Course Overview
DNT 354 - CONTROL PRINCIPLE
Date: 10th July 2008
Prepared by: Megat Syahirul Amin bin Megat Ali
Email: megatsyahirul@unimap.edu.my
COURSE SYNOPSIS

Provides a background of control principles in
various engineering applications. Basic
mathematical tools such as Laplace transform,
transfer function, block diagram, signal flow graph,
mathematical modeling of dynamic systems, time
response analysis, stability of linear system, root
locus and frequency domain analysis are utilized.
COURSE OUTCOMES (CO)

CO1


CO2


Ability to obtain mathematical models for such mechanical, electrical
and electromechanical systems.
CO3


Ability to apply various mathematical principles (from calculus and linear
algebra) to solve control system problems.
Ability to derive equivalent differential equation, transfer function and
state space model for a given system.
CO4

The ability to perform system’s time and frequency-domain analysis with
response to test inputs. Analysis includes the determination of the
system stability.
COURSE EVALUATION
Assignments
:
:
:
:
50%
25%
15%
10%
Total Mark
:
100%

Final Examination

Lab Assessment

Mid-Semester Test

LIST OF REFERENCES

Textbook
i.

Nise N.S. (2004). Control System Engineering (4th Ed), John
Wiley & Sons.
References
ii.
iii.
Ogata K. (2002). Modern Control Engineering (4th Ed), Prentice
Hall.
Dorf R.C., Bishop R.H. (2001). Modern Control Systems (9th Ed),
Prentice Hall.
ACADEMIC STAFF MEMBERS

Lecturer
 En. Megat Syahirul Amin bin Megat Ali
B.B.Eng. (Malaya), M.Sc. (Surrey)

Teaching Engineer (PLV)
 Pn. Faridah binti Hassan
B.Eng. (UTP)
TEACHING PLAN
Week
Course Content
1-2
Introduction to Control Systems
3-4
The Basics of Control Theory
5-6
Mathematical Model of Systems
7-9
System Stability
10-11
Time-Domain Analysis
12-13
The Root Locus Method
14
Frequency Response Method
15
Controller
LAB SESSIONS
Lab
Title
1
Introduction to MatLab Simulink
2
Open-loop System Characteristics
3
Closed-loop System Characteristics
4
Study of Time-Response for 1st Order
Systems
5
Study of Open-loop System Models
6
Study of Closed-loop System Models.
Introduction to Control System
DNT 354 - CONTROL PRINCIPLE
Date: 10th July 2008
Prepared by: Megat Syahirul Amin bin Megat Ali
Email: megatsyahirul@unimap.edu.my
CONTENTS
Basic Concepts
 Control System Examples
 Control System Design

BASIC CONCEPTS

System


Dynamic System



A collection of components which are coordinated together to
perform a function.
A system with a memory.
For example, the input value at time t will influence the output at
future instant.
A system interact with their environment through a controlled
boundary.
BASIC CONCEPTS

The interaction is defined in terms of variables.
i.
ii.
iii.
System input
System output
Environmental disturbances
SYSTEM VARIABLES




The system’s boundary depends upon the defined objective
function of the system.
The system’s function is expressed in terms of measured
output variables.
The system’s operation is manipulated through control input
variables.
The system’s operation is also affected in an uncontrolled
manner through disturbance input variables.
CONTROL SYSTEM



Control is the process of causing a system variable to conform
to some desired value.
Manual control
Automatic control (involving machines only).
A control system is an interconnection of components forming a
system configuration that will provide a desired system
response.
Input
Signal
Control
System
Energy
Source
Output
Signal
MANUAL VS AUTOMATIC CONTROL


Control is a process of causing a system variable such as
temperature or position to conform to some desired value or
trajectory, called reference value or trajectory.
For example, driving a car implies controlling the vehicle to
follow the desired path to arrive safely at a planned destination.
i.
If you are driving the car yourself, you are performing manual control of
the car.
ii.
If you use design a machine, or use a computer to do it, then you have
built an automatic control system.
RESPONSE CHARACTERISTICS

Transient response:


Steady-state response:


Gradual change of output from initial to the desired condition
Approximation to the desired response
For example, consider an elevator rising from ground to the 4th
floor.
BLOCK DIAGRAM


Component or process to be controlled can be represented by a
block diagram.
The input-output relationship represents the cause and effect of the
process.
Input

Process
Output
Control systems can be classified into two categories:
i.
Open-loop control system
ii.
Closed-loop feedback control system
CONTROL SYSTEM CLASSIFICATION

An open-loop control system utilizes an actuating device to control
the process directly without using feedback.
Desired Output
Response

Actuating
Device
Process
Output
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.
Desired
Output
Response
Comparison
Controller
Process
Measurement
Single Input Single Output (SISO) System
Output
CONTROL SYSTEM CLASSIFICATION
Missile Launcher System
Open-Loop Control System
CONTROL SYSTEM CLASSIFICATION
Missile Launcher System
Closed-Loop Feedback Control System
CONTROL SYSTEM CLASSIFICATION
Desired
Output
Response
Controller
Process
Measurement
Multi Input Multi Output (MIMO) System
Output
Variables
PURPOSE OF CONTROL SYSTEMS
i.
Power Amplification (Gain)

ii.
Remote Control

iii.
Robotic arm used to pick up radioactive materials
Convenience of Input Form

iv.
Positioning of a large radar antenna by low-power rotation of a
knob
Changing room temperature by thermostat position
Compensation for Disturbances

Controlling antenna position in the presence of large wind
disturbance torque
HISTORICAL DEVELOPMENTS
i.
Ancient Greece (1 to 300 BC)

ii.
Cornellis Drebbel (17th century)

iii.
Temperature control
James Watt (18th century)

iv.
Water float regulation, water clock, automatic oil lamp
Flyball governor
Late 19th to mid 20th century

Modern control theory
WATT’S FLYBALL GOVERNOR
HUMAN SYSTEM
The Vetruvian Man
HUMAN SYSTEM
i.
Pancreas

ii.
Regulates blood glucose level
Adrenaline

Automatically generated to increase the heart rate and oxygen in
times of flight
iii.
Eye
iv.
Follow moving object
Hand
 Pick up an object and place it at a predetermined location
v.
Temperature


Regulated temperature of 36°C to 37°C
TEMPERATURE CONTROL

Figure shows a schematic diagram of temperature control of an electric furnace.
The temperature in the electric furnace is measured by a thermometer, which is
analog device. The analog temperature is converted to a digital temperature by
an A/D converter. The digital temperature is fed to a controller through an
interface. This digital temperature is compared with the programmed input
temperature, and if there is any error , the controller sends out a signal to the
heater, through an interface, amplifier and relay to bring the furnace
temperature to a desired value.
TRANSPORTATION
Car and Driver





Objective: To control direction and speed of car
Outputs: Actual direction and speed of car
Control inputs: Road markings and speed signs
Disturbances: Road surface and grade, wind, obstacles
Possible subsystems: The car alone, power steering system,
breaking system
TRANSPORTATION

Functional block diagram:
Desired
course
of travel +
Error
-
Driver
Steering
Mechanism
Automobile
Measurement, visual and tactile

Time response:
Actual
course
of travel
TRANSPORTATION

Consider using a radar to measure distance and velocity to
autonomously maintain distance between vehicles.

Automotive: Engine regulation, active suspension, anti-lock breaking
system (ABS)
Steering of missiles, planes, aircraft and ships at sear.

PROCESS INDUSTRY

Control used to regulate level, pressure and pressure of refinery
vessel.
Coordinated
control system
for a boilergenerator.

For steel rolling mills, the position of rolls is controlled by the
thickness of the steel coming off the finishing line.
MANUFACTURING INDUSTRY

Consider a three-axis control system for inspecting individual
semiconducting wafers with a highly sensitive camera
HOMES
i.
CD Players

ii.
The position of the laser spot in relation to the microscopic pits
in a CD is controlled.
Air-Conditioning System

Uses thermostat and controls room temperature.
CONTROL SYSTEM COMPONENTS
i.
System, plant or process

ii.
Actuators

iii.
Converts the control signal to a power signal
Sensors

iv.
To be controlled
Provides measurement of the system output
Reference input

Represents the desired output
GENERAL CONTROL SYSTEM
Disturbance
Set-point
or
Reference
input +
Controlled
Signal
Error
-
+
Controller
Feedback Signal
Manipulated
Variable
Actuator
Sensor
+
+
+
Process
Actual
Output
CONTROL SYSTEM DESIGN PROCESS
1. Establish control goals
2. Identify the variables to control
3. Write the specifications for the variables
4. Establish the system configuration and identify the actuator
If the performance does not
meet specifications, then
iterate the configuration
and actuator
5. Obtain a model of the process, the actuator and the sensor
6. Describe a controller and select key parameters to be adjusted
7. Optimize the parameters and analyze the performance
If the performance meet the specifications, then finalize design
TURNTABLE SPEED CONTROL

Application: CD player, computer disk drive
Requirement: Constant speed of rotation
Open loop control system:

Block diagram representation:


TURNTABLE SPEED CONTROL

Closed-loop control system:

Block diagram representation:
DISK DRIVE READ SYSTEM


Goal of the system: Position the reader head in order to read
data stored on a track.
Variables to control: Position of the reader head
DISK DRIVE READ SYSTEM


Specification:
i.
Speed of disk: 1800 rpm to 7200 rpm
ii.
Distance head-disk: Less than 100nm
iii.
Position accuracy: 1 µm
iv.
Move the head from track ‘a’ to track ‘b’ within 50ms
System Configuration:
ASSIGNMENT 1
Describe the principle of operation for Watt’s
Flyball Governor. Include the relevant block
diagram and indicate the functional
components of the system.
 Your report should be no more than 2 pages
long.
 The report should be submitted on Tuesday
(15/7/2008) during the tutorial session.

FURTHER READING…

Chapter 1
i.
ii.
Nise N.S. (2004). Control System Engineering (4th Ed), John
Wiley & Sons.
Dorf R.C., Bishop R.H. (2001). Modern Control Systems (9th Ed),
Prentice Hall.
“The right half of the brain controls the left half of the body. This
means that only left handed people are in their right mind…”
THE END…