Control Engineering, Control system Engineering,Feedback

1. PE-3032 Introduction to Control Systems
Engineering
Professor Charlton S. Inao
Control System Engineering/Mechatronics
Defence Engineering University College
2012 Bishoftu, Ethiopia

2.  Introduction to control systems, open and closed loop control,
control building blocks and transfer functions, Laplace
transformation, mathematical model of physical systems,
servomechanism, characteristics, and performance of
feedback control systems, transient response analysis of zeros,
first and second order systems stability analysis in feedback
controls, Root locus and frequency response method,
Nyquist/Bode diagrams, lead-lag PID compensators.
Introduction to digital control, state space analysis and control
systems hardware considerations.

3. At the end of the whole course, the student is expected to develop the following:
 CO1
 Ability to apply various mathematical principles (from calculus and linear
algebra) to solve control system problems.
 CO2
 Ability to obtain mathematical models for such mechanical, electrical
and electromechanical systems.
 CO3
 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.

4.  Mid-Term : 30%
 Final Examination : 50%
 Lab Assessment : 10%
 Assignments : 10%
Total Mark : 100%

5.  Textbook
Ogata K. (2002). Modern Control Engineering (3rd Ed), Prentice Hall.
 References
1. W. Bolton , Control Engineering ,3rd Edition, 2005, Longman
Publication
2. Benjamin C. Kuo and Farid Golnaraghi, “Automatic Control Systems”,
John Wiley, 2003
3. Norman S. Nise, Benjamin Cummings, “Control Systems Engineering”,
4th edition, 2004
4. Richard C. Dorf and Robert H. Bishop, “Modern Control Systems”,
Addison Wesley, 7th Edition, 1995

6.  Lecturer
Prof. Charlton S. Inao
BS. Mech .Eng (Philippines, M.Eng (Germany),
AdvancedProduct Design and Development Study major in Automation
–
- Germany
Advanced Plant Process and Control and Mechatronics - Japan
Advanced Research and Experimental Design, Six Sigma and Taguchi
Method Studies, Laser Printer Control and Design
- IBM- Lexmark, Kentucky,
USA

7. Week Course Content
1-2 Introduction to Control Systems
3-4 The Basics of Control Theory
5-6 Mathematical Model of Systems
7-8 System Response and Stability
10-12 The Root Locus Method
13-14 Frequency Response Method
15 PID Controllers
16-17 State Space Analysis and Digital Control

8.  Basic Concepts
 Classification of systems and signals
 Classification of control systems
 Control System Application examples
 Exercises

9.  System
 A collection of components which are coordinated together to
perform a function.
 Dynamic System
 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.

10.  The interaction is defined in terms of variables.
i. System input
ii. System output
iii. Environmental disturbances

11.  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.

12.  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.
Control
System
Output
Signal
Input
Signal
Energy
Source

13.  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.

14.  Transient response:
 Gradual change of output from initial to the desired condition
 Steady-state response:
 Approximation to the desired response
 For example, consider an elevator rising from ground to the 4th
floor.

15.  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

16.  An open-loop control system utilizes an actuating device to control
the process directly without using feedback.
Actuating
Device Desired Output Process Output
Response
 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 Output
Measurement
Single Input Single Output (SISO) System

17.  In an open loop control system, the input
to the plant does not 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.

18. An open-loop control system is one in which the control action
is independent of the output.

19.  Motor
 low pass filter
 Inertia supported between two bearings
 Heater /boiler
 Cooking Oven
 Water valve system in a pool or sink

21.  The biggest problem with the open loop control
systems is that they rely totally in calibration, and
ca not 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.

22.  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.

23. Feedback is that property of a closed-loop
system which permits the output (or some
other controlled variable) to be compared
with the input to the system (or an input
to some other internally situated
component or subsystem) so that the
appropriate control action may be formed
as some function of the output and input

24.  Comparison element
 Control element
 Correction Element
 Process element
 Measurement element

25. A closed-loop control system is one in which the
control action is somehow dependent on the output.

29.  Guided missiles
 automatic gain control in radio receivers
 satellite tracking antenna
 Etc.

32. Missile Launcher System
Open-Loop Control System

33. Missile Launcher System
Closed-Loop Feedback Control System

34. Desired
Output
Response
Measurement
Output
Variables
Controller Process
Multi Input Multi Output (MIMO) System

35. i. Power Amplification (Gain)
 Positioning of a large radar antenna by low-power rotation of a
knob
i. Remote Control
 Robotic arm used to pick up radioactive materials
i. Convenience of Input Form
 Changing room temperature by thermostat position
iv. Compensation for Disturbances
 Controlling antenna position in the presence of large wind
disturbance torque

36. i. Ancient Greece (1 to 300 BC)
 Water float regulation, water clock, automatic oil lamp
i. Cornellis Drebbel (17th century)
 Temperature control
i. James Watt (18th century)
 Flyball governor
i. Late 19th to mid 20th century
 Modern control theory

38. The Vetruvian Man

39. i. Pancreas
 Regulates blood glucose level
i. Adrenaline
 Automatically generated to increase the heart rate and oxygen in
times of flight
i. Eye
 Follow moving object
i. Hand
 Pick up an object and place it at a predetermined location
i. Temperature
 Regulated temperature of 36°C to 37°C

40.  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.

41. 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

42.  Functional block diagram:
 Time response:
Steering
Mechanism Automobile DDrriviveerr Automobile
Steering
Mechanism
Measurement, Measurement, v visisuuaal la anndd t atacctitliele
Desired
course
of travel
Actual
course
+ Error of travel
-

43.  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.

44.  Control used to regulate level, pressure and pressure of refinery
vessel.
Coordinated
control system
for a boiler-generator.
 For steel rolling mills, the position of rolls is controlled by the
thickness of the steel coming off the finishing line.

45.  Consider a three-axis control system for inspecting individual
semiconducting wafers with a highly sensitive camera

46. i. CD Players
 The position of the laser spot in relation to the microscopic pits
in a CD is controlled.
i. Air-Conditioning System
 Uses thermostat and controls room temperature.

47. i. System, plant or process
 To be controlled
i. Actuators
 Converts the control signal to a power signal
i. Sensors
 Provides measurement of the system output
i. Reference input
 Represents the desired output

48. +
+ CCoonntrtroolllelerr AAcctutuaatotorr + PPrroocceessss
SSeennssoorr
Set-point
or
Reference
input
Actual
Output
Error
Controlled
Signal
Disturbance
Manipulated
Variable
Feedback Signal
+
-
+

49. If the performance does
not meet specifications,
then iterate the
configuration and
actuator

50.  Application: CD player, computer disk drive
 Requirement: Constant speed of rotation
 Open loop control system:
 Block diagram representation:

51.  Closed-loop control system:
 Block diagram representation:

52.  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

53.  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:

54. Control
System
Application
Examples

59. PROBLEM: Describe the block diagram of a person playing a video
game. Suppose that the input device is a joystick and the game is
being played on a desktop computer.

60. Consider the inverted pendulum shown in Figure
El. 13. Sketch the block diagram of a feedback
control.

62. Unmanned aerial vehicles (UAVs) are being
developed to operate in the air autonomously
for long periods of time By autonomous, we
mean that there is no interaction with human
ground controllers. Sketch a block diagram of
an autonomous UAV that is tasked for crop
monitoring using aerial photography.The UAV
must photograph and transmit the entire land
area by flying a pre-specified trajectory as
accurately as possible.

64. Future advanced commercial aircraft will be Enabled.
This will allow the aircraft to take advantage
of continuing improvements in computer power and
network growth. Aircraft can continuously communicate
their location, speed, and critical health parameters
to ground controllers, and gather and transmit
local meteorological data. Sketch a block diagram
showing how the meteorological data from multiple
aircraft can be transmitted to the ground, combined
using ground-based powerful networked computers
to create an accurate weather situational awareness,
and then transmitted back to the aircraft for optimal
routing.

66. Describe the block diagram of the speed control system of a
motorcycle with a human driver.

67. Modern automated highways are
being implemented around the
world. Consider two highway lanes
merging into a single lane. Describe
a feedback control System carried
on the automobile trailing the lead
automobile that ensures that the
vehicles merge with a prescribed
gap between the two vehicles.
Problem:

68. SOLUTION :

69.  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.