eee 325 - lecture 01 introduction.pdf

8/19/2019 EEE 325 - Lecture 01 Introduction.pdf

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EEE 325 Control Systems

Lecture 01

-

Introduction

Muhammad Rizwan Azam

COMSATS Institute of Information Technology (CIIT)

Islamabad, Pakistan.


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Instructor Details

(Muhammad Rizwan Azam)• Educational Background

o PHD .. (Control Systems)

o MS (Control Systems)

o BSc Eng. (Electronics)

• Contact Details

o Room # 316, EE Block

o [email protected]


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Marks Distribution (Theory)

Sessional -1 10%

Sessional 2 15%

Quizzes (4) 15%

Assignments (4) 10%

Terminal Exam 50%

Note:Quizzes will be announced as well un announced.

Expect a quiz after submission of assignment.

Copied assignments and assignments submitted after the due

date will be marked zero.


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Topics

to be Covered

1. Introduction and classification of everyday control systems .(1 week)

2. The Laplace transform ,Inverse Laplace transform and solution to

differential equations.(1 week)

3. Mathematical modeling of electrical, mechanical and electromechanical

systems. (1 weeks)4. Block Diagram reduction techniques and Signal Flow graphs-Mason gain

formula.(1 week)

5. Time response of first order and second order systems.(1 week)

6. Effects of poles and zeroes on system response. (1 week)

7. Steady state error analysis and design. (1 week)

8. Routh-Hurwitz criterion for stability. (1 week)

9. Introduction to design using root locus method and Analysis.(1 week)


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Topics

to be Covered

10. Frequency domain analysis, Bode analysis, Technique of drawing Bode

plot. Phase margin, Gain margins and Design using Bode plots .(2 weeks)

11. Introduction to Nyquist analysis, complex analysis, Encirclement and

enclosure of poles and zeros, Principle of Argument. Stability analysis, Gain

margins and phase margins.(2 weeks)12. State space, Introduction to state space analysis of systems presented by

Transfer function. Controllability and Observability. Solution of Time

invariant state equations.(2 weeks)


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Course Material

• Textbook

Ogata K. (2002). Modern Control Engineering (5thEd), Prentice Hall.

•References Books1. Norman S. Nise, Benjamin Cummings, “Control

Systems Engineering”, 6th edition

2. Richard C. Dorf and Robert H. Bishop, “Modern

Control Systems”, Addison Wesley, 12th Edition


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Control System

• System, A collection of components which are coordinated

together to perform a function.

• Control is the process of causing a system variable to conform

to some desired value.

• A control system provides an output or response for a given

input or stimulus


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Systems

• Definition of Controls revolve around Systems.

• Identify systems in this room

o Air-conditioners

o Bracket fans

o Amplifiers

o Humans (Combination of sub-systems)

o Power Supply of a PC

o Multimedia

o Mobile Phones


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Some other Systems

• Aircrafts, Missiles

• Planes and ships at sea

• Automotive

•Space Shuttles

• Nuclear Reactors

• Industrial Processes

• Robots

• Human Systems


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Control System Classification•

An open-loop control system utilizes an actuating device to control the process directly without using feedback.

• A closed-loop feedback control system uses a measurement of the

output and feedback of the output signal to compare it with the desired

output or reference.

Actuating

DeviceProcess Output

Desired Output

Response

Desired

OutputResponse

Measurement

OutputController ProcessComparison

Single Input Single Output (SISO) System


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1. Open Loop Control System

• In an open loop control system, the input to the plant doesnot in any way depend on the current and past values of the

output of the plant.

• Relatively simple and consequently low cost with

generally good reliability.


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Examples of Open Loop

• Motor

• Heater /boiler

• Cooking Oven

• Dish Washer

• Washing Machine

• Toaster

• Water valve system in a pool or sink

• Sprinkler System


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Example 1 – DC Motor Turntable

Open-Loop Control System


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Example 2: Missile Launcher System

Open-Loop Control System


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Disadvantage of Open Loop

• Rely totally in calibration, and cannot effectively deal

with exogenous disturbances.

• They can not effectively deal with changes in the

process.• Can not deal with uncertainty.

• Can not stabilize an unstable system.

• Often in accurate since there is no correction for error.


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2. Closed Loop Control System

• Closed loop control system make the control system robust

to uncertainty and disturbances.

• It senses the output of the system and adjust the control input

using feedback rules, which are based on how the system

output deviates from the system behaves.

• The feedback helps compensate for the differences, if the

system behaves slightly differently than the model.

• Relatively accurate in matching the actual to the required

values.

• More complex, and more expensive, grater chance of

breakdown due to number of components.


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Closed Loop

• A closed-loop control system is one in which the control action

is somehow dependent on the output.


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Basic Elements of a Closed Loop

Control system

• Comparison element

• Control element

•Correction Element

• Process element

• Measurement element


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Example of Closed Loop

• Guided missiles

• Automatic gain control in radio receivers

• Temperature Control

• Satellite tracking antenna

• Automatic Car Cruise System


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Example 1 – DC Motor Turntable

Closed-Loop Feedback Control System


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Missile Launcher System

Closed-Loop Feedback Control System


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Control System Classification

Desired

Output

Response

Measurement

Output

VariablesController Process

Multi Input Multi Output (MIMO) System


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Purpose of Control Systems

i. Power Amplification (Gain)

o Positioning of a large radar antenna by low-powerrotation of a knob

ii. Remote Control

o Robotic arm used to pick up radioactive materials

iii. Convenience of Input Form

o Changing room temperature by thermostat position

iv. Compensation for Disturbanceso Controlling antenna position in the presence of large

wind disturbance torque


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Control System Componentsi. System, plant or process

o To be controlled

ii. Actuators

o Converts the control signal to a power signal

iii. Sensors

o Provides measurement of the system output

iv. Reference input

o Represents the desired output


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General Control System

Sensor

Actuator ProcessController ++

Set-point

or

Reference

input

Actual

Output

Error

Controlled

Signal

Disturbance

Manipulated

Variable

Feedback Signal

+

-

++


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Further Reading…• Chapter 1

i. Nise N.S. (2004). Control System Engineering (4th Ed),John Wiley & Sons.

ii. Dorf R.C., Bishop R.H. (2001). Modern Control

Systems (9th Ed), Prentice Hall.

eee 325 - lecture 01 introduction.pdf

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