The slide used in Second Workshop for freshers.

1. TECHNOLOGY ROBOTICS SOCIETY Indian Institute of Technology, Kharagpur

2. A Tutorial on Robotics Part III : Motors & Motor Drivers

3. Copyright © Robotix Team, IIT Kharagpur Basic Parts Of Our Mobile Robot Locomotion system Power supply system Actuators Sensory devices for feedback Sensor Data processing unit Control system

4. Potentiometer

5. Capacitors

6. LED

7. IR LED

8. Diodes

9. Current Flow in a Diode

10. Multimeter

11. Transformer

12. POWER SUPPLY (RECTIFIER CIRCUIT)

13. IC7805 1 - Input 2 - Ground 3 - Output

14. THE RECTIFIER CIRCUIT

15. USES OF RECTIFIER CIRCUIT Rectifier circuit is used to convert Alternating Current to Direct Current. We get Alternating Current as Power Supply in our homes, but electronic components in robots use Direct Current.

16. STEPS OF CONVERTING AC TO DC First the Transformer, converts 220V AC to 12V AC. The Diodes rectify the current in a single direction. The Capacitor then normalizes the current. The little distortions are further rectified by the IC7805.

17. Copyright © Robotix Team, IIT Kharagpur End Actuators They convert the electrical energy into meaningful mechanical work Mechanical output can be rotational or linear (straight line) Motors provide rotational motion Electromagnets provide linear motion

18. Copyright © Robotix Team, IIT Kharagpur Motors are of various kinds AC Motors : Not used much in robotics Stepper Motors : For controlled rotation DC Motors : Finds extensive general use Servo Motors : DC motor with in built feedback & error compensation

19. Copyright © Robotix Team, IIT Kharagpur DC Motors As the name suggests, a motor which uses a DC (Direct Current) power Can run in both directions Speed Controllable

22. Operating Current : Current drawn at a certain load on the shaft

23. Stall Current : Maximum current drawn, when motor not allowed to rotate

25. Copyright © Robotix Team, IIT Kharagpur DC Motor Characteristics Cont... DC Motors are high–speed, low-torque devices Using gears, the high speed of the motor is traded off into torque

27. Highest speed while free running (zero load)

29. A low current control signal is converted into a proportionally higher current signal that can drive the motor

31. Copyright © Robotix Team, IIT Kharagpur H – Bridge Working

34. Duty Cycle Fundamentals

35. Copyright © Robotix Team, IIT Kharagpur Duty Cycle Cont… The time period (τ) is the duration after the voltage waveform repeats itself Duty Cycle is the % time of τ, the voltage is equal to the operating voltage The average voltage is equal to the ‘Duty Cycle’ % of the Operating Voltage

37. This forms the backbone of our speed control circuit

39. LDR - Light Dependent Resistor Made of cadmium sulphide Resistance between two terminals vary depending on the intensity of light Can be used to differentiate contrast colours

40. Comparator + Z X - Y

41. Sensor Interfacing Light Sensing Module using LED-LDR combination

42. Sensor Interfacing Bump Detector Module

45. Block Layout of Line Follower Optical Sensor Array Steering Controller Left Motor Right Motor

46. Line Following Algorithm All the sensors are assigned some weight such as Sensor 1 = a1 = 3 Sensor 2 = a2 = 2 Sensor 3 = a3 = 1 Sensor 4 = a4 = -1 Sensor 5 = a5 = -2 Sensor 6 = a6 = -3

47. Monday (9th August 2010) Section 1-4 5:30 PM – 8:30 PM Section 5-7 8:30PM - 10:30PM Tuesday(10th August 2010) Section 8-11 5:30 PM – 8:30 PM Section 11-14 8:30PM - 10:30PM Wednesday(11th August 2010) Free Slot 5:30PM onwards ROBOTIX Interviews