CHAPTER 1: INTRODUCTION 1.1 Introduction Accidents occur due to technical problem within the vehicle or due to mistake of driver. Sometimes the drivers lose control over the vehicle and sometimes accident occurs due to rash driving. When the drivers come to know that vehicle is going to collide they become nervous and they don’t apply the brakes. Majority of the accidents occur this way. The system designed will prevent such accidents. It keeps track of any vehicles in front. It will continuously keep the track of the distance between the two vehicles. When two come dangerously close the microprocessor in the system activates the brakes and it will stop the vehicle. Driving is a compulsory activity for most people. People use cars to move from one place to another. The number of vehicles is increasing day by day. It is produced tacked tightly and risk to accident. Nowadays, the numbers of accident is so high and uncertainly. Accidents occur frequently and cause worst damage, serious injury and death. These accidents are mostly caused by delay of the driver to hit the brake. This project is designed to develop a new system that can solve this problem where drivers may not brake manually but the vehicles can stop automatically due to obstacles. 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 1
Transcript
CHAPTER 1: INTRODUCTION 1.1 Introduction
Accidents occur due to technical problem within the vehicle or due to mistake of driver.
Sometimes the drivers lose control over the vehicle and sometimes accident occurs due to
rash driving. When the drivers come to know that vehicle is going to collide they become
nervous and they don’t apply the brakes. Majority of the accidents occur this way. The
system designed will prevent such accidents. It keeps track of any vehicles in front. It will
continuously keep the track of the distance between the two vehicles. When two come
dangerously close the microprocessor in the system activates the brakes and it will stop the
vehicle. Driving is a compulsory activity for most people. People use cars to move from one
place to another. The number of vehicles is increasing day by day. It is produced tacked
tightly and risk to accident. Nowadays, the numbers of accident is so high and uncertainly.
Accidents occur frequently and cause worst damage, serious injury and death. These
accidents are mostly caused by delay of the driver to hit the brake. This project is designed to
develop a new system that can solve this problem where drivers may not brake manually but
the vehicles can stop automatically due to obstacles. 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 speed running speed is of 50 Km 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.
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1.1Need of Automatic Reverse Braking
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.
A) 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.
B) 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.
1.2Benefits 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.
Figure 1.1 Intelligence Braking System
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CHAPTER 2: LITERATURE SURVEY The Reverse Alert System is first developed by Surveillance Guard Corporation (SVG). It
was the world first aftermarket 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. [4] 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 mph and apply brakes
automatically.
CHAPTER 3: FACTORS CONSIDERED
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Factors considered in designing the system are:
Braking distance
Distance of obstacle in front
3.1 Braking Distance
The braking distance is the main factor considered in this system. Braking distance for a
particular speed is the distance between the point of application of the brakes and the point at
which the vehicle comes to a complete stop from the present speed.
It is calculated by using following formula:
Braking Distance = V2 / 2µg (meter)
Where V= Velocity of the vehicle (m/s)
µ = Coefficient of friction of road = 0.8
g = Acceleration due to gravity = 9.81(m/s2)
In this formula the condition of brakes and the road conditions are not considered for
coefficient of friction µ.
Table showing braking distance:
Velocity (km/hr) Braking Distance (m)
60 17.69
50 12.28
40 7.86
30 4.42
05 0.12
Table 3.1 Braking Distance
3.2. Distance of obstacle in front
The distance of any obstacle, a parked or a moving vehicle or a road block is sensed using an
Optical sensor and it is fed to microcontroller.
CHAPTER 4: BLOCK DIAGRAM AND DESCRIPTION
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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.
Figure 4.1 Block Diagram of Intelligent Reverse Braking System
The above block diagram shows the main components intelligent 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.
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.
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Figure 4.2 Circuit Diagram of the Intelligent Reverse Braking System
Generally, IR sensors are fitted at rear of the vehicle and solenoid valve is located at the front
wheel.
4.1 Park Mode and Override Buttons
Intelligent reverse braking has override mode as well as park mode. In these two modes
difference is the length of operation of the braking. In override mode the length of operation
is about 1.6m, but for parking mode the length of operation is 40cm.
To allow the driver to park the vehicle or engage in tight reversing maneuvers, the system has
a park mode. In this mode the sensors are reduced to 40cm. In addition, the system has an
override button that overrides the braking system when held.
Figure 4.3 Park Mode and Override Buttons
When the override button is released, the automatic braking system is again engaged. This
mode is activated when the driver needs to reverse closer than 40cm, or when the reversing
angle is so extreme that the sensors detect the terrain.
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CHAPTER 5: COMPONENTS AND DESCRIPTION As Intelligent Reverse Braking is a sensor operated pneumatic brake, it has both mechanical
as well as electronic component. So it can be referred as an electro-mechanical system.
Figure 5.1 Layout of the Intelligent Braking System.
5.1 Power Supply and Control Unit
An electric power is needed to run the control unit and IR sensor. Voltage required is 24V
DC supply which can be taken from the battery whose charge is done earlier charged when
engine runs. A control unit is supplies the power to the IR sensors. A 24V DC supply is
required for IR sensors.
5.2 Sensor Unit
Sensor unit consist of IR transmitter for generating the ultrasonic rays and IR receiver to
receive ultrasonic rays when they reflected back from obstacle. When waves reflected from
the obstacle, is received by IR received it sends to control unit. The control unit then
determined the distance of obstacle from the car and if the distance is within certain range it
sends signal to solenoid valve and finally brake is applied.
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Figure 5.2 Operation of sensor
5.2.1 IR Transmitter
An ultrasonic transducer is used in IR transmitter operates to radiate ultrasonic waves through
the air. Ultrasonic sound waves are the sound waves that are above the range of human
hearing capability and, so it has a frequency above 20,000 hertz. Any frequency which is
above 20,000 hertz may be considered as ultrasonic.
5.2.2 IR Receiver
An IR receiver receives the ultrasonic waves radiated by IR transmitter when they reflected
back from an obstacle and a signal sends to control unit.
5.3 Compressor
A continuous supply of compressed air is required to solenoid valve to operate the brakes
whenever needed. A compressor can compress air to the required pressures. It converts the
mechanical energy from motors and engines into the potential energy in compressed air. A
single central compressor can supply various pneumatic components with compressed air,
which is transported through pipes from the cylinder to the pneumatic components.
5.4 Pneumatic Cylinder
The pneumatic cylinder used is spring return single acting pneumatic cylinder.
Pneumatic cylinder consist of
A) Piston
B) Cylinder
A Single acting cylinder consists of a simple cylinder piston arrangement in which a spring is
loaded in opposite side if the working area of the fluid. In single acting cylinder only one
connection of pressurized air has to be given. When flow from the input port is come into the
cylinder, due to the pressure force the piston is moves forward to compensate the pressure
difference. This forward motion is against the spring force. This position of the piston
remains as it is till pressurized air stay in cylinder. Once the pressure input from the port is
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withdrawal due to spring in the cylinder, piston moves backward. Hence for reverse motion,
no force is required.
Figure 5.3 Pneumatic Symbol of a Spring Return Single Acting Cylinder
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.
5.5 Solenoid Valve
The solenoid valve is the valve which controls the flow of pneumatic (Air) by an electronic
signal.
Figure 5.4 Pneumatic Symbol of a Spring Return Single Acting Cylinder
The solenoid valve used here is 3/2 spring return pilot solenoid valve. 3/2 valve means it has
three ports that is we can give three connections to the valve and it has two positions which
means there are two positions that this valve can be operated.
The three connections of the solenoid valve are as follows:
1) Pressure Port (P) referred as port number 1.
2) Output Port (A) referred as port number 2.
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3) Return Port (R) referred as port number 3.
At the still position the pressure port is blocked which output is null. When signal from
control unit is obtained then valve shift from current right position to the left position. At
situation, pressure port is connected to the output port which means that air supply passed
through the valve and an output is obtained at port number 2. This completes the braking
processes. The brake is continuously applied till signal from IR receiver is obtained.
When signal from IR receiver is not obtained, then control does not send any signal to the
solenoid valve. Hence solenoid valve automatically comes to right position due springing
action.
5.6 Flow Control Valve
A flow control valve is used to control the amount of flow of air in one direction only. This
valve is used to avoid any disturbances to the compressor. A flow control valve is formed by
a non-return valve and a variable throttle.
(a) (b)
Figure 5.5 Flow Control Valve (a) Cross Section (b) Pneumatic Symbol
A flow control valve is connected in between solenoid valve and compressor. But most of the
time flow control valve is already attached to the cylinder. By using this valve the time
consumption is reduced because of the faster movement of the piston.
5.7 Braking Arrangement
An output is connected through flexible cable specially design for pneumatic operation to the
single acting cylinder. Piston is attached to the universal brake pedal clamp that is fitted on
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brake pedal. When solenoid valve is activated, piston takes forward motion. This forward
motion of the piston pulls the brake pedal, consequently stopping the vehicle automatically.
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.
5.7.1 The Advantages of Pneumatic Systems
Pneumatic control systems are widely used in our society, especially in the industrial sectors
for the driving of automatic machines. Pneumatic systems have a lot of advantages.
(1) High effectiveness.
(2) High durability and reliability.
(3) Simple design.
(4) High adaptability to harsh environment.
(5) Safety.
(6) Easy selection of speed and pressure.
(7) Environmental friendly.
(8) Economical.
5.7.2 Limitations of Pneumatic Systems
Although pneumatic systems possess a lot of advantages, they are also subject to many
limitations.
(1) Relatively low accuracy.
(2) Low loading.
(3) Processing required before use.
(4) Uneven moving speed.
(5) Noise.
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CHAPTER 6 FUTURE SCOPE The introduced intelligent reverse braking system in this seminar is very cheap and is
affordable for anybody. But the actual importance for the safety increases the value of this
system. Due to this the various changes, modifications, new ideas are introduced. These
changes are observed and analyzed the importance of this system. So these automobile
industries are about to launching the various intelligent systems to increase safety of
customers. National and international organizations evaluate Motorcycle ABS as an
important factor to increase safety and reduce motorcycle accident numbers. The European
Commission passed legislation in 2012 that made the fitment with ABS for all new
motorcycles above 125cc to be mandatory from 1 January 2016. A new technology from
Volvo may launch which allow cars to park automatically. Recently, Volvo has announced its
working automatic parking system dubbed Autonomous Parking. It uses sensor system to
park the vehicle without driver. This feature will include in next XC90.The reliable
intelligent driver assistance systems and safety warning systems is still a long way to go.
However, as computing power, sensing capacity, and wireless connectivity for vehicles
rapidly increase, the concept of assisted driving and proactive safety warning is speeding
towards reality. As technology improves, a vehicle will become just a computer with tires.
Driving on roads will be just like surfing the Web: there will be traffic congestion but no
injuries or fatalities. Advanced driver assistant systems and new sensing technologies can be
highly beneficial, along with large body of work on automated vehicles. These findings
suggest that the research into autonomous vehicles within the ITS field is a short term reality
and a promising research area and these results constitute the starting point for future
developments. Some of the 169 suggestions towards extension and/or future related works
are identified and are summarized below:
New sensory systems and sensory fusion is to be explored to plug additional
information to the control system.
This work can be extended to include different maneuvers to make the driving
system capable of dealing with all driving environments.
Future issues may also include an algorithm for autonomous formation of the
cooperative driving.
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Thus, with the current and growing awareness of the importance of security,
trustworthy vehicle autonomous systems can be deployed in few years
CHAPTER 7: CONCLUSION The Infrared Braking System, if executed in auto it deflects heaps of mishaps and can spare
human lives and property. Execution of such a propelled framework can be made mandatory
like wearing of safety belts with the goal that mischances can be deflected to some degree.
Our Infrared Braking System gives a look into the eventual fate of car wellbeing and the
amount more propelled this individual framework can be for staying away from mischances
and ensuring vehicle tenants when they are incorporated into one framework. The fate of car
security is more than simply building up another innovation; it is moving the way to deal with
wellbeing. INFRARED BRAKING SYSTEM approach speaks to a huge movement from the
conventional way to deal with wellbeing, yet it is crucial to accomplishing the significant
advantages. In the present work, a prototype of an ultrasonic distance measurement for
stationary obstacle is obtained. And controlling the speed of vehicle accordingly to
predetermined distance is shown. An ultrasonic sensor, cheaper and less demanding of
hardware than other types of sensors presently used, such as the sensors based on computer
vision or radar , is used to measure the distance between vehicle and the obstacle. The
relative speed of the vehicle with respect to the obstacle is estimated using consecutive
samples of the distance calculated. These two quantities are used by the control system to
calculate the actions on both the accelerator and also the brake, thus to adjust the speed in
order to maintain a safe distance to prevent accidents. As ultrasonic sensors can detect any
kind of obstacle, this system can also prevent collision of the vehicle with pedestrians, or can
at least reduce the injuries occurring. Since the control system does not use the absolute speed
to calculate the safety distance as done by the currently existing systems, the interaction with
automotive electronics is limited to actions on the accelerator and brake. This matter, coupled
with the fact of lower cost of ultrasonic sensors compared with other kinds of sensors, could
facilitate the application and mounting of the system in many low-end vehicles, helping to
improve comfort and safety and offer a hassle free driving experience at a reduced cost.
