A basic guide to a technical journey……A COMPILATION COMPRISING OF BASIC KNOWLEDGE ON ROBOTICS..

What do we first imagine to hear of robotics ?

Is it chitti or iron man or some other action hero . It is one which may talk ,walk , laugh and remind us of one of our favourite heroes like the Terminator.

Yes they too soon may be there in existence with advancing technology and researches.

They fascinate us ,climb up to our nerves but it too started with a small step which we are going to discuss.

Let’s start with the basics of robotics and help you make a real manually controlled car.

What we need ? How to get started ?

Here is the answer . As all the electronic components which we come across can be

broadly divided to be made up of a few categories . We are going to discuss the same.

Before this you need to have a basic knowledge about the small articles which we are going to use for our endeavor.

Let’s discuss the components and branches you need to emphasize upon to make by yourself a self controlled car.

These are the individual broad fields in the field of robotics.

LOCOMOTIONPower and locomotion comprises the mechanical design (the first steps :P)

POWER SOURC

E

SENSORS

These in company of control system makes the user friendly interface for execution .

CONTROL SYSTEM

PARTS OF MOBILE ROBOT TO DISCUSS :

POWER SOURCE

LOCOMOTION SYSTEM

RECTIFIER CIRCUIT

SENSORS

H- BRIDGE

COMPARATORS

SWITCHES

ASSEMBLING

THE POWER SYSTEM

Without food as none can work same applies to the working live structures we make.

In India , the main power which is available is 220V at 50 Hz. But most of the components which are easily available and are used, are designed to have lesser rating of around 12 V . They are D. C. components .

This problem can be sorted by use of :

1• A battery of required rating .

2• An Adapter

3• A rectifier circuit

COMPONENTS TO BE USED.

TRANSFORMER

• Increase voltage of generator’s output and adjusts voltage to a usable level.

Transmit high power at low current

PRINTED CIRCUIT BOARDs

A printed circuit board, or PCB, is used to mechanically support and electrically connect  electronic components using conductive pathways and tracks.

ADAPTER

It converts A.C. supply to a D.C. supply

It is used in video games, speaker etc.

It has internal transformer in-built.

SOLDER

This is the binding solution to electronic components.

It is used to design our own circuit and bind wires together.

RELIMATES These are wires with special

attachments at the end enabling easy switching mechanism.

DIODES These are bidirectional components

meant to act as valves to the direction of flow current.

CAPACITORS This is a charge storage which

stores electrical energy and discharges it slowly.

Integrated circuits These are designed for specific

tasks and may function from smoothening the pulsating waves to acting as the fundamental part.

SENSORS (the feedback mechanism)

These are the sensory organs of the robots.With advancing technology and researches robots too possess the power of senses . VARIOUS APPLICATIONS OF SENSORS.

Sensor interfacing: It’s direct application may be seen in line or wall following robots. They are a

link between us and bots as they act as an interface.

Acts as a trusted safeguard It is used in fire alarms, parking sensors in vehicles etc.

It is used in Xbox series and is a major component of artificial intelligence in robotics.

1. Their eyes As we have eyes robots too have a vision mechanism in which combination of LDR and

LEDs form the most basic system. They even find application in image processing.

Light Dependent Resistors It’s resistance depends upon the

intensity of light and it’s made of CdS .

Light Emitting Diodes This is used to give a visible response

of the bot to the stimuli to the user.

2. LISTENING and SPEAKING The sound receptors in combination with speaking mechanism is an essential field

in of artificial intelligence. Besides today this is found in almost every mobile. It’s the speaking animals that imitate us and is used as a fun tool in almost every mobile.

It’s most common use may be seen in speech recognitions sensors in computers and mobiles.

3. NOSE The electronic nose was developed in order to mimic human olfaction that

functions as a non- separative mechanism: i.e. an odour / flavor is perceived as a global fingerprint.

Electronic noses include three major parts: a sample delivery system, a detection system and a computing system.

And who is going to forget the Google nose though it was a prank.

THE LOCOMOTION SYSTEM In the robotics world we come across a lot new mechanisms meant for

different types of venture. Similarly in locomotion as well a lot new mechanisms have been invented depending upon our need like the ones in the upcoming slides.

Basically we’ll be dealing with differential drive which is one of the most common and simpler driving mechanism.

And at the end , creativity is what

brings in a visually appealing special

touch to it.

1. DIFFERENTIAL DRIVE This is the most common

drive used for manually controlled bots.

It comprises of chasse having wheels and motor connected with a control box ( which is an organized assembly of switches, wires )

It enables your bot to move forward , backward ,take left or right turns and even zero radius turns.

2. Skid Steer Drive

It is used mostly in tracked machines e.g. tanks.

The left and right wheels are driven independently.

Multiple drive wheels on each side give increased traction.

This effect enables it to have better control .

Finds application in some four /six wheeled robots.

3. CAR TYPE DRIVE

It is characterized by a pair of driving wheels and a separate pair of steering wheels.

The turning mechanism must be accurately controlled .

He system is Non- Holonomic hence path planning is extremely difficult as well as in accurate

There is no direct directional actuator.

4. ARTICULATED DRIVE An articulated robot is one

which uses rotary joints to access its work space.

Usually the joints are arranged in a “chain”, so that one joint supports another further in the chain.

These are in great use in industrial robots from steel industries to bakeries.

5. PIVOT DRIVE

It is composed of a four wheeled chassis and a platform that can be raised or lowered .

The wheels are driven by a motor for translation motion in a straight line

For rotation one motor is needed to lower/raise the platform & another to rotate the chassis around the platform

This system can guarantee perfect straight line motion as well as accurate in – place turns to a desired heading

6. SYNCRONOUS DRIVE

These function same as they sound . This is an assembly of drive belts, steer belts, steering and driving motors.

These together work in a synchronous manner to enable movement in desired direction.

This is quite a complex system.

7. DUAL DIFFERENTIAL

DRIVE  We use two differentials

because the excess force from one differential automatically feeds into the 2nd diff, and therefore we have a mechanical guarantee of straight-line motion.

These are used in making stronger robots which may work well even on rough terrains.

THE H-BRIDGE

An H bridge is an electronic circuit that enables a voltage to be applied across a load in either direction.

These circuits are often used in robotics and other applications to allow DC motors to run forwards and backwards.

H bridges are available as integrated circuits, or can be built from discrete components

COMPARATORS

These are not sensors.

These are meant for analog to digital conversion.

It is the main component which makes the input data as sensed by the bot be electrically judged.

They are available in different models based on the need.

These find wide applications in embedded system of robotics.

THE RECTIFIER CIRCUIT

Rectifiers are combination of diodes ,capacitors, ICs , transformer in such a way that it may convert A.C. current into D.C. .

It works as one way valve allowing current to pass through only one direction.

The output wave form is a pulsating dc wave which after passing through capacitors and ICs turn into a usable D.C. source.

Components needed 1 PCB

4 x diodes

1 x 1000µF Electrolytic Capacitor 25 V

1 x IC7812

Soldering rod and wire

2 pin Relimates

Transformer 12V

Plug connected to a long strand of wire

Single/ Multi stranded wire

2 x 12V D.C. motors of 100rpm

2 x normal wheels

1x caster wheel

SWITCHES

As clear from the name it’s the key which turns our bot to power.

It even facilates us to have multiple controlling methods.

Here to make a differential drive we need a two way switch with the following arrangement of wire.

This gives us a two way control

The middle parts are connected to power source.

While the wires coming from the ends are connected to the motors as shown in the figure.

ASSEMBLING THE DIFFERENT PARTS. Once the rectifier circuit is made

and the switch is connected to the motors , we can see the model working but we need a strong framework or chasse.

The chasse comprises of a solid base of wood or metal having the motors and wheels placed in position.

You may use a caster wheel in front to balance it.

Once done we may switch on the power supply and see our mobile manually controlled differential drive working.

QUIZZIE….

CONCLUSION

This is just the starting. A new era is waiting for us though the exposure is quite less we may see the impact which they have made upon us . Robotics has a global platform in world level competitions as well like Robosoccer and FIRA . You may find them in almost every field and soon it will be an integral part of life.

Have fun with your differential

drives :D