Indian Institute of Technology Delhi by nikeborome


     FILL THE BUNKERS: A Test of Speed

     ROBO COMBAT: A Show of Power
what you need to know . . .

                   The first robot is always the hardest.

           So we will take the KISS approach:
           Keep It Simple, Stupid!
your first robot will have 2 wheels
driven under the most basic algorithm – Differential Drive.

                                                  • to drive straight both wheels move
                                                  forward at same speed
                                                  • to drive reverse both wheels move
                                                  back at same speed
                                                  • to turn left the left wheel moves in
                                                  reverse and the right wheel moves
                                                  • to turn right the right wheel moves in
                                                  reverse and the left wheel moves
                   Wheels and Motors

• Big wheels will let your robot move faster. Small wheels for slower.
• But bigger wheels means your robot has less torque to carry a heavy

• Choosing motors would involve calculations of weight, gearing ratios,
desired terrain, desired velocity and acceleration, voltage, power
consumption, controllability and a whole range of things too overwhelming
for a beginner

                        Arey IIT JEE ke
                        funde lagaayo yaar!!
                                Types of motors to use

• DC geared motors
• Drive trains

                                                         Motor on which a gear
                                                         box is mounted.

                 Set of gears arranged in a pattern

                    Voltage: 6V - 24V
                    Torque: double what you think you will need
                       Specific components you may need

    – Voltage Regulator
    – L293D - Motor driver + H bridge

                                                  • Drive a pair of DC
                                                  motors/Geared Motors
                                                  • Motor supply voltage can go
                                                  up to 24Volts
                                                  • Maximum of only 600mA
                                                  • Enough to drive small DC
                                                  geared motors

Remember to add 0.22uF capacitors across both the motors to reduce the effect
of noise on the circuitry
What about higher current requirement ?

                          • Use ULN2003 – current amplifier
                          • …and relays for switching
                                  (as explained earlier)

                              Use protection diode for relays
                           Wired / Wireless Remote control

• Wireless remote control complexes the circuitry
• But you can get rid of that long wired tail dangling out of your remote control robot
• Easiest solution would be to hack those cheap wireless toy cars, take their
electronic guts out and use them in your robot
• For more flexibility, you can build a custom remote control system

        Use RF Tx/Rx modules
        and encoder/decoder ICs
Tools and some other components

                       Diodes           Transistor

Circuit board

                                                     Solder sucker   Soldering iron
                                                                     with stand
                           Battery clips

Wire Stripper Pliers            Variable resistors                    Switches
                      Always follow the principle
                      ‘ DESIGN,THEN BUILD ’

          planning things is generally always a good idea

“for every hour spent on design is one less hour spent on construction”
                  (and usually low quality construction at that!)
                             Mechanical Aspects

• Make sure that the machine is properly balanced.

• Bring the machine’s CG as low as possible.

• Achieve this by bringing the motors as close as possible to the ground.

• Make the weight of the front and rear of the machine nearly equal to prevent

• Check your motors for enough torque.

• Try to reduce total machine’s weight by using lighter materials and as less
material as possible.
     • basic structure to which you attach everything else.
     • probably the largest part of your robot.
     • make sure it is made of a light weight rigid material such as aluminum.
     • Reasonably cheap
     • Easy to work on
     • Strong enough
                                   Wheel Basics
• Wheel diameter ( discussed earlier )
• Wheel texture : smooth wheel will not have much friction
                  skid while accelerating and braking
                  really rough wheel, has higher friction with the ground
                  consider wear and tear
• Wheel width : increased resistance to rotating the wheel on a surface
• Wheel centre hole diameter : depends on length and diameter of your motor
output shaft
Gripper design – mechanisms

                              • Material used : Aluminum
                              • Use 2 motors, one each
                              for the hands of gripper.
                              • Use single motor mounted
                              on one hand and other
                              coupled to it using gears.
                              • gripper should be light
                              weight : use light weight
                              • use foam or rubber to
                              increase friction
                              • Design the grip acc. to the
                              For picking up the ball
                              use cup shaped grip.
Tools and some other components
                                   Places to acquire materials
Lajpat Rai Shop no. 629
Motors, Solenoids, Light sensors, Encoder disks
Mehta Brothers
Lajpat Rai Shop No. 614
ICs,SMD components,LCD,Wireless Radio modules,
Connecters computer type,

Shop No. 463          Lajpat Rai

Prakash Radio
1675       Bhagirath Palace
Relays + connecters, switches,push buttons

R Kumar
Shop no. 3602 , Ph. 23912860
Mechanical components
‘difficult to describe but you will know one if you see one’

To catch up the demonstration of some of our BOTS,
you all are welcomed to assemble in Robotics room,
SAC at 8 pm, today…

To top