WIRELESS SPEED & DIRECTION

CONTROL OF DC MOTOR WITH

ANTI COLLISION SYSTEM

EE 4TH YEAR

PRESENTED BY…

ANUTAM PAUL [09238016031]ARINDAM BANERJEE [09238016044]PARTHA DHARA [09238016037]PRITAM DATTA [09238016038]

INTRODUCTIONIn 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.

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CONTENTPractical AspectsDC MotorDC Geared MotorSteering & NavigationCar WheelsFour Quadrant Operation of DC MotorPulse Width Modulation Technique(PWM)Anti-collision SystemObstacle Sensing Devices Wireless(RF) Control

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PRACTICAL ASPECTS1.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. 

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DC MOTORAn 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 Motor2. Series DC Motor 4. Universal DC Motor

5. Compound DC Motor

PartsDC motor consists the basic parts of

Axel Rotor Stator

Commutator Field Magnet Brushes

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SPEED CONTROL OF DC MOTOR

The equation of speed of dc motor isN=(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.

9

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DC GEARED MOTORIn 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

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USE OF DC GEARED MOTOR IN THIS PROJECT

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

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STEERING & NAVIGATION

Left Motor

Right Motor

CarStatus

Stopped Rotate Turn Left

Rotate Stopped Turn Right

Rotate Rotate Go Forward (Clock wise)

Stopped Stopped Stopped

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CAR WHEELSWheels 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

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FOUR QUADRENT OPERATION OF DC MOTORHere in this project we use four quadrent operation of dc motor

1. Forward Motoring. 3. Reverse Motoring.2. Forward Braking. 4. Reverse Braking.

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PULSE WIDTH MODULATION TECHNIQUE

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)

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SPEED CONTROL BY PWM TECHNIQUE

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.

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ADVANTAGE OF PWM TECHNIQUE

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%

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ANTI-COLLISION SYSTEMWe 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.

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OBSTACLE SENSING DEVICES

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.

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FLOW CHART OF ANTI-COLLISION SYSTEM

START

IR TRANSMITTER IR RECEIVER

ADC0804

µC

VALUE CHECKING

MOTOR CONTINUOUS

END INSTANTANIOUS BRAKING OF MOTOR

INTENSITYMEASUREMT

( OBSTRACLE DETECTION)

LOW(NO)

HIGH(YES)

GREATER(YES)

LESS(NO)

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WIRELESS(RF) CONTROLThe D.C motor is controlled wirelessly by a RF controlled

remote control.The mechanism is described by the following block

diagrams.

RFENCODER

RF TRANSMIT-

TERANTENNA

TX-2BPOWERON/OFF

SW2

SW1

SW3

SW4

Transmitter Unit

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Continued….

RFRECEIVER

MOTOR DRIVER

CHIPL293D

RX-2B

RFDECODER

PWM GENERATO

R CHIPTIUC3525A

M

Receiver Unit

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Continued….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.

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FUTURE DEVELOPMENT1. 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.

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BIBLIOGRAPHY1.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.com8.www.engineeringgarage.com9.www.wikipedia.com10.www.robotforum.com 

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CONCLUSIONIn 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.

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