Control System (EC-404) - Important Questions

Define what a control system is and explain its classification with suitable real-life examples.

For the given signal flow graph of a system, find the transfer function Y(s)/U(s) using Mason's gain formula.

Reduce the given block diagram to single-block form using block diagram reduction rules and find the overall transfer function.

Compare open-loop and closed-loop control systems with block diagrams, including advantages, disadvantages and advantages of feedback.

Determine the stability of the system and the number of right-half s-plane roots from the given characteristic equation using Routh-Hurwitz criterion.

For a unity feedback system with G(s)=K/[s(1+sT1)(1+sT2)], determine the range/value of K in terms of T1 and T2 for stability using Routh-Hurwitz criterion.

What is root locus? What are the steps/rules for sketching the root locus of a system?

The open-loop transfer function of a unity feedback system is given by G(s). Determine the steady-state error using error series for the given input r(t).

Using Nyquist criterion, determine the closed-loop stability for the given open-loop transfer function G(s)H(s).

State and explain the Nyquist stability criterion and describe assessment of relative stability using Nyquist plot, including gain margin and phase margin.

Draw the Bode plot for the given open-loop transfer function and determine the gain crossover frequency, phase crossover frequency, gain margin and phase margin.

Explain proportional (P), integral (I), derivative (D) and composite / PID controllers with examples.

What is compensation? Draw the phase-lead network / lead compensator, explain it and obtain its transfer function.

Design a compensating network for G(s)=K/[s(1+0.2s)(1+0.01s)] so that its phase margin is at least 40 degrees and the steady-state velocity error does not exceed 2%.

Explain/define the concepts of controllability and observability, their importance in modern control systems, with example.

For the given second-order state equation, test controllability and calculate the state transition matrix.