SAGAR INSTITUTE OF RESEARCH, TECHNOLOGY & SCIENCE

BHOPAL (M.P.)

DEPARTMENT OF MECHANICAL ENGINEERING

Session [2015-2016]

MAJOR PROJECT REPORT ON

“REVERSE BRAKING SYSTEM”

Submitted By

Gautam Wadhwani

Sachin Sahu

Peyush Kumar Mehto

Vikash Kumar

Under the Guidance of

Dr. Vikas S. Pagey

Rajiv Gandhi Proudyogiki Vishwavidyalaya, Bhopal, M.P.

Airport Bypass Road, Gandhi Nagar, Bhopal, 462033

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SAGAR INSTITUTE OF RESEARCH, TECHNOLOGY & SCIENCE

BHOPAL (M.P.)

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

This is to certify that Mr.Gautam Wadhwani, Mr. Sachin Sahu, Mr. Peyush Kumar Mehto,

Mr. Vikash Kumar have completed the Major Project titled “Reverse Braking System” during

the session 2015-2016 under my supervision and guidance.

The project report is approved for submission towards partial fulfillment of Bachelor of

Engineering Degree in Mechanical Engineering.

PROJECT GUIDE HEAD OF DEPARTMENT

Dr. Vikas S. Pagey Dr. Vidosh Mahate

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SAGAR INSTITUTE OF RESEARCH, TECHNOLOGY & SCIENCE

BHOPAL (M.P.)

DEPARTMENT OF MECHANICAL ENGINEERING

We, GAUTAM WADHWANI, SACHIN SAHU, PEYUSH KUMAR MEHTO, VIKASH

KUMAR the students of Bachelor of Engineering in Mechanical Engineering Department,

Session 2015-2016, Sagar Institute of Research, Technology & Science, Bhopal (M.P.),

hereby declare that the work presented in this major project entitled “Reverse Braking System”

is the outcome of our own work, is bona fide and correct to the best of our knowledge and this

work has been carried out taking care of Engineering Ethics. The work presented does not

infringe any patented work and has not been submitted to any university or anywhere else for the

award of any degree or professional diploma.

Gautam Wadhwani 0186ME121020

Sachin Sahu 0186ME121048

Peyush Kumar Mehto 0186ME121036

Vikash Kumar 0186ME121060

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ACKNOWLEDGEMENT

An engineer with only theoretical knowledge is not a complete engineer. Practical knowledge is

very important to develop and to apply engineering skills. It gives us a great pleasure to have an

opportunity to acknowledge and to express gratitude to those who were associated with us during

our completion of major project. Special thanks to Dr. VIKAS S. PAGEY. For providing us with

an opportunity to undergo major project under his guidance & for his valuable deep rooted

interest, inspiration and continuous encouragement throughout our major project completion

which helped us to learn about the working technology of brakes.

We express our sincere thanks and gratitude to MECHANICAL ENGINEERING

DEPARTMENT authorities for allowing us to undergo the major project in this prestigious

organization. We will always remain indebted to them for their constant interest and excellent

guidance in our project work, moreover for providing us with an opportunity to work and gain

experience.

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ABSTRACT

Braking is nothing but bringing a moving vehicle or moving body to a stop. Now-a-days safety

is become important aspects of automobile industries. And automation is the key which keep the

safety at our fingers. In other words, an unskilled or less exampled can handle the automobile

vehicle with greater safety.

Various accidents happen with the automobile vehicles which cause serious injury, and

inefficient braking is most probable reason. It is incontestable, statistically proved fact, that year

on year incidents involving a reversing vehicle account for between 20-30% of all reported work

related serious injuries or fatalities. While parking or taking reverse turn, driver unable to see

what is behind the vehicle and obviously up to what distance, eventually vehicle strike with the

obstacle behind.

Presently, cars have the alarm system where when the car gets too close to an object an

alarm is triggered which warns the driver about an object close by. But this feature has produced

lot of problems and is prone to human error. We have enhanced the facility by using the same

system but we have altered it so that the car brakes automatically when an obstacle is close by.

This report introduces a control systems based on electronically controlled automotive

braking system is called “Intelligent Reverse Braking System”. A Sensor Operated Pneumatic

Brake consists of IR transmitter and Receiver circuit, Control Unit, Pneumatic breaking system.

The IR sensor is used to detect the obstacle. If there is any obstacle in the path, the IR sensor

senses the obstacle and giving the control signal to the breaking system. The pneumatic breaking

system is used to brake the system. So basically here the car brakes on its own by determining

the distance from the object.

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CONTENTS

Chapter

No

Title Page

No

Certificate 1

Declaration 2

Acknowledgement 3

Abstract 4

Contents 5

List of Figures 6

1 Introduction 7

1.1 Need of Automatic Reverse Braking 7

1.2 Benefits to the Customers

1.3 Types of braking

1.4 IR Sensor

1.5 Pneumatics

8

8

14

17

2 Literatures Survey 18

3 Components and Description

3.1 Pneumatic Single Acting Cylinder

3.2 Solenoid Valve

3.3 Flow Control Valve

3.4 IR Sensor Unit

3.5 Wheel & Brake Arrangement

3.6 PU Connector,reducer,hose collar

3.7 Stand

3.8 Single Phase Induction Motor with pulley

20

21

24

26

27

28

28

28

28

28

28

4 Block Diagram 33

5 Working Operation 34

6 Applications & Advantages 36

7

8

9

10

List of Materials

Cost Estimation

Conclusion

References

37

38

39

40

6

LIST OF FIGURES

Figure No. Name of Figure Page No.

1.1 Drum Brake 10

1.2 Hydraulic Brake 11

1.3 Air Brake 12

1.4 Electric Brake 13

1.5 IR Sensor 14

1.6 Sensor Characteristics 15

3.1 Pneumatic Single Acting Cylinder 21

3.2 Solenoid Valve 24

3.3 Flow Control Valve 26

3.4 IR Transmitter Circuit Diagram 27

3.5 Torque Speed Graph of Motor 29

4.1 Block Diagram of Pneumatic & Electrical Control Unit 33

5.1 Circuit Diagram of Pneumatic Braking System 34

5.2 Sensor Operated ARBS 35

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1. INTRODUCTION

An intelligent reverse braking system is compiled with IR sensor circuit which operates a

pneumatic braking system. The main target for this project is cars can run reverse automatic

braking due to obstacles when the sensor senses the obstacles. The braking circuit function is to

brake the car automatically after received signal from the sensor. This mainly concern in

replacement of human effort by the mechanical braking. So it is the best safety feature for the

vehicles.

The pneumatically braking system stops the vehicle in 2 to 3 seconds when running speed

is of 50 kmph and the distance of stopping the vehicle is 1.6m. The Intelligent braking system is

fully automated. To allow the driver to park the vehicle in tight place, it has parking mode

system. In this mode sensor sensing length is reduced to 40cm distance.

Degrees of automation are two types:

Semi Automation

Full Automation

The semi automation is manual efforts with mechanical power whereas in full automation

manual participation in the work is very negligible. Intelligent automatic reverse braking is of

full automation type automation.

1.1 Need of Automatic Reverse Braking System

Years ago, when car is get too close to an obstacle an alarm is triggered which worn the

driver. In this process human error is also included. The actual time to stop the car is response

time taken by the driver plus the time required to taken by the braking system to brake the car

and time of response of driver is much greater.

Hence, it is required to make automatic reverse braking. We use pneumatically operated

reverse braking which is activate when IR sensor senses an obstacle.

This system is mainly divided into two categories according to operation:

A) Electronic operation

B) Mechanical operation.

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1.2 Electronic operation

For the detection of obstacle behind the car, the IR sensor transmitter and receiver circuit is

required. The output from this circuit is sends to the solenoid valve which helps in pneumatic

braking.

1.3 Mechanical operation

When IR sensor gives input to solenoid valve then a pneumatic brake applied to the car. For this

operation pneumatic force is used to apply the brake.

1.4 Benefits to the Customers

Intelligent reverse braking system offers the safe driving with reliable reverse braking. As it uses

pneumatic force to operate the brake, it does not require any manual force which consequently

reduces the fatigue in braking.

1.5 TYPES OF BRAKING

The brakes for automotive use may be classified according the following considerations.

1. PURPOSE

2. LOCATION

3. CONSTRUCTION

4. METHOD OF ACTUATION

5. EXTRA BRAKING EFFORT

Based on the above considerations, brakes are classified with respect to following factors.

1. With respect to application,

a. Foot brake

b. Hand brake

2. With respect to the number of wheels,

a. Two wheel brakes

b. Four wheel brakes

3. With respect to the method of braking contact

a. Internal expanding brakes

b. External contracting brakes

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4. With respect to the method of applying the braking force.

a. Single acting brake

b. Double acting brakes.

5. With respect to the brake gear,

a. Mechanical brake

b. Power brakes

6. With respect to the nature of power employed

a. Vacuum brake

b. Air brake

c. Hydraulic brake

d. Hydrostatic brake

e. Electric brake

7. With respect to power transmission,

a. Direct acting brakes

b. Geared brakes

The foot brake or service brake is always applied by a pedal, while the parking brake is applied

by a hand lever. The parking brake is intended chiefly to hold the car in position. The parking

brake can be set in the “ON” position by means of a latch while the service brake remains on

only as long as the driver presses down on the pedal.

The hand brake is normally used only after the driver has stopped the car by using the foot brake.

Its other use is as an emergency brake to stop the car if the foot braked system should fail. The

hand or parking brakes operates on a pair of wheels, frequently the rear wheels. When drum

type rear brakes are used, the same shoes can be used for both hand and foot control.

The drum type of brake may either be a band brake or a shoe brake. Both band brakes and shoe

brakes may be either external or internal. The band brakes generally are external and shoe

brakes internal. In drum brakes the drum is attached to the wheel and revolves with it. Friction

to slow the drum is applied from inside by the shoes which do not rotate but are mounted on a

stationary metal back plate. There are different types of drum brakes such as a two leading shoe

arrangement – which gives an augmented response to pedal effort because of its self applying

arrangement. A leading-trailing shoe is a cheaper and better alternative as it is equally effective

whether the car is going forward or backwards.

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Fig 1.1 Drum Brake

Manufacturers design drum brakes so that rain, snow or ice or grit cannot get inside and decrease

braking efficiency for moisture greatly reduces the friction between the linings and the drum.

The dissipate quickly the considerable amount of heat generated when braking a fast moving

heavy car large brake drums would be required. Disc brakes do the job more efficiently, for the

cooling air can get to the rubbing between each piston and the disc, there is a friction pad held in

position by retaining pins, spring plates etc. Passages are drilled in the caliper for the fluid to

enter or leave the each housing. These passages are also connected to another one for bleeding.

Each cylinder contains a rubber selling ring between the cylinder and the piston.

The brakes are applied, hydraulically actuated piston move the friction pads into contact with the

disc, applying equal and opposite forces on the later. On releasing the brakes, the rubber sealing

rings act as return springs and retract the pistons and the friction pads away from the disc.

MECHANICAL BRAKE:

In a motor vehicle, the wheel is attached to an auxiliary wheel called drum. The brake shoes are

made to contact this drum. In most designs, two shoes are used with each drum to form a

complete brake mechanism at each wheel. The brake shoes have bake linings on their outer

surfaces. Each brake shoe is hinged at one end by on anchor pin; the other end is operated by

some means so that the brake shoe expands outwards. The brake linings come into contact with

the drum. Retracting spring keeps the brake shoe into position when the brakes are not applied.

The drum encloses the entire mechanism to keep out dust and moisture. The wheel attaching

bolts on the drum are used to contact wheel and drum.

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The braking plate completes the brake enclosure, holds the assembly to car axle, and acts the

base for fastening the brake shoes and operating mechanism.

HYDRAULIC BRAKES:

The hydraulic brakes are applied by the liquid pressure. The pedal force is transmitted to the

brake shoe by means of a confined liquid through a system of force transmission.

The force applied to the pedal is multiplied and transmitted to brake shoes by a force

transmission system. This system is based upon Pascal‟s principle, which states that “The

confined liquids transmit pressure without loss equally in all directions”.

Fig 1.2 Hydraulic Brake

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It essentially consists of two main components – master cylinder and wheel cylinder the master

cylinder is connected by the wheel cylinders at each of the four wheels. The system is filled with

the liquid under light pressure when the brakes are not in operation. The liquid is known as

brake fluid, and is usually a mixture of glycerin and alcohol or caster-oil, denatured alcohol and

some additives Spring pressure, and thus the fluid pressure in the entire system drops to its

original low valve, which allows retracting spring on wheel brakes to pull the brake shoes out of

contact with the brake drums into their original positions. This causes the wheel cylinder piston

also to come back to its original inward position. Thus, the brakes are released.

AIR BRAKE:

Air brakes are widely used in heavy vehicle like buses and trucks which require a heavier

braking effort that can be applied by the driver‟s foot. Air brakes are applied by the pressure of

compressed air, instead of foot pressure, acting against flexible diaphragms in brake chamber.

The diaphragms are connected to the wheel brakes. These diaphragms are controlled through a

hand or foot operated valve. The brake valve controls brake operation by directing the flow of

air from a reservoir against diaphragms in the brake chamber when the brakes are applied and

from brake chambers to tube atmosphere when the brakes are released. The air compressor,

driven by the engine furnishes compressed air to the reservoir fall below a set valve.

Fig 1.3 Air Brake

ELECTRIC BRAKE:

Electric Brakes are also used in some motor vehicles, although these are not very popular.

Warner electric brake is one of the examples of such brakes. An electric brake essentially

consists of an electromagnet within the brake drum. The current from the battery is utilized to

energize the electromagnet, which actuates the mechanism to expand the brake shoe against the

brake drum, thus applying the brakes. The severity of braking is controlled by means of a

rheostat, which is operated by the driver through the foot pedal.

13

Electric brakes are simpler. These brakes do not require complicated operating linkage. Only

cable is required to take current from the battery to the electromagnet. Also, these are very quick

in action as compared to other types of brakes.

Fig 1.4 Electric Brake

VACUUM BRAKES / SERVO BRAKES:

A serve mechanism fitted to the braking system reduces the physical effort the driver has to use

on the brake pedal most servo mechanisms are of the vacuum assistance type. A pressure

differential can be established by subjecting one side of the piston to atmospheric pressure and

the other side to a pressure below atmospheric pressure by exhausting air from the corresponding

end of the servo cylinder.

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1.4 IR SENSOR

Fig 1.5 IR Sensor

SENSORS

A sensor is a transducer used to make a measurement of a physical variable. Any sensor requires

calibration in order to be useful as a measuring device. Calibration is the procedure by which the

relationship between the measured variable and the converted output signal is established.

Care should be taken in the choice of sensory devices for particular tasks. The operating

characteristics of each device should be closely matched to the task for which it is being utilized.

Different sensors can be used in different ways to sense same conditions and the same sensors

can be used in different ways to sense different conditions.

TYPES OF SENSOR:

Passive sensors detect the reflected or emitted electro-magnetic radiation from natural sources,

while active sensors detect reflected responses from objects which are irradiated from artificially

generated energy sources, such as radar. Each is divided further in to non-scanning and

scanning systems.

A sensor classified as a combination of passive, non-scanning and non-imaging method is a

type of profile recorder, for example a microwave radiometer. A sensor classified as passive,

non-scanning and imaging method, is a camera, such as an aerial survey camera or a space

camera, for example on board the Russian COSMOS satellite.

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Fig 1.6 Sensor Characteristics

Sensors classified as a combination of passive, scanning and imaging are classified further into

image plane scanning sensors, such as TV cameras and solid state scanners, and object plane

scanning sensors, such as multi-spectral scanners (optical-mechanical scanner) and scanning

microwave radiometers. An example of an active, non-scanning and non-imaging sensor is a

profile recorder such as a laser spectrometer and laser altimeter. An active, scanning and imaging

sensor is radar, for example synthetic aperture radar (SAR), which can produce high resolution,

imagery, day or night, even under cloud cover.

The most popular sensors used in remote sensing are the camera, solid state scanner, such as the

CCD (charge coupled device) images, the multi-spectral scanner and in the future the passive

synthetic aperture radar. Laser sensors have recently begun to be used more frequently for

monitoring air pollution by laser spectrometers and for measurement of distance by laser

altimeters.

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CHARACTERISTICS OF OPTICAL SENSOR:

Optical sensors are characterized specified by spectral, radiometric and geometric performance.

The spectral characteristics are spectral band and band width, the central wavelength, response

sensitivity at the edges of band, spectral sensitivity at outer wavelengths and sensitivity of

polarization.

Sensors using film are characterized by the sensitivity of film and the transmittance of the filter,

and nature of the lens. Scanner type sensors are specified by the spectral characteristics of the

detector and the spectral splitter. In addition, chromatic aberration is an influential factor.

The radiometric characteristics of optical sensors are specified by the change of electro-

magnetic radiation which passes through an optical system. They are radiometry of the sensor,

sensitivity in noise equivalent power, dynamic range, signal to noise ratio (S/N ratio) and

other noises, including quantification noise.

The geometric characteristics are specified by those geometric factors such as field of view

(FOV), instantaneous field of news (IFOV), band to band registration, MTF, geometric

distortion and alignment of optical elements.

IFOV is defined as the angle contained by the minimum area that can be detected by a scanner

type sensor. For example in the case of an IFOV of 2.5 milli radians, the detected area on the

ground will be 2.5 meters x 2.5 meters, if the altitude of sensor is 1,000 m above ground. In our

project IR transmitter and IR receiver are used to detect the obstacle. These sensors are fitted at

the front side of the vehicle.

IR TRANSMITTER:

The IR transmitting circuit is used in many projects. The IR transmitter sends 40 kHz (frequency

can be adjusted) carrier under 555 timer control. IR carriers at around 40 kHz carrier frequencies

are widely used in TV remote controlling and ICs for receiving these signals are quite easily

available.

IR RECEIVER:

The transmitted signal reflected by the obstacle and the IR receiver circuit receives the signal and

giving control signal to the control unit. The control unit activates the pneumatic breaking

system, so that break was applied.

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1.5 PNEUMATICS

The word „pneuma‟ comes from Greek and means breather wind. The word pneumatics is

the study of air movement and its phenomena is derived from the word pneuma. Today

pneumatics is mainly understood to means the application of air as a working medium in

industry especially the driving and controlling of machines and equipment.

Pneumatics has for some considerable time between used for carrying out the simplest

mechanical tasks in more recent times has played a more important role in the

development of pneumatic technology for automation. Pneumatic systems operate on a

supply of compressed air which must be made available in sufficient quantity and at a

pressure to suit the capacity of the system. When the pneumatic system is being adopted

for the first time, however it wills indeed the necessary to deal with the question of

compressed air supply.

The key part of any facility for supply of compressed air is by means using reciprocating

compressor. A compressor is a machine that takes in air, gas at a certain pressure and

delivered the air at a high pressure. Compressor capacity is the actual quantity of air

compressed and delivered and the volume expressed is that of the air at intake conditions

namely at atmosphere pressure and normal ambient temperature.

The compressibility of the air was first investigated by Robert Boyle in 1962 and that

found that the product of pressure and volume of a particular quantity of gas.

This is usually written as

PV = C (or) P1V1=P2V2

In this equation the pressure is the absolute pressured which for free is about 14.7 Psi and

is of courage capable of maintaining a column of mercury, nearly 30 inches high in an

ordinary barometer. Any gas can be used in pneumatic system but air is the mostly used

system now a days.

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2. LITERATURE SURVEY

The Reverse Alert System is first developed by Surveillance Guard Corporation (SVG). It was

the world first after market automatic braking system that can be fitted to any vehicle. This

system firstly fitted in Australian vehicles and has been taken extensively trialed across the

passenger vehicle market, road transportation and taxi industries. This system begins with

ultrasonic sensors that were fitted at rear of the vehicle. These sensors detect an object at 1.6m a

signal is sent to a solenoid located at the front of the vehicle. The solenoid is attached to a

flexible cable that runs through the firewall and is attached to a universal brake pedal clamp that

is fitted on the brake pedal. Subsequently, when the solenoid is activated this pulls the brake

pedal -stopping the vehicle automatically.

The Reverse Alert Technology was installed on following vehicles:

Two Ford Ranger Light Commercial Vehicles (1 x 1.6m and 1 x 2.5m systems) and;

Two Hino Trucks (both equipped with the 1.6m system) – EWP and Line Truck.

ABS (Anti-lock Braking System) which helps the rider gets a hassle free braking experience in

muddy and watery surfaces. It applies a distributed braking and prevents skidding and wheel

locking. In 1988 BMW sold for the first time electronic-hydraulic motorcycles. The first

Japanese maker selling motorcycles with ABS was Honda ST1100 equipped optionally with

electro-hydraulic ABS module in 1992. With the ABS, if the rider only brakes with the front or

rear wheel, the braked wheels tends to lock up faster as if both brakes would have been applied.

A Combined Braking System (CBS) distributes the brake force also to the non-braked wheel to

lower the possibility of a lock up, increase deceleration and reduce suspension pitch.

Volvo is all set to launch its new XC60 SUV which will sport laser assisted braking which will

be capable to sense a collision up to 50 kmph and apply brakes automatically.

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1. Divya Thakur [2015], in this world automation of various systems has been designed just to

reduce the time and human error. Vehicles, particularly four wheelers are very difficult to drive

in the reverse direction. As personally one is very careful about, otherwise damage being caused

to the vehicle. In view of this to provide a proper guidance to the vehicle in reverse direction,

means are provided. Presently the vehicle has alarm system for maintaining the safe distance

between vehicle and object while moving in reverse direction. When the vehicle gets too close to

the object, the alarm is triggered this warns the driver about an object. But this feature has many

Problems and is prone to human error. Our aim is to design the “Automatic Reverse Braking

System” using FPGA ( Field Programmable Gate Array)which can avoid the accident in

reversing the heavy loaded vehicles like trucks, buses and all the vehicles consisting of braking

system. For this purpose we have developed a model which consists of FPGA, obstacle sensors,

sensing circuit which serves as the complete mechanism of automated braking system while

reversing the vehicles to prevent collision between the vehicle and objects. If there is object in

reverse path, the sensor senses the object and the break is applied automatically. In this, FPGA is

used as a control unit to which the devices and sensors are interfaced. This system is suitable for

commercial vehicles such as car, emergency services vehicles, trucks and buses.

2. D.E.Keyser [2012], the intent of this paper is to create a clear understanding of full power

pneumatic brake actuation system design as it relates to off-highway vehicles and equipment.

The paper is divided into four main sections. The first section outlines six design prerequisites

used for selecting the service brakes and the full power brake actuation system. The second

section, Brake Actuation Systems, includes advantages of a full power brake system and a brief

description of reverse modulation brake systems. Section three is a discussion of open center,

closed center and load sensing pneumatic systems and the integration of a full power brake

actuation system into these systems. Section three also explains the operation, related

components and some common problems to be avoided in the actuation system design process.

The fourth section describes reverse modulating brake actuation and how it differs from full

power pneumatic brake actuation. The actual selection of the service brakes is beyond the scope

of this paper. However, it is assumed the vehicle's brakes have been properly sized and are fully

operational.

3. Ravi Ingle [2014], in this world mechatronics and automation of various systems has been

developed just to reduce the time and human error. The automated braking system is a part of

mechatronics. Presently the vehicle has alarm system for maintaining the safe distance between

moving vehicle. When the vehicle gets too close to the object, the alarm is triggered this warns

the driver about an object. But this feature has many problems and is prone to human error. We

have developed a model, by using the same sensor system but with the automated breaking

pneumatic system which restricts the backward motion of the vehicle. Our aim is to design the

system which can avoid the accident in reversing the heavy loaded vehicles like trucks, buses

and all the vehicles consisting of pneumatic braking system. For this purpose we have developed

a model which consists of pneumatic cylinder, solenoid valve, IR sensors, control unit etc. which

serves as the complete mechanism of automated braking system while reversing the vehicles.

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3. COMPONENTS AND DESCRIPTION

SELECTION OF PNEUMATICS:

Mechanization is broadly defined as the replacement of manual effort by mechanical

power. Pneumatics is an attractive medium for low cost mechanization particularly for

sequential or repetitive operations. Many factories and plants already have a compressed

air system, which is capable of providing both the power or energy requirements and the

control system (although equally pneumatic control systems may be economic and can be

advantageously applied to other forms of power).

The main advantages of an all-pneumatic system are usually economy and simplicity, the

latter reducing maintenance to a low level. It can also have out standing advantages in

terms of safety.

PNEUMATIC COMPONENTS AND ITS DESCRIPTION

The pneumatic bearing press consists of the following components to fulfill the

requirements of complete operation of the machine.

1) PNEUMATIC SINGLE ACTING CYCLINDER

2) SOLENOID VALVE

3) FLOW CONTROL VALVE

4) IR SENSOR UNIT

5) WHEEL AND BRAKE ARRANGEMENT

6) PU CONNECTOR, REDUCER, HOSE COLLAR

7) STAND

8) SINGLE PHASE INDUCTION MOTOR WITH PULLEY

21

1) PNEUMATIC SINGLE ACTING CYLINDER:

Pneumatic cylinder consist of

A) PISTON B) CYLINDER

The cylinder is a Single acting cylinder one, which means that the air pressure operates

forward and spring returns backward. The air from the compressor is passed through the

regulator which controls the pressure to required amount by adjusting its knob.

A pressure gauge is attached to the regulator for showing the line pressure. Then the

compressed air is passed through the single acting 3/2 solenoid valve for supplying the air

to one side of the cylinder. One hose take the output of the directional Control (Solenoid)

valve and they are attached to one end of the cylinder by means of connectors. One of

the outputs from the directional control valve is taken to the flow control valve from

taken to the cylinder. The hose is attached to each component of pneumatic system only

by connectors.

Fig 3.1 Pneumatic Single Acting Cylinder

CYLINDER TECHNICAL DATA:

Piston Rod: M.S. hard Chrome plated

Seals: Nitrile (Buna – N) Elastomer

End Covers: Cast iron graded fine grained from 25mm to 300mm

Piston: Aluminum.

Media: Air.

Temperature Range: 0ºC-85

ºC

22

Parts of Pneumatic Cylinder

Piston:

The piston is a cylindrical member of certain length which reciprocates inside the

cylinder. The diameter of the piston is slightly less than that of the cylinder bore

diameter and it is fitted to the top of the piston rod. It is one of the important parts which

convert the pressure energy into mechanical power.

The piston is equipped with a ring suitably proportioned and it is relatively soft rubber

which is capable of providing good sealing with low friction at the operating pressure.

The purpose of piston is to provide means of conveying the pressure of air inside the

cylinder to the piston of the oil cylinder.

Generally piston is made up of:

Aluminium alloy-light and medium work.

Brass or bronze or CI-Heavy duty.

The piston is single acting spring returned type. The piston moves forward when the

high-pressure air is turned from the right side of cylinder. The piston moves backward

when the solenoid valve is in OFF condition. The piston should be as strong and rigid as

possible. The efficiency and economy of the machine primarily depends on the working

of the piston. It must operate in the cylinder with a minimum of friction and should be

able to withstand the high compressor force developed in the cylinder and also the shock

load during operation.

The piston should posses the following qualities.

a. The movement of the piston not creates much noise.

b. It should be frictionless.

c. It should withstand high pressure.

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Piston Rod

The piston rod is circular in cross section. It connects piston with piston of other

cylinder. The piston rod is made of mild steel ground and polished. A high finish is

essential on the outer rod surface to minimize wear on the rod seals. The piston rod is

connected to the piston by mechanical fastening. The piston and the piston rod can be

separated if necessary.

One end of the piston rod is connected to the bottom of the piston. The other end of the

piston rod is connected to the other piston rod by means of coupling. The piston

transmits the working force to the oil cylinder through the piston rod. The piston rod is

designed to withstand the high compressive force. It should avoid bending and withstand

shock loads caused by the cutting force. The piston moves inside the rod seal fixed in the

bottom cover plate of the cylinder. The sealing arrangements prevent the leakage of air

from the bottom of the cylinder while the rod reciprocates through it.

Cylinder Cover Plates

The cylinder should be enclosed to get the applied pressure from the compressor and act

on the pinion. The cylinder is thus closed by the cover plates on both the ends such that

there is no leakage of air. An inlet port is provided on the top cover plate and an outlet

ports on the bottom cover plate. There is also a hole drilled for the movement of the

piston.

The cylinder cover plate protects the cylinder from dust and other particle and maintains

the same pressure that is taken from the compressor. The flange has to hold the piston in

both of its extreme positions. The piston hits the top plat during the return stroke and hits

the bottom plate during end of forward stroke. So the cover plates must be strong enough

to withstand the load.

Cylinder Mounting Plates:

It is attached to the cylinder cover plates and also to the carriage with the help of „L‟

bends and bolts.

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3. SOLENOID VALVE WITH CONTROL UNIT:

The directional valve is one of the important parts of a pneumatic system. Commonly

known as DCV, this valve is used to control the direction of air flow in the pneumatic

system. The directional valve does this by changing the position of its internal movable

parts.

This valve was selected for speedy operation and to reduce the manual effort and also for

the modification of the machine into automatic machine by means of using a solenoid

valve. A solenoid is an electrical device that converts electrical energy into straight line

motion and force. These are also used to operate a mechanical operation which in turn

operates the valve mechanism. Solenoids may be push type or pull type. The push type

solenoid is one in which the plunger is pushed when the solenoid is energized

electrically. The pull type solenoid is one is which the plunger is pulled when the

solenoid is energized.

Fig 3.2 Solenoid Valve

The name of the parts of the solenoid should be learned so that they can be recognized

when called upon to make repairs, to do service work or to install them.

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Parts of a Solenoid Valve

1. Coil

The solenoid coil is made of copper wire. The layers of wire are separated by

insulating layer. The entire solenoid coil is covered with an varnish that is not

affected by solvents, moisture, cutting oil or often fluids. Coils are rated in

various voltages such as 115 volts AC, 230 volts AC, 460 volts AC, 575 Volts

AC, 6 Volts DC, 12 Volts DC, 24 Volts DC, 115 Volts DC & 230 Volts DC.

They are designed for such frequencies as 50 Hz to 60 Hz.

2. Frame

The solenoid frame serves several purposes. Since it is made of laminated sheets,

it is magnetized when the current passes through the coil. The magnetized coil

attracts the metal plunger to move. The frame has provisions for attaching the

mounting. They are usually bolted or welded to the frame. The frame has

provisions for receivers, the plunger. The wear strips are mounted to the solenoid

frame, and are made of materials such as metal or impregnated less fiber cloth.

3. Solenoid Plunger

The Solenoid plunger is the mover mechanism of the solenoid. The plunger is

made of steel laminations which are riveted together under high pressure, so that

there will be no movement of the lamination with respect to one another. At the

top of the plunger a pin hole is placed for making a connection to some device.

The solenoid plunger is moved by a magnetic force in one direction and is usually

returned by spring action. Solenoid operated valves are usually provided with

cover over either the solenoid or the entire valve. This protects the solenoid from

dirt and other foreign matter, and protects the actuator. In many applications it is

necessary to use explosion proof solenoids.

26

WORKING OF 3/2 SINGLE ACTING SOLENOID (OR) CUT OFF VALVE:

The control valve is used to control the flow direction is called cut off valve or solenoid

valve. This solenoid cut off valve is controlled by the emergency push button. The 3/2

Single acting solenoid valve is having one inlet port, one outlet port and one exhaust port.

The solenoid valve consists of electromagnetic coil, stem and spring. The air enters to the

pneumatic single acting solenoid valve when the push button is in ON position.

Technical Data:

Size : ¼”

Pressure : 0 to 7 kg / cm2

Media : Air

Type : 3/2

Applied Voltage : 230V A.C

Frequency : 50 Hz

4. FLOW CONTROL VALVE:

Technical Data:

Size : ¼”

Pressure : 0 to 10 kg / cm2

Media : Air

Fig 3.3 Flow Control Valve

27

1 8

2 7

IC 555 3 6

4 5

Purpose:

This valve is used to speed up the piston movement and also it acts as an one – way

restriction valve which means that the air can pass through only one way and it can‟t

return back. By using this valve the time consumption is reduced because of the faster

movement of the piston.

4. IR SENSOR UNIT:-

The IR transmitter and IR receiver circuit is used to sense the obstacle. It is fixed to the

back side of the frame stand with a suitable arrangement. The pneumatic cylinder is

controlled by the flow control valve, single acting solenoid valve and control unit.

IR TRANSMITTER CIRCUIT:

Fig 3.4 IR Transmitter Circuit Diagram

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AT NORMAL CONDITION:

The IR transmitter sensor is transmitting the infrared rays with the help of 555 IC timer

circuit. These infrared rays are received by the IR receiver sensor. The Transistor T1, T2

and T3 are used as an amplifier section. At normal condition Transistor T5 is OFF

condition. At that time relay is OFF, so that the vehicle running continuously.

AT OBSTACLE CONDITION:

At Obstacle conditions the IR transmitter and IR receiver, the resistance across the

Transmitter and receiver is high due to the non-conductivity of the IR waves. So the

output of transistor T5 goes from OFF condition to ON stage. In that time the relay is ON

position. In that time, the solenoid valve is on so that the vehicle stops.

5. WHEEL AND BRAKING ARRANGEMENT:

The simple wheel and braking arrangement is fixed to the frame stand. Near the brake

drum, the pneumatic cylinder piston is fixed.

6. PU CONNECTIORS, REDUCER AND HOSECOLLAR:

In our pneumatic system there are two types of connectors used; one is the hose

connector and the other is the reducer. Hose connectors normally comprise an adapter

(connector) hose nipple and cap nut. These types of connectors are made up of brass or

Aluminium or hardened steel. Reducers are used to provide inter connection between two

pipes or hoses of different sizes. They may be fitted straight, tee, “V” or other

configurations. These reducers are made up of gunmetal or other materials like hardened

steel etc.

7. STAND:

This is a supporting frame and made up of mild steel.

8. SINGLE PHASE INDUCTION MOTOR WITH PULLEY:-

This is used to drive the wheel by using two pulleys with belt drive mechanism.

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Single-Phase Theory

Because it has but a single alternating current source, a single-phase motor can only

produce an alternating field: one that pulls first in one direction, then in the opposite as

the polarity of the field switches. A squirrel-cage rotor placed in this field would merely

twitch, since there would be no moment upon it. If pushed in one direction, however, it

would spin.

The major distinction between the different types of single-phase AC motors is how they

go about starting the rotor in a particular direction such that the alternating field will

produce rotary motion in the desired direction. This is usually done by some device that

introduces a phase-shifted magnetic field on one side of the rotor.

The figure the performance curves of the four major types of single-phase AC motors.

They are described below.

Fig 3.5 Torque Speed Graph of Motor

30

1. Split-Phase Motors:

The split phase motor achieves its starting capability by having two separate windings

wound in the stator. The two windings are separated from each other. One winding is

used only for starting and it is wound with a smaller wire size having higher electrical

resistance than the main windings. From the rotor's point of view, this time delay coupled

with the physical location of the starting winding produces a field that appears to rotate.

The apparent rotation causes the motor to start.

A centrifugal switch is used to disconnect the starting winding when the motor reaches

approximately 75% of rated speed. The motor then continues to run on the basis of

normal induction motor principles.

Fig 3.6 Split Phase Motor

2. Capacitor-Start Motors

Capacitor start motors form the largest single grouping of general purpose single phase

motors. These motors are available in a range of sizes from fractional through 3HP. The

winding and centrifugal switch arrangement is very similar to that used in a split phase

motor. The main difference being that the starting winding does not have to have high

resistance. In the case of a capacitor start motor, a specialized capacitor is utilized in a

series with the starting winding.

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Fig 3.7 Capacitor Start motor

The addition of this capacitor produces a slight time delay between the magnetization of

starting poles and the running poles. Thus the appearance of a rotating field exists. When

the motor approaches running speed, the starting switch opens and the motor continues to

run in the normal induction motor mode.

This moderately priced motor produces relatively high starting torque, 225 to 400% of

full load torque. The capacitor start motor is ideally suited for hard to start loads such as

conveyors, air compressors and refrigeration compressors. Due to its general overall

desirable characteristics, it also is used for many applications where high starting torque

may not be required.

The capacitor start motor can usually be recognized by the bulbous protrusion on the

frame where the starting capacitor is located.

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Permanent-Split Capacitor Motors

The capacitor of this motor is left in series with the starting winding during normal

operation. The starting torque is quite low, roughly 40% of full-load, so low-inertia loads

such as fans and blowers make common applications. Running performance and speed

regulation can be tailored by selecting an appropriate capacitor value. No centrifugal

switch is required.

Fig 3.8 Permanent split capacitor Motor

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4. BLOCK DIAGRAM

Fig 4.1 Block Diagram of Pneumatic & Electrical Control Unit

Ultrasonic ranging and detecting devices make use of high-frequency sound waves to detect the

presence of an object and its range. An ultrasonic sensor typically utilizes a transducer that

produces an electrical output pulse in response to the received ultrasonic energy.

The above block diagram shows the main components of reverse braking system. There

are two types of power supply are required viz. electric supply for the operation of control unit

and IR sensor, and the air power supply to operate the pneumatic brake. IR sensor consists of IR

transmitter and IR receiver. IR transmitter transmits ultrasonic waves continuously. When car

gets too close to an obstacle, the ultrasonic waves reflect back which was then receive by the IR

receiver. After receiving the reflected signal, it gives the impulse to the control unit. This control

unit make ON the solenoid valve. These complete processes are electronic based which required

electric supply.

POWER

SUPPLY

CONTROL

UNIT

IR

TRANSMITTER

PNEUMATIC

CYLINDER

SOLINOID

VALVE

BREAK

ARRANGEME

NT

IR RECEIVER

FLOW

CONTROL

VANVE

AIR TANK

(COMPRESSOR)

34

5. WORKING OPERATION

The important components of our project are,

IR transmitter

IR receiver

Control Unit with Power supply

Solenoid Valve

Flow control Valve

Air Tank (Compressor)

The IR TRANSMITTER circuit is to transmit the Infra-Red rays. If any obstacle is there in a

path, the Infra-Red rays reflected. This reflected Infra-Red rays are received by the receiver

circuit is called “IR RECEIVER”.

The IR receiver circuit receives the reflected IR rays and giving the control signal to the control

circuit. The control circuit is used to activate the solenoid valve. The operating principle of

solenoid valve is already explained in the above chapter.

A continuous supply of air through air tank is supplied to solenoid valve. The flow control valve

is used to control the flow of air which allows the air to flow in one direction only that is only in

forward direction and block in reverse direction. When signal from control unit receives by

solenoid valve, a supply of compressed air supplied to pneumatic single acting cylinder. Then the

piston takes forward motion and consequently brake applied to the wheel. This stops the car and

accident is avoided.

Fig 5.1 Circuit Diagram of Pneumatic Braking System

35

If the solenoid valve is activated, the compressed air passes to the Single Acting

Pneumatic Cylinder. The compressed air activates the pneumatic cylinder and moves the

piston rod.

If the piston moves forward, then the breaking arrangement activated. The breaking

arrangement is used to break the wheel gradually or suddenly due to the piston

movement. The breaking speed is varied by adjusting the valve is called “FLOW

CONTROL VALVE”.

In our project, we have to apply this breaking arrangement in one wheel as a model. The

compressed air drawn from the compressor in our project. The compressed air flow

through the Polyurethane tube to the flow control valve. The flow control valve is

connected to the solenoid valve as mentioned in the block diagram.

Fig 5.2 Sensor Operated ARBS

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6. APPLICATIONS AND ADVANTAGES

APPLICATION:

For automobile application

Industrial application

ADVANTAGES

Brake cost will be less.

Free from wear adjustment.

Less power consumption

Less skill technicians is sufficient to operate.

It gives simplified very operation.

Installation is simplified very much.

To avoid other burnable interactions viz.… (Diaphragm) is not

used.

Less time and more profit.

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7. LIST OF MATERIALS

Sl. No. PARTS Qty.

i. Single Acting Pneumatic Cylinder 1

ii. Flow Control Valve 1

iii. Wheel 1

iv. Solenoid Valve 1

v. Single Phase induction motor 1

vi. Sensor Unit 1

vii. Pulley 2

viii. Polyethylene Tube -

ix. Hose Collar and Reducer -

x Stand (Frame) 1

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8. COST ESTIMATION

MATERIAL COST

Sl. No. PARTS Qty. Amount (Rs)

i. Single Acting Pneumatic Cylinder 1 1500

ii. Flow Control Valve 1 500

iii. Wheel 1 750

iv. Solenoid Valve 1 400

v. Single Phase induction motor 1 600

vi. Sensor Unit 1 250

vii. Pulley 2 500

viii. Polyethylene Tube - 200

ix. Hose Collar and Reducer - 300

x Stand (Frame) 1 1000

Total cost 6000

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9. CONCLUSION

This project work has provided us an excellent opportunity and experience, to use our limited

knowledge. We gained a lot of practical knowledge regarding, planning, purchasing, assembling

and machining while doing this project work. We feel that the project work is a good solution to

bridge the gates between institution and industries.

We are proud that we have completed the work with the limited time successfully. The sensor

operated pneumatic brake is working with satisfactory conditions. We are able to understand the

difficulties in maintaining the tolerances and also quality. We have done to our ability and skill

making maximum use of available facilities.

In conclusion remarks of our project work, let us add a few more lines about our impression

project work. Thus we have developed an “REVERSE BRAKING SYSTEM” which helps to

know how to achieve low cost automation. The application of pneumatics produces smooth

operation. By using more techniques, they can be modified and developed according to the

applications.

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10. REFERENCES

1. G.B.S. Narang, “Automobile Engineering”, Khanna Publishers, Delhi, 1991, pp 671.

2. William H. Crowse, “Automobile Engineering”.

3. Donald. L. Anglin, “Automobile Engineering”.

4. Pneumatic Control System----Stroll & Bernaud, Tata Mc Graw Hill Publications,

1999.

5. Pneumatic System----Majumdhar, New Age India International (P) Ltd Publishers,

1997.

Web sites:

www. Profc.udec.cl/~gabriel/tutorials.com

www.carsdirect.com/features/safetyflatures

www.hwysafety.org