6.53
CONTROL SYSTEM
DMR40323
Muhammad Fairuz Bin Muhammad Nasir
BEng Aerospace (UPM)
MEng Mechanical Industry (UMP)
CHAPTER 1:
INTRODUCTION TO CONTROL SYSTEM

TOPICS
1.1 General
Terms of
Control
System
1.2 Element
of Control
System
1. 3 Control
System
Configuration
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1.4
Advantages of
Control
System

LEARNING OUTCOMES
Define the general
terms in control
system
Recognize the
elements of
control system
Describe the
differences of
open loop and
closed control
system
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At the end of this chapter, student should be able to:
List the
advantages of
control system
Describe some
examples of
control system

ENGINEERING AND
NON-ENGINEERING
FIELDS
Use : To achieve the increase of productivity and
improved performance of production system
Control Engineer : Responsible to plan and design an
entire automatic or process control system
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Electrical
Aeronautical
Chemical
Mechanical
Nuclear
Economics
Management
biomedical
Biological
others

CLASSIFICATION CONTROL SYSTEM
Nature Control System
Created by Almighty God
(human body immunization)
Automatic Control System
Created by human
(auto pilot flight operation, satellite system, space
shuttle, robotic system
Combination Between Nature and
Automatic Control System
(car driven by human)
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1.1 GENERAL TERMS OF CONTROL SYSTEM
Control System
A system that consist of subsystems and processes assembled for purposes of control the output
of process
Interconnection of components forming a system configuration that will provide a desired
response
Automatic Control System
A control system that is self regulating or self control without human intervention
Process Control System
An automatic regulating system in which the output is a variable such as temperature, pressure,
flow, liquid level or ph is called process control system
Feedback control system
A system that maintains a prescribed relationship between the output and input by comparing
them and using the difference
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Disturbance
a signal that tends to adversely affect the value of the output of the system

Controlled Variable
The quantity or condition that is measured and controlled. Normally controlled variable is the
output of the system
Manipulated Variable
The quantity or condition that is varied by the controller so as affect the value of the controlled variable
Plants
A piece of equipment/set of a machine functioning together, which perform a particular operation
Process
Progressively continuously operation that consists of a series of controlled action to achieve a
particular result
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Systems
A combination of components that act together and perform a certain objective
Servo Systems
Is a feedback control system in which the output is some mechanical position, velocity or
acceleration

1.2 ELEMENTS OF CONTROL SYSTEM
OBJECTIVES OF CONTROL SYSTEM
INPUT / STIMULUS / ACTUATING SIGNAL
CONTROL SYSTEM COMPONENTS
PROCESS
OUTPUT OF CONTROL SYSTEM
output / controlled variable
THE PURPOSE
• to get the output of the system as per desired input
• to control the outputs in some prescribed manner by the inputs
through the elements of the control system.
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1.3 CONTROL SYSTEM CONFIGURATION
OPEN LOOP
▪ Control system in which the control or regulating action is independent of the output where output has no effect on the control action.
▪ A system operates without feedback and directly generates the output in response to an input signal.
▪ The output of open loop control system is not compared with the reference input
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Process / Plant
Input
reference / set point
Output
controlled variable
Controller
Function to drives
the process or
plant.

OPEN LOOP
ADVANTAGES
• Simple construction
• Easy maintenance
• No stability problem
• Convenient when output is hard
to measured & not economy to
produced
DISADVANTAGES
• The output may different from
desired input if there is calibration
error causes by disturbance/changes
• Re-calibration is required from time
to time to maintain the required
output
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CONTROL SYSTEM CONFIGURATION
CLOSED LOOP
• A control system in which the
control action is influence by the
output where the actual output is
feedback to the desired input or
reference for comparison.
• A system that uses a
measurement of the output and
compares it with desired input
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Process /
Plant
Desired Input Actual Output
Controller
Output
Transducer /
Sensor
measurement device to measure
the controlled variable/ actual
output response
feedback
path
Summing
Junction
Error / actuating signal
Make corrective action and drive
the process to desired output

CLOSED LOOP
ADVANTAGES
• greater accuracy
• less sensitive to noise and
disturbances
• convenient control of transient
response and steady state error
DISADVANTAGES
• more complex and expensive
• stability problem
• higher cost
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THE DIFFERENCE
between closed loop control system and open loop control system
Open Loop Control System
• Does not have the feedback path
• Low accuracy
• Sensitive to noise, disturbances
and changes in the environment
• The system cannot compensate
and correct disturbance
• Simple and inexpensive
Closed Control System
• Have the feedback path
• Greater accuracy
• Less sensitive to noise, disturbances
and changes in the environment
• The system can compare the output
response with the input and make a
correction if there is any difference
• Complex and expensive
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VS

ADVANTAGES OF CONTROL SYSTEM
❑ Power Amplification – Control system can produce the needed
power for amplification called as power gain such as huge radar
antenna is positioned by low-power rotation of small knob
❑ Remote Control – Control system useful in remote or dangerous
location such as remote-controlled robot used to handle radioactive
material
❑ Convenience of Input Form – Control system used to provide
convenience by changing the form of input
❑ Compensation For Disturbances – Control System Able To
Compensate Disturbances In Order To Achieve The Correct Output

EXAMPLES OF
CONTROL SYSTEM
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CAR SPEED CONTROL SYSTEM
LIQUID LEVEL CONTROL SYSTEM
ROBOTIC ARM CONTROL SYSTEM
TEMPERATURE CONTROL SYSTEM

THE DESIGN PROCESS
TRANSFORM
REQUIREMENTS INTO
A PHYSICAL SYSTEM
DRAW A
FUNCTIONAL BLOCK
DIAGRAM
TRANSFORM THE PHYSICAL
SYSTEM INTO A SCHEMATIC
STEP 1
CHAPTER 1, 3
ANALYZE, DESIGN AND TEST
TO SEE THAT REQUIREMENTS
AND SPECIFICATIONS ARE MET
IF MULTIPLE BLOCKS, REDUCE
THE BLOCK DIAGRAM TO A
SINGLE BLOCK OR CLOSED
LOOP SYSTEM
USE THE SCHEMATIC TO
OBTAIN A BLOCK DIAGRAM,
SIGNAL FLOW DIAGRAM, OR
STATE SPACE
REPRESENTATION
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STEP 2
CHAPTER 1, 2
STEP 3
CHAPTER 1,3
STEP 4 CHAPTER 2
STEP 5 CHAPTER 2
STEP 6 CHAPTER 4,5,6,7

CAR SPEED CONTROL SYSTEM
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The car speed is controlled by pressed or
depressed the accelerator pedal, which is,
controls the fuel quantity to car engine
Desired Speed
Transducer
Plant
Actual Speed
Controller
(human driver)
(car engine)
(speedometer)
Set point Output
Actuator
(pedal)

IDENTIFIED
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Process/plant :
Controller :
Sensor/ Transducer:
Input reference :
Controlled Variable :
Manipulated Variable :
▪ The controller(driver) measures the car speed through speedometer.
▪ When the speed of the car exceed than desire speed, the driver will depress the
accelerator pedal to slow down the car.
▪ The car speed control is classified as closed loop or feedback control system.
Car engine
Driver
Speedometer
Desired Speed ( Exp : 110 km/h)
Actual speed
Fuel quantity

LIQUID LEVEL CONTROL SYSTEM
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The objective of this control system is
to maintain/control the liquid level in
the tank at desire value
Plant
Desired Level Actual Level
Controller
Transducer
(liquid tank)
(level sensor)
Set point Output
Actuator
(control valve)
error signal

IDENTIFIED
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Process/plant :
Sensor/ Transducer:
Input reference :
Controlled Variable :
Manipulated Variable :
Liquid Tank
Lever sensor
Desired level ( Exp : 5 m high)
Liquid level
Liquid flow
▪ The fluid level in the tank can be controlled by changing /manipulating the water flow into the
tank
▪ The differences between input reference & output signal will generate an error signal.
▪ If the actual level is lower than desired level, the controller will open the control valve to allow a
higher flow rate into the tank.
▪ If the actual level is higher than desired level, the control valve turn close to reduce the inflow
rate

ROBOTIC ARM CONTROL SYSTEM
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The industrial robot task is pick, move and
place parts from one station to another
station by pattern recognition process
Plant
Desired pattern Work Station
Controller
Transducer
(robotic arm)
(vision sensor)
Set point Output
Actuator
(computerized)

IDENTIFIED
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Process/plant :
Sensor/ Transducer:
Input reference :
Controlled Variable :
Manipulated Variable :
▪ The vision sensor act as a feedback element.
▪ It recognizes the pattern and determines the presence and orientation of the part or object.
▪ The vision signal then is feedback into computerized controller to actuate the robotic arm.
▪ Bar code reading is one of an example of the pattern recognition process.
▪ Then the robot will pick up the part and place it at the work station for work process.
Robotic arm
Vision sensor
Desired pattern
Pattern/bar code
Part Recognition /line/
barcode

TEMPERATURE CONTROL SYSTEM
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Plant
Furnace
Desired
Temperature Heat
Controller
Transducer
(Thermocouple)
Set point Output
Actuator
(computerized)

IDENTIFIED
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Process/plant :
Sensor/ Transducer:
Input reference :
Controlled Variable :
Manipulated Variable :
▪ Thermometer(sensor) to measure the temperature in electric furnace.
▪ The analog signal from thermometer than converted into digital signal by A/D converter and fed into
digital controller in computer through interface module.
▪ The actual temperature then compare with input temperature.
▪ If any error occurs, the digital controller sends a signal to the heater through an interface module,
amplifier, and relay to bring the temperature of electric furnace to desired value.
Furnace
Thermocouple
Desired Temperature
Temperature
Current / Heating element

THANK YOU
Muhammad Fairuz Bin Muhammad
Nasir
019 6600 013
fairuz.nasir@kuantan.kktm.edu.my
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