ME527 Mechatronics (1)

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ME527 Mechatronics (1)
Dr. Mohamed Elghamry Last update Sep 2008
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Contents
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Definition
synergetic integration
The of with and (in the design,
manufacture and operation of industrial products
and processes)
physical systems
information technology
complex-decision making
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Definition
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Examples

• Air-bag system

• Washing machine

• Computer hard disk

• Smart suspension truck

• Intelligent cruise control

• CNC and industrial robots

• Auto-focus and auto-exposure camera

• Machine monitoring and diagnostic system

• Film processing and photo printing machines

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Diesel Engine Condition Monitoring And
Diagnostic system
Objective
Design and develop an intelligent monitoring and
diagnostic system capable of on-line measuring
and analyzing the critical engine parameters to
diagnose engine failures to secure high level of
engine performance
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Diesel Engine Condition Monitoring And
Diagnostic system
Signal processing
State identification
Controller
Decision making
Symptom analysis
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Diesel Engine Condition Monitoring And
Diagnostic system
System components

• Engine

• Sensing elements

• Signal conditioning circuits

• Analogue to digital converter

• PC with interpretation and analysis software

• Feed back control mechanism

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Diesel Engine Condition Monitoring And
Diagnostic system
Engine
4-stroke DE 2 cylinder 111 mm bore 13 BHp Water
cooled coupled with electrical generator
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Diesel Engine Condition Monitoring And
Diagnostic system
Sensing elements
Temperature
Resistive Temperature Detectors RTD
Pressure
Piezoelectric pressure sensor
Speed
Proximity sensor
Gas emission
Exhaust gas analyzer
Break power
Power consumption analogue sensor
Fuel consumption
Level float sensor
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Diesel Engine Condition Monitoring And
Diagnostic system
Signal conditioning circuits

• Resistance to voltage conversion

• Frequency filter

• Amplification and attenuation

• Level shift

• Signal filtering

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Diesel Engine Condition Monitoring And
Diagnostic system
Analogue to digital converter

• Speed

• Resolution

• Number of channels

• Data record size

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Diesel Engine Condition Monitoring And
Diagnostic system
analysis software
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Diesel Engine Condition Monitoring And
Diagnostic system
Feed back control mechanism

• Speed control

• Cooling water temperature control

• High load shut-off

• Regulated automatic loading

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Self-learned projects

• Dancing fountain

• 3-dimensional CNC machine design

• Film processing and photo printing machines

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Stand alone Microcontrollers

• PIC Microcontroller

• AMTEL / AVR

• FPGA

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Mechatronic components
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Sensors
1- Temperature sensors
2- Force and pressure sensors
3- Position and speed sensors
PC Interfacing
4- Light sensors
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Sensors
Transfer function
An equation used to convert the measure signal in
either volt, amp or charge into a meaningful
value like temperature in degree Celsius or
pressure in bar
PC Interfacing
For example
T 1 3 V - 2V2 oC
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Sensors
Transfer function
PC Interfacing
Y m X c
T 0.66 V 1.2
T 2 V
m tan ?
c intersection with Y-axis
A - First order equation
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Sensors
Transfer function
PC Interfacing
B Second and higher order equation
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Sensors
Transfer function
PC Interfacing
C Polynomial equation
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Temperature sensors
1- Semiconductor devices
2- Thermocouples
3- RTD
PC Interfacing
4- Thermistors
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Temperature sensors
1- Semiconductor devices
A- Temperature sensitive voltage source (LM35CZ)
PC Interfacing
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Temperature sensors
1- Semiconductor devices
A- Temperature sensitive voltage source (LM35CZ)

• The accuracy of this device is 1 oC

• Voltage linearly increase by 10 mV for each
  degree Celsius

• If the output is connected to a ve reference
  voltage the
• sensor will give meaningful output for
  temperature
• range of 40 (-400 mV) to 110 oC (1.1 V)

PC Interfacing

• The output is adjusted to 0 V to 0 oC

• Temperatures below zero provide a negative output
  voltage

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Temperature sensors
1- Semiconductor devices
A- Temperature sensitive voltage source (LM35CZ)

• Its disadvantage is voltage drop over long
  connecting wires

B- Temperature sensitive current source (AD590J)

• No voltage drop over long connecting wires

• It produces current of 1 ?A / 1 ok

PC Interfacing

• Using a load resistance of 1 k Ohm produces I mV
  / 1 ok

• ok oC273.15 oC (oF-32)/1.8

• Subtracting 272.2 mV (AD580 Volt reference) will
  give 0 V at 0 oC

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Temperature sensors
2- Thermocouples

• Whenever two different metals are put in contact
  , a
• small voltage is produced between them

• Depending on the the metals used, the voltage
• increase between 7 and 75 ?V for each degree
  Celsius

PC Interfacing

• Wide operating range can be achieved from 184
  to
• 1600 oC

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Temperature sensors
2- Thermocouples
PC Interfacing
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Thermocouple data
Temperature sensors
2- Thermocouples
PC Interfacing
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Temperature sensors
2- Thermocouples disadvantages
1- The output is very small and must be amplified
a great deal to bring it up to the rang of
the A/D
PC Interfacing
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Temperature sensors
2- Thermocouples disadvantages
2- Due to the difficulty of getting the 0 oC
within the measurement system, a cold
junction compensation circuit is required
PC Interfacing
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Temperature sensors
2- Thermocouples disadvantages
2- Due to the difficulty of getting the 0 oC
within the measurement system, a cold
junction compensation circuit is required
PC Interfacing
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Temperature sensors
2- Thermocouples disadvantages
3- The output voltage does not change linearly
with temperature, linearity can either be
done by software in the computer based
systems, or using analog circuitry which
change gain of an amplifier according to the
value of the signal
PC Interfacing
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Temperature sensors
3- Resistance Temperature Detector (RTD)

• Resistors which increase its values with the
  change in
• temperature

• Its response is not linear, but it have
  excellent stability and
• repeatability, thus they are used for high
  precise applications

PC Interfacing

• Its useful working range is 250 to 850 oC

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Temperature sensors
4- Semiconductor thermistors

• It is semiconductor material whose resistance
  decrease
• nonlinearly with temperature

• It is relatively inexpensive and it has very
  fast response time,
• and they are useful in application where
  precise measurement
• is not required

PC Interfacing
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Force and pressure sensors
1- Strain gauges and load cells
2- Piezoelectric crystal alloys
PC Interfacing
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Force and pressure sensors
1- Strain gauges and load cells

• Strain gauges is a small resistor whose value
  changes
• when its length is changed

• It may be made if thin wire, thin foil or
  semiconductor
• material

• Because strain gauge resistance changes with
  temperature,
• two strain gauges are mounted at right angle to
• compensate this problem,

PC Interfacing

• The full scale differential output voltage is 2
  or 3 mV for
• each volt of excitation voltage applied to the
  top of the bridge

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Force and pressure sensors
1- Strain gauges and load cells
PC Interfacing
If 10 V is applied to the top of the bridge, the
full load output voltage will be 20 or 30 mV
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Force and pressure sensors
2- Piezoelectric crystal alloys

• The physical properties of this alloy produce
  change in
• voltage across its terminal proportional to the
  pressure
• applied on its surface

• It is used for many application from domestic
  uses to
• industrial application

PC Interfacing

• It is sensitive to high temperatures thus
  protective cases
• and cooling system may be used

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Position and speed sensors
1- Opto-coupler
2- Reed switch
PC Interfacing
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Position and speed sensors
1- Opto-coupler
It is composed of a LED and phototransistor
separated by a small gap with a rotating slotted
disk in between , the light emitted by the LED
causes the current to flow in the phototransistor
circuit
PC Interfacing
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Position and speed sensors
1- Opto-coupler
The emitter LED is powered with 5 V dc and a
current limiting resistor R1, and a pull-up
resistor R2 is added to the phototransistor to
provide 5 V digital output
PC Interfacing
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Position and speed sensors
2- Reed switches
Two small pieces of springy metal that overlap on
another and slightly spaced apart so that they
are not in electrical contact.
PC Interfacing
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Position and speed sensors
2- Reed switches
If a reasonably strong Bar magnet is placed next
to it the two reeds become temporarily magnetized
and have opposite poles, thus they are attracted
to one another
PC Interfacing
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Light sensors
1- Light Dependent Resistor LDR
A Candium sulfide material is used where its
resistance depends on the amount of light applied
on its surface
The resistance of the CL905 LDR varies from about
15 M Ohm when in the dark to 15 k Ohm when in
bright light
PC Interfacing
It does not have a very fast response with time,
and not stable with temperature, but they are
inexpensive, durable and sensitive
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Signal conditioning circuits

• Resistance to voltage conversion

• Frequency filter

• Amplification and attenuation

PC Interfacing

• Level shift

• Signal filtering

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Passive circuits

• Potential Divider
• Convert the change in resistance into change in
  voltage
• A load resistance is used to achieve the above
  goal as well as to limit the current

PC Interfacing
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Passive circuits
How much is Rl ?
PC Interfacing
Potential divider
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Passive circuits
At T10 C Rt104.4 At T100C Rt138.8
0.0034 A
Vs 5 V
Potential divider
PC Interfacing
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Active circuits
To get use of the full working range (0.1 V)
1- Subtraction of 0.35 V
2- Magnification by
i.e. Vo30 (Vin-0.35)
PC Interfacing
Op-Amps
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Operational Amplifiers
PC Interfacing
741 Op Amps pin-out
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
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Operational Amplifiers
PC Interfacing
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Operational Amplifiers
PC Interfacing
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Analog / Digital converters
How many bits of resolution are required?
Resolution is the number of bit n that the ADC
uses to represent the analog signal into 2n
units (LSB).
PC Interfacing
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Analog / Digital converters
How fast must the converter operate?
Multiple channel system
PC Interfacing
    Multiplexed input with single A/D    
Simultaneous conversion Combination of both
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Analog / Digital converters
Output format
Serial
        Simpler in design         Reduce PC
board space         Cost effective if isolation
is required Slower to read the digitized
value
PC Interfacing
Parallel
  Faster to read the digitized value Data bus
width can be 8-bit or 16-bit
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Analog / Digital converters
PC Interfacing
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Analog / Digital converters
PC Interfacing
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Analog / Digital converters
PC Interfacing
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Analog / Digital converters
PC Interfacing
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PC Interfacing
PC port types
Sensors
1- Digital parallel ports (printer port and
expansion slots) 2- Digital serial ports
(COM1 and COM2, USP) 3- Analogue port
(joystick port)
Analog to Digital converters
PC Interfacing
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I/O Interfacing techniques
1- Comparison according to signal type
Sensors
Analog to Digital converters
PC Interfacing
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I/O Interfacing techniques
2- Comparison according to digital signal
streaming
Sensors
Analog to Digital converters
PC Interfacing
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PC printer port
Sensors
Analog to Digital converters
PC Interfacing
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LPT1 Printer port pin out
Sensors
Analog to Digital converters
PC Interfacing
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LPT1 Printer port pin out
Sensors
Analog to Digital converters
PC Interfacing
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LPT1 Printer port pin out
Sensors
Analog to Digital converters
PC Interfacing
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LPT1 Printer port pin out
Sensors
Analog to Digital converters
PC Interfacing
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C Programming
Sensors
Output outportb ( register address , value )
Example outportb (0x378 , 10) Input
Variable name inportb (register address)
Example data inportb (0x379)
Analog to Digital converters
PC Interfacing
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C Programming
include ltdos.hgt include ltconio.hgt main() int
data outportb ( 0x378 , 10) dealy ( 1000)
data inportb (ox378) printf( the value
recorded d , data)
Sensors
Analog to Digital converters
PC Interfacing