2. CO1: Install and maintain the sensors and
transducers of mechatronics systems
Teaching
hours
Distribution of theory marks
Total marks
R
(Remember)
U
(Understand)
A
(Apply)
14
hours
6 8 6
20
marks
3. INTRODUCTION
⊡Mechatronics basically is the addition of two branches of engineering-
Mechanical and Electronics.
⊡However, is an interdisciplinary branch of engineering that focuses on
the combination of electrical, robotics, computer, telecommunications
systems, control and product engineering, instrumentation and many
more to define.
⊡The intention of mechatronics is to produce a design solution that
unifies each of these various subfields.
⊡The applications falls under various industry like- Home automation,
biomedical fields, microcontrollers and processors, PLCs, etc.
3
6. ⊡Sensors: Sensors or transducers represent physical devices that convert
one form of energy into another.
⊡Actuators: They convert electrical impulses into physical actions or
objects.
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MECHATRONIC
SYSTEM
ARCHITECTURE
8. ⊡Signal conditioning: It takes the input from the sensor and manipulates
the signal which is suitable for display.
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MECHATRONIC
SYSTEM
ARCHITECTURE
9. ⊡Controllers: They are control system operations and decide
the kind of action taken in response to an error.
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MECHATRONIC
SYSTEM
ARCHITECTURE
11. ADVANTAGES OF
MECHATRONICS
SYSTEMS
High reliability and safety
Improved and less expensive
High level of integration
Increased functionality & better design
Increased speed and precision of performance
Less interference from operator
11
13. Real Time
Mechatronics Systems
* There is no time lag in requirement of data & response of the
system
* FMS & CIM are the manufacturing systems that work in real time
14. Flexible Manufacturing
System
⊡ FMS, is a computerized production process that allows manufacturers to
produce more goods faster and more efficiently than ever before.
⊡ FMS is a production method that is designed to easily adapt to changes in the
type and quantity of the product being manufactured.
⊡The primary purpose behind flexible manufacturing systems is to maximize
productivity while minimizing costs and waste.
14
16. FMS
⊡The FMS is shown with two machining centers viz. milling center and turning
center.
⊡Besides it has the load/unload stations, AS/RS for part and raw material
storage, and a wire guided AGV for transporting the parts between various
elements of the FMS.
⊡ This system is fully automatic means it has automatic tool changing (ATC) and
automatic pallet changing (APC) facilities.
⊡The central computer controls the overall operation and coordination amongst
the various constituents of the FMS system.
16
17. FMS
⊡Benefits of FMS are-
• Flexibility to change part variety
• Higher productivity
• Higher machine utilization
• Less rejections
• High product quality
• Reduced work-in-process and inventory
• Better control over production
• Just-in-time manufacturing
• Minimally manned operation
• Easier to expand
17
18. Computer-Integrated
Manufacturing
⊡CIM refers to the use of computer-controlled machineries and automation
systems in manufacturing products.
⊡CIM combines various technologies like computer-aided design (CAD) and
computer-aided manufacturing (CAM) to provide an error-free manufacturing
process that reduces manual labor and automates repetitive tasks.
⊡It is widely used in the automotive, aviation, space and ship-building industries.
⊡All the operations are controlled by computers and have a common storage and
distribution.
18
19. CIM
⊡The various processes involved in a CIM are-
• Computer-aided design
• Prototype manufacture
• Ordering of the necessary materials needed for the manufacturing process
• Computer-aided manufacturing of the products with the help of computer numerical controllers
• Quality controls at each phase of the development.
• Product assembly with the help of robots
• Quality check and automated storage
• Automatic distribution of products from the storage areas to awaiting lorries/trucks
• Automatic updating of logs, financial data and bills in the computer system
19
20. CIM
⊡The major components of CIM are as follows:
• Data storage, retrieval, manipulation and presentation mechanisms
• Real-time sensors for sensing the current state and for modifying processes
• Data processing algorithms
⊡The CIM approach has found a wide range of applications in industrial and
production engineering, mechanical engineering and electronic design
automation.
⊡CIM increases the manufacturing productivity and lowers the total cost of
manufacturing.
⊡It also offers great flexibility, quality and responsiveness.
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21. SENSORS
⊡These are the devices which are helpful in making things done
without human intervention.
⊡Even the smartphones which we daily use will have some sensors
like hall sensor, proximity sensor, accelerometer, touch screen,
microphone etc. These sensor acts as eyes, ears, nose of any
electrical equipment which senses the parameters in outside world
and give readings to devices or Microcontroller.
⊡The sensor can be defined as a device which can be used to
sense/detect the physical quantity like force, pressure, strain, light
etc and then convert it into desired output like the electrical signal
to measure the applied physical quantity.
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22. SENSORS
⊡A signal conditioning unit
is used in order to
maintain sensor’s output
voltage levels in the
desired range with respect
to the end device that we
use where the output of
the sensor may be
amplified, filtered or
modified to the desired
output voltage.
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23. SENSORS
⊡ Position Sensors detect the position of something which means that
they are referenced either to or from some fixed point or position.
⊡One method of determining a position, is to use either “distance”,
which could be the distance between two points such as the distance
travelled or moved away from some fixed point, or by “rotation”
(angular movement).
⊡Position Sensors can detect the movement of an object in a straight
line using Linear Sensors or by its angular movement using
Rotational Sensors.
⊡Proximity sensors are used to determine when an object has moved
to within some particular critical distance of the sensor.
⊡It is able to detect the presence of nearby objects without any
physical contact.
23
24. PHOTOELECTRIC
SENSORS
⊡ They detect objects, changes in surface conditions, and other items
through a variety of optical properties.
⊡A Photoelectric Sensor consists primarily of an Emitter for emitting
light and a Receiver for receiving light.
⊡When emitted light is interrupted or reflected by the sensing object, it
changes the amount of light that arrives at the Receiver. The Receiver
detects this change and converts it to an electrical output.
⊡The light source for the majority of Photoelectric Sensors is infrared or
visible light (generally red, or green/blue for identifying colors).
24
25. PHOTOELECTRIC
SENSORS
⊡ Following are the features of the sensors-
1. Long Sensing Distance- can detect objects more than 10 m away.
2. Virtually No Sensing Object Restrictions- can be used to detect
virtually any object, including glass, plastic, wood, and liquid.
3. Fast Response Time- light travels at high speed.
4. High Resolution- from advanced design technologies that yielded a
very small spot beam and a unique optical system for receiving light.
5. Non-contact Sensing- There is little chance of damaging sensing
objects or Sensors.
6. Color Identification- depends on both the wavelength of the emitted
light.
7. Easy Adjustment- Positioning the beam on an object is simple as the
beam is visible. 25
26. PHOTOELECTRIC
SENSORS
⊡ Through beam sensors- The Emitter and Receiver are installed
opposite each other to enable the light from the Emitter to enter the
Receiver. When a sensing object passing between the Emitter and
Receiver interrupts the emitted light, it reduces the amount of light
that enters the Receiver. This reduction in light intensity is used to
detect an object.
26
27. PHOTOELECTRIC
SENSORS
⊡ Diffuse reflective sensors- The Emitter and Receiver are installed in
the same housing and light normally does not return to the Receiver.
When light from the Emitter strikes the sensing object, the object
reflects the light and it enters the Receiver where the intensity of light
is increased. This increase in light intensity is used to detect the
object.
27
28. PHOTOELECTRIC
SENSORS
⊡ Retro reflective sensors- The Emitter and Receiver are installed in
the same housing and light from the Emitter is normally reflected back
to the Receiver by a Reflector installed on the opposite side. When
the sensing object interrupts the light, it reduces the amount of light
received. This reduction in light intensity is used to detect the object.
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29. HALL EFFECT
SENSORS
⊡ One type of magnet sensor whose output signal is a function of
magnetic field density around it is called the Hall Effect Sensor.
⊡ These are the devices which are activated by an external magnetic
field and their output signal is the function of magnetic field density
around the device.
⊡When the magnetic flux density around the sensor exceeds a certain
pre-set threshold, the sensor detects it and generates an output
voltage called the Hall Voltage, VH.
⊡Hall Effect Sensors consist basically of a thin piece of rectangular p-
type semiconductor material such as gallium arsenide (GaAs), indium
antimonide (InSb) or indium arsenide (InAs) passing a continuous
current through itself.
29
30. HALL EFFECT
SENSORS
⊡ Generally, Hall Effect sensors and switches are designed to be in the
“OFF”, (open circuit condition) when there is no magnetic field
present. They only turn “ON”, (closed circuit condition) when
subjected to a magnetic field of sufficient strength and polarity.
⊡Hall effect sensors are activated by a magnetic field and in many
applications the device can be operated by a single permanent
magnet attached to a moving shaft or device.
⊡There are many different types of magnet movements,
such as “Head-on”, “Sideways”, “Push-pull” or
“Push-push” etc. sensing movements.
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31. OPTICAL
ENCODERS
SENSORS
⊡ The optical encoder is composed of a light emitting device (LED),
photo sensors, and a disc called a code wheel with slits (holes) in the
radial direction, and detects rotational position information as an
optical pulse signal.
⊡ When a code wheel attached to a rotating shaft
such as a motor rotates, an optical pulse is
generated depending on whether light emitted
from a fixed LED passes through a slit of the code
wheel or not.
⊡ Photo sensor detects the optical pulse, converts
it into an electrical signal, and outputs it.
31
32. OPTICAL
ENCODERS
SENSORS
⊡ Optical encoders are classified into two types according to their
structure. They are, "transmissive type" in which the light emitting
device (LED) and photo sensor sandwich the code wheel, and
"reflective type" in which the LED and photo sensor are placed on
the same side and the code wheel reflects the light.
Transmissive Reflective
32
33. EDDY CURRENT
SENSORS
⊡ Eddy current sensors are primarily
used for displacement and proximity
measurement of electrically conductive
targets.
⊡ They are generally used for
measuring ferromagnetic and non-
ferromagnetic materials.
⊡They are suitable for applications in
harsh industrial environments due to
their superior tolerance for oil, dirt,
dust, moisture and magnetic
interference fields.
33
34. EDDY CURRENT
SENSORS
⊡ Eddy current sensor operates based on the inductive eddy-current
principle.
⊡It measures the distance based on the extraction of energy from an
oscillating circuit, which is required to generate eddy current in an
electrically-conductive materials.
⊡When the sensing coil is supplied with an alternating current, it
causes a magnetic field to form around the coil. If an electrically
conducting material is placed in this field, eddy current field is
induced.
⊡When the object moves, it causes the change in the impedance of
the coil, which is proportional to the change in the distance between
the sensor and the target.
34
35. INDUCTIVE
SENSORS
⊡ An inductive sensor is a device that uses the principle of
electromagnetic induction to detect or measure objects.
⊡An inductor develops a magnetic field when a current flows through it;
alternatively, a current will flow through a circuit containing an
inductor when the magnetic field through it changes.
⊡This effect can be used to detect metallic objects that interact with a
magnetic field.
⊡ Non-metallic substances such as liquids or some kinds of dirt do not
interact with the magnetic field, so an inductive sensor cannot
operate in wet or dirty conditions.
35
36. CAPACITIVE
SENSORS
⊡ Capacitive proximity sensors are non-contact devices that can detect
the presence or absence of virtually any object regardless of material.
⊡They utilize the electrical property of capacitance and the change of
capacitance based on a change in the electrical field around the
active face of the sensor.
⊡A capacitive sensor acts like a simple capacitor. A metal plate in the
sensing face of the sensor is electrically connected to an internal
oscillator circuit and the target to be sensed acts as the second plate
of the capacitor.
⊡Unlike an inductive sensor that produces an electromagnetic field a
capacitive sensor produces an electrostatic field.
36
37. ELECTROMAGNETIC
TRANSDUCER
⊡ Electromagnetic acoustic transducer (EMAT) is a transducer for non-
contact acoustic wave generation and reception in conducting
materials.
⊡Its effect is based on electromagnetic mechanisms, which do not
need direct coupling with the surface of the material.
⊡EMATs are suitable to generate all kinds of waves in metallic and/or
magneto strictive materials (emf energy into mechanical and vice
versa).
⊡EMAT has found its applications in many industries such as primary
metal manufacturing and processing, automotive, railroad, pipeline,
boiler and pressure vessel industries.
⊡There are two basic components in an EMAT transducer. One is a
magnet and the other is an electric coil. The magnet can be a
permanent magnet or an electromagnet, which produces a static or a
37
38. TACHO
GENERATORS
⊡ Tachometer generators (or tacho generators) are
electromechanical devices which output a voltage proportional to
their shaft speed.
⊡They are used to power tachometers and to measure the speed of
motors, engines, and other rotational devices.
⊡The majority of modern tachogenerators are permanent magnet
types.
⊡These devices use a rotating armature, one end of which is
attached to a machine shaft, to measure rotational speed.
⊡The armature rotates within a fixed magnetic field, so that its rotation
induces emf (voltage) proportional to the shaft's speed.
⊡The armature contacts are connected to a voltmeter circuit, which
converts the voltage into a speed value.
38
39. TACHO
GENERATORS
⊡ The commutator between the armature and voltmeter circuit serves
to convert internally generated AC voltage into DC for compatibility
with the voltmeter.
⊡ Tachometer generators are
therefore ideal in control or
measurement applications which
require directional indication.
⊡Tachometer generators are
frequently used to measure engine and motor speed, as well as the
corresponding speed of powered equipment such as conveyors, mixers,
fans, and machine tools.
39
40. STROBOSCOPE
⊡ A stroboscope is an instrument that can be used to measure
revolutions, velocity, and frequency of rotating components or moving
parts.
⊡ It is also known as a strobe, this device can measure periodic or
rotary motions.
⊡This instrument can make a cyclically moving object appear to be
slow-moving or stationary and it is done by the stroboscopic effect.
⊡This instrument is a source of variable frequency flashing brilliant light
and the flashing frequency can be adjusted by the operator. The
circuit is based on a variable frequency oscillator which controls the
flashing frequency. Speed can be measured by adjusting the
frequency and because of that, the moving objects are visible only at
specific intervals of time.
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41. STROBOSCOPE
There is a whirling disc and a stationary mask,
both having the opening of the same shape
and size. When the two openings on the disc
and stationary mask coincide then the observer
can catch glimpses of the object behind the
mask. If the object is rotating and the speed of
the disc is synchronized with the motion of the
object then the object will appear to be
motionless. When the disc is rotating at a
lesser speed than the object then the object
would appear to creep forward and if the disc is
rotating at a slightly faster speed then the
rotating object will appear to creep backward.
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42. PYROELECTRIC
SENSORS
⊡ Pyroelectric detectors are sensors for light
which are based on the pyroelectric effect.
⊡They are widely used for detecting laser pulses
(rather than continuous-wave light), often in the
infrared spectral region, and with the potential
for a very broad spectral response.
⊡Pyroelectric detectors are used as the central
parts of many optical energy meters, and are
typically operated at room temperature.
⊡A pyroelectric detector contains a piece of
ferroelectric crystal material with electrodes on
two sides.
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43. STRAIN GAUGE
⊡Strain gauge is an
electromechanical device that
measures acceleration forces.
⊡A cantilever beam fixed to the
housing of the instrument.
⊡A mass is fixed to the free end
of the cantilever beam.
⊡Two bounded strain gauges
are mounted on the cantilever
beam.
⊡Damping is provided by a
viscous fluid filled inside the
housing.
43
44. STRAIN GAUGE
⊡The accelerometer is fitted on to the structure whose acceleration is
to be measured.
⊡Due to the vibration, vibrational displacement of the mass occurs,
causing the cantilever beam to be strained.
⊡Hence the strain gauges mounted on the cantilever beam are also
strained and due to this their resistance change.
⊡But the resulting strain of the cantilever beam is proportional to the
vibration/acceleration and hence a measure of the change in
resistance of the strain gauges becomes a measure of
vibration/acceleration.
⊡The leads of the strain gauges are connected to a wheat stone bridge
whose output is calibrated in terms of vibration/acceleration.
44
45. PIEZOELECTRIC
⊡Piezoelectric transducers convert mechanical energy (when strained)
to an electric signal through the piezoelectric effect.
⊡The active element in a piezoelectric accelerometer is a piezoelectric
ceramic. One side of the ceramic is rigidly connected to the
accelerometer body, the other side has a seismic mass added.
⊡Due to the piezoelectric effect, a charge output proportional to the
applied force is generated from this vibration or shock.
⊡The sensor measures the acceleration of the accelerometer body.
⊡There are 3 main sensor configurations: shear mode, compression,
and bender.
45
46. PIEZOELECTRIC
⊡Shear mode- The piezo wafers are configured to undergo shear
deformation from acceleration (i.e. the piezo wafers are perpendicular
to the base).
46
48. PIEZOELECTRIC
⊡Bender mode- The easiest-to-conceptualize configuration is with the
piezoelectric element acting as a cantilevered beam with a tip mass.
48
49. LVDT
⊡LVDT is an acronym for Linear Variable Differential Transformer.
⊡It is a common type of electromechanical transducer that can convert
the rectilinear motion of an object to which it is coupled mechanically
into a corresponding electrical signal.
⊡The transformer's internal structure consists of a primary winding
centered between a pair of identically wound secondary windings,
symmetrically spaced about the primary.
⊡The coils are wound on a one-piece hollow form of thermally stable
glass reinforced polymer, encapsulated against moisture, wrapped in
a high permeability magnetic shield, and then secured in a cylindrical
stainless steel housing. This coil assembly is usually the stationary
element of the position sensor.
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51. LOAD CELLS
⊡A load cell is a type of pressure sensor, which converts force into a
measurable electrical output.
⊡A load cell works by converting mechanical force into digital values
that the user can read and record.
⊡A load cell measures mechanical force, mainly the weight of objects.
⊡There are different types of load cells for different applications.
Commonly used ones include:
- Single point load cells
- Bending beam load cells
- Compressive force load cells
- Tensile load cells
51
52. LOAD CELLS
⊡Single point load cell: a load
cell is located under a
platform that is loaded with a
weight from above
52
⊡Bending beam load cell:
several load cells are
positioned under a steel
structure and are loaded with
a weight from above
53. LOAD CELLS
⊡Compressive force load cell:
several high-capacity load cells
are positioned under a steel
structure that is loaded with a
weight from above
53
⊡Tensile load cell (S shape): a
weight is suspended from one
or more load cells
54. TORQUE
MEASUREMENT BY
STRAIN GAUAGE
⊡To measure torque by acquiring reliable data from moving objects,
strain gauges are very popular due to their simple integration.
⊡A strain gauge converts torque into an electrical signal, the sensor is
bonded to a rotating shaft that deforms when a torque is applied.
⊡Generally, four strain gauges are attached to the rotating shaft in the
form of a Wheatstone bridge circuit, placed precisely at 45 degrees
with the shaft axis, with gauge 1 and 3 being diametrically opposite, as
must gauge 2 and 4.
54
55. TORQUE
MEASUREMENT BY
STRAIN GAUAGE
⊡When torque is applied to the
shaft, the shaft gets twisted to
the direction of rotation, thereby
producing shear strain. This
causes elongation in gauges 1
and 3 and compression in
gauges 2 and 4.
⊡This process results in an
unbalanced bridge, which
produces an electrical output
corresponding to the applied
torque.
55
56. SIGNAL CONDITIONING
⊡Signal conditioning is the technique of making a signal from a sensor
or transducer suitable for processing by data acquisition equipment.
⊡Example, If you were measuring a voltage signal smaller than a few
millivolts, you might need to amplify it. If you had a signal
contaminated with noise you could filter it.
⊡Proper signal conditioning is essential in getting an accurate
measurement of your signal. It is the first step of computerized data
acquisition.
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57. SIGNAL CONDITIONING
⊡Amplification-
- It increases a voltage signal to a level suitable for output.
- A small voltage, such as that coming from a thermocouple or strain
gauge bridge, may need to be amplified 1000 times to make it
between 0 and 10 V (which is a typical voltage range).
⊡Attenuation-
- By contrast to amplifiers, attenuation is the process of decreasing the
amplitude.
- For example, to get the high voltage signal fit within the optimal
range of the device.
57
58. SIGNAL CONDITIONING
⊡Filtering-
- Filtering reduces noise errors in the signal.
- For most applications a low-pass filter is used. This allows through
the lower frequency components but attenuates the higher
frequencies.
⊡Isolation-
- A high transient voltage at one input may damage not only the input
circuit, but can also propagate to other equipment connected to that
input.
- This can be prevented by providing isolation between inputs which
filter out the voltage spikes.
58
59. SIGNAL CONDITIONING
⊡Linearization-
- Linearization is needed when the signals produced by a sensor don't
have a straight-line relationship with the physical measurement.
⊡Typical Signal processing problems are-
- Eliminating noise
- Correcting distortion
- Extracting an indirect quantity from measured signal
59
60. SIGNAL CONDITIONING
⊡Solutions-
- Isolate: using isolators, the signal is reproduce, transmitting a higher
quality.
- Convert: converting one type to another.
- Split: One input signal to two or more output signal.
- Amplify: Amplifying from low level to high level.
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