Introduction to Mechatronics

MECHATRONICS
ME602
You have played enough with toy models.
Now its time to BUILD some.
Prof. Kumar Naik M
Mechanical Engineering dept,
ACED, Alliance university

Introduction
 The term “Mechatronics” was coined by Tetsuro Mori, a senior
Japanese engineer at Yasakawa Company in 1969.
 The word mechatronics is composed of “mecha” from mechanical
and the “tronics” from electronics.
Mechanical + Electronics = Mechatronics
“Mecha” + “tronics” = Mechatronics
 Mechatronics is a multidisciplinary field of science that includes
a combination of mechanical engineering, electronics, computer
engineering, telecommunications engineering, systems
engineering and control engineering.

It is in the form of human, has been
programmed for specific function
depending on requirement.
ROBOTICS
The aim of the Mechatronics

Origin of the Mechatronic system
 The word Mechatronics was coined by Japanese in the late 1970‟s
to describe the philosophy adopted in the design of subsystem of
electromechanical systems.
 The field has been derived by rapid progress in the field of
microelectronics.
 At R&D level the following areas have been recognized under
Mechatronics discipline.
 Motion control actuators and sensor
 Micro devices and optoelectronics
 Robotics
 Automotive systems
 Modeling and design
 System integration
 Manufacturing
 Vibration and noise control.

Evolution of Mechatronic system
The technology has evolved through several stages that are termed as
levels. The evolution levels of Mechatronics are:
 Primary level Mechatronics (first)
 Secondary level Mechatronics (second)
 Tertiary level Mechatronics (third)
 Quaternary level Mechatronics (fourth)

 Primary level Mechatronics (first)
In the early days Mechatronics products were at primary level
containing devices such as sensors, and actuators that integrated
electrical signals with mechanical action at the basic control level.
Examples: electrically controlled fluid valves
 Secondary level Mechatronics (second)
This level integrates microelectronics into electrically controlled
devices.
Examples: cassette player.

 Tertiary level Mechatronics (third)
Mechatronics system at this level is called ‘smart system’ and the
control strategy includes microelectronics, microprocessor and
other application specific integrated circuits‟ (ASIC).
Examples: DVD player, CD drives, automatic washing
machine, CD drives, etc.
 Quaternary level Mechatronics (fourth)
This level includes intelligent control in Mechatronics system. The
level attempts to improve smartness a step ahead by introducing
intelligence and fault detection and isolation (FDI) capability
system.
Examples: artificial neural network and fuzzy logic
technologies.

Basic elements of a mechatronic system
Mechanical
system
Electronic
device/Microprocessor
SensorActuator
 Sensor: Senses condition of mechanical system. Provides input to
microprocessor for control
 Electronic device: Provides signal to actuator
 Actuator: Activates mechanical system to bring it to required
condition

Contd…
Mechanism
Sensor
Electronic
Device
Actuator
Physical Signal
Physical Signal
Electronic signalElectronic signal
Power
Power
Mechanical
Electronic

Mechatronic system
 Sensing
 Analyzing/Controlling
 responding

Sensors
 Temperature- thermocouple, thermistors, etc.
 Light- light dependent resistors(LDR)
 Force- strain gauges
 Displacement- potentiometers
Controller
 Analyzes the output of the sensor
 Decides what have to be done
 Command the actuator accordingly
Actuator
 Actuates as per the signal from the controller
 Led’s , alarms, heaters, etc.
 DC/AC motors, servos, solenoids.

Examples
Refrigerator
 Sensor – Temperature sensor
 Controller – Timer and temperature control
 Actuator – Fan and compressor
Weighing scale
Purely mechanical: Having spring, rotator, pointer
Mechatronic: Load cell with strain gauge, microprocessor, digital
readout
Temperature controller
Purely mechanical: Bimetallic strip operates on/off switch.
Mechatronic: Thermo-diode sensor, microprocessor controlled

Mechanical system V/S Mechatronics system
• Strong, large and heavy
• Repairable
• Reliable
• Design is difficult
• costly
• Light
• Easily reprogrammable
• Less space consuming
• Easy replacement
• Complex to common man

Advantages:
• The products produced are cost effective and very good quality.
• Greater extent of machine utilization
• High degree of flexibility
• Greater productivity
• High life expected by proper maintenance.
Disadvantages:
• Higher initial cost of the system
• Requires more expertise
• It is expenses to incorporate Mechatronics approaches to existing/old
systems
• Specific problem of various systems will have to be addressed
separately and properly

Micro to Macro
Applications
Mechatronics Systems
MEMS
Consumer
Electronics
Tools
Computers
Cars
Stealth Bomber
High Speed Trains

Mechatronics systems in an automobile

“Smart”
Doorlock
Switchboard with
CAN Bus Gateway
“Smart” Window Lift-unit
CAM Bus
“Smart” Mirror motor-
unit pin-header
- Door System/Module-

-Seat System/Module-
Seat Harness Architecture showing various
smart connector interconnections solutions

•Desktop sized Factory
•Build small parts with a small
factory
•Greatly reduces space, energy,
and materials
-Manufacturing Applications-
Micro Factory
Micro Factory Drilling Unit

CNC Machining
Advantages
•Deliver the highest accuracies
•Can create very complex shapes
-Manufacturing Applications-

-Smart Robotics Application-
System Can
•Carry 340 lb
•Run 4 mph
•Climb, run, and walk
•Move over rough terrain
BigDog
Advantages
•Robot with rough-terrain mobility that could
carry equipment to remote location.

Typical Applications
•Brake-By-Wire system
•Steer-By-Wire
•Integrated vehicle dynamics
•Camless engines
•Integrated starter alternator
Automobiles
Advantages
•Reliability
•Reduced weight
•Fuel economy
•Manufacturing flexibility
•Design freedom
•Advanced safety features
•Cost
-Transportation Applications-

•Train Position and Velocity
constantly monitored from
main command center.
•Error margin in scheduling no
more than 30 seconds
•Fastest trains use magnetic
levitation
High Speed Trains
JR-Maglev
Top Speed: 574 km/h (357 mph)
Country: Japan
Transrapid
Top Speed: 550 km/h (340 mph)
Country: German
Magnetic Levitation

Advantages
•Simple and intuitive
personal
transportation device
Systems Uses
•Tilt and pressure sensors
•Microcontroller
•Motors
•Onboard power source
Segway

-Smart Robotics Aplications-
•Robots can vacuum floors and
clean gutters so you don't have to.
Cleans Gutter
Vacuum Floors

-Space Exploration Application-
System Can
•Collect specimens
•Has automated onboard
lab for testing specimens
Advantages
•Robot that can travel to other
planets and take measurements
automatically.
Phoenix Mars Lander's

-Medical Applications-
Prosthetics
•Arms, Legs, and other body parts
can be replaced with
electromechanical ones.

-Medical Applications-
•Used by patients with slow or
erratic heart rates. The pacemaker
will set a normal heart rate when it
sees an irregular heart rhythm.
•Monitors the heart. If heart
fibrillates or stops completely it will
shock the heart at high voltage to
restore a normal heart rhythm.
Pace Maker
Implantable Defibrillation

-Defense Applications-
•Advanced technology is making
our soldiers safer.
•Some planes can now be flown
remotely.
Unmanned Aerial Vehicle
Stealth Bomber

-Sanitation Applications-
System Uses
•Proximity sensors
•Control circuitry
•Electromechanical valves
•Independent power source
Advantages
•Reduces spread of germs by making
device hands free
•Reduces wasted water by automatically
turning off when not in use

-Sanitation Applications-
Advantages
•Reduces spread of germs by making
device hands free
•Reduces wasted materials by
controlling how much is dispensed
Systems Uses
•Motion sensors
•Control circuitry
•Electromechanical
actuators
•Independent power source
Soap Dispenser
Paper Towel Dispenser

-Sports Applications-
Advantages
•Automatically changes
cushioning in shoe for
different running styles and
conditions for improved
comfort
Running Shoes

Washing MachineSolution Power Supply
Rectifiers/Regulator
Pressure Sensor
MPX5006/MPX2010
-Smart Home Applications-

System
 System can be thought of as a box which has an input and output.
 we are not concerned with what goes on inside the box but only
relationship between the output and input.

Measurement system
 Measurement system can be thought of as a black box which is used
for making measurements.
 It has as its input quantity being measured and its output the value of
that quantity.

Measurement system
Three basic elements:
1. Sensor- Responds to the quantity being measured by giving as its
output a signal related to the quantity.
E.g. Thermocouple: input is temperature and output is an emf
related to the temperature value.
2. Signal conditioner- Takes the signal from the sensor and
manipulates it into a condition which is suitable either for display
or for use to exercise control.
E.g. small emf from a thermocouple can be amplified. The
amplifier is the signal conditioner.
3. Display system- where the output from the signal conditioner is
displayed.
E.g. a pointer on a scale or digital readout.

Control system
 Control system are an integral part of our lives and play very
important role.
 From a simple bread toaster to complex power plant, control system
are all around us and inseparable part of modern society.
 Launching a satellite in orbit, regulating a power plant, tracking
enemy on radar are some of man made control system.
 Control system occur in nature also. Human body is a great example
of complex Control system, because we've so many control system
by nature i.e. respiratory, Digestive system etc.

 Control system : A control system is an arrangement or a
combination of various physical components, also called sub-
systems, connected in such a manner so as to attain a certain
objective.
 Input : The excitation applied to the system from an external
source to attain a output is called input signal.
 Output : The actual signal attain from system is called output
signal.
 Control action : is a quantity responsible for activating the system.
Basic Block Diagram of Control System

Control system
 Control some variable to some particular value.
E.g. A central heating system where the temperature is
controlled to a particular value.
 Control the sequence of events.
E.g. A washing machine where the dials are set to, say ‘white’
and the machine is controlled to a particular washing cycle.
Sequence of events, appropriate to that type of clothing.
 Control whether and event occurs or not.
E.g. a safety lock on a machine where it cannot be operated
until a guard is in position.

Concept of feedback
In order to maintain the accuracy of the output, the input may need to
be adjusted using FEEDBACK.
Examples
 When body temperature goes below normal, the body is made to
shiver to increase the temperature. Similarly, when temp. goes above
normal, sweating takes place.

 when you want to pick up the pencil, feedback guides the hand to
the exact spot.

Open-Loop System
Closed-Loop System
Types of control system

Open loop control system
 Those systems in which the output has no effect on the control
action are called open-loop control systems. i.e. It doesn’t
automatically correct the changes in the output.
 A system in which control action is independent of the output of the
system is called as open loop system.

 In open loop system, the output remains constant for a given
input provided the external conditions are the same.
There is no connecting action taking place in an open loop
system i.e. No Feedback

Examples of Open loop system
 Electric Hand Drier
 Automatic Washing Machine
 Bread Toaster
Advantages
• Simple Construction &
Design
• Economic
• Easy maintenance
• Stability
Disadvantages
• Incorrect and unreliable
• Internal Disturbance
• Recalibration is required time
to time

Close loop control system
 A system in which the control action is dependent on the output
is called close loop system. In close loop system the output is
constantly monitored and adjusted to the required value by the
system.
 The output signal is fed back.

 Depending upon the difference between the output signal
and reference input, corrective actions can be taken by the
controller to adjust the output.

Examples of Close loop system
 Automatic Electric Irons
 Voltage Stabilizer
 DC motor speed control by Tachometer
 Missile Launcher
Advantages
• Accuracy is high
• Facilitates Automation
Disadvantages
• Complicated in design and
maintenance costlier.
• Problem of Stability

Comparison of Open loop and Close loop system

Basic Elements of Closed Loop System
1.Comparison element
2.Control element
3.Correction element
4. Process elements
5.Measurement elements

Basic Elements of Closed Loop System
Comparison element
compares the reference value of the variable condition being controlled
with the measured value of what is being achieved and produces an
error signal.
Error signal = reference value signal – measured value signal.
Negative feedback – signal related to the actual condition
being achieved is feed back to modify the input signal to a
process.
Positive feedback – occur when the signal feedback adds to
the input signal

Control element
It Decides what action to take when it receives an error signal
Correction element
Produces a change in the process to correct or change the
controlled condition.
Process element
The process that is being controlled. E.g. room whose temperature
is being controlled, tank whose level is being controlled.
Measurement element
Produces a signal related to the variable condition of the process
that is being controlled. E.g. a switch which is switched on when a
level is reached or an emf when a temperature is reached.

Analogue and digital control systems
Analogue systems are ones where all the signals are continuous
functions of time and it is the size of the signal which is the a measure
of the variable.
Analogue signal: measures the size of
the variable

Digital signal: the value of the variable is
represented as a series of ON/OFF pulses
Digital signals are a sequence of on/off signals, the value of the
variable being represented by the sequence of on/off pulses.

Comparison of Analogue & Digital systems
 Analogue to digital converter (ADC) and Digital to analogue
converter (DAC) elements are placed in the loops.
 So that the microprocessor systems can be supplied with digital
signals for processing and then produce an output which is converted
to an analogue signal to operate the correction units.
Process
Measurement
Control
elementComparison
Reference
value
Correction
elementError
signal
Process
Measurement
Control
elementComparison
Reference
value
Correction
elementError
signal
ADC
DAC

Introduction to controllers
 Most industrial processes require that certain variables such as flow,
temperature, level or pressure should remain at or near some reference
value, called SET POINT.
 The device that serves to maintain a process variable value at the set point
is called a CONTROLLER.
 A Controller is a device that receives data from a measurement instrument,
compares that data to a programmed set point, and, if necessary, signals a
control element to take corrective action.
 Controllers may perform complex mathematical functions to compare
activities a set of data to set point or they may perform simple addition or
subtraction functions to make comparisons.
 Controllers always have an ability to receive input, to perform a
mathematical function with the input, and to produce an output signal.

Types of controllers
There are a number of ways by which a control unit can react to an error signal
and supply an output for correcting elements:
 Proportional controller
 Integral controller
 Derivative controller
 Proportional Integral controller
 Proportional Integral Differential controllers
 Microprocessor based controllers

Proportional controller
 Proportional mode which produces a control action that is
proportional to error. The correcting signal thus becomes bigger, the
bigger the error.
 Thus as the error is reduced the amount of correction is reduced and
the correcting process slowdown.
 In other words, the output of a proportional controller is the
multiplication product of the error signal and the proportional gain.

Example:
• Watt’s governor
• Flush tank filling valve

Contd…
Constant rate of change of error
Time
Error
0
Time
Controlleroutput
0
Constant rate of change of
controller output

Integral controller
 Which produce a control action that is proportional to the integral
of the error with time.
 Thus a constant error signal will produce an increasing correcting
signal.
 The correction continues to increase as long as the error persists.
 The integral controller can be considered to be ‘looking back’,
summing all the errors and thus responding to changes that have
occurred.

Contd…
The rate of change of controller output (I) is proportional to the input
error signal e.
𝑑𝐼
𝑑𝑡
= 𝐾𝐼 𝑒
Where e is the error and KI is a constant of proportionality having the
units 1/s. Integrating we get
𝐼0
𝐼 𝑜𝑢𝑡
𝑑𝐼 =
0
𝑡
𝐾𝐼 𝑒𝑑𝑡
Therefore 𝐼 𝑜𝑢𝑡 − 𝐼0 = 0
𝑡
𝐾𝐼 𝑒𝑑𝑡
Where I0 is the controller output at time 0 and Iout is the output at time t.

Integral control
Constant rate of change of error with time
Time
Error
0
Time
Controlleroutput
0

Derivative controller
 Which produces a control action that is proportional to the rate at
which the error is changing.
 When there is a sudden change in the error signal the controller
gives a large correcting signal, when there is a gradual change only a
small correcting signal is produced.
 Derivative control is not used alone but always in conjunction with
proportional control and often integral control.

Contd…
The controller output is proportional to the rate of change with time of
the error signal.
𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑙𝑒𝑟 𝑜𝑢𝑡𝑝𝑢𝑡 = 𝐾 𝐷
𝑑𝑒
𝑑𝑡
Where e is the error and KD is a constant of proportionality.
 As soon as the error signal begins to change, there can be quite a
large controller output.
 However, there is no response to steady state errors.
 Derivative controllers are therefore combined with proportional
controllers.

Derivative controller
Constant rate of change of error with time
Time
Error
0
Time
Controlleroutput
0

Proportional plus Integral (PI) control
 The integral mode of control is not usually used alone but is
frequently used in conjunction with the proportional mode.
 When integral action is added to a proportional control system the
controller output is given by
Where KP and KI are the proportional and integral control constants and
e is the error.
𝑐𝑜𝑛𝑡𝑟𝑜𝑙𝑙𝑒𝑟 𝑜𝑢𝑡𝑝𝑢𝑡 = 𝐾 𝑃 𝑒 + 𝐾𝐼 𝑒𝑑𝑡

Proportional plus Integral plus derivative (PID)
control also known as three-mode control
Combining all three modes of control (proportional, integral and
derivative) gives a controller knows as a three-mode controller or PID
controller.
Where KP, KI, and KD are the proportional, integral and derivative control
constants respectively and e is the error.
𝑐𝑜𝑛𝑡𝑟𝑜𝑙𝑙𝑒𝑟 𝑜𝑢𝑡𝑝𝑢𝑡 = 𝐾 𝑃 𝑒 + 𝐾𝐼 𝑒𝑑𝑡 + 𝐾 𝐷
𝑑𝑒
𝑑𝑡

Microprocessor based controllers
 Hard-wired circuits are now more likely to have been replaced by a
Microprocessor based controlled system,
 And sequencing being controlled by means of a software program.

Sequential controllers
An illustration of sequential control, consider the domestic washing
machine. A number of operations have to be carried out in the correct
sequence. These may involve:-
 A pre-wash cycle when the clothes in the drum are given a wash in
cold water
 A main wash cycle when they are washed in hot water
 A rinse cycle when they are rinsed with cold water a number of
times.
 Spinning to remove water from the clothes
Each of these operations involve a number of steps.

Example :- Pre wash cycle involves following steps
 Opening a valve to fill the machine drum to thee required level
 Closing the valve
 Switching on the drum motor to rotate the drum for specific time
 Operating the pump to empty the water from the drum.
The operating sequence is called a program , the sequence of
instructions in each program being predefined and built into the
controller used.

Introduction to Mechatronics

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