LIST-I LIST-II A. Nyquist Criterion I. Polar Plots B. Bode Plot II. Rectangular Plots C. Phase Margin III. Amount of additional phase lag at the gain crossover frequency required to bring the system to the verge of instability D. Gain Margin IV. It is the reciprocal of the magnitude $|G(j\omega)|$ at the frequency at which the phase angle is $-180^\circ$.
Matching Control System Concepts
The question requires matching key concepts from control system stability analysis (LIST-I) with their corresponding definitions or representations (LIST-II).
Analysis of Matches
- A. Nyquist Criterion is directly associated with analyzing system stability using frequency response plots. The Nyquist plot itself is a type of I. Polar Plot.
- B. Bode Plot consists of two graphs, magnitude and phase, plotted against frequency, typically using logarithmic scales on II. Rectangular Plots (semi-log axes).
- C. Phase Margin quantifies stability by measuring how much additional phase lag is needed at the gain crossover frequency to destabilize the system. This matches the definition: III. Amount of additional phase lag at the gain crossover frequency required to bring the system to the verge of instability.
- D. Gain Margin quantifies stability concerning gain variations. It is defined based on the system's gain at the phase crossover frequency (where phase is $-180^\circ$). The definition provided is: IV. It is the reciprocal of the magnitude $|G(j\omega)|$ at the frequency at which the phase angle is $-180^\circ$.
Correct Matching
Based on the analysis:
- A matches with I
- B matches with II
- C matches with III
- D matches with IV
This corresponds to the pairing A-I, B-II, C-III, D-IV.
Important Questions from Basics of Control Systems
- Which of the following statement is not correct in respect of Transfer Function of linear Time Invariant System
A. In any open loop control system, the output is not compared with the reference input.
B. Traffic control by means of signals operated on a time basis is an example of closed loop control.
C. Closed loop control always implies the use of feedback control action in order to reduce system error.
D. Washing machine is an example of open loop system.
E. Stability is a major concern in open loop control system.
Choose the correct answer from the options given below:
Read the following statements about the transfer function of a system :
(a) The transfer function provides complete insight into the structure of the system.
(b) It offers a symbolic picture about the dynamic characteristics of the system.
(c) It does not give any insight into the structure of the system.
(d) If the transfer functions of individual components of the system are known, the overall characteristics of the system can be determined just by taking their product.
Which of the above statements are correct ?
The mass-spring-damper system shown in the following figure represents :
The error detector element in a control system gives
