Anna University Coimbatore 2009 B.E Electrical and Electronics Engineering Control system - Question Paper

2. What is the drawback in P-controller?
The drawback in P-controller is that it develops a constant steady-state fault.
3. What is integral control action?
In integral control action, the control signal is proportional to integral of fault signal.
4. What is the advantage and disadvantage in integral controller?
The advantage in Integral controller is that it eliminates or decreases the steady-state fault. The disadvantage is that it can make a system unstable.
5. What is PI controller?
The PI controller is a device, which produces a control signal consisting of 2 terms-one proportional to fault signal and the other proportional to the integral of fault signal.
6. What is PD controller?
The PD controller is a device, which produces a control signal consisting of 2 terms-one proportional to fault signal and the other proportional to the derivative of fault signal.
7. What is PID controller?
The PID controller is a device which produces a control signal consisting of 3 terms-one proportional to fault signal, a different 1 proportional to integral of fault signal and the 3rd 1 proportional to derivative of fault signal.
8. What is time response?
The time response is the output of the closed loop system as a function of time. It is denoted by c(t). It is provided by inverse
Laplace of the product of input and transfer function of the system.
The closed loop transfer function, C(s)=G(s)_____R(s) l + G(s)H(s)
Response in s-domain, C(s)=_R (s) G(s)_1+G(s)H(s) Response in time domain, c(t) = L-1[C(s)] = L-1 _R (s) G(s)_1+G(s)H(s)
9. What is transient and steady state response?
The transient response is the response of the system when the input modifications from 1 state to a different. The response of the system as t _ _ is called steady-state response.
10. What is the importance of test signals?
The test signals can be easily generated in test laboratories and the characteristics of test signals resembles, the characteristics of true input signals. The test signals are used to predetermine the performance of the system. If the response of a system is satisfactory for a test signal, then the system will be suitable for practical applications.
11. Name the test signals used in control system:
The commonly used test input signals in control system are impulse, step, ramp, acceleration and sinusoidal signals.
12. describe Step signal:
The step signal is a signal whose value modifications from 0 to A and remains constant at A for t > 0. The mathematical representation of step signal is

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