MAJOR PROJECT on Automatic Braking System

AUTOMATIC BRAKING SYSTEM & PATH FINDER  A MAJOR PROJECT SUBMITTED IN THE FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF

BACHELOR OF TECHNOLOGY IN

MECHANICAL ENGINEERING OF

KURUKSHETRA UNIVERSITY, KURUKSHETRA

BY

NAVNEET KUMAR (1504284) NARENDER KUMAR (1504285) HAPPY YADAV (1504286)

UNDER THE GUIDANCE OF Mr. SACHIN WADHWA

DEPARTMENT OF MECHANICAL ENGINEERING N.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 a chieve 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 possi possibl ble e ways. ways. We expr expres ess s ou ourr since sincere re than thanks ks towar towards ds ou ourr guide guide for for his his unstinted support & commitment to make our project see light of today and the college for use of their facilities.

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 a chieve 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 possi possibl ble e ways. ways. We expr expres ess s ou ourr since sincere re than thanks ks towar towards ds ou ourr guide guide for for his 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) (1504286)

In fulf fulfil illm lmen entt for for the the awar award d of degr degree ee of bach bachel elor or in tech techno nolo logy gy 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: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 fullbraking 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 realtime. 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, highbandwidth 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 fiberoptic 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, threelevel 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 systemwide 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-theloop" 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 safetycritical 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 fiberoptic 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 IC555 is square wave from Pin No. 3. T1 gets biasing current to out put of IC555 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 IRsignal 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 antilock 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; allwheel-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 hillstart assist, plus skid plates, Rancho performance dampers, adjustable pedals, and rear A/C. Pathfinders can tow up to 6000 pounds, and a receivertype 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