The GATE Grind

GATE Control Systems: Controllers and compensators – Previous Year Questions

3 GATE previous year questions on Controllers and compensators (Control Systems, Instrumentation Engineering) with answers and explanations, from every paper.

  1. GATE 2023 IN Q48 (2 marks, Numerical answer) – A standard negative-feedback system has G(s)=1/[(s-2)(s-3)] and PID controller C(s)=K P+K I/s+K Ds. The root locus of G(s)C(s) is shown. Given C(j)=2…
  2. GATE 2025 IN Q47 (2 marks, Multiple choice) – The shown closed-loop system has plant G(s)=1/s2 and lead compensator C(s). The desired dominant closed-loop poles are -1.5 j27/2. The phase lead…
  3. GATE 2025 IN Q50 (2 marks, Multiple select) – The feedback-system plant is P(s)=a/(s2-b2), with a>0 and b>0. Which controller types C(s) cannot stabilize this plant?