Control systems miscellaneous

Control systems miscellaneous

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Control Systems

Control systems miscellaneous
  1. The open-loop transfer function of a unity negative feed back control system is given by
    G(s) =
    K(s + 2)
    (s + 1)(s - 7)

    the stability of the open-loop and closed-loop configuration of the system are respectively—








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    Since there is a pole in right half plane. Hence the open loop system is unstable.
    For unity feedback closed-loop system, the C.E. is
    K (s + 2) + (s + 1) (s – 7) = 0
    or s2 + s (K – 6) + (2K – 7) = 0
    s2 1 2K-7
    s1 K-6 0
    s0 2K-7
    K – 6 > 0 for stable system, since for value K > 6 all the elements in the first column of R.H. array are positive.

    Correct Option: B

    Since there is a pole in right half plane. Hence the open loop system is unstable.
    For unity feedback closed-loop system, the C.E. is
    K (s + 2) + (s + 1) (s – 7) = 0
    or s2 + s (K – 6) + (2K – 7) = 0
    s2 1 2K-7
    s1 K-6 0
    s0 2K-7
    K – 6 > 0 for stable system, since for value K > 6 all the elements in the first column of R.H. array are positive.

  1. For a second order system, damping ratio (ξ) is 0 < ξ <1, then the roots of the characteristic polynomial are—








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    Refer synopsis.

    Correct Option: C

    Refer synopsis.

  1. Which one of the following statements are true of a type 1 system having unit gain in the forward path and a unity feedback?
    1. Positional error constant Kp is equal to infinity
    2. Acceleration error constant Ka is equal to zero
    3. Steady-state error ess to a unit step displacement input is equal to one. Select the correct answer using the codes given below








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    Refer synopsis

    Correct Option: B

    Refer synopsis

  1. GA (jω), GB (jω) and GC (jω) are three transfer function whose phase variations are shown in the given figure. The magnitude variation with respect to frequency is the same for both GA (jω) and GC (jω), but their phase variation is as indicated by the curves labelled A and C in the given figure. The transfer function GB (jω) is such that
    φC (jω) = φA (jω) + φB (jω)
    GA, GB and GC are respectively—










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    Refer synopsis.

    Correct Option: B

    Refer synopsis.

  1. The pole-zero configuration of a phase-lead compensator is given by—








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    In phase-lead compensator zero is nearer to the pole.
    Hence alternative (A) is the correct choice.

    Correct Option: A

    In phase-lead compensator zero is nearer to the pole.
    Hence alternative (A) is the correct choice.