-
1
Introduction to
Mechatronics Adnan Rauf.
Assistant Professor,
Biomedical Engineering Center,
and
Electrical Engineering Department, UET,
KSK Campus.
-
Text Book
Mechatronics
Electronic Control Systems in Mechanical and
Electrical Engineering
Fourth Edition
By William Bolton
Published By: Pearson
ISBN 978-81-317-3253-3
2
-
3
-
4
-
5
MECHATRONICS
Originally Mechatronics just included the combination between
mechanics and
electronics, hence the word is a combination
of MECHanics and elecTRONICS.
However, as technical systems have
become more and more complex the word
has been updated during recent years to include more technical
areas.
-
6
What is Mechatronics?
Mechatronics is a design process that includes a combination of
mechanical engineering, control engineering and computer
engineering.
Examples are a robotic car, photocopier and a disk drive.
-
7
-
Integration of Other Engineerings
The integration across the traditional
boundaries of mechanical engineering,
electrical engineering, electronics and
control engineering has to occur at the
earliest stages of the design process if
cheaper, more reliable, more flexible
systems are to be developed.
8
-
Examples of Mechatronics System
Consider an automated production line.
Such a line may involve a number of
production processes which are all
automatically carried out in the correct
sequence and in the correct way with a
reporting of the outcomes at each stage in
the process.
9
-
10
Benefits of Mechatronics Enhanced features and improved
functionality.
More user friendly
More precision control
More efficient
Lower cost
Flexible Design (Programmability)
Safe
Smaller
-
11
True Mechatronics
The products designed with mechanical and
electronics technologies through synergistic
integration for example a photocopier
machine.
With the development of microprocessor by
INTEL, integration of computational systems
with mechanical system become practical.
The microprocessor is the heart of modern
mechatronics and smart products.
-
12
-
13
Robots in Manufacturing
-
14
-
15
Actuators
Solenoid
Stepper Motors
Servo Motors
Hydraulics
Pneumatics
-
16
Sensors
Switches
Strain Gauges
Potentiometers
Thermocouples
Photoelectric Sensors
Digital Encoders
-
17
Electronics
-
18
Output-Displays
TFT (Thin Film Transistor)
CRT
LED
LCD
-
19
-
Embedded System
The term Embedded System is used where microprocessors are
embedded into
the systems and it is this type of system, we
are generally concerned with in
mechatronics.
An embedded system is a microprocessor
based system that is designed to control a
range of functions and is not designed to be
programmed by the end user in the same
way that a computer is. 20
-
Design Process The design process for any system can
involve series of different steps. Such as:
The need:
The need could be from the customer or client.
This may be identified by market research being
used to establish the needs of potential
customers.
Analysis of the problem:
First of all the true nature of the problem is
analyzed. This is an important stage in that not
defining the problem accurately can lead to
wasted time on designs that will not fulfill the
need. 21
-
Preparation of a specification:
In preparing specifications, all the functions
required of the design, together with any
desirable features, should be specified.
Thus there might be a statement of mass,
dimensions, types and range of motion
required, accuracy, input and output
requirements of elements, interfaces, power
requirements, operating environment, relevant
standards and codes of practice, etc.
22
Design Process
-
Generation of Possible Solutions:
This is often termed as the Conceptual Stage. Outline solutions
are prepared which are
worked out in sufficient detail to indicate the
means of obtaining each of the required
functions e.g., approximate sizes, shapes,
materials and costs. It also means finding out
what has already been done before for similar
problems, there is no sense in reinventing the
wheel. 23
Design Process
-
Selection of a Suitable Solution:
The various solutions are evaluated and the
most suitable one is selected. Evaluation will
often involve the representation of a system by
a model and then simulation to establish how it
might react to inputs.
Production of a detailed design:
The detail of the selected design has now to be
worked out. This might require the production of
prototypes in order to determine the optimum
details of the design.
24
Design Process
-
Production of working drawings:
The selected design is then translated into
working drawings, circuit diagrams, etc., so that
the item can be made.
There will often be a need to return to an
earlier stage and give it further
consideration. Thus when at the stage of
generating possible solutions there might
be a need to go back and reconsider the
analysis of the problem. 25
Design Process
-
Measurement Systems
Measurement systems can be divided into
three basic elements. Which are:
Sensor: A sensor which responds to the
quantity being measured by giving a signal as
its output, which is related to the quantity.
For example, a thermocouple is a temperature
sensor. The input to the sensor is a temperature
and the output is an emf which is related to the
temperature value.
26
-
Signal Conditioner:
A signal conditioner takes the signal from the
sensor and manipulates it into a condition which
is suitable either for display, or, in the case of a
control system for use to exercise control.
For example, the output from a thermocouple is
a rather small emf and might be fed through an
amplified to obtain a bigger signal. The amplifier
is the signal conditioner.
27
Measurement Systems
-
Display System:
A display system where the output from the
signal conditioner is displayed.
This might, for example, be a pointer moving
across a scale or a digital readout.
28
Measurement Systems
-
Consider a digital thermometer. This has an
input of temperature to a sensor, probably a
semiconductor diode.
The potential difference across the sensor
is, at constant current, a measure of the
temperature. This potential difference is
then amplified by an operational amplifier to
give a voltage which can directly drive a
display. 29
Measurement Systems
-
30
Measurement Systems
-
Control Systems
A control system can be thought of as a
system which can be used to:
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 when set to a specific tab,
then the machine is controlled to a particular
washing cycle, i.e. sequence of events,
appropriate to that type of clothing. 31
-
Control, whether an event occurs or not, e.g., a
safety lock on a machine where it cannot be
operated until a guard is in position.
32
Control Systems
-
Topics to be Covered by Yourself
Feed back
Open and Closed Loop System
Basic Elements of a Closed Loop System
Analogue and Digital Control System
Sequential Controllers
33
-
Programmable Logic Controller
A programmable logic controller (PLC) is a
microprocessor based controller which uses
programmable memory to store instructions
and to implement functions such as logic,
sequence, timing counting and arithmetic to
control events and can be readily
reprogrammed for different tasks.
34
-
PLCs are widely used in industries where
on/off control is required.
For example, they might be used in process
control where a tank of liquid is to be filled
and then heated to a specific temperature
before being emptied.
The control sequence might be:
35
Programmable Logic Controller
-
1. Switch on pump to move liquid into the
tank.
2. Switch off pump when a level detector
gives the on signal, so indicating that the
liquid has reached the required level.
3. Switch on heater.
4. Switch off heater when a temperature
sensor gives the on signal to indicate the
required temperature has been reached.
36
Programmable Logic Controller
-
Switch on pump to empty the liquid from the
container.
Switch off pump when a level detector gives
an on signal to indicate that the tank is
empty.
37
Programmable Logic Controller
-
38
Thank You
