Control Engineering — Winter 2018

Draw a generalized closed loop feedback system with its components.

Define transfer function. List important characteristics of transfer function.

Explain Force-Voltage and Force-Current analogy.

Define:

Control variable

Manipulated Variable

Process

Simplify the block diagram shown in figure-1.

In a liquid-level system assume that the outflow rate Qm3/sec through the out flow valve is related to the head Hm by Q = K√H = 0.01√H . Assume that when the inflow rate Qis 0.015 m3/sec the head stays i constant. At t = 0 the inflow valve is closed and so there is no inflow for t ≥0. Find the time necessary to empty the tank to half the original head. The capacity Cof the tank is 2 m2.

Simplify the block diagram shown in figure-2. Obtain the transfer function relating C(s) and R(s).

Explain the ramp input mathematically and graphically.

k(1 + 2s) For the following system:G(s) = Find the value of k to s(1 + s)(1 + 0.4s)2 limit the steady state error to 10% for input t.

Draw the signal flow graph for the following setoff algebraic equation: y = ay − gy ; y = ey + cy ; y = by − dy . Hence find the gain.

Discuss the effect of time constant on first order system response for unit step input.

Give four points difference between Block diagram method and Signal Flow Graph method.

Find the time response of a second order system for Unit step Response.

Enlist limitations of Routh’s stability criterion.

1 Prove that steady state error for Step input is gives as E = , K = ss p 1+ Kp error constant

Using Routh criterion, discuss about the stability for the system having characteristics equation is given as 3s7 +9s6 + 6s5+ 4s4 + 7s3 + 8s2+ 2s + = 0

Write the draw backs of hydraulic system.

Plot the root locus for a unity feedback system whose forward transfer 10(s + 1) function is G(s) = s(s − 3)1

k(s + 13) Aunity feedback control system has G(s) = Using Routh’s s(s + 3)(s+7) criterion calculate the range of k for which the system is

Stable

Write three rules for drawing Signal flow graph.

With the help of neat diagrams, explain how the direction control valves are classified.

Draw the schematic diagram of Hydraulic PID controller. Explain its working and derive its transfer function.

Explain FRL unit.

Write the comparison between a Pneumatic system and Hydraulic system.

Draw the schematic diagram of Pneumatic PI controller. Explain its working and derive its transfer function. Figure-1 Figure-2