CONTROL SYSTEMS (18EE61)

CONTROL SYSTEMS

• Course Code-18EE61 
• CIE Marks-40
• Number of Lecture Hours/Week (L:T:P)-3:2:0 
• SEE Marks-60
• Credits-04 
• Exam Hours-03

Course Learning Objectives:

• · To define a control system
• · To explain the necessity of feedback and types of feedback control systems.
• · To introduce the concept of transfer function and its application the modeling of linear systems.
• · To demonstrate mathematical modeling of control systems.
• · To obtain transfer function of systems through block diagram manipulation and reduction
• · To use Mason’s gain formula for finding transfer function of a system
• · To discuss transient and steady state time response of a simple control system.
• · To discuss the stability of linear time invariant systems and Routh-Hurwitz criterion
• · To investigate the trajectories of the roots of the characteristic equation when a system parameter is varied.
• · To conduct the control system analysis in the frequency domain.
• · To discuss stability analysis using Bode plots.
• · To determine the controller or compensator configuration and parameter values relative to how it is
• connected to the controlled process given the design specifications.

 Module-1

Introduction to Control Systems: Introduction, classification of control systems.
Mathematical models of physical systems: Modelling of mechanical system elements, electrical
systems, Analogous systems, Transfer function, Single input single output systems, Procedure for
deriving transfer functions, servomotors, synchros, gear trains.

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Module-2

Block Diagram: Block diagram of a closed loop system, procedure for drawing block diagram and block diagram reduction to find transfer function. Signal Flow Graphs: Construction of signal flow graphs, basic properties of signal flow graph, signal flow graph algebra, construction of signal flow graph for control systems.

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Module-3

Time Domain Analysis: Standard test signals, time response of first order systems, time response of
second order systems, steady state errors and error constants, types of control systems.
Routh Stability Criterion: BIBO stability, Necessary conditions for stability, Routh stability criterion,
difficulties in formulation of Routh table, application of Routh stability criterion to linear feedback
systems, relative stability analysis.

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Module-4

Root locus Technique: Introduction, root locus concepts, construction of root loci, rules for the
construction of root locus. Frequency Response Analysis: Co-relation between time and frequency response – 2nd order systems only.
Bode Plots: Basic factors G(iw)/H(jw), General procedure for constructing bode plots, computation of
gain margin and phase margin.

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Module-5

Nyquist plot: Principle of argument, Nyquist stability criterion, assessment of relative stability using
Nyquist criterion.
Design of Control Systems: Introduction, Design with the PD Controller, Design with the PI Controller,
Design with the PID Controller, Design with Phase-Lead Controller, Design with Phase - Lag Controller, Design with Lead-Lag Controller.

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Course Outcomes: At the end of the course the student will be able to:

· Analyze and model electrical and mechanical system using analogous.
· Formulate transfer functions using block diagram and signal flow graphs.
· Analyze the stability of control system, ability to determine transient and steady state time response.
· Illustrate the performance of a given system in time and frequency domains, stability analysis using Root locus and Bode plots.
· Discuss stability analysis using Nyquist plots, Design controller and compensator for a given specification.

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Question paper pattern:

• · The question paper will have ten questions.
• · Each full question is for 20 marks.
• · There will be 2 full questions (with a maximum of three sub-questions in one full question) from each module.
• · Each full question with sub-questions will cover the contents under a module.
• · Students will have to answer 5 full questions, selecting one full question from each module.

Text Book

1 Control Systems Anand Kumar PHI 2ndEdition,2014

Reference Books

1 Automatic Control Systems Farid Golnaraghi, BenjaminC. Kuo Wiley 9 the Edition,2010
2 Control System Engineering NormanS. Nise Wiley 4 th Edition,2004
3 Modern Control Systems Richard C Dorfetal Pearson 11 th Edition,2008
4 Control Systems, Principles and Design M. Gopal McGawHill 4 th Edition,2012
5 Control Systems Engineering S. Salivahananet al Pearson 1 st Edition,2015