. CS/B.Tech/ECE(O)/ODD/SEM-S/EC-503/2019-20 ‘otras Doty ‘cicaoar honr MAULANA ABUL KALAM AZAD UNIVERSITY OF TECHNOLOGY, WEST BENGAL Paper Code : EC-503 PUID: 05054 (To be mentioned in the main answer script} CONTROL SYSTEM Time Allotted : 3 Hours Full Marks : 70 The figures in the margin indicate full marks. Candidates are required to give their answers in their own _ words as far as practicable, GROUP-A ( Multiple Choice Type Questions ) "1. Choose. the correct alternatives for any ten of the following : 10x1=10 i) If the root locus lies only on the negative, real axis then the time response is a) overdamped b) underdamped c) _ oscillatory: d) sustained oscillations. * *-5403/5(0). . [Tarn over https://www.makaut.comCS/B.Tech/ECE(0)/ODD/SEM-5/EC-503/2019-20 ii) iii) v) The steady state error is determined as the difference between ‘the reference input, and the system output at a) t=t b): t= infinity c) t=Time constant d) t=0. Rk The transfer function is Brier aer ay" The break point will lie between a) O0&-1 b) -1&~2 ) 28-3 d) beyond -3. The terms in the first column of Routh's array of a characteristic equation are 6, 9; 2, 4, -3. Then number of roots of characteristic equation in the right half of s-plane is equal to a) O b) 3 od 4 a 1. Given that the transfer function G(s) is —_X s?(1+sT) The type and order of the system are a) 2&3 b) 3&2 co) 3&3 qd) 2&2. %# #-5403/5(0) 2 https://www.makaut.comCS/B.Tech/ECE(0}/ODD/SEM-5/EC-803/2019-20 vi) The characteristic equation of a second order system is s? + 6s + 25> 0. The system is a) underdamped b) overdamped c) undamped @) critically damped. vii) A second order control system with § = 0 is always a) marginally stable b) stable c) unstable d) cannot be said. viii) A system has."4 poles and one zero.. Its high frequency. asymptote in its magnitude plot has a slope of . a) -100dB/decade b) 100 dB/decade c) -60 dB/decade d) 60 dB/decade. ix) The origin for: the investigation of closed-loop stability in relation to Nyquist criterion is a) -l+jo b). 1-70 c) ot jlo: ad) O-f1. : x) The frequency at which the phase curve of a Bode plot crosses -180° line is called “ a) natural frequency : . b) phase crossover frequency 7 c) gain crossover frequency . d) corner frequency. * #-5403/5(O) 3 8 [ Turn over https://www.makaut.comCS/B.Tech/ECE(0)/ODD/SEM-5/EC-503/2019-20 xi) -20 dB/decade is equivalent with a) - 40 dB/octave b) -8 dB/octave c) - 18 dB/octave d) -6 dB/octave: xii) The slope, of asymptotic Bode plot at low . frequencies for a type 3 transfer. function is a) -30 dB/decade b) -60 dB/decade c) - 20 dB/decade ad) - 40 dB/decade. GROUP - B ( Short Answer Type Questions } Answer any three of the following. © 3x 5=15 2. Find the equivalent force-yoltage analogy circuit of the following mechanical translational system. 5 ben ln K(S+a) 3. A unity feedback control system G(S)= {S +B)? is to be designed to meet the following Specifications. Steady state error for a unit step input is 0.1. Damping ratio & = 0.5, natural frequency of oscillation #, = J10. Find the values of K, a and B. 5 *#-5403/5(0) 4 https://www.makaut.comCS/B.Tech /ECE(O)/ODD/SEM-5/EC-503/2019-20 4. The characteristic equation of a feedback system is 1 +4s* +16s? +165+48=0. Check whether the system is oscillatory. If so, determine the frequency of oscillation using Routh-Hurwitz criteria. - 5 5, The.open loop transfer function of a feedback system is otsynts) = ROS? ae . : (s)H(s)=——— .. Comment on stability using Nyquist plot: 5 *6. What are the properties of state transition matrix? = 5 : GROUP - C { Long Answer Type Questions } Answer any three of the following. 3 x 15 = 45 7. a) The open loop transfer function of a unity feedback control system is given by G(s)= —7——~ > s(s? +s+i)(s+4) Applying Routh-Hurwitz criterion, discuss the stability of close loop system as a function of K. Determine the value of K ‘Which will cause sustained oscillation in the closed loop system. What is the corresponding oscillation frequency ? b) The close loop [ve feedback) system with forward path transfer function G(s) = 5S ses6)" and feedback path transfer function “H (s) = 0.2 with given unit step input. Determine the damping ratio (, Maximum over shoot (Mp), Rise time (t; ). 8+7 # #-5403/5(0) 5 [ Turn over https://www.makaut.comCS/B.Tech/ECE(O)/ODD/SEM-5/EC-503/2019-20 . 8. a) Sketch the Root locus for the open loop transfer function of a unity feedback control system given below : K G(s)H(s)= ‘ ‘s(s+4)(s? +45 +20) Show all relevant steps b) What is the ‘Analogous system' ? Explain the ‘Force-current analogy’. 12+1+2 9. Sketch. the asymptotic Bode plot for the transfer 2(s+0.25 function given G(s)H(s)=“"——"_ From the s?(s+1)(s+0.5) Bode plots determine i) P.C.F ii) G.C.F iii) PM. iv) GM (All have usual meaning) for above transfer functions © and mention about the stability condition. * . 10. a) Given the open loop transfer function : aces an where K = 1. Draw the complete Nyquist plot and determine the stability of close loop system. "BJ . For the Bode plot shown in the figure below, find the transfer function. 1045 “%s g-5403/5(0) 6 https://www.makaut.com11. a} b) The open loop transfer function of a unity feedback ¢) CS/B.Tech/ECE(O)/ODD/SEM-5/EC-503/2019-20 Consider characteristic equations of the system given below. How many roots. of characteristic equation are in the right half, left half and on jw axis ? Find the stability condition using R-H criteria. s® +55 4854 +689 +205? +85+16=0 te ge 7 K _ control system is given by Gsl= ayer ols) i) State the corner frequencies ii) Determine the gain K for gain: crossover frequency of 5 red/second. How can you determine the stability condition from Bode plot using gain margin (GM) and phase margin (PM). Show the different conditions of stability. S+54+5 hetps://www.makaut.com Whatsapp @ 9300930012 Send your old paper & get 10/- waa qt tee ss ste 10 eas ore, Paytm or Google Pay & https://www.makaut.com