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Sunday, 10 February 2013

Automatic control systems-Model question paper for B.E/B.Tech


1(a) Explain the two types of electrical analogies for the mechanical system. (4 Marks)
(b) What are the domain quantities which characterize a transient response? Derive an expression for percentage overshoot of a second order system. (8 Marks)
(c) Define delay time, rise time and peak time. (3 Marks)
(d) A thermometer has a time constant of 15.33 sec. It is quickly taken from a temperature 00C to a water bath having a temperature 1000C. What temperature will be indicated after 600C? (5 Marks)
2(a) State how type and order of a control system is determined? (6 Marks)
(b) Write notes on dynamic error coefficient and positional error coefficient. (6 Marks)
(c) Define static error constant. (4 Marks)
(d) Find the dynamic error coefficients of the unity feedback system whose forward path transfer function G(s) = 10/s(s+1). (4 Marks)
3(a) What is a polar plot? Write the procedure to sketch the polar plot. (6 Matrks)
(b) What is a Bode plot? Mention its advantages. (6 Marks)
(c) Define phase margin and gain margin. (4 Marks)
(d) Open loop transfer function of unity feedback control system is G(s)= (as+1)/s2. Determine the value of ‘a’ if the phase angle is 450.  (4 Marks)
4(a) State Routh-Hunwitz criterion. Mention its advantages and limitations. (8 Marks)
(b) What is root locus? Write a note on angle and magnitude condition of root locus. (4 Marks)
(c) State Lyapunov stability theorem. (4 marks)
(d) Draw the Nyquist plot for unit feedback control system, with open loop transfer function G(s) = K(1-s)/(s+1)  (4 Marks)
5(a) Write the procedure for phase lead compensation. (5 Marks)
(b) Draw the Bode plot for phase lag network. (5 Marks)
(c) What is compensation? Discuss various types of compensations. (6 Marks)
(d) Write short note on phase portraits. (4 Marks)
6(a)Define controllability and observability. (6 marks)
(b) Write a short note on limitations of state variable approach. (4 Marks)
(c) What is a tachogenerator? Mention some applications. (6 Marks)
(d) Obtain the inverse Laplace transform of the function F(s)=5e-s/(s+1) (4 Marks)
7(a) With a suitable diagram, show the elements and working of industrial automatic controller. (8 Marks)
(b) Write short note on derivative and integral control action. (6Marks)
(c) Write notes on PD,PI and PID control actions. (6 Marks)
8(a) Compare ac servomotors with dc servomotors. (8 Marks)
(b) Explain the principle of operation of synchro error detector. (6 Marks)
(c) a unity feedback system is characterized by an open loop transfer function G(s) = K/s(s+10). Determine the gain K so that the system will have a damping ratio of 0.5. For this value of K, determine setting time, peak overshoot and peak time for a unit step input. (6 Marks)