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Roll Number: Branch: Group:THAPAR UNIVERSITY PATlALA

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERINGBE- ECE (VII Semester) ESE EC-030: Modem Control EngineeringDec 20)0Time: 03 Hours; MM: 45 Name of Faculty: Mr . Arun Chatterjee,. Mr. Sanjay Kumar.Note: (A) If required, make reasonable approximations & assumptions. Stale & j ustify such assumptions

& approximations.(B) Attempt all the questions il l serial number manner . Otherwise, IlO evaluation will be done.(C) No discussions with the Course Instructors will be entertained.(D) Use appropriate Grapb sheets only, wherever required.In digital computers, large disk-storage devices are widely used today . As the disk ist.spinning, the data head is moved to various positions. This movement must be made veryfast and very accurately. A simplified block diagram of the closed-loop head-positioncontrol system is given below . The mathematical model of the head is approximated by athird-order system and the particular controller applied is of the phase lead or lag type,depending on the parameter fJ. Determine: For fJ = 3, the range of values of K for which theclosed-loop system is stable .

(1)

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~ (8) pI> & , l1'Ov,v (,8)k (J5f-P'L (IS)-= : : ;&t 2) ~ t S ) (! + i)

Qt. The block diagram model of a position control system is as shown below.(2) (a) In the absence of derivative feedback (K, = 0), determine the damping ratio of thesystem for the amplifier gain KA 5. Also, find the steady state error to unit ramp (1 0);0input.

(b) Find suitable values of the parameters KA and Kt so that damping ratio of the system isincreas ed to 0.7 without affecting the steady state errol' as obtained in part (a) .

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Using the Masons Gain formula, obtain the overall transfer function whose signal flowt. graph is given below :3)(06)

1 c> tIi

Consider a unity feedback control system with the following feedforward transfer functionKQt.(4) ( o ~ )G(s) = -s:-S-=-2-+-4-s-+-8C-:-)Plot the root loci for the s stem?

Qt. Sketch the Bode plot for the following transfer functionS12(s + 3) ( o ~ )5) G(s) = -s.,...s""""2-+-1-'-6-s-+----'-2S-'-6--=The specification on a second-order unity feedback control system with closed-loop transfert. function6) CCs) wn 2 (01-)2Res) s 2 + 2(wns + wnare that the maximum overshoot must not exceed 30%. Find the corresponding limitingvalues of resonant eak (M,) and bandwidth (BW)?

-tloNOTE : The Evaluated Answer-sheets will be shown on06Dee' 2010. After this, no queries will beentertained. l ; y ~ : 5: co.pm-S;4-s'.pM L L ' . J L 2 . . J L ~ , )

S . / 6;30 ~ eLf) l-s, L6)N O - O N ~ ) wiLQ e.ptQ..l'",tn.I'r\ o . ~ . k r ' Jk c.1o u:Q. r-: J-jn"Q .-Jo:1A.

P.T.O.