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Introduction to Automatic Control and
Intelligent Systems
Prof Kang Li
Email: [email protected]
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 Lecture objectives: Introduce the concept of control and intelligent systems in an
engineering context
Indicate the wide range of applications
Give brief historical background
 Teaching Method: 24 x 1 hour lectures + Tutorials
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 Textbooks:
1. Dorf, R C, Bishop, R H: Modern Control Systems. 10th Ed.
Addison-Wesley 2004
2. Franklin, G F, Powell, J D and Emami-Naeini, A: Feedback
Control of Dynamic Systems. 3rd Ed. Addison-Wesley
1994
3. Nise, N S: Control Systems Engineering. 3rd Ed. The
Benjamin/Cummings Publishing Company, Inc. 2000
4. Phillips, C L and Harbor, R D: Feedback Control Systems.
Prentice/Hall 1988
5. DiStefano III, J J, Stubberud, A R and Williams, I J:
Feedback and Control Systems. Shaum Pub. Co 1967
6. Cannon, R H: Dynamics of Physical Systems. McGraw-Hill
1967
7. Douce, J L: Introduction to the Mathematics of
Servomechanisms. EUP 1963
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
1
2-5
6-8
Module Content:
Introduction - 1st chapter of any textbook on Control
Modelling - Dorf ch 2, Canon chs 1,2
Mathematical tools - Laplace transforms, Transfer
functions, Block diagrams - Dorf ch 2
9-10 Characteristics of Feedback Systems - Dorf ch 4
11-12 Performance measures for Feedback Systems - Dorf
ch 5
13-16 Stability considerations - Hurwitz criterion, Nyquist
criterion - Douce ch4, Dorf chs 6,8,9
17-24 Introduction to intelligent systems and control
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1.1
Preliminaries
Module objectives, outline and textbooks as per
handout sheet.
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1.2
The Concept of Control
We are familiar with the concept of control from such areas
as quality control, financial control, production control,
stock control, command and control etc. These activities
have common features:- there is a system, an objective,
an input, freedom to take action, constraints and
disturbances. For example the ‘system’ from the
perspective of the manager of a chemical plant might be
the entire plant.
Disturbances
Market
fluctuations
Weather
Raw materials
Final product
System
Inputs
Outputs
Chemical plant
Energy
Waste
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For an engineer in the plant the ‘system’ may be one reaction
vessel:Ambient
temperature
steam
Heat exchanger and
chemical reactor
temperature
It is really this latter context in which our module is set. We
want to be able to understand, analyse, design and implement
control schemes for such engineering applications. However it
is worth noting that the concepts also apply in business,
commerce, medicine etc. Some of the most effective control
systems operate in our bodies eg temperature control, heart
rate, hand movements, walking etc.
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1.3
Range of Applications
semiconductor manufacture
eg Intel, NISRC
electrical power generation
eg PowerGen
chemical plant
eg Kevlar, DuPont
food processing
eg Dale Farm
water and sewage
eg DoE Water Executive
car manufacture
eg robots, machine tools at
Visteon (Ford Motor Company)
automobiles
eg electrical system, auto pilot, eg Mercedes
aircraft
eg autopilot, Bombardier Shorts
rocket launching
eg NASA
satellites
eg Global Positioning System
space exploration
eg Mars rover
domestic
eg heating, CD or video player etc
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1.4
Three Important Control Strategies
Open-loop, Feed-forward and Feedback or Closed-loop
Energy
Disturbances
Desired
output
Output
Controller
Process
(a) Open-loop strategy
Disturbances
Desired
output
Energy
Output
Controller
Process
(b) Feed-forward strategy
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Energy
Desired
output
Disturbances
Error
Output
Controller
+
Process
Measurement
(c) closed-loop strategy or feedback strategy
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1.5
Definitions
 An open-loop control system is one in which the
control action is independent of the output.
 A closed-loop control system is one in which the
control action is somehow dependent on the
output.
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1.6
Historical Background
 Watt’s fly-ball governor 1769
 Fantail windmill
 Bode, Nyquist etc on feedback amplifiers 1930s
 World war 2 1940s
 Space program1960s
 Automation and robots 1960
 Computers and microprocessors
 Intelligent systems, Neural networks
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Centrifugal governor
A centrifugal governor is a specific type of
governor that controls the speed of an engine by
regulating the amount of fuel admitted, so as to
maintain a near constant speed whatever the
load or fuel supply conditions. It uses the
principle of proportional control.
It is most obviously seen on steam engines
where it regulates the admission of steam into
the cylinder(s). It is also found on internal
combustion engines and variously fueled
turbines.
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It is connected to a throttle valve and to the prime
mover. The action of the governor is dependent on
centrifugal force. As the speed of the prime mover
increases, the central spindle of the governor
rotates at a faster rate and the two masses move
outwards, and this motion is translated by the
series of rods and arms to the throttle valve,
reducing its aperture. The rate of steam entering
the cylinder is thus reduced and the speed of the
prime mover falls. If the speed of the prime mover
falls, the reverse effect occurs and the throttle valve
opens further.
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 Fantail windmill
Fantail was mounted on the cap of the mill for turning the
mill automatically into the wind through gearing and a
rack round the top of the tower.
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