introduction to mechatronics

ME- 435 Mechatronics
Lecture # 01
Introduction to Mechatronics
Department of Mechanical Engineering
Sarhad University of Science & Information Technology, Peshawar

What is Mechatronics?
• The word mechatronics is composed of “mecha” from
mechanical and the “tronics” from electronics.
Mechanical + Electronics = Mechatronics
“Mecha” + “tronics” = Mechatronics
• The term “Mechatronics” was coined by Tetsuro Mori, a
senior Japanese engineer at Yasakawa Company in 1969.
robotics.msa@gmail.com

• Mechatronics is synergistic integration of mechanical
engineering, electronics engineering, control engineering and
computer science.
• Mechatronics engineering is the design of computer-
controlled electromechanical systems.
• A mechatronic system is a computer controlled mechanical
system.

Model of a Typical Mechatronic System
Action Control
Sensing the
environment

Modules of a Mechatronic System
1. Sensing
I. Sensors
II. Signal Conditioning
III. Analog-to-Digital and Digital-to-Analog Conversion
2. Control
I. Open Loop and Closed Loop Control
3. Action
I. Drive Circuits
II. Actuators
III. Motors

Components of a Mechatronic System
• Mechanical
• Electronics
• Sensors
• Actuators
• Control
• Computing

Evolution of automated systems:
1. Completely mechanical automatic systems (before and early
1900s)
2. Automatic devices with electronic components such as relays,
transistors, op-amps (early 1900s to 1970s)
3. Computer controlled automatic systems (1970s–present)

• Early automatic control systems performed their automated
function solely through mechanical means.
• For instance, a water level regulator for a water tank uses a
float connected to a valve via a linkage.
• The desired water level in the tank is set by the adjustment of
the float height or the linkage arm length connecting it to the
valve.
• The float opens and closes the valve in order to maintain the
desired water level.

• A mechatronic system has at its core a mechanical system
which needs to be commanded or controlled by a controller.
• The controller needs information about the state of the
system. This information is obtained from sensors.
• In many cases, the signals produced by the sensors are not in
a form ready to be read by the controller and need some
signal conditioning operations performed on them.
• The conditioned, sensed signals are then converted to a
digital form by Analog-to-Digital Convertor (ADC) and are
then sent to the controller.

• The controller is the ‘mind’ of the mechatronic system, which
processes user commands and sensed signals to generate
command signals to be sent to the actuators in the system.
Actuators are devices that can convert electrical energy to
mechanical energy
• The user commands are obtained from a variety of devices,
including command buttons, graphical user interfaces (GUIs),
touch screens, or pads.

• In some cases, the command signals are sent to the actuators
without utilizing any feedback information from the sensors.
This is called open-loop system, and for it to work, this
requires a good calibration between the input and output of
the system.
• The more common mode of operation is the closed-loop
mode in which the command signals sent to the actuators
utilize the feedback information from the sensors. This mode
of operation does not require calibration information.

Open Loop System
Closed-Loop System

• Every computer controlled system has four basic functional
blocks:
1. A process to be controlled
2. Sensors
3. Actuators
4. Controller

• The analogy between a human controlled system and
computer control system is shown in figure.
• If a process is controlled and powered by a human operator,
the operator observes the behavior of the system (i.e. using
visual observation), then makes a decision regarding what
action to take, then using his muscular power takes a
particular control action.
• One could view the outcome of the decision making process
as a control or decision signal, and the action of the muscles
as the actuator signal which is the amplified version of the
control (or decision) signal.

• The same functionalities of a control system can be
automated by use of a digital computer as shown in the
figure.
• The sensors replace the eyes, the actuators replace the
muscles, and the computer replaces the human brain.
• Every mechatronic system has some sensors to measure the
status of the process variables.
• The sensors are the “eyes” of a computer controlled system.
• Actuators are the “muscles” of a computer controlled system.

Examples of Mechatronic Systems
• Antilock Brake System (ABS)
• Electronic Fuel Injection (EFI)
• Traction Control System (TCS)
• Adaptive Cruise Control (ACC)
• Automatic Camera
• Scanner
• Hard Disk Drive
• Industrial Robots
• Mobile Robots (Wheeled Robots, Legged Robots)

Wheeled Robots

Aerial Robots

Legged Robots

Autonomous Cars

Hard Drives Underwater Robots

Industrial Robots

Benefits of Mechatronic Systems
• Enhanced features and functionality
A mechanical design typically provides only one function.
Designing with a microcontroller offers the flexibility of
adding features like LCD displays, lighting LEDs, a user
interface, programmability, safety features, speed control
etc. Modern washing machines, for instance, offer many
features over the mechanical designs of old. These features
include a display that gives cycle information as well as
providing a stain removal guide. These machines use
microcontrollers to efficiently vary the speed of different
cycles based on the content being washed.

• More user-friendly
Mechatronic systems are more user-friendly e.g. power door
locks, keyless entry, cruise control etc.
• Precision control
Flow rate, speed, position, and any number of other variables
can be controlled precisely with a microcontroller.
Cruise control in an automobile is a great example of how a
mechatronic solution allows for precise control. In order to
give the car a smooth acceleration to the desired speed as
well as maintaining a constant velocity over varying load
conditions.

• More efficient
The efficiency of a system can be improved by adding
intelligence to the design. Certain portions of the system can
be shut-off when not in use or a microcontroller can make
better use of the energy available.
• Lower cost
A complex mechanical solution may be simplified using a
microcontroller-based approach. Design time, product size,
and reliability can all be improved with a mechatronic
solution.

• Flexible design (reprogrammable)
Mechatronic systems are flexible and can be easily switched
to perform different jobs by simply changing the robot control
program. This procedure is called "reprogramming“.
• More reliable
Mechanical designs are prone to wear and tear over time.
For example mechanical odometers use a direct drive system
that consists of a flexible cable running from the transmission
to the odometer gage.
The solution is unreliable because the cable is prone to
failure. The modern mechatronic solution consists of an
optical encoder and digital display, which increases system
reliability.

• Smaller size
Adding a microcontroller to a system may result in space
savings.
• Safer
Adding intelligence to a system makes it safer. Whether you
add an automatic shutdown to a coffee pot or sense when a
system is overheating, numerous safety checks can be easily
added to a system when a microcontroller is controlling the
system.

introduction to mechatronics

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