GATE Control Systems: Stability and frequency response – Previous Year Questions
13 GATE previous year questions on Stability and frequency response (Control Systems, Instrumentation Engineering) with answers and explanations, from every paper.
- GATE 2021 IN Q23 – Take clockwise Nyquist encirclements as positive and counterclockwise as negative. The number N of encirclements of (-1,0) for G(s)=3/(s-1) is .
- GATE 2021 IN Q39 – A unity negative-feedback system has plant G(s)=1/[(s+1)(s+3)] and PID controller C(s)=K(s+3-j)(s+3+j)/s, with scalar K. The closed loop is .
- GATE 2022 IN Q15 – A unity-gain negative-feedback control system has loop gain L(s)=6/[s(s-5)]. The closed-loop system is .
- GATE 2022 IN Q43 – The Nyquist plot of stable open-loop G(j) for 0< intersects the unit circle at P=-0.77-0.64j. Points on the plot are Q=14.40+0.00j and R=-0.21+0.00j.…
- GATE 2022 IN Q53 – A unity-gain feedback system has plant P(s)=0.001/[s(2s+1)(0.01s+1)] and lag compensator C(s)=(s+10)/(s+0.1). The asymptotic Bode magnitude slope of…
- GATE 2023 IN Q24 – The number of zeros of P(s)=s3+2s2+5s+80 in the right half-plane is .
- GATE 2023 IN Q25 – The number of times the Nyquist plot of G(s)H(s)=12(s-1)(s-2)(s+1)(s+2) encircles the origin is .
- GATE 2023 IN Q43 – Which transfer function matches the magnitude and phase plots shown?
- GATE 2023 IN Q50 – The phase margin of G(s)=2(1-s)/(1+s)2 is degrees (nearest integer).
- GATE 2024 IN Q18 – The sinusoidal transfer function corresponding to the polar plot shown, for T>0, is
- GATE 2024 IN Q55 – A unity-negative-feedback system has the open-loop pole-zero map shown; crosses mark poles. If s=j, >0, lies on its root locus, is (nearest integer).
- GATE 2025 IN Q28 – Consider the control-system block diagram in Figure (a). The loop transfer function G(s)H(s) has no poles on the j axis. The counterclockwise contour…
- GATE 2026 IN Q60 – The system G(s)=K/(s+1)4 has a gain margin of 20 dB. The value of K is . (Rounded off to two decimal places.)