safe crusing system - iit delhi

8/13/2019 Safe Crusing System - IIT Delhi

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SAE INDIA 0301036

SAFE CRUISING SYSTEM

Sumit SarkarNetaji Subhas Institute of Technology, New Delhi

Abhishek JainSGSITS,Indore

Copyright 2003 SAE International

ABSTRACT

SAFE CRUISING SYSTEM is an intelligent andadaptive cruise control gadget based on a technology,

which has been devised to reduce the number of roadaccidents, by manifold. This system ensures automatic,

intelligent adaptive control of the vehicle by automaticcontrol of brakes and throttle. In this paper, light is thrown

on how electronics and computers can be combined toachieve what will become a bare necessity in the near

future. This system would be just an additional gadgetthat has to be fitted to the car, so no change in the

assembly line of a car is required. The system can adaptto any kind of situation while driving (be it crowded roads

or highways) and to any kind of condition (be it rain, snow,

fog, day or night).This system incorporates a strip of Ultrasonic sensors inconjunction with vision camera, and corresponding

controllers and is applicable up to a range of 15 metres.This system deals with automatically controlling all

systems, thereby leaving the driver with the job of steeringthe vehicle, ensuring that he cannot have an accident

under any circumstances.

INTRODUCTION

This system has been made, keeping in mind the current

needs of the automobile industry, but the same can beimplemented for any other moving object. This projectproves to be an effective Anti Collision Device and

provides Automatic Control of Acceleration and Brake toproduce Accident Free Cars.

Today, in this highly competitive automobile industry,

vehicles have various provisions for safety, butunfortunately most of these provisions are disposed

towards safety after the accident has actually occurredand very few methods are taken to prevent the accident.

SAFE CRUISING SYSTEM, is an intelligent and

adaptive cruise control gadget based on a technology,which has been devised to reduce the number of road

accidents, by manifold. This system ensures automatic,intelligent adaptive control of the vehicle by automatic

control of brakes and throttle. In this paper light is thrownon how electronics and computers can be combined to

achieve what will become a bare necessity in the nearfuture.All systems are automatically controlled, thereby leavingthe driver with the job of steering the vehicle, ensuring that

he cannot have an accident under any circumstances.This paper also includes a topic on Future Proposals

that will help in improving modern day car by leaps andbounds. The future proposals aim at improving various

existing facilities in the existing vehicles as well as addinga few gadgets, which will help the driver to have utmost

comfort while driving.

MAIN SECTION

PRIME OBJECTIVES: -1.PRIMARY AIM Safety of Vehicles.

2. Adaptive and Intelligent Control System.3. Automatic Acceleration and Deceleration.

Working Procedure: -This system incorporates a strip of Ultrasonic sensors,

microprocessors and a tachogenerator. The Ultrasonictransducer generates an acoustic wave, which will be

reflected upon touching any object whether a stationaryobject (divider, wall, etc) or moving object (another car,

motorcycle, scooter, etc). The ultrasonic distancemeasurements are based on the determination of time of

flight in the real time. The intensity of acoustic wavesvaries as inverse of the square of the distance from the

transducer. For higher frequency the beam divergenceangle is small and hence the directivity of the sensor is

more. A time gap is maintained between the subsequentgeneration of waves so that there is no interference. This

system will be applicable up to a range of 15 metres.

The distance at which the vehicle has to start braking isproportional to the speed of the car. For the purpose of

measuring this speed, a Tachogenerator is used. TheTachogenerator is attached to the main engine shaft. The


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received pulse from the obstacle is amplified and then

time of flight is calculated. Then it is calibrated in terms ofvoltage using the given circuit and compared with a range

of values. This signal is then fed to the microprocessors,which is coded . The output of the microprocessors, using

a 2-way switch, taps the signal to the brake or

acceleration cables before it reaches the ElectronicControl Unit (ECU). The acceleration and brake systemsare thus controlled accordingly as per the signal given by

the ECU.

For convenience, the sensor is first explained with circuitand block diagram. The algorithm used is described by

dividingthe whole range desired into three zones.

ULTRASONIC SENSORSThe operating principle is based on the measurement of

the Time of Flight (TOF), that is, the time necessary for anultrasonic wave to travel from the transmitter to the

receiver after being reflected from the target. The objectdistance from the transducer D = [C * (TOF)/2], where C

is the velocity of Sound, which is approximated at 330m/s. Pulse-Echo techniques are often used in commercial

systems for industrial applications. To achieve accuracydetection of target occurs not only with the amplitude of

the signal but also with the number of waves in thereceived signal. Ultrasonic Sensors used in many

applications are piezoelectric ceramic type. Thepiezoelectric effect causes the crystal to produce an

electrical potential when it is subjected to mechanicalvibration. The most commonly used piezoelectric

materials are Rochelle salt and Quartz.

SENSOR FUNCTIONING

The transmitter has to be excited with a 40 KHz squarewave signal of atleast 9 Vrms. A pulse contains 16 cycles

of 40 KHz signal, as the time period is 25 sec so 16cycles take 0.4 ms. To generate such pulse micro

controller is the best solution. The echo signal receivedfrom target is the information about the distance of the

object. The receiver receives most part of this noise signalhaving a frequency of 40KHz. This gives an amplification

of about 5000. According to a standard the comparator

level should be set in such a level so that when signal to

noise ratio is 2:1, the minimum for the detection occurs.The signal conditioner makes this output compatible with

the micro controller by removing the DC signal. An Echosignal will be treated as an echo from the target object

when it will contain 4 cycles of waves. The Time of flight

between the transmitted and received pulse is measuredusing a 16-bit timer.

SENSOR CIRCUIT

Theory of OperationThe transmitter emits an ultrasonic signal at 40kHz. The

555-timer of the transmitter provides the driving 40kHzfrequency. Every time the reset pin (Pin4) of the 555-timer

goes high, a resulting signal of 40kHz on pin 3 is used todrive the ultrasonic transducer. The receiver simply listens

for the echo. The small echo signal, when detected, isamplified 1000 times using a standard operational

amplifier (LM741 op-amp). The signal is then fed into atone decoder (LM567) set to lock onto a 40kHz signal.

The output of the tone decoder is high when no echo ispresent and swings low when an echo is detected. The

output from the tone decoder can now be fed into a microcontroller or some other type of IC to detect the echo.


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SYSTEM OPERATION MODE

Once distance of the obstacle is calibrated in terms of

voltage which corresponds to the intensity of the wavereceived, the algorithm is improvised using a

microcontroller, which gives output to acceleration andbreak line. According to the relative distance of the next

obstacle in front of the vehicle, the system generateselectrical signals using ICs, which are then tapped onto

the Accelerator and Break cables using a two-way switch. This helps the driver by easing his stresses and thereby

automatically controlling the speed of the car.

REAL TIME IMPLICATION 1. Red Zone Safety Limit.

2. Yellow Zone Proportional Braking.3. Green Zone Proportional Acceleration.

The space in front of the car bumper is divided into 3

regions: - Red belt This is the region adjacent to the car

bumper, and its length is one metre. It is the danger

zone, when the obstacle enters this region full brakes are

applied. Yellow belt This is the region extending from

end of red belt to starting of green belt. Its length isvariable, that is, its length is dependent on the speed of

car. It varies linearly with speed of car. In this region if an

obstacle enters, proportional braking is applied, braking isproportional to distance of obstacle from car. Proportionalbraking makes sure that there is no jerk involved while

braking and that it is the most efficient braking. Length ofthis belt is varied with speed because the braking time

required to retard is more when speed is high. Green belt This is the region in front of the

yellow belt till the range desired. This is the region ofproportional acceleration. Depending on the distance of

the obstacle from the car (or the yellow belt) proportionalacceleration is applied. Thus when the obstacle is about

to enter the yellow belt, already acceleration applied isminimum.

Thus it is a kind of autopilot for vehicles. Not only does it

eliminate the need of skill required during driving, it hasalmost a full proof safety mechanism. This application

requires automatic transmission, so that the electronicgadget takes over the control, leaving the driver with the

job of steering the vehicle as per his needs.

Incase of manual transmission, visual as well as voicemessages are incorporated to control the functioning of

the car. Alert messages are displayed when an obstacleenters the danger limit. This is in accordance with the

Global Version as well as the regional version as per

countries market requirements.

CALCULATION OF YELLOW REGION

The length of the yellow belt is variable and it depends on

the speed of the vehicle. The tachogenerator attached tothe engine shaft gives the current speed of the vehicle by

calculating the engine revolutions. The yellow region isvaried, as while traveling at greater speed the braking time

required for the vehicle to decelerate is more than that inthe case of a slow moving vehicle. This ensures optimum

braking without skidding. This system gives greater fuel

efficiency.The yellow belt starts after the red belt, which has beengiven a limit of one metre. Green belt begins from the

point of termination of the yellow belt and extends till therange of the sensor. For example, when the speed of the

vehicle is 40 Km/hr, the length of the yellow belt is 4metres, and the green belt is 10 metres.

In general, the following formula relating the length of theyellow belt and the speed of the car may be given: -

where,

YLength of yellow belt (Metres).X Speed of the vehicle detected by the tachogenerator

(Km/hr).It will be clearer from the following table: -

RED ZONE

YELLOW ZONE

GREEN ZONE


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SPEED Vs LENGTH OF YELLOW BELT

S.No. Speed of the vehicle

(Km/hr) [X]

Length of Yellow

Belt

(Metres)[Y]

1. 0 0

2. 10 1.0

3. 20 2.0

4. 30 3.0

5. 40 4.0

6. 50 5.0

7. 60 6.0

8. 70 7.0

9. 80 8.0

10. 90 9.0

11. 100 10.0

The utility of the variable belt can be understood with the

help of following examples:

1.Incase Of Moving Obstacle: -

Supposing a car is driven at a speed of 40 km/hr andanother car in front is at a speed of 30 km/h and distancebetween the two vehicles is about 5 m and there is a

traffic signal showing red light some distance ahead. Thefirst car starts applying the brakes. Meanwhile, the car in

front has entered the yellow zone. After some time whenthe distance between the two cars reduces to 1 m as the

car in front has stopped at the traffic signal, the first carapplies full brakes. Now the distance remaining between

the two cars is the length of the red zone. When the car infront has gone ahead by a sufficient distance, the first car

again starts accelerating proportionally. This is when thegreen zone comes into picture. The first car keeps on

accelerating till top speed is reached as desired by thecar driver, say 100 km/hr. Again when the car in front is in

the vicinity of, say, about 15 m, this time the brakes areapplied at a distance of 11 m from that car. Note how the

length of the yellow belt has changed.

2.Incase Of Static Obstacle: - Consider another case, when driving on a highway at a

speed of 100 km/hr, there is an obstacle at about 15 m.Right now this obstacle is in the green zone and the

acceleration is reduced by lifting the throttle. But as soonas the distance between the divider and the car reduces

to 11 m, the yellow zone starts functioning and brakes areapplied. This process of proportional braking is continued

until there is just about 1 m to go between the car and the

obstacle. The car comes to a halt and ensures that the

passengers sitting inside are safe and reduces any kind ofjerk that could have been produced by manual application

of brakes.

ADVANTAGES

1. Ensures Safe Driving, even on crowded roads.2. Increases Fuel Efficiency.3. Less Chances of Human Error.

4. Comfort Driving.5. Lane Driving within Optimum Limits.

6. Attains the Desired Top Speed.7. The System comes at an affordable price keeping

the consumer in mind.

The system comes at a very affordable price, keeping theconsumer in mind. The top speed desired while driving in

different conditions may also be varied and automaticallyacceleration may be increased or decreased by the

system. For example, cars run at high speeds onhighways and slow down on crowded roads. The top

speed can be varied as the driver can input his desired topspeed.

LIMITATIONS

The major drawback of this system is that in case of a Tjunction or a Four way crossing, the obstacle cannot be

detected, that is coming perpendicular to the car and thecar can only be detected at the last minute and therefore

chances of collision remain in the system.

Path of Car 1

Path of Car 2

FUTURE PROPOSALS

As far as the reliability of the system is considered, it is avery safe and sound system, which ensures safe driving

and almost 100% accuracy. This system stops the driverfrom smashing his car into a static or moving obstacle but

Collision at this siteas both cars sense

each other at thelast second only


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still provides the car with certain functions, which might be

the future for the Automobile Industry. These functionswould ensure even more safety and a time would come

when two cars would actually communicate betweenthemselves to avoid a collision. The proposals listed below

are in line with the upcoming automation in the car

industry, which is an influx of mechanical and electronics,giving the ultimate motor driving gadgets.

1. Multi Modal: - This includes a camera to befitted along with the array of sensors which would

act as an added functionality and would go a longway in ensuring 100% safety in car driving. This

system would be based on the principles of ImageProcessing, which would check for the pixel density

of the image it captures. As the pixel density wouldgo on increasing, this would indicate the closeness

of the object in front and according to this either thebrakes or acceleration would be applied. This

system would assist sensor based system andwould go a long way in making it a full proofsystem.

2. Crash Bags: - Crash bags are proposed to be

used in front of the radiator which would beincorporated in the Red Zone of the Car. These

bags would be inflated when any object comesperilously close to the front bumper of the car.

These crash bags would prevent an accidentrather than being implemented after the accident

has taken place. This is what the current safetyfeatures in a car are based on but the emphasis

is on preventing an accident rather than applying

features after the accident has taken place. Thisway the damage is minimized and safety isensured up to great limits.

3. Global Positioning System: - or GPS system

as it is famously known has a great role to play inthe future of any Automobile Industry. The GPS

system would help a car industry in taking giantstrides towards ensuring communication between

two cars. The GPS system would be fitted on theunderbody of every car and would transmit their

longitude and latitude through satellitecommunication. This would help each car in

determining the exact position of the car in frontof it, this would provide a two way communication

between two cars, thereby reducing the chancesof an accident taking place to a bare negligible

amount.

4. Image Processing for Red Lights and SpeedBreakers: - This is a feature, which would be

provided in every car along with Adaptive CruiseControl gadget. This is based on the principle of

Image Processing, which would compare theimages the Red Lights and Speed Breakers and

would help in slowing down the car as per thedesired needs. Contour matching is used to

match red lights junctions as well as speed

breakers. When the red light image is captured

the driver gets a signal asking him to confirm theimage captured by the high focal length camera.

As per the confirmation given by the driver thegadget acts accordingly. The above-mentioned

features can be used together in conjunction

to achieve a higher degree of accuracy andsafety.

CONCLUSION

I am currently working on a project known as SafeCruising System, an Adaptive Cruise Control System,

which is a concept entirely developed by me and would

help in reducing car accidents to a great extent, byremoving the human element in car driving and therebyreducing human error. This system ensures maximum

safety and will aid the human comfort while driving byautomatic control of Throttle and Brake.

ACKNOWLEDGMENTS

We are highly indebted to all those who have extendedtheir kind support and guidance for the successful

accomplishment of this paper. Their vast practicalknowledge and expertise in the industry helped us in

giving this idea a realistic touch.

We would like to express our heartfelt gratitude to ourHead of Department, Manufacturing Process and

Automation Engineering, Prof M.K.Muju, whoseexperience at IIT Kanpur helped us in understanding the

practical implementations of this project.

We would also like to thank Dr. S.K.Sinha, who hashelped us at every stage of development of this concept.


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REFERENCES

Books: -

1. D.Marioli, C.Narduzzi, C Offelli, Digital Time of FlightMeasurement for Ultrasonic Sensor in IEEE

transaction on instrumentation and measurement.

VOL. 41. NO. 1, February 1992.2. C.Cai and Paul P.L.Regtein. Accurate Digital Time of

Flight Measurement using Self-Interference in IEEE

transaction on instrumentation and measurement.VOL. 42. NO.6, December 1993.

3. Survey on Ultrasonic Sensors by Richard KendallMiller.

Websites: -

1. www.spkecl.com/htdoc/electret.htm

2. http://robios.me.wisc.edu/Courses/me601/sonar/sonar.html

3. http://robios.me.wisc.edu/Courses/me601/sonar/sonar.html

4. http://www.acroname.com/robotics/parts/R11-

6500.html5. http://store.yahoo.com/webtronics/lm567.html

6. http://www.ee.nmt.edu/~thomas/ee322_s01/labs/tone_decoder.html

CONTACT

SUMIT SARKAR,J-1897,

CHITTRANJAN PARK,NEW DELHI 110019

EMAIL:- [email protected],[email protected]

safe crusing system - iit delhi

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