)Reduce the block diagram to its canonical form and obtain C( s ) R ( s) (8M) .

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4th Semester B.E. / B.Tech.

First Internal Assessment Test Jan/Feb 2015Sub. Title: CONTROL SYSTEM ENGINEERINGDate : 30-01-2015Sub. Code:Branch : ECEDuration: 3 HoursMax. Marks: 100 Answer all questions

Part A - (10 x 2 = 20)1. Write the properties of signal flow graph.2. Give the mathematical model of the given mass-spring-dashpot system in fig. 3. Compare open loop control system with closed loop control systems4. How a control system is classified depending on the value of damping?5. What are transient and steady state responses of a control system?6. Write Masons Gain formula.7. Why negative feedback is invariably preferred in closed loop system?8. Write the analogous electrical elements in force current analogy for the elements of mechanical translational system.9. What are time domain specifications?10. What is the effect of PD controller on the system performance?Part B - (5 x 16 = 80Marks)11. a) i)Reduce the block diagram to its canonical form and obtain (8M) . ii) Determine the transfer function of the network given in figure (8M).

OR11.(b) (i) Draw the torque-voltage electrical analogous circuit for the following mechanical system shown.(8M)

(ii) Find the overall gain Y(S) / U(S) for the signal flow graph shown in fig (8M)

12.(a) Write the differential equation governing the mechanical translational systems and find the transfer function. Draw the force voltage and force current electrical analogies. (16)

OR(b) For the block diagram shown below, find the output C due to R and due to disturbance D. (16)

13.(a) The open loop transfer of a unity feedback system is given by, where K and T are positive constant. By what factor should the amplifier gain K be reduced, so that the peak overshoot of unit step response of the system is reduced from 75% to 25 %. (16)OR(b) i) A unity feedback system has the forward transfer function . When the input r (t) =1+6t. Determine the minimum value of K1 so that the steady state error is less than 0.1. (8) ii) The closed loop transfer function of a second order system is Find the damping ratio, natural frequency of oscillation, rise time, settling time& peak overshoot. (8)

14(a) . Derive the expressions for second order system for under damped case and when the input is unit step. (16)OR (b) (i) Certain measurements were conducted on a servo mechanism which shows the system response as c(t) =1+0.2 -60t +1.2e -10t when subjected to a unit step input. Find the expression for closed loop transfer function and .Obtain the undamped natural frequency and damping ratio (8)

(i) The system is described by the following equation. Find the response and maximum peak for the step input of 2.5 units. (8)

15.(a) Construct the equivalent Signal Flow Graph and obtain C/R using Mason's formula. (16) OR(b) A unity feedback system G(s)=10/s(s+1)(s+2).Find the steady state error when it is subjected to the i/p r(t)=1+2t+1.5t2 (16)