CONTROL SYSTEM (NEE-503)
B.Tech | Semester V | Section-wise Important Questions & Notes
SECTION A – Short Answer (2 × 10 = 20 Marks)
This section focuses on basic theory, definitions, and small numericals. Answers should be brief but clear.
Important Questions
Major types of control systems with examples
Definition of P, PI, and PID controllers
Stability test of a system using characteristic equation
Derivation of transfer function from a given network
Polar plot of a simple transfer function and its properties
Open loop vs Closed loop control system (block diagram + explanation)
Expression of error E(s) for a unity feedback system
Definition of signal flow graph
Importance of negative feedback
Purpose of block diagram reduction rules
Key Notes
Open loop → simple but less accurate
Closed loop → accurate, stable, less sensitive to disturbances
PID controllers improve steady-state and transient response
Negative feedback improves stability and bandwidth
SECTION B – Analytical & Numerical (Attempt Any 3, 10 × 3 = 30)
This section is very important and often repeated in exams.
Important Questions
Find system type, error constants, and steady-state error for step, ramp, and parabolic inputs
Check controllability and observability using state-space matrices
Draw root locus for a unity feedback system
Short notes on:
Centroid
Breakaway points Steady-state error
Determine system type and error for a given unity feedback transfer function
Key Notes
System type depends on number of poles at origin Error constants: Kp, Kv, Ka
Root locus shows closed-loop pole movement
Controllability & observability depend on matrix rank
SECTION C – State Space Concepts (10 Marks)
Important Questions
Convert a differential equation into state-space representation
Define state and state variables Advantages of state-space analysis
Key Notes
State variables represent system memory State-space method works well for MIMO systems
Time-domain based approach
