a beginners guide to robotics

7/31/2019 A Beginners Guide to Robotics

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A Beginners Guide toRobotics

&

Embedded System

By

Udit SangwanPresident: Tech Robotrix Society

(Electrical & Electronics Department)

Chapter : 1- Introduction ToRobotics


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You must be thinking about what must actually a robot is____________, rajnikanth? Transformers? , funny, well theanswer is really very simple the machine that solves yourtask, works efficiently without getting tired. Well a robot is amachine with motion, like we can call a JCB as a robot butnot a photocopy machine.

Robot making needs total engineering skills, mechanical fordesigning, electronics for circuitry, electrical for powermanagement and cs/it for programming a robot.

Well there are basically two types of robot:1. Manual Robot2. Autonomous Robot

Manual Robot:No Brain, No intelligence results to

manual robot, these types of robots are too controlledmanually. We can also know them as remote controlledrobot, there designing are done as for specific task and

then they are controlled manually.

Autonomous Robot:


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Intelligent Robots are autonomousrobot, they have brains and controlled through Micro

controller (to be discussed) . Although this brain isembedded by us, then programmed by us for the specifictask. But they are intelligent as perform there task withoutour help.

Special Type of Robot i.e. Semiautonomous Robot ,These robots are robots with brain but need our assistanceto work properly.

Now , I think we are ready to start discussing about theconstruction detail of robots in different chapter for differenttypes of robot.

Chapter: 2 Manual Robots

Manual robotics is nothing but it is an introduction toMechanical & Electrical Aspects in Robotics. Manual Roboticsis one in which human controlled robots using switches,relays and joystick.

Manual robotics is just consist

1. Chassis And Drive Mechanism2. Gripper And Lifting Mechanism3. Power Supply

Chassis And Drive Mechanism:-


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Chassis is the base of robot, so you need to decide whatmaterial to be used while making base i.e. (Wooden or Mfr

sheet, Fiber or iron).While making base following point keep following point inmind.

It should bear weight of the entire component to beplaced over it.

Extra strength to be provided to avoid damage.

Dimension and material should be strong but of lessweight.

Now i think we should talk formally and start building amanual robot of just 2- wheel, 1 caster wheel a chassis,wish it may give you brief idea what I am talking from lastfew minute. Actually we need 2- D.C Motor to drive therobot, but I think discussing about motor is not the correcttime, so lets construct a chassis first then we will discuss.

To build a chassis you need a base, lets for example we

take a fiber base and now we need to mount motor andcaster wheel on it. Caster wheel is to be fixed in front tobalance the robot. To mount motor clips are attached tobase, so that it can hold your motor then tires areattached to your motor and your base is ready. Theimage1shown is mounting brackets for small dc motors,

motors are fixed in center thenthese clips are screwed on thebase.

Image -2 is of dc motors, image -3

is tires mount on motors and 4th isof caster wheel.


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Few Images showing complete structure of robot.

(Front view)

(Top View)


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(Bottom View)

Now, I think you have got idea of building a simple base of

robot. So lets move on to the driving mechanism, that how todrive a robot.Once connection of battery is made to motors then

If you rotate both motor in same direction robot willgo straight.

If you stop left motor, and rotate only right motorthen robot will turn left, vice versa robot will turnrobot right.

If you rotate left motor in forward direction and

rotate right motor in backward direction then robotwill take sharp turn.

If you are planning to build an high speed robot with hightorque then you need to use gear mechanism drive to drivethe robot. Well speed and torque both are inverselyproportional to each other if speed that is if rpm of motorincreases its torque will decrease, so to maintain both gearsmechanism is used. You can also increase your speed ofrobot by increasing radial radius of tires as we all know,

v = * r, where v= linear velocity and is angular velocity and r is the radiusIn this case to increase the linear speed you need to increase the radius, i.e. radius of tires as angular

velocity is constant that is rpm of motor.


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Thus concept of increasing speed is now clear in upcomingsection we will discuss how to increase the speed using

gears, actually some dc motors are of very high r.p.m butthere torque is very less so gears are used to decrease therespeed and increase the torque, as there r.p.m is about 3000r.p.m.

Concept Of Gears :-

Gripper And Lifting Mechanism:-


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Gripper and lifting mechanism are two common problemtask of any robot if you need to drag something then you

have to grip it and if you want to lift it then you need togrip as well as you need to lift.For gripping mechanism there can be two best

possibilities:-

1-fixed arm and other arm to be their in motion. Both arms to be in motion, the motors with gears are

responsible for armmotion.

Images show the griping

mechanism the black isrepresenting Dc Motor use todrive the gears. If Motormoves in left then its startclosing and if if moves towardright it start opening. Similarlylifting mechanism need a rodthat to b placed horizontallyand a motor is to be placed on

its bottom, so when motorsets in motion is start lifting your entire mechanism.

Power Supply:-

There are two ways to provide power supply to a robot i.e.on board and off board in On-Board power supply is giventhrough battery and in Off- Board it is provided through

adapters.

Making of a 12 Volt Adapter:-


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Things that you will need to make this power supply are...

1. A step down transformer 240/12v2. Capacitor(1500mf/12v)

3. Bridge rectifier4. Shunt resister

1st connect bridge rectifier on secondary side of the transformer. Then filter the

output supply by using a capacitor and connect a shunt resister for finding constantcurrent.

The power supply is of 1 amps constant .

Here, we end up with manual robotics, or we can basic needof a robot as, each robot need a chassis, power supply and amechanism to perform various task. I think I m forgetting totell you how to control a robot with a switch, but you candirectly control motion of robot using LT controllers inavailable at very less rate in market. Robotics is not going toend here still many things and many topics are left toachieve. Its very simple just a proper guidance is needed, I msure that from today you are not going to ask from where I

can startup for robotics.

a beginners guide to robotics

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