Wednesday, January 9, 2008

LINEAR CONTROL SYSTEMS PAPER 4

DOWNLOAD ELECTRONICS ENGINEERING PREVIOUS YEARS QUESTION PAPERS B.TECH PTU

LINEAR CONTROL SYSTEM (B.Tech 4th Semester,2052)


NOTE:- This paper consist of Three Sections. Section A is compulsory. Do any Four questions from
Section B and any two questions from Section C

Section-A Marks : 20

1(a) Plant and Controller
(b) Servomechanics and regulating systems.
(c) Comtinuous and sampled data controlled systems.
(d) Advantages and disadvantages of transfer approach.
(e) Steady state error and error coefficients.
(f) Concept of absolute stability and relative stability.
(g) Error detectors and error sensors.
(h) Stability analysis ans sensitivity analysis.
(i) Loop T.F. and closed Loop T.F.
(j) Concept of Routh-Hurwitz criterion and Nyquist criterion.

Section-B Marks:5 Each

2. Define state variables and mention its importance in system modeling . Develop state variables modelling for a series RLC circuit with suitable input, output and state variables.
3. Enumerate time domain specifications of a control system. Obtain the rate feedback constant of a unity feedback system with a minor rate feedback loop shown in figure that improves the damping factor of the system to 0.800 with this value of damping factor, calculate the overshoot of response.

4. Define gain margin ang phase margin sketching Bode's Plots and Nyquist plots. Explain how is problem stability analysed in terms of these margins.
5. Define stady state errors and explain how are these minimised. Determine the position, velocity and accerelation error constants for the u.f.b. control system and open loop T.F., G(s) given by: G(s) = K/s(s2 + 4s + 20).
6. Enemurate and explain frequency response specifiations Explain relation between time and frequency response of a second order system.

Section-C Marks : 10 Each

7. Define stability of a linear system and explain how is Routh-Hurwitz criterion applicable to such systems. Explain limitations of this criterion. A u.f.b. control system is described by its open loop TF, G(s) = K/(s2 +4s)(s + 5). Obtain 'K' for which above system remains stable.
8. What do you mean by Root locus technique? Explain how will you sketch the root locus plot. The open loop T.F. of u.f.b. system is given by g(s) = k/s(s + 1)(s + 5) Sketch the root locus diagram and obtain 'k' for which the above system to remain critically stable.
9. Write short notes on the following:
(a) Applications of Magnetic amplifiers
(b) Various compensated networks and applications of Lag-compensation.

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