AUTOMATIC BRAKING SYSTEM&

PATH FINDER

A MAJOR PROJECTSUBMITTED IN THE FULFILLMENT OF THE REQUIREMENT

FOR THE AWARD OF THE DEGREE OF

BACHELOR OF TECHNOLOGYIN

MECHANICAL ENGINEERINGOF

KURUKSHETRA UNIVERSITY, KURUKSHETRA

BY NAVNEET KUMAR (1504284) NARENDER KUMAR (1504285)

HAPPY YADAV (1504286)

UNDER THE GUIDANCE OF Mr. SACHIN WADHWA

DEPARTMENT OF MECHANICAL ENGINEERINGN.C. COLLEGE OF ENGINEERING

ISRANA (PANIPAT)JUNE 2008

ACKNOWLEDGEMENT

To execute a project honestly is the cherished desire of any would be

engineer and to do this we are no exception that we have managed to achieve

this at all.

We thank the INKOTECH Pvt. Ltd for helping in the Research Experiences for

Undergraduates (REU) program and providing this educational opportunity.

We also thank Mr. SACHIN WADHWA for his guidance & helping us in all the

possible ways. We express our sincere thanks towards our guide for his

unstinted support & commitment to make our project see light of today and

the college for use of their facilities.

CERTIFICATE

This is to certify that the dissertation report entitled “AUTOMATIC BRAKING AND PATH FINDER” being submitted by: -

a) NAVNEET KUMAR (1504284)

b) NARENDER KUMAR (1504285)

c) HAPPY YADAV (1504286)

In fulfillment for the award of degree of bachelor in technology in

Mechanical Engineering at the department of Mechanical Engineering,

NEMI CHAND COLLEGE Of ENGG.ISRANA is a record of students own work

carried by them under my supervision & guidance.

MR. SACHIN WADWA

(Sr.lecturare)

Mechanical Deptt.

CHAPTER 1: INTRODUCTION

To find auto break when enter accident area by proximity system when

the two disciplines (Mechanical &Electronic) are brought together, a whole

new world of interesting possibilities opens up. Here is a very simple and

useful circuit for security purposes.

Any vehicle when entered without break in proximity area become

safe, one can seek the help of security proximity system. The project has two

main parts an intruder sensor cum transmitter and a receiver.

IR transmitter and receiver pair can be used to realize a proximity

detector. The circuit presented here enables you to detect any object capable

of reflecting the IR beam and moving in front of the IR LED photo detector pair

up to a distance of about 5 meter from it.

Here is a illustrative project, where a simple hardware circuit is directly

interfaced to other vehicle. It can object counter for an assembly line

conveyer belt, and so on. With a little modification of the hardware.

Braking system of vehicles:-

The hybrid vehicle brake system includes both standard hydraulic brakes

during this phase of braking; the hydraulic brakes are not used. When more

rapid deceleration is required, the

hydraulic brakes are activated to provide additional stopping power.

The sensors can become contaminated with metallic dust and fail to detect

wheel slip; this is not always picked up by the internal ABS controller

diagnostic.

Here, two more sensors are added to help the system work: these are a wheel

angle sensor, and a gyroscopic sensor. The theory of operation is simple:

when the gyroscopic sensor detects that the direction taken by the car doesn't

agree with what the wheel sensor says, the ESC software will brake the

necessary wheel(s) (up to three with the most sophisticated systems) so that

the car goes the way the driver intends. The wheel sensor also helps in the

operation of CBC, since this will tell the ABS that wheels on the outside of the

curve should brake more than wheels on the inside, and by how much.

Typical System (No ABS):-

Typical Layout of System (with ABS) :-Typical System (ABS):-

Components:-Components:-

Sliding Caliper

Fixed Caliper

Pressure Control Valves

HARDWARE DESCRIPTION

The transmitter part consists of two 555 timers (IC1, IC2 for driving an

infrared LED. the infrared detector to sense the transmission; To save power,

the duty cycle of the 38kHz a stable multi vibrator is maintained at 10 per

cent.

The receiver part have an infrared detector comprising (IC3, IC4, IC5,

IC7 ) wired for operation and timer, followed by (T1) & (T2) transistor. Upon

reception of infrared signals to pin-2 of IC-4, the 555 (IC4) timer (mono) is

turned ‘on’ and it remain ‘on’ as long as the infrared signals are being

received.

Effectiveness

A 2003 Australian study by Monash University Accident Research Centre found

that ABS:

Reduced the risk of multiple vehicle crashes by 78 percent.

Reduced the risk of run-off-road crashes by 35 percent.

On high-traction surfaces such as bitumen, or concrete many ABS-equipped

cars are able to attain braking distances better (i.e. shorter) than those that

would be easily possible without the benefit of ABS. Even an alert, skilled

driver without ABS would find it difficult, even through the use of techniques

like threshold braking, to match or improve on the performance of a typical

driver with an ABS-equipped vehicle, in real world conditions. ABS reduces

chances of crashing, and/or the severity of impact. The recommended

technique for non-expert drivers in an ABS-equipped car, in a typical full-

braking emergency, is to press the brake pedal as firmly as possible and,

where appropriate, to steer around obstructions. In such situations, ABS will

significantly reduce the chances of a skid and subsequent loss of control.

In gravel and deep snow, ABS tends to increase braking distances. On these

surfaces, locked wheels dig in and stop the vehicle more quickly. ABS

prevents this from occurring. Some ABS calibrations reduce this problem by

slowing the cycling time, thus letting the wheels repeatedly briefly lock and

unlock. The primary benefit of ABS on such surfaces is to increase the ability

of the driver to maintain control of the car rather than go into a skid — though

loss of control remains more likely on soft surfaces like gravel or slippery

surfaces like snow or ice. On a very slippery surface such as sheet ice or

gravel it is possible to lock multiple wheels at once, and this can defeat ABS

(which relies on detecting individual wheels skidding). Availability of ABS

relieves most drivers from learning threshold braking.

When drivers do encounter an emergency that causes them to brake hard and

thus encounter this pulsing for the first time, many are believed to reduce

pedal pressure and thus lengthen braking distances, contributing to a higher

level of accidents than the superior emergency stopping capabilities of ABS

would otherwise promise. Some manufacturers have therefore implemented

Mercedes-Benz's "brake assist" system that determines that the driver is

attempting a "panic stop" and the system automatically increases braking

force where not enough pressure is applied. Nevertheless, ABS significantly

improves safety and control for drivers in most on-road situations

The ABS equipment may also be used to implement traction control on

acceleration of the vehicle. If, when accelerating, the tire loses traction with

the ground, the ABS controller can detect the situation and take suitable

action so that traction is regained. Manufacturers often offer this as a

separately priced option even though the infrastructure is largely shared with

ABS. More sophisticated versions of this can also control throttle levels and

brakes simultaneously.

Design and selection of components

Given the required reliability it is illustrative to see the choices made in the

design of the ABS system. Proper functioning of the ABS system is considered

of the utmost importance, for safeguarding both the passengers and people

outside of the car. The system is therefore built with some redundancy, and is

designed to monitor its own working and report failures. The entire ABS

system is considered to be a hard real-time system, while the subsystem that

controls the self-diagnosis is considered soft real-time. As stated above, the

general working of the ABS system consists of an electronic unit, also known

as ECU (electronic control unit), which collects data from the sensors and

drives the hydraulic control unit, or HCU, mainly consisting of the valves that

regulate the braking pressure for the wheels.

How Automatic-Braking System Work

The communication between the ECU and the sensors must happen quickly

and at real time. A possible solution is the use of the CAN bus system, which

has been and is still in use in many ABS systems today (in fact, this CAN

standard was developed by Robert Bosch GmbH, for connecting electronic

control units!). This allows for an easy combination of multiple signals into one

signal, which can be sent to the ECU. The communication with the valves of

the HCU is usually not done this way. The ECU and the HCU are generally very

close together. The valves, usually solenoid valves, are controlled directly by

the ECU. To drive the valves based on signals from the ECU, some circuitry

and amplifiers are needed (which would also have been the case if the CAN-

bus was used).

The sensors measure the position of the tires, and are generally placed on the

wheel-axis. The sensor should be robust and maintenance free, not to

endanger its proper working, for example an inductive sensor. These position

measurements are then processed by the ECU to calculate the wheel-spin.

The hydraulic control unit is generally located right next to the ECU (or the

other way around), and consists of a number of valves that control the

pressure in the braking circuits. All these valves are placed closely together

and packed in a solid block. This makes for a very simple layout, and is thus

very robust.

The central control unit generally consists of two microcontrollers, both active

simultaneously, to add some redundancy to the system. These two

microcontrollers interact, and check each other's proper working. These

microcontrollers are also chosen to be power-efficient, to avoid heating of the

controller which would reduce durability. The software that runs in the ECU

has a number of functions. Most notably, the algorithms that drive the HCU as

a function of the inputs, or control the brakes depending on the recorded

wheel spin. This is the obvious main task of the entire ABS-system. Apart from

this, the software also needs to process the incoming information, e.g. the

signals from the sensors. There is also some software that constantly tests

each component of the ABS system for its proper working. Some software for

interfacing with an external source to run a complete diagnosis is also added.

As mentioned before the ABS system is considered hard real-time. The control

algorithms, and the signal processing software, certainly fall in this category,

and get a higher priority than the diagnosis and the testing software. The

requirement for the system to be hard real-time can therefore be reduced to

stating that the software should be hard real-time. The required calculations

to drive the HCU have to be done in time. Choosing a microcontroller that can

operate fast enough is therefore the key, preferably with a large margin. The

system is then limited by the dynamic ability of the valves and the

communication, the latter being noticeably faster. The control system is thus

comfortably fast enough, and is limited by the valves.

Parts of automatic braking system:-

There are four main components to an ABS system:

Speed sensors

Pump

Valves

Controller

Speed Sensors

The braking system needs some way of knowing when a wheel is about to lock

up. The speed sensors, which are located at each wheel, or in some cases in

the differential, provide this information

Valves

There is a valve in the brake line of each brake controlled by the ABS. On

some systems, the valve has three positions:

In position one, the valve is open; pressure from the master cylinder is

passed right through to the brake.

In position two, the valve blocks the line, isolating that brake from the

master cylinder. This prevents the pressure from rising further should

the driver push the brake pedal harder.

In position three, the valve releases some of the pressure from the brake.

Pump

Since the valve is able to release pressure from the brakes, there has to be

some way to put that pressure back. That is what the pump does; when a

valve reduces the pressure in a line, the pump is there to get the pressure

back up.

Controller

The controller is a computer in the car. It watches the speed sensors and

controls the valves.

methodology for the interpretation of sensor data, route planning,

and vehicle control

Radar Signal processing software provided with the Epsilon Lambda Electronics

ELSC71-1A 3D radar will produce a data map of the field of view with the

range, azimuth, elevation, velocity, and signal amplitude for each object

detected. The azimuth is known as a function of time because the radar

antenna is mechanically scanned across the field of view by a stepper motor.

The range

is found from a beat signal with amplitude. The velocity is found by Doppler

frequency, and the elevation angle is found by taking the phase difference

between two IF channels. Range resolution is approximately 1 meter, azimuth

resolution is 1.8 degrees, and elevation resolution is about 1 degree.

We will interpret abrupt changes of elevation as obstacles for the vehicle to

avoid. Targets which seem to be moving relative to most of the field of view

will be interpreted as moving obstacles, probably other Challenge Vehicles,

and given an especially wide berth. We may be able to use the amplitude of a

signal return to further classify objects (e.g., a stronger return would be

expected from a metal vehicle than from a desert plant).

Vision The vision system will consist of several video cameras, each rigidly mounted

to the vehicle. We will know the rigid transformations describing the position

and orientation of each camera and the radar system with respect to the

vehicle coordinate system and the other cameras, at every instant of time. We

also know the internal parameters of each camera, which can be obtained

using standard rig calibration techniques [Bouguet].

In this case, a point in space, X, projects onto each camera. Most points will be attached to the same rigid surface, the terrain. Some will be on opposing vehicles, which can be modeled as separate rigid bodies moving in an independent manner. Still other points in space will belong to miscellaneous objects which may or may not be rigid, such as birds or clouds. For objects within the range and field of view of the radar, the vision system will know the approximate depth and velocity of locations in space. This greatly simplifies various vision tasks, since the relative change in pose between two instants of time is known. This provides a great deal of information for tasks such as feature tracking, motion estimation/segmentation, and geometric reconstruction. Objects beyond radar range will also need to be detected, tracked, and potentially identified, but since geometric information may not be easily obtained, we will use image-based techniques, such as

color segmentation and 2D recognition. We will also investigate the efficacy of more advanced Level Set tracking methods [Cremers]. Detection of Other Challenge Vehicles The initial detection of a potential vehicle will occur in both the vision and radar systems. The radar will indicate the presence of an obstructing object in its depth map, assuming the object falls within the field and depth of view. Simultaneously, the vision system will detect the presence of one or more lights of the specified alert-light color in an invariant color space (such as HSV). When this occurs, the car-detection software module will attempt to find periodic flashing, which will positively indicate the presence of an opposing vehicle. The other vehicle’s position in space can be updated by tracking the image-plane coordinates of its lights and other areas-of-interest on the image of the vehicle, as well as by using radar data if any.

Detection of Miscellaneous Objects The radar system should detect most medium and large positive obstacles in

its field of view. We rely on the vision system to detect negative obstacles,

positive obstacles which are significant but too small for the radar to resolve,

and obstacles which are outside of the radar’s field of view or which could not

be seen until they were inside the radar’s minimum range.

In the environment we will be traveling through, there are many regions of the

image with very regular appearances. Rocky and sandy surfaces will present a

difficult problem for image feature

tracking due to the similarity of appearance of many nearby areas in the

images. Hence, traditional structure-from-motion schemes will likely fail for

the task of detecting dangerous objects. Luckily, we can exploit other

information about the structure of the environment and a priori knowledge.

Since the system will know the time of day, its orientation, and the lighting

conditions, it can employ a shape-from-shading and shape-from-shadow

system to determine the approximate position and dimensions of obstacles

like large rocks or craters.

Classification of Terrain Understanding of the type of surface on which the vehicle is traveling is

essential for determining a safe speed and control technique. Paved roads or

dry lakebeds will allow aggressive control at high speed, while rocky or

uneven terrain must be traversed with more care. The radar system might

provide some information regarding the terrain type from the amplitude of the

signal return, but generally we expect better data from the vision system. Our

terrain classification system will use Bayesian sensor fusion techniques,

whereby the signals from the cameras and the radar are jointly interpreted to

provide an estimate of the terrain type in the field of view. A statistical model

will be trained using recorded data from the cameras and radar, and the

parameters of the Bayesian network will be learned in a supervised manner.

Other inputs to the model will be time of day and weather, both of which will

influence the lighting conditions of the environment.

Determination of Local Road Geometry While the GPS system and maps will provide medium and long-range path

planning goals (waypoints), knowledge of the local upcoming road geometry

can only be determined by on-board sensing. This information is crucial for

short-range control and path generation. In particular, the control system will

need to know the boundaries of the beaten trail, which will provide the safest

route through the terrain in the absence of other obstacles. Determining these

boundaries will be difficult due to the similarity of appearance of most parts of

the images. From initial experiments with off-road trail video, we have

determined that a distinguishable characteristic of the path is its relatively low

spatial frequency. In general, a beaten path will be smoother since it will have

fewer jagged rocks, little or no vegetation, and a somewhat consistent

material.

Route Planning After the Route Definition Data File is provided, a nominal minimum-cost route

from each waypoint to the next will be computed based on map data using a

wavefront-propagation path planner. The output of this planner will be

nominal desired headings and target speed as a piecewise-polynomial

function of latitude and longitude across the permitted corridor between and

around each waypoint pair, and this information will be stored for

consideration at the appropriate point in the Route.

At all times after the vehicle passes the Departure Line, it should have an

estimate of its current location and heading, and nominal desired headings

version of the wavefront-propagation path planner to find the optimal

obstacle-free trajectory that will take it to a point on the sensor horizon with

as close as possible to the precomputed nominal desired heading and speed.

This second algorithm will be adapted to the local planning problem in that it

will more finely differentiate (x,y,theta) space and take more account of the

vehicle kinematics and dynamics (e.g., steering linkage position, turning

radius as a function of speed).

If there is no unobstructed path to the nominal computed route within the

vehicle’s field of view, the vehicle will slow down, in anticipation that the route

might be blocked and it might be about to receive an E-Stop signal. If space

permits, the vehicle will turn to shift its field of view and possibly find another

route. If the vehicle can neither turn nor progress forward, it will come to a

stop and wait for an E-Stop, or for the route to clear.

In any case, at each instant the planner should provide a desired speed and

heading. PID control loops for the steering and accelerator/brake will then

attempt to correct the current speed and heading. The planner is responsible

for providing the PID controller with a “desired” trajectory that is within the

limits of the actuators and the vehicle dynamics, e.g. the planner should not

demand a turn which is unsafe at either the current or desired speeds.

CHAPTER 2: LITERATURE REVIEW

Though lot of literature survey has been done for this work. Problem was the

industry generated and for its solution a thorough literature survey has been

done, from that we find out that there is lot of scope of improvement in

industrial productivity by Work Study techniques. Some of the main papers

are as follows:

Edward C. Francis (1986) explained that Automatic Vehicle Control

Overview

PRT 2000™ operates with a highly responsive control system, custom

developed by Raytheon to provide reliable and safe transit of passengers,

delivering maximum system capacity by operating with a minimum distance

between vehicles. This Automatic Vehicle Control (AVC) system has been

developed based on the principles common to all Automatic Train Control

(ATC) systems, following the new American Society of Civil Engineers (ASCE)

Automatic People Mover (APM) standards, and specific requirements unique to

this application. PRT 2000™ response times are fractions of a second, allowing

vehicles to operate at headways as short as 2.5 seconds at 30 mph. Vehicle

motion is continuously monitored and adjusted in real time to safely and

efficiently merge streams of traffic where guideway sections join, and to

properly switch vehicles toward their destination where a single guideway

section diverges into two. Empty vehicles are automatically routed to stations

where passenger demand exists.

PRT2000's™ AVC system is constructed in a three-level hierarchy. Every

vehicle carries an on-board controller. These vehicle controllers receive

direction from and report status to stationary wayside controllers, responsible

for coordinating vehicle activities within fixed regions of the guideway. An RF

data link mounted within the guideway structure allows continuous, high-

bandwidth communications between the vehicle and wayside. The following

figures depict a typical alignment and the partitioning of the control function

to the distributed waysides.

The wayside controllers are connected to each other via a high-speed fiber-

optic network to coordinate vehicles transitioning from one region of guideway

to the next. The fiber network extends to a central System Control Center

(SCC), providing the System Control Operators with comprehensive status and

oversight of the system's behavior. Within this modular, three-level computing

hierarchy, PRT 2000's™ AVC system provides the functions required for the

safe, automated control of vehicles. Automatic Vehicle Protection (AVP),

Automatic Vehicle Operation (AVO) and Automatic Vehicle Supervision (AVS)

functions are provided, in accordance with ASCE standards.

Automatic Vehicle Protection

AVP protects passengers, personnel and equipment from potentially

hazardous situations; it has precedence over AVO and AVS functions. By

reliably monitoring vehicle movement and equipment status within the

system, AVP is able to revert the system to a safe state whenever a

potentially hazardous condition is detected.

AVP autonomously monitors the position and speed of each vehicle, the state

of its doors and door locks, and the state of its in-vehicle switch. The AVP

system is based on a principle of permissive action; no action is permitted

unless AVP can ensure it is safe. Continuous, positive action by AVP is required

to allow vehicles to proceed along the guideway. As shown in the inset, a

complete set of AVP functions is provided.

All processing associated with AVP is performed in parallel by a pair of

redundant safety processors which are cross-checked for agreement. This

agreement is a condition for any vehicle motion. A fail-safe hardware

watchdog module on each vehicle keeps propulsion disabled and emergency

braking engaged unless it receives periodic indication that its processors are

operating correctly and the suite of safety checks they perform are all

satisfied. In addition, the watchdog must receive regular assurance that

communications with the wayside controller is functioning properly. In the

wayside controller, a similar fail-safe architecture uses a hardware watchdog

module to inhibit communications with vehicles unless it receives periodic

indication that its safety processors are operating correctly and that their

safety checks are satisfied.

All devices vital to safety are handled directly by AVP hardware and software.

Safety-critical equipment sensors are triple redundant; a majority voting

scheme provides for safe and reliable operation. AVO access to the door locks,

the in-vehicle switch, and the parking brakes is via request to AVP. AVP

satisfies a request only if it is safe to do so.

Automatic Vehicle Operation

AVO controls vehicles to provide automatic origin to destination passenger

service between all stations in the system. This requires commanding the

propulsion system to move the vehicle along the mainline guideway and

within the stations, operating the in-vehicle switch to pursue a route to the

vehicle's destination, and operating vehicle doors for boarding and

deboarding. Vehicle movement is performed such that system capacity is

maximized while observing all necessary constraints for safety and ride

comfort. In particular, AVO operates the vehicles so that hazard protections

are not invoked within AVP, which serves as the fail-safe monitor for the PRT

2000 control system.

AVO moves vehicles throughout the system in accordance with their

destinations. Each vehicle carries its current destination with it as it travels,

supplying it to the wayside controllers as part of its regularly reported status.

Vehicle destinations change automatically as passenger trips begin and end,

as empty vehicles are distributed, or as vehicles are added to or recalled from

active service. The System Control Operator can also change vehicle

destinations via manual intervention.

AVO controls the route that a vehicle takes to reach its destination by

commanding its in-vehicle switch assembly either left or right each time the

vehicle travels through a diverge region. Routing tables distributed by AVS to

the wayside controllers provide the basis for AVO's positioning of the switch.

PRT 2000's off-line passenger stations allow vehicles to travel directly from

their origin to their destination, bypassing all intermediate stations along the

way. As the vehicle approaches its destination station, AVO manages its

entrance to the station, assigns it a berth and precision aligns it. AVO applies

the parking brake and holds the vehicle at zero speed until passenger

boarding completes, then coordinates the exit of the vehicle from the station

back out onto the mainline.

AVS provides automatic and System Control Operator (SCO) initiated system-

wide monitoring and control capabilities. There are three sets of related

responsibilities.

First, AVS compares system performance against established levels of service

and automatically adjusts or controls the system to meet varying patron

demands. Routing tables are distributed to each of the wayside controllers to

specify the current best path to reach each destination. In most cases, all

vehicles are given the same direction for a given destination, corresponding to

the quickest path. However, in situations where there are multiple paths to

the destination that may be traversed in approximately equal time, the

system may specify that a percentage goes one way and the remaining

percentage goes the other. Empty vehicle management instructions are

specified for each station, based on demand. AVS controls audible and visual

interfaces with patrons throughout the course of their interaction with the

system, and controls the attendant ticket processing to initiate trips.

Second, AVS monitors vehicle traffic and equipment health, maintaining an

active log of vehicle status, trip summary data, faults, and alarms. To the

degree it can, AVS may also initiate certain automated fault recovery

operations in response to unexpected events. For example, if one of the two

redundant traction motors fail, AVS will automatically recall the vehicle from

service after completing the current trip. As part of its system monitoring

responsibility, AVS provides statistical accounting of trips and equipment

usage to support ridership analysis and maintenance activities.

Finally, based on monitored system behavior and performance, AVS provides

information to and accepts controls from the SCO to modify the automatic

operations of the system or manually intervene in extraordinary

circumstances. The SCO's role is primarily one of monitoring stations for

safety and security, and responding to patron requests for assistance. At the

same time, when an abnormal situation arises, AVS provides "human- in-the-

loop" controls for fault management.

AVC Hardware Components

AVC computer and data communications hardware is distributed between the

System Control Center, the wayside and the vehicles, providing the platform

for AVP, AVO, and AVS functions. This hardware operates in conjunction with

resident software and interfaces with other equipment to provide the required

system level performance.

Vehicle Controller

One vehicle controller resides in each vehicle in a dual-redundant

configuration; it is automatically reconfigured to continue to operate through

hardware and software faults. The vehicle controller monitors and controls a

myriad of subsystems in the vehicle, as depicted in the figure below:

Each vehicle controller can sense and drive a vehicle's switches, annunciators,

display, sensors and actuators and other supporting control/communication

equipment by way of resident real-time operating software. The vehicle

controller interfaces to the local wayside controller using its Vehicle

Communications (VCOM) RF communication antennas. Two antennas mount

on the chassis for bi-directional communication via the guideway antenna

located on the left or right side.

The vehicle controller has a dual redundant architecture, containing two

independent Vehicle Control Sets (VCS). Each VCS is an independent

computer with a complete complement of I/O. Only one VCS is active at a

time, with the active VCS controlling actuators and VCOM communication. The

non-active VCS operates in a standby mode, ready to takeover if the active

VCS goes down.

Within a VCS, a cross-checking pair of safety processors provides a safety-

critical computing environment. Each member of the pair communicates with

the other and issues a heartbeat at regular intervals to a watchdog module

only after insuring its own health and that of its partner. If either both VCSs or

the VCOM is deemed unhealthy, the watchdog module will stop the vehicle

using the vehicle's propulsion / brake interlock.

Each vehicle carries a permanent unique code as a Vehicle ID which is

accessible by software. This code is contained in an assembly that is

permanently mounted in the cabin and is separate from the Controller.

Within the vehicle controller there is also a set of non-redundant hardware for

non-safety-critical functions including controlling the vehicle doors and

interfacing to the passengers with a text display and audio board.

Wayside Controller

A wayside controller is configured to communicate to vehicles utilizing up to

four separate communications antennas. Each single antenna spans a

separate region of the guideway. Redundant hardware allows controllers to

operate through single hardware failures. Interfaces to ticketing equipment,

station signs, audio and other building equipment are provided, as depicted in

the following figure.

Eight processors typically reside in a wayside controller. Four of the

processors provide two redundant pairs that manage all the AVO and AVS

functions. An additional four processors are used to provide safety-critical

operations, configured as two cross-checking pairs. Each member of a safety

pair communicates with the other and issues a heartbeat at regular intervals

to a watchdog module only when it considers both itself and its corresponding

processor to be healthy.

The watchdog module monitors the heartbeats from the four safety

processors, and selects one pair to monitor the safe operation of the system.

If, through the absence of heartbeats, the watchdog module determines that

neither processor pair is healthy, the watchdog shuts down the VCOM region

controlled by the wayside controller. The vehicle controller is designed to

ensure that when VCOM messages cease, the vehicle is brought to a stop,

guaranteeing a safe state.

Data Communications

Two distinct data communications services are provided by the PRT 2000™

AVC system. Data exchange between the vehicle controller and wayside

controller is provided by an RF link that affords a non-contact mechanism for

exchange between the moving vehicle and stationary wayside. Wayside to

wayside communication is provided by a fiber-optic link that features the

range and high-speed data rates required to manage the system. This fiber-

optic link is also used by the System Control Center to communicate with all

the waysides.

Timothy A. Springer (1991) examined the initial step in leukocyte

accumulation in inflamed tissue is a rolling interaction on the vessel wall. The

driving force for rolling is the hydrodynamic force of the bloodstream acting on

the adherent cell; rapid formation and breakage of adhesive bonds are

required for the adhesive contact between the leukocyte and the vessel wall

to be maintained and to be translated along the vessel wall during

rolling .Rolling occurs in a series of steps or jerks that appear to represent

receptor-ligand dissociation events From measurements of the dimension of

the adhesive contact zone in the direction of flow and the average step

distance, it has been estimated that as few as two adhesive bonds between

the cell and the substrate are sufficient to support rolling .

The selectin glycoproteins are limited in expression to vascular cells and are

specialized to mediate rolling. L-selectin is expressed on leukocytes and binds

to carbohydrate ligands on endothelium and other leukocytes; E-selection and

P-selectin are expressed on endothelium and bind carbohydrate ligands on

leukocytes. The structures of several of these molecules are known from

crystals or electron micrographs and equilibrium constants, kinetics, and effect

of applied force on kinetics are known for several of the molecular interactions

Rolling should be an inherently unstable transition state, delicately poised

between firm adhesion and lack of adhesion. However, rolling through

selectins is highly stable to alterations in selectin density and hydrodynamic

force acting on the cell this force is proportional to and can be calculated from

the shear stress at the vessel wall. The velocity of rolling cells varies little in

vivo or in vitro despite wide variation in wall shear stress). This stability in the

velocity of rolling leukocytes is likely to be important in the postulated

function of rolling as a checkpoint in the process of leukocyte accumulation in

inflammation. Rolling enables leukocytes to survey endothelium for signs of

inflammation, including chemoattractants that can activate firm adhesion

through integrins, and provide directional cues for transendothelial migration

Particularly in early or in mild inflammation, leukocytes may roll through a

postcapillary venule without developing firm adhesion, and thereby reenter

the circulation . It appears that a threshold level of activation must be

exceeded before firm adhesion is stimulated. Rolling velocity will determine

the time duration of exposure of a leukocyte to activating stimuli on the vessel

wall, and hence should be of key importance in determining whether

activation occurs. Therefore, for proper control of activation of rolling

leukocytes, it may be important for rolling velocity to be relatively

independent of wall shear stress, which varies widely depending on tissue and

physiologic and inflammatory state. Even for different postcapillary venules

within a single tissue, wall shear stress can vary markedly; e.g., it ranges from

3-36 dyn/cm2 for 30-40-µm venules in cat mesentery

Recently, a number of constants critical to an understanding of rolling at the

cellular and molecular level have been measured. Most measurements come

from studies of the dissociation rate constants for "transiently tethered" cells.

Transient tethers occur when leukocytes in a hydrodynamic flow chamber

interact with a substrate, i.e., the lower wall of the flow chamber, that bears

selectins or ligands at densities too low to enable rolling . Under these

conditions, leukocytes moving at the hydrodynamic flow velocity will

momentarily bind to the substrate and remain almost motionless, then

dissociate and resume movement at the hydrodynamic velocity. Transient

tethers have first-order dissociation kinetics and may reflect unimolecular

binding and dissociation events.

Gregson K. (1993) suggested how to judge between competing work-study

projects in order that efforts were wisely and profitably directed. Showed that

factor analysis could be a useful technique to determine which of a number of

possible paths of an investigation were likely to yield the best results.

Described factor analysis by citing a specific example.

CHAPTER 3: WORKING

3.1 PROCESS IN SENSOR

This project was based on photo diodes and photo transistor. Photo diodes

had been used as a transmitter and photo transistor as a receiver. This project

had been divided in two part, First part transmitter section and second part

receiver section.

TRANSMISSION SECTION:- Transmitter module uses IC-555 as a stable

multivibrator operating at a frequency of around 1 KHz with a PNP transistor in

IRED (photo diode) driver stage at the output. This module emits modulated

infrared light. IRED is connected in series for more range and wider directivity.

The module can transmit IR rays up to few meters without use of any external

lens.

FIG. TRANSMISSION COMPONENT

When a vehicle comes nearly person, circuit is energized. The output of IC-555

is square wave from Pin No. 3. T1 gets biasing current to out put of IC-555 and

the IR-LED is connected to T1 collector with R5. The transmit IR beams

modulated at same frequency 1KHz. The oscillator frequency can be shifted

by adjusting preset VR-1. The receiver uses infrared module. The IR- signal

form the transmitter is sensed by the receiver sensor. The same automatically

turns ‘off’, as the person moves away.

RECEIVER SECTION:- Block diagram of the circuit is shown in transmitter

section consists of a power supply, an oscillator, and an output sage, whereas

the receiver section comprises power supply, an infra-red detector module,

time delay circuit, op-amp with noise filter, and an output section. The

complete schematic diagrams of the transmitter and receiver sections are

shown in circuit diagram respectively.

FIG. RECEIVER COMPONENT

This section is divided in a three part, witch pe-amp., amp. and switching

section. The receiver uses infrared modules IR-signal from the transmitter is

sensed by the sensor and its output PIN 1 goes low and switched IC-3. IC-3 is

worked on astable pulse which receives at Pin No. 2. Its output at Pin No 6

troughs high, witch amplifier to weak signals.

The receiver part have an infrared detector comprising (IC3,IC4,IC5,IC7 )

wired for operation in Amp.mode and timer, followed by pnp (T1) & npn (T2)

transistor. Upon reception of infrared signals to pin-2 of IC-4, the 555 (IC4)

timer (mono) is turned ‘on’ and it remain ‘on’ as long as the infrared signals

are being received.

The op-amp are in the set state. Pin 6 of IC-5 are high. The computer reads its

parallel port, to see if pin number 11 is low. Remember, whenever a aeroplane

passes in front of the radar, IC-3 are received input pulse, and pin 6 of IC-3

goes high and IC-4 receives input pin-2 form T2. IC-4 is worked as a power

amp, Pin-3 of IC-4 is A burst output of 38 kHz, modulated at 100 Hz. IC-5

works as a switching, collector of T4 is low , IC-5 take input plus at pin-2 and

output goes at pin-6 (high). As soon as The computer reads its collector of

T5, a software inside the computer starts ticking. After a are checked to see if

the aeroplane has crossed without information to IR beam also. This fact is

displayed on the screen. Pin-2 of PC is high output, The computer is switched

the gun. If, aeroplane is passed signal, second receiver is switched to

proximity system.

The same arrangement can be turned into a burglar alarm by just modifying

the software.

3.2 WORKING PRINCIPLE

Any vehicle when entered without break in proximity area become

safe, one can seek the help of security proximity system. The project has two

main parts an intruder sensor cum transmitter and a receiver.

IR transmitter and receiver pair can be used to realize a proximity

detector. The circuit presented here enables you to detect any object capable

of reflecting the IR beam and moving in front of the IR LED photo detector pair

up to a distance of about 5 meter from it.

Here is a illustrative project, where a simple hardware circuit is directly

interfaced to other vehicle. It can object counter for an assembly line

conveyer belt, and so on. With a little modification of the hardware.

Braking system of vehicles:-

The hybrid vehicle brake system includes both standard hydraulic brakes

during this phase of braking; the hydraulic brakes are not used. When more

rapid deceleration is required, the hydraulic brakes are activated to provide

additional stopping power.

The sensors can become contaminated with metallic dust and fail to detect

wheel slip; this is not always picked up by the internal ABS controller

diagnostic.

Here, two more sensors are added to help the system work: these are a wheel

angle sensor, and a gyroscopic sensor. The theory of operation is simple:

when the gyroscopic sensor detects that the direction taken by the car doesn't

agree with what the wheel sensor says, the ESC software will brake the

necessary wheel(s) (up to three with the most sophisticated systems) so that

the car goes the way the driver intends. The wheel sensor also helps in the

operation of CBC, since this will tell the ABS that wheels on the outside of the

curve should brake more than wheels on the inside, and by how much.

Given the required reliability it is illustrative to see the choices made in the

design of the ABS system. Proper functioning of the ABS system is considered

of the utmost importance, for safeguarding both the passengers and people

outside of the car. The system is therefore built with some redundancy, and is

designed to monitor its own working and report failures. The entire ABS

system is considered to be a hard real-time system, while the subsystem that

controls the self-diagnosis is considered soft real-time. As stated above, the

general working of the ABS system consists of an electronic unit, also known

as ECU (electronic control unit), which collects data from the sensors and

drives the hydraulic control unit, or HCU, mainly consisting of the valves that

regulate the braking pressure for the wheels.

3.2 PURPOSE OF AUTOMATIC BRAKING SYSTEM

A preceding vehicle following control apparatus includes a sensor sensing an

actual vehicle speed, a sensor sensing an actual vehicle spacing from a

controlled vehicle to a preceding vehicle ahead, and an actuator for regulating

a driving/braking force of the controlled vehicle. A controller controls the

vehicle speed or the vehicle spacing in a following control mode with the

actuator, and starts a deceleration control if an anti-lock brake control is

started in the following control mode. The controller cancels the deceleration

control when the vehicle spacing becomes greater than a predetermined

spacing value

3.2.1 BETTER CONTROL

A vehicle speed sensor to sense an actual vehicle speed of the controlled

vehicle. Vehicle spacing sensor to sense actual vehicle spacing from the

controlled vehicle to a preceding vehicle; a vehicle speed controller to vary

the actual vehicle speed of the controlled vehicle in accordance with a desired

vehicle speed; anti-lock brake controller to perform an anti-lock brake control

for preventing wheel locking; and

vehicle speed controller to determine the desired vehicle speed in accordance

with the actual vehicle speed and the actual vehicle spacing, the controller

comprising,

following control section to perform a preceding vehicle following control by

setting a desired vehicle spacing from the controlled vehicle to a preceding

vehicle in accordance with the actual vehicle speed and actual vehicle spacing

and determining the desired vehicle speed to bring actual vehicle spacing

closer to desired spacing,

deceleration control section to perform a deceleration control determining the

desired vehicle speed to decrease the actual vehicle speed of the controlled

vehicle, and mode change control section to cancel the following control of

the following control section and instead compulsorily initiating the

deceleration control of the deceleration control section in response to a start

of the anti-lock brake control of the anti-lock brake controller.

3.2.2 CUT CAR CRASHES

it detects the risk of a crash, and automatically applies the brakes if it judges

that the car may have trouble avoiding an object. The Collision Mitigation

Brake System (CMS), a world first, also automatically tightens seatbelts just

before a collision. Honda has fitted it to its new top-of-the-range sedan, the

Inspire, which went on sale in June. The Ministry of Land, Infrastructure, and

Transport has taken the lead in encouraging domestic carmakers to develop

advanced safety vehicles (ASVs), and some of these are now approaching the

stage where they are ready for practical use. Automakers are looking to

develop and commercialize a wide range of safety systems to reduce road

risks.

3.2.3 STABLIZATION IN DRIVING

Wall shear stress in postcapillary venules varies widely within and between

tissues and in response to inflammation and exercise. However, the speed at

which leukocytes roll in vivo has been shown to be almost constant within a

wide range of wall shear stress, i.e., force on the cell. Similarly, rolling

velocities on purified selections and their legends in vitro tend to plateau. This

may be important to enable rolling leukocytes to be exposed uniformly to

activating stimuli on endothelium, independent of local homodynamic

conditions. Wall shear stress increases the rate of dissociation of individual

selectin-ligand tether bonds exponentially (, ) thereby destabilizing rolling. We

find that this is compensated by a shear-dependent increase in the number of

bonds per rolling step. We also find an increase in the number of microvillus

tethers to the substrate. This explains (a) the lack of firm adhesion through

selections at low shear stress or high legend density, and (b) the stability of

rolling on selections to wide variation in wall shear stress and legend density,

in contrast to rolling on antibodies (). Furthermore, our data successfully

predict the threshold wall shear stress below which rolling does not occur. This

is a special case of the more general regulation by shear of the number of

bonds, in which the number of bonds falls below one.

3.2.4 FOR MAX. WINDING EFFICENCY

The Automatic Braking System (ABS) supplies the advanced tool required for

efficiently locating and correcting defects. It increases winder or re-reeler

capacity by optimizing the time to locate the defects to be patched or culled.

When manual control is used, the unwinding rate must be reduced to crawl

speed well in advance of suspected problem areas in order to avoid missing

the defect. This often leads to the winder/re-reeler function becoming a bottle-

neck in the paper production line.

Automatic Braking can be effectively utilized in virtually any paper type or

grade.

By taking into consideration both the location of the defect and the limitations

of the customer specific winder drive, Automatic Braking calculates the

optimal speed curve to the defect. It then automatically slows down the drive

to crawl speed or alternately stops the winder or re-reeler at the precise

selected defect location. The status of the unwinding, e.g. the length to the

next stopping position, is continuously updated on the display. With Automatic

Braking, the operators have the additional facility of virtually unwinding the

reel in advance. With the help of the defect classification and high resolution

images, operators are able to easily determine the severity of the defects and

thus minimize unnecessary stops..

3.2.5 PATH FOLLOWER

A Path Follower is an invisible thing that follows a path of Interpolation Points

and can provide something for a camera to aim it if you want the camera to

follow a path with a complicated aiming sequence.

The Path Follower (9071) takes three parameters:

1. low byte: low byte of tid of first Interpolation Point in path.

2. high byte: high byte of tid of first Interpolation Point in path.

3. options: (Add any of the following values; i.e. for options 2 and 4, this

parameter would be 6):

o 1: path is linear instead of curved.

o 2: Camera will adjust its angle to match those of the points it

passes.

o 3: Camera will adjust its pitch to match those of the points it

passes.

o 4: When used with 2 and/or 4, the camera faces in the direction of

movement instead of the direction the Interpolation Points are facing

.

An obstacle detection device for a vehicle includes an area determining section for determining a detection area extended forward of a running vehicle and provided for detecting an obstacle, a split section for splitting the area into a plurality of small split zones, a detecting section for detecting an obstacle in each of the small split zones, inferring section for an inferring a path of the vehicle in the obstacle detection area, and a judging section for judging a rank of danger of an obstacle in the detection area. The obstacle can be properly detected so that the vehicle can take a responsive and appropriate action for avoiding the obstacle.

Path-finder would bear a strong family resemblance to the full-size Armada SUV, we were afraid. Very afraid. The old Path-finder was a good-looking truck, whereas the Armada is the Shrek of its field.

Fortunately, the new Pathfinder has real character, even though the styling is hardly beautiful. Like every new mid-size SUV, it is bigger inside and out, more powerful, and heavier, and it features a third-row seat.

Unlike the old Pathfinder, the new one uses body-on-frame construction. It has upper- and lower-control-arm front and rear suspension, with coil springs and antiroll bars at both ends. Ground clearance varies between 8.5 and 9.2 inches, depending on the model.

The Pathfinder is the first recipient of the latest VQ V-6 engine. Displacing 4.0 liters (in-stead of 3.5), it has been tuned to produce good midrange torque, with 80 percent of the peak 291 pound-feet being available below 2000 revs. It also makes 270 horsepower and mates to a five-speed automatic transmission.

Nissan expects that around 30 percent of Pathfinders will be rear-wheel-drive, but there's a choice of two all-wheel-drive systems: a part-time system that can be shifted on the fly and an on-demand version that shunts up to 50 percent of the torque to the front wheels in case of wheel slippage. All Pathfinders have a standard skid-control system and antilock brakes; all-wheel-drive models also have "Active Braking Limited Slip," which uses the traction-control system to move up to 50 percent of the engine torque to any one wheel. SE Off-Road models with 4wd have hill-descent control and hill-start assist, plus skid plates, Rancho performance dampers, adjustable pedals, and rear A/C. Pathfinders can tow up to 6000 pounds, and a receiver-type hitch is neatly integrated into the rear bumper.

The base XE comes reasonably well equipped, but the SE adds running boards, an easy-clean cargo area, and an eight-way power driver's seat. A six-disc in-dash CD changer, a moonroof, and dual-zone climate control are included in options packages. The upscale LE has cheesy wood-grain trim, leather seats, a power passenger's seat, and full length curtain air bags. A navigation system and DVD entertainment system are optional.

This impressive mid-size SUV rides nicely, steers well, and has good passing performance, although the V-6 lacks the low-down steam of a big American V-8. The five-speed automatic is well matched to the engine, and it's pretty good on back roads. You'll definitely notice the 4400-to-4800-pound bulk as it pummels into deep dips. Off-road, the awd systems will conquer most The mid-size-SUV market is crowded, but the Pathfinder is up near the top. The

CHAPTER 4: Future scope of AUTOMATIC BRAKING AND PATH FINDER

When we heard that the new Path-finder would bear a strong family Fortunately, the new Pathfinder has real character, even though the styling is hardly beautiful. Like every new mid-size SUV, it is bigger inside and out, more powerful, and heavier, and it features a third-row seat.

Pathfinder, the new one uses body-on-frame construction. It has upper- and lower-control-arm front and rear suspension, with coil springs and antiroll bars at both ends. Ground clearance varies between 8.5 and 9.2 inches, depending on the model.

The Pathfinder is the first recipient of the latest VQ V-6 engine. Displacing 4.0 liters (in-stead of 3.5), it has been tuned to produce good midrange torque, with 80 percent of the peak 291 pound-feet being available below 2000 revs. It also makes 270 horsepower and mates to a five-speed automatic transmission.

Pathfinders will be rear-wheel-drive, but there's a choice of two all-wheel-drive systems: a part-time system that can be shifted on the fly and an on-demand version that shunts up to 50 percent of the torque to the front wheels in case of wheel slippage. All Pathfinders have a standard skid-control system and antilock brakes; all-wheel-drive models also have "Active Braking Limited Slip," which uses the traction-control system to move up to 50 percent of the engine torque to any one wheel. Inside, the Pathfinder is spacious and versatile