3. In this project the speed & direction of a DC motor
is controlled wirelessly by a RF remote control.
An anti-collision system is used to detect external
objects from a permissible limit, so by instantaneous
braking collision can be avoided.
The whole system is implemented by a manually
controlled robotic car.
4. Practical Aspects
DC Motor
DC Geared Motor
Steering & Navigation
Car Wheels
Four Quadrant Operation of DC Motor
Pulse Width Modulation Technique(PWM)
Anti-collision System
Obstacle Sensing Devices
Wireless(RF) Control
5. 1.Wireless control of D.C Motor enables us to use this in
the field of Robotic application.
2.This particular application can be used as modern surgery
equipments.
3.The use of PWM technique in speed control of D.C
motor enables us precise and low loss control.
4.The anti-collision system has a huge aspect in avoiding
accidents.
5.The wireless robotic car can be used as a very good
surveillance device.
6. An electric dc motor as well as all motor is a machine which
converts electrical energy into mechanical energy.
Type
DC motors are classified depending upon the way their
field windings
1. Shunt DC Motor 3. Permanent Magnet DC Motor
2. Series DC Motor 4. Universal DC Motor
5. Compound DC Motor
Parts
DC motor consists the
basic parts of
Axel
Rotor
Stator
Commutator
Field Magnet
Brushes
7. The equation of speed of dc motor is
N=(V-IaRa)/kΦ
V= supply voltage (volts)
Ia = armature current (amps)
Ra= armature resistance (ohms)
Φ= flux per pole (Weber)
So speed can be varied by following methods
1. Armature Resistance Control.
2. Field Flux Control.
3. Armature Voltage Control.
8. In this project we will use dc geared motor. Gear motors are
designed to reduce the output speed while increasing the torque.
Salient Features of D.C geared motor:
12 volt, 1200 rpm to 3600 rpm
Quieter operation due to integral castings
Minimum risk of lubricant leakage
Optimum power management and power
utilization
Space saving, durable, low energy consumption
9. We will use two geared motor with
two wheels attached through motor shaft.
This is mainly a permanent magnet dc
motor.
To steer the vehicle through turns
we used the motor driver ic L293D.L293D
11. Wheels are also very important part of designing the car.
Velocity of car not only depends on the RPM of the motor, It also
depends on the Wheel Diameter .
Velocity of car = RPM X Wheel Periphery.
But It is always preferred to use Medium Speed and Medium Wheel
Size.
Different
types of
wheels
12. Here in this project we use four quadrent operation of dc motor
1. Forward Motoring. 3. Reverse Motoring.
2. Forward Braking. 4. Reverse Braking.
13. Pulse-width modulation (PWM) is a commonly used technique
for controlling power to inertial electrical devices, made practical by
modern electronic power switches.
In this method normally a sine wave is modulated with high
frequency carrier signal to derive
the pwm signal.
The speed of the dc motor is
controlled by varying the duty
cycle of the signal.
Duty cycle=(ton/T)
14. Pulse width modulation control works by switching the
power supplied to the motor on and off very rapidly. The DC
voltage is converted to a square wave signal, alternating between
fully on (nearly 12v) and zero, giving the motor a series of power
“kicks”.
In our project as our RF controller does not have the
provision to use an extra variable resistance to control the PWM
method .
So, We use an embedded PWM chip TIUC3525A to generate
the PWM signal . This signal is changed by the RC and fed to the
D.C motor.
15. Cheap to make.
Little heat whilst working.
Low power consumption.
Can utilize very high frequenzies (50-100 Khz is not uncommon.)
Very energy-efficient when used to convert voltages or to dim light
bulbs.
High power handling capability.
Efficiency up to 90%
16. We have used IR sensing system for obstacle detection and
interfaced through ADC0804 with AT89C51 microcontroller for
instantaneous braking.
AT89C51 standard features:
4Kbytes of Flash.
128 bytes of RAM.
32 I/O lines.
Two 16-bit timer/counters.
Five vector two-level interrupt
architecture.
A full duplex serial port.
On-chip oscillator and clock circuitry.
17. Obstacle
We have used IR sensing devices to
detect the obstacles.IR sensor consists of
a transmitter & a receiver.
Actually receiver is a photo diode which
receive the transmitted rays returned
from obstacle.
18. START
IR TRANSMITTER IR RECEIVER
ADC0804
µC
VALUE
CHECKING
MOTOR
CONTINUOUS
END INSTANTANIOUS
BRAKING OF MOTOR
INTENSITY
MEASUREMT
( OBSTRACLE
DETECTION)
LOW(NO)
HIGH(YES)
GREATER(YES)
LESS(NO)
19. The D.C motor is controlled wirelessly by a RF controlled
remote control.
The mechanism is described by the following block diagrams.
RF
ENCODER
RF
TRANSMIT-
TER
ANTENNA
TX-2B
POWER
ON/OFF
SW2
SW1
SW3
SW4
Transmitter Unit
21. Here we use a spring
sliding switch for convenience and
precision.
HereSW1,SW2,SW3,SW4,
are DPDT switches. SW1 and
SW2 are combined in a single
switch which will control the
speed and direction of D.C motor
and SW3 and SW4 are combined
together for navigation & steering
purposes.
22. 1. In our project additional modifications can be made by
adding extra close circuit camera. A servo motor and
additional circuitry to make this an excellent surveillance
device.
2. The anti-collision system can be further modified into an
autonomous robot which will avoid the obstacle
automatically.
3. The mechanical power transmission system can be made
better further by using suitable gears and other
equipments.
4.The Power supply unit can be made solar powered.
23. 1.The 8051 Microcontroller –Kenneth .G.Ayala.
2.The 8051 Microcontroller and Embedded Systems –Mazidi &
Mazidi.
3.The Handbook of Robotics,SPRINGER.
4.Robotics Demystified—Edwin Wise,TMH.
5.The Robot Builders Cookbook-Owen Bishop,Newens.
6.The Power Electronics Handbook—Malestorm..
7.www.atmel.com
8.www.engineeringgarage.com
9.www.wikipedia.com
10.www.robotforum.com
24. In this semester we have came familiar to many
new things such as wireless communications, learned
how this type of communication works, Different type of
PWM controllers, the Transmitter, Receiver etc. The
Anti-collision system algorithm is designed and also the
wireless system for speed control of d.c motor.
