Introduction: Definition, Multidisciplinary Scenario, Evolution of Mechatronics, Design of Mechatronics system, Objectives, advantages and disadvantages of Mechatronics Transducers and sensors: Definition and classification of transducers, Difference between transducer and sensor, Definition and classification of sensors, Principle of working and applications of light sensors, proximity switches and Hall Effect sensors.

1. Department of Mechanical Engineering
JSS Academy of Technical Education, Bangalore-560060
MECHATRONICS
(Course Code:18ME36B)

2. TEXT BOOKS
• Mechatronics Electronic control system in Mechanical and Electrical Engineering, W Bolton,
Pearson Education, 1st Ed., 2005.
• Mechatronics-Principles, Concepts and Applications, Nitaigour Premchand Mahalik, Tata
McGraw Hill, 1st Edition, 2003
REFERENCE BOOKS:
• Mechatronics by HMT Ltd. - Tata McGrawHill, 1st Edition, 2000
Further Reference:
National Programme on Technology Enhanced Learning (NPTEL)
https://nptel.ac.in/courses/112103174/1 by Dr. S. N. Joshi (IITG)

3. • Understand the evolution and development of Mechatronics as a discipline.
• Substantiate the need for interdisciplinary study in technology education.
• Understand the applications of microprocessors in various systems and to know the
functions of each element
• Demonstrate the integration philosophy in view of Mechatronics technology.
Learning Objectives

4. • Illustrate various components of Mechatronics systems.
• Assess various control systems used in automation.
• Develop mechanical, hydraulic, pneumatic and electrical control systems.
Outcomes

5. MECHATRONICS
CHAPTER 1: Introduction to Mechatronics

6. Module 1
Introduction: Definition, Multidisciplinary Scenario, Evolution of Mechatronics,
Design of Mechatronics system, Objectives, advantages and disadvantages of
Mechatronics
Transducers and sensors: Definition and classification of transducers, Difference
between transducer and sensor, Definition and classification of sensors, Principle of
working and applications of light sensors, proximity switches and Hall Effect
sensors.

7. INTRODUCTION
• Mechatronics is a concept of Japanese origin (1970’s).
• The term Mechatronics coined by “Tetsuro Mori”.
• Defined as the application of electronics and computer technology to control the
motions of mechanical systems.

8. INTRODUCTION
• It is a multidisciplinary approach to product and manufacturing system design.
• It involves application of electrical, mechanical, control and computer
engineering to develop products, processes and systems with greater flexibility,
ease in redesign and ability of reprogramming.

9. INTRODUCTION
• It concurrently includes all these disciplines.

10. INTRODUCTION
Examples of Predominately Mechanical devices
Ball valve
Bimetallic strip

11. INTRODUCTION
Examples of Mechatronics system
• Domestic washing machines
Passenger cars automobiles are equipped with safety
• Installations such as air-bags
• Parking (proximity) sensors
• Antitheft electronic keys
• Autofocus, auto-exposure camera etc.

12. INTRODUCTION
Examples of Mechatronics system

13. INTRODUCTION
Examples of Mechatronics system

14. INTRODUCTION
Examples of Mechatronics system

15. INTRODUCTION
Examples of Mechatronics system

16. INTRODUCTION
Importance of Mechatronics in automation
• Today’s customers are demanding more variety and higher levels of flexibility
in the products
• Demands and competition in the market
• Essential to automate the manufacturing and assembly operations of a
product.

17. INTRODUCTION
Evolution
First Level
Second
Level
Third Level
Fourth Level
Incorporates l/O devices like sensors and actuators, integrates electrical
signals with mechanical action. E.g. Fluid valves and relays
Integrates microelectronics into electrically controlled devices.
E.g.: Cassette player
Incorporates advanced feed back functions. “Smart Systems”
E.g. Hard disk, CD drives, automatic washing machines
Intelligent control in mechatronic system
E.g. Fault Detection and Isolation (FDI) capability systems.

18. INTRODUCTION
Basic Elements in Mechatronics system

19. INTRODUCTION
Basic Elements in Mechatronics system

20. INTRODUCTION
Basic Elements in Mechatronics system
• The actuators produce motion.
• The sensors detects the state of the system parameters, inputs and outputs.
• Digital devices control the system.
• Conditioning and interfacing circuits provide connection between the control
circuits and the input/output devices.
• Graphical displays provide visual feedback to users.

21. INTRODUCTION
Basic Elements in Mechatronics system
• Actuators: D.C. motors; Stepper motors; Servomotor; hydraulics; pneumatics.
• Sensors: Switches; Potentiometer, Strain guage, Thermocouple; accelerometer etc.
• lnput signal conditioning and interfacing: Discrete circuits; Amplifiers, Filters; A/D, D/D.
• Digital control architectures: Logic circuits; Microcontroller, PLC, Sequencing and timing,
• Output signal conditioning and interfacing: D/D, A/D; Amplifiers, Power transistors ;
Power Opamps.

22. INTRODUCTION
Embedded systems
• The term embedded system refers to where microprocessors
are embedded into systems.
• A microprocessor is a collection of logic gates and
memory elements that are not wired up as individual
components, but logical functions are implemented by means
of software.
• An embedded system is a microprocessor-based system that
is designed to control a range of functions.
• Not designed to be programmed by the end user
• E.g.: Washing Machine, Engine Management, ABS, FIP, Cell
phone

23. Design Process
1. The need
2. Analysis of the problem
3. Preparation of a specification
4. Generation of possible solutions
5. Selections of a suitable solution
6. Production of a detailed design
7. Production of working drawings
Design process for any system involves a number of stages.

24. Design Process
In designing mechatronic systems; one of the steps is the creation of a model of
the system, that predictions can be made regarding its behaviour with reference
to the inputs.
System: A box or block diagram which has an input and an output.
• Only concerned with the relationship between the output and the input.
E.g. of systems

25. Mechatronic Design Process
The mechatronic design process consists of three phases:
• Modeling and simulation
• Prototyping
• Deployment / Life cycle

26. Mechatronic Design Process

27. Advantages and Disadvantages of Mechatronics
Advantages Disadvantages
Cost effective and reliable product High initial cost of the system.
High degree of flexibility and productivity
Imperative to have knowledge of
different engineering fields for design
and implementation.
Greater extent of machine utilisation.
Specific problems for various systems
will have to be addressed separately
and properly.
Reduction in the capital expense due to
integration of complex systems.
Expensive to incorporate mechatronics
approach to an existing/old system

28. MECHATRONICS
CHAPTER 1: Transducers and Sensors

29. Transducers and Sensors
• Definition and classification of transducers.
• Difference between transducer and sensor.
• Definition and classification of sensors.
• Principle of working and applications of light sensors.
• Proximity switches and Hall Effect sensors.

30. Sensors
Automotive Sensors

31. Sensors
• Sensor is an element which produces a signal relating to the quantity being
measured.
• An input device which provides an output (signal) with respect to a specific
physical quantity.
• A device that converts signals from one energy domain to electrical domain.

32. Sensors

33. • Dial indicator: the indicating spindle acts as a sensor/detector for displacement.
• Bourdon tube of a pressure gauge is twofold:
• Firstly to sense the pressure & secondly to give the output in the form of
displacement. Here the tube acts a sensor/detector transducer.
• Compressive load cell: the platform detects the force and gives an output in the
form of deflection.
This deflection may be further converted into an electrical output by strain gauges
(called secondary transducer).
Sensors Examples

34. Sensors
• Sensors that combined with signal conditioning and microprocessors are
referred as smart sensors.
Smart Sensor
Smart sensors Applications
• Communications
• Computations
• Multi sensing
• Self calibration

35. Sensors
The normal sensors have three crucial parts which are
• Sensing element (Transistor, Capacitors, Photo Diode etc).
• Conduction of signals and processing.
• Sensor Interface.

36. Classification of Sensors
The sensors are classified into the following criteria:
1. Primary Input quantity (Measurand)
2. Transduction principles (Using physical and chemical effects)
3. Material and Technology
4. Property
5. Application

37. Classification of Sensors
• Active Sensor: Active Sensors are those which require an external excitation
signal or a power signal. E.g.: LiDAR (Light detection and ranging), photoconductive cell.
• Passive Sensor: Do not require any external power signal and directly
generates output response. E.g.: Radiometers, film photography
Based on the means of detection
• Some of the means of detection are Electric, Biological, Chemical, Radioactive
etc.

38. Classification of Sensors
• Sensors that are commonly used in various applications.
All these sensors are used for measuring one of the physical properties like
Temperature, Resistance, Capacitance, Conduction, Heat Transfer etc.
•Temperature Sensor
•Proximity Sensor
•Accelerometer
•IR Sensor
•Pressure Sensor
•Light Sensor
•Ultrasonic Sensor
•Smoke, Gas and Alcohol Sensor
•Touch Sensor
•Color Sensor
•Humidity Sensor
•Tilt Sensor
•Flow and Level Sensor

39. Classification of Sensors
Based on the conversion phenomenon i.e. the input and the output.
• Some of the conversion phenomena are Photoelectric, Thermoelectric,
Electrochemical, Electromagnetic, Thermo-optic, etc.
• Analogue sensors: Produce an analog output.
• Digital Sensors: Work with discrete or digital data.

40. Principle of working of Light sensors (Passive)
Light Sensors are photoelectric devices / Photo sensors that convert light energy (photons)
whether visible or infra-red light into an electrical signal.
Photodiodes
Applications
Smoke detectors, compact disc players, and televisions,
remote controls in VCRs, clock radios, street light

41. Principle of working of Light sensors (Passive)
• Are semiconductor junction, connected into a circuit in reverse
bias giving a very high resistance.
• With no incident light, the reverse current is almost negligible
and is termed the dark current.
• When light falls on the junction, extra hole–electron pairs are
produced and there is an increase in the reverse current and
the diode resistance drops.
• The reverse current is very nearly proportional to the intensity of
the light.
Photodiodes

42. Principle of working of Light sensors (Passive)
Phototransistors
• The phototransistors have a light-sensitive collector–base p–n junction.
• When there is no incident light there is a very small collector-to-emitter current.
• When light is incident, a base current is produced that is directly proportional to the light intensity.
This leads to the production of a collector current which is a measure of the light intensity.
• Phototransistor are connected in a Darlington arrangement with a conventional transistor, for
higher current gain.
In electronics, a multi-transistor
configuration called Darlington pair

43. Photoresistor:
A photoresistor (or light-dependent resistor, LDR, or photo-conductive cell) is
a light-controlled variable resistor. The resistance of a photoresistor decreases with
increasing incident light intensity (photoconductivity).
Principle of working of Light sensors (Passive)

44. Photoresistor:
Principle of working of Light sensors (Passive)
• As the light energy falling on the photoconductive
material increases, number of valence electrons
that gain energy and leave the bonding with the
nucleus increases.
• This leads to a large number of valence electrons
jump to the conduction band, ready to move with
an application of any external force like an
electric field.

45. Applications of Photoresistor:
Principle of working of Light sensors (Passive)
• Automatic Street Lights
• Light meters in camera
• Light sensors
• Clock radios

46. Principle of working of Proximity switches
A proximity sensor is a sensor able to detect the presence of nearby objects
without any physical contact.
The microswitch is a small electrical switch which requires physical contact and
a small operating force to close the contacts.
For example: A conveyor belt.

47. Principle of working of Proximity switches
(a) Lever-operated (b) roller-operated (c) cam-operated switches.

48. Principle of working of Proximity switches
Reed switch
• It consists of two magnetic switch contacts sealed in a glass tube.
• When a magnet is brought close to the switch, the magnetic reeds
are attracted to each other and close the switch contacts.
• It is a non-contact proximity switch.
Applications: Checking the closure of doors, used with tachometers etc.

49. Hall effect sensors
A Hall effect sensor is a device that is used to measure the magnitude of a
magnetic field.
• Its output voltage is directly proportional to the magnetic field strength through it.
• Hall effect sensors are used for proximity sensing, positioning, speed detection,
and current sensing applications
Principle
• When a beam of charged particles passes through a magnetic field, forces act on
the particles and the beam is deflected from its straight line path.
• This effect was discovered by E.R. Hall in 1879 and is called the Hall effect.

50. Hall effect sensors
Working
• Consider electrons moving in a conductive plate with a magnetic field
applied at right angles to the plane of the plate.
• As a result of the magnetic field, the moving electrons are deflected to one
side of the plate, and that side becomes negatively charged, while the
opposite side becomes positively charged since the electrons are directed
away from it.
• This charge separation produces an electric field in the material.
• The charge separation continues until the forces on the charged particles
from the electric field just balance the forces produced by the magnetic
field.

51. Hall effect sensors
• The result is a transverse potential difference V given by
B= magnetic flux density
I = current
KH = constant, Hall coefficient
t= plate thickness

52. Hall effect sensors
• Applications
Fluid-level Detector
A wheel containing two magnets passing by
a Hall effect sensor
• Position sensing
• Automotive fuel level indicator
• Keyboard switch

53. Transducer / Gauges / Signal Generators / Pickups

54. Transducer / Gauges / Signal Generators / Pickups
• A device that converts variations in a physical quantity, such as pressure or
brightness, into an electrical signal, or vice versa.
• A transducer is an electronic device that converts energy from one form to
another.
• E.g. microphones, loudspeakers, thermometers, position and pressure sensors,
and antenna
TransducerPhysical Qty.
Excitation
Electrical Output

55. Transducer
Mechanical detector-transducer elements are;
1. Elastic members/elements
2. "Mass" sensing elements
3. Thermal detectors
4. Hydro-pneumatic elements
MECHANICAL DETECTOR -TRANSDUCER ELEMENTS

56. Transducer
MECHANICAL DETECTOR -TRANSDUCER ELEMENTS
Elastic members / elements:
Works on the principle of direct tension or compression, bending and torsion.
The common elastic members/elements are
• Proving ring (stress ring).
• Elastic torsion member
• Springs
• Bourdon tube, Bellows, diaphragms

57. Transducer
MECHANICAL DETECTOR -TRANSDUCER ELEMENTS
Mass Sensing elements:
Works on the principle of inertia of a concentrated mass
The common Mass sensing members/elements are
• Accelerometers.
• Vibration pickups
• Manometers

58. Transducer
MECHANICAL DETECTOR -TRANSDUCER ELEMENTS
Thermal detectors: Temperature measuring devices
The common thermal detectors are;
• Glass thermometers.
• Pressure gauge thermometers
• Bimetallic thermometers
• Resistance thermometers
• Thermistors
• Pyrometers
• Thermocouples.

59. Transducer
MECHANICAL DETECTOR -TRANSDUCER ELEMENTS
Hydro-Pneumatic Sensors: Temperature measuring devices
The common Hydro-Pneumatic sensors are;
Static conditions
Dynamic conditions
• Simple Float
• Hydrometer
• Orifices and Venturies
• Pitot tube
• Vanes

60. Transducer
• Mechanical Transducers: Convert physical quantities into mechanical ones.
• Electrical Transducers: Transducers that convert physical quantities into
electrical.
• E.g. A thermocouple that changes temperature differences into a small voltage.
Linear variable differential transformer (LVDT) used to measure displacement
Classification of Transducers

61. Transducer
Classification of Transducers
Active Transducer Analogue
Based on the type of output
Passive Transducer
Digital

62. Classification of Transducers
Based on electrical Principle
Variable-resistance type
• Strain
• Pressure gauges
• Thermistors
• RTD
• Photoconductive cell
Variable-inductance type
• LVDT
• Reluctance pick-up
• Eddy current gauge
Variable-capacitance type
• Capacitor microphone
• Pressure gauge
• Dielectric gauge.
Voltage-generating type
• Thermocouple
• Piezoelectric pick-up
• Photovoltaic cell
• Rotational motion tachometer
Voltage-Divider type
• Pressure-actuated voltage divider.
• Potentiometer position sensor.

63. Active
Transducer
Passive
Transducer
Analogue
Digital
Self-generating type transducers.
They develop their own voltage or current.
Externally-powered transducer.
May absorb some energy.
Convert input into analogue.
O/p is continuous function of time.
Convert input into electrical output In form
of pulse
Classification of Transducers
• Thermocouple, Piezoelectric
pick-up, Photovoltaic cell
• RTD, Thermistor, DT,
Photoemission cell
• Thermocouple, Strain gauge,
LVDT

64. Terms associated with Transducers
Transducer Sensitivity: The relation between the measurand and the transducer
output signal.
• Sensitivity of a transducer should be usually as high as possible, for easier
measurements.

65. Terms associated with Transducers
Specifications for Transducers
• Ranges available.
• Sensitivity.
• Squaring system.
• Maximum working temperature
• Linearity and hysteresis
• Temperature coefficient of zero drift
• Method of cooling employed
• Mounting details
• Maximum depth.
• Output for zero input.
• Natural frequency.

66. Difference between Sensor and Transducers
Transducer – these are elements
when subjected to physical
change experience a related
change.
Sensors – the term sensor is used for
an element which generates a signal
which is proportional to the quantity
being measured.

67. Difference between Sensor and Transducers

68. Difference between Sensor and Transducers
Basis For
Comparison
Sensor Transducer
Definition
Senses the physical changes occurs in
the surrounding and converting it into a
readable quantity.
The transducer is a device which,
when actuates transforms the
energy from one form to another.
Components Sensor itself Sensor and signal conditioning
Function
Detects the changes and induces the
corresponding electrical signals.
Conversion of one form of energy
into another.
Examples
Proximity sensor, Magnetic sensor,
Accelerometer sensor, Light sensor,
Barometer, Gyroscope etc.
Thermistor, Potentiometer,
Thermocouple, etc.

69. End of Module