7.(a) Explain how exact Bode plot is obtained from asymptotic plot with figure. (b)The open loop transfer function of a unity feed back system is G(s) = 50K/s(s +10)(s +5)(s +1) i)Gain margin and phase margin ii.The value of steady state error coe cient for a gain of 10 db and the value which will make the closed loop system marginally stable. 8. (a) State & explain Nyquist stability criteria. (b) Check stability of system by Nyquist Criteria G(s) =10/s2+(1+0:2s)(1+0:5s 8. (a)Explain about the Polar Plots. (b)The open loop transfer function of a unity feed back control system is given by G(s)H(s)=K(s+5)(s+40) . Discuss the stability of a closed loop system as a 3 s (s+200)(s+1000) function of k. Determine values of K which will cause sustained oscillations in the closed loop system. What are the frequencies of oscillations? Use Nyquist approach. 2.(a) Explain the term frequency response analysis. (b) Sketch the Bode Plot for the Transfer function G(s) =Ke 0:5s/ s(2+s)(1+0:3s) and deter-mine the system gain `K for the gain crossover frequency !0 to be 5 rad/sec. 3.(a) Draw & explain polar plots for type-0, type-1 & type-2 systems. (b) Write a note on relation between root loci & Nyquist plots. 5.a) Explain clearly the steps involved in the construction of Bode plots of a system with loop transfer function consisting of i.An open loop gain K ii.One pole at the origin 5.a) Explain why it is important to conduct frequency domain analysis of linear control systems. b) Sketch the Bode Magnitude plot for the transfer function Ks2 G(s) = . (1+0.2s)(1+0.02s) Hence find ‘K’ such that gain cross over frequency is 5 r/s. [6+10] 6.a) Distinguish between polar plots & Nyquist plots. b)Discuss the effect of adding poles & zeros to G(s)H(s) on the shape of Nyquist plots iii.One quadratic factor b)Given G(s) = ((ss +−55)) . Determine the phase angle at 0, 5 & 1 frequencies. 6.a) Explain Nyquist stability criterion. b)With the help of Nyquist plot assess the stability of a system G(s) = 3 . What happens to stability if the numerator of the function is s(s +1)(s +2) changed from 3to 30? 6.a) Explain frequency domain specifications. b)Determine gain margin and phase margin of a system, whose transfer function is given by G(s)= 3000 s(s +10)(s +100) . 5. Sketch the Bode plots for a system G(s) = s(s2+16s+100) Hence determine the stability of the system. 5.(a) What are error graphs in relation to Bode plots? Explain their usage in brief. (b)Sketch the Bode plots for the system 25 G(s) = s(1+s)(1+0.1s) Hence find gain cross over frequency & phase cross over frequency. [4+12] 6. (a) Distinguish between polar plots & Nyquist plots. (b) Discuss the effect of adding poles & zeros to G(s)H(s) on the shape of Nyquist plots Ks(1+s)(1+2s) by Nyquist Criterion. (b) In addition to providing absolute stability the Nyquist Criterion also gives information on the relative stability. Elaborate.
Posted on: Wed, 30 Oct 2013 07:43:38 +0000
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