1. EE2253 CONTROL SYSTEM PRESENTED BY S.S.KARTHIKA, AP/EEE

2. Objective
A control system consisting of interconnected components is designed to achieve a desired purpose.
Modern control engineering practice includes the use of control design strategies for improving manufacturing processes, the efficiency of energy use, advanced automobile control, including rapid transit, among others.

3. Introduction
System – An interconnection of elements and devices for a desired purpose.
Control System – An interconnection of components forming a system configuration that will provide a desired response.
Process – The device, plant, or system under control. The input and output relationship represents the cause-and-effect relationship of the process.

4. Introduction Open-Loop Control Systems
utilize a controller or control actuator to obtain the desired response.
Closed-Loop Control Systems utilizes feedback to compare the actual output to the desired output response.

5. History

6. History
18th Century James Watt’s centrifugal governor for the speed control of a steam engine.
1920s Minorsky worked on automatic controllers for steering ships.
1930s Nyquist developed a method for analyzing the stability of controlled systems
1940s Frequency response methods made it possible to design linear closed-loop control systems
1950s Root-locus method due to Evans was fully developed
1960s State space methods, optimal control, adaptive control and
1980s Learning controls are begun to investigated and developed.
Present and on-going research fields. Recent application of modern control theory includes such non-engineering systems such as biological, biomedical, economic and socio-economic systems

7. The Future of Control Systems

8. Control System Design

9. UNIT I SYSTEMS AND THEIR REPRESENTATION
Basic elements in control systems
Open and closed loop systems
Electrical analogy of mechanical and thermal systems
Transfer function
Synchros – AC and DC servomotors
Block diagram reduction techniques
Signal flow graphs

10. UNIT II TIME RESPONSE Time response Time domain specifications
Types of test input – I and II order system response
Error coefficients
Generalized error series
Steady state error
P, PI, PID modes of feedback control

11. UNIT III FREQUENCY RESPONSE
Bode plot
Polar plot
Determination of closed loop response from open loop response
Correlation between frequency domain and time domain specifications

12. UNIT IV STABILITY OF CONTROL SYSTEM
Characteristics equation
Location of roots in S plane for stability
Routh Hurwitz criterion
Root locus construction
Effect of pole, zero addition
Gain margin and phase margin
Nyquist stability criterion.

13. UNIT V COMPENSATOR DESIGN
Performance criteria
Lag, lead and lag-lead networks
Compensator design using bode plots

14.   TEXT BOOKS
I.J. Nagrath and M. Gopal, ‘Control Systems Engineering’, New Age International Publishers, 2003.
2. Benjamin C. Kuo, Automatic Control systems, Pearson Education, New Delhi, 2003.

15. REFERENCES
K. Ogata, ‘Modern Control Engineering’, 4th edition, PHI, New Delhi, 2002.
2. Norman S. Nise, Control Systems Engineering, 4th Edition, John Wiley, New Delhi, 2007.
3. Samarajit Ghosh, Control systems, Pearson Education, New Delhi, 2004
4. M. Gopal, ‘Control Systems, Principles and Design’, Tata McGraw Hill, New Delhi, 2002.