1. Control Engineering Principles
EMT 364/4
Control Engineering Principles

2. Lecturer Dr. Neoh Siew Chin (Coordinator)
Dr. Mohamad Halim Bin Abd. Wahid
Mr STEVEN A/L TANISELASS

3. Related Topics Introduction to Control Systems
Mathematical Models of Control Systems
State-Variable Models of Control Systems
State Transition Matrix & Design
Feedback Control Systems
Time-Domain Analysis
Transient response
Stability of Linear Feedback Systems
Root Locus Method
Frequency Response Method
Stability in Frequency Domain
Design of Feedback Control Systems
Controller Design
Digital Control Systems

4. Course Evaluation Examination : 70% Course work : 30% Final Exam : 50%
Mid Term Exam : 20%
Course work : 30%
Laboratory (4 labs) : 15%
Assignment : 15 %

5. Course Outcomes
CO1: Ability to apply and evaluate the mathematical model for electrical/electronic and mechanical systems.
CO2: Ability to evaluate system’s time-domain analysis with response to test inputs. Analysis includes the determination of the system stability.
CO3: Ability to evaluate system’s frequency-domain analysis with response to test inputs. Analysis includes the determination of the system stability.
CO4: Ability to design and evaluate P, PI, PD, PID, lead, lag controllers and digital control systems.

6. Text Book:
Modern Control Systems 12th ed., Richard C.Dorf, Robert H.Bishop, 2011.
References:
Control Systems Engineering 5th ed., Norman S.Nise, John Wiley & Sons, 2008.
Automatic Control System 8th ed., Kuo B.C., Prentice Hall, 1995.
Modern Control Engineering, Ogata K., Prentice Hall, 1999.

7. Introduction to Control Systems
Chapter 1
Introduction to Control Systems

8. Basic Concepts System Dynamic 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.

9. 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.
Control System
Output Signal
Input Signal
Energy Source

10. 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.
If you are driving the car yourself, you are performing manual control of the car.
If you use a designed machine, or use a computer to do it, then you have built an automatic control system.

11. 1.3 What is control? 1.4 Open-loop system
Objectives
Model
Analysis
Design
1.4 Open-loop system
controller
plant +
input
output
disturbance
Disturbance is unwanted signal that may sway the output
Controller is a subsystem that is used to ensure the
output signal follows the input signal

12. 1.5 Closed-loop system
controller
plant +
input
output
disturbance
error -
A closed-loop control system uses a measurement of the output and feedback of this signal to compare it with the desired output
Open-loop : Toaster, mechanical systems consisting pf a mass, spring and damper
with a constant force positioning the mass.
Closed-loop : A person steering an automobile (assuming his or her eyes are open) by
Looking at the auto's location on the road and making the appropriate adjustments.
Examples

13. Figure 1.1 Block diagram of control system- open-loop system
Example of an open-loop system
motor
rheostat
amplifier
Turn-table
amplifier
motor
Turn-table
Actual speed
Required speed
Figure 1.1 Block diagram of control system- open-loop system

14. Figure 1.1 Block diagram of control system- closed-loop system
Example of closed-loop system
motor
tachometer
differential amplifier
rheostat
Turn-table
amplifier
motor
Turn-table
tachometer
Required speed
Actual speed
Figure 1.1 Block diagram of control system- closed-loop system

15. 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 Device
Process
Output
Desired Output Response
Desired Output Response
Measurement
Output
Controller
Process
Comparison
Single Input Single Output (SISO) System

16. Control System Classification
Missile Launcher System
Open-Loop Control System

17. Control System Classification
Missile Launcher System
Closed-Loop Feedback Control System

18. Control System Classification
Desired Output Response
Measurement
Output Variables
Controller
Process
Multi Input Multi Output (MIMO) System

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

20. 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.

21. 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

22. Transportation Functional block diagram: Time response:
Measurement, visual and tactile
Steering Mechanism
Automobile
Driver
Desired course of travel
Actual course of travel
Error + -

23. 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.

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

25. Manufacturing Industry
Consider a three-axis control system for inspecting individual semiconducting wafers with a highly sensitive camera

26. Homes CD Players Air-Conditioning System
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.

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

28. General Control System
Sensor
Actuator
Process
Controller +
Set-point or Reference input
Actual Output
Error
Controlled Signal
Disturbance
Manipulated Variable
Feedback Signal -

29. 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
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
If the performance does not meet specifications, then iterate the configuration and actuator

30. Turntable Speed Control
Application: CD player, computer disk drive
Requirement: Constant speed of rotation
Open loop control system:
Block diagram representation:

31. Turntable Speed Control
Closed-loop control system:
Block diagram representation:

32. 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

33. Disk Drive Read System Specification:
Speed of disk: 1800 rpm to 7200 rpm
Distance head-disk: Less than 100nm
Position accuracy: 1 µm
Move the head from track ‘a’ to track ‘b’ within 50ms
System Configuration:

34. Foto 1.12: Sistem kawalan proses untuk tujuan pengajaran di makmal.

35. 1.7 Servo control

36. 1.6 Process control

37. 1.9 Analysis Transient state Steady state Stability
a state whereby the system response after a perturbation
before the response approach to a steady state
Steady state
a state whereby the system response becomes steady after a
transient state
Stability
The condition of the steady state. If the response converges to
a finite value, it is said to be in a stable condition. If the
response diverges, it is known to be unstable.

38. Response Characteristics
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.

39. Analysis and Design Objectives
Transient Response
In the case of elevator, slow transient response makes passengers impatient.
Excessive response makes passenger uncomfortable and could also cause permanent physical/ structural damage.
Steady-State Response
This response resembles the input and is usually refers to the response remains after transients have decayed to zero.
This response refers to the accuracy
E.g. the elevator stop near the fourth floor, head of disk stop at the correct track
Steady-state error is analyzed for corrective action

40. Analysis and Design Objectives (Cont’)
Stability
Nature response is dependent only on the system, not the input
Forced response is dependent on input
For a desirable control system, natural response must eventually approach zero, leaving only the forced response
When natural response grow much greater than forced response, the system is no longer controlled and instability arise.
Instability could lead to destruction of physical device
Other Considerations
E.g. hardware selection, specification, choice of sensor, financial consideration, robustness.
System parameters changed dynamically and affect the performance of the system. The sensitivity of systems toward parameter changes is less.