seminar driverless car

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    INTRODUCTION

    An autonomous car, also known as a driverless car, self-driving car or robot car, is

    an autonomous vehicle capable of fulfilling the human transportation capabilities

    of a traditional car. As an autonomous vehicle, it is capable of sensing its

    environment and navigating without human input. Robotic cars exist mainly as

    prototypes and demonstration systems, but are likely to become more widespread

    in the near future.

    Fig.-1.1 -A look of a Driverless Car

    Autonomous vehicles sense their surroundings with such techniques as radar, Lidar

    GPS, and computer vision. Advanced control systems interpret sensory

    information to identify appropriate navigation paths, as well as obstacles and

    relevant signage. Some autonomous vehicles update their maps based on sensory

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    input, allowing the vehicles to keep track of their position even when conditions

    change or when they enter uncharted environments.

    Some quasi-autonomous demonstration systems date back to the 1920s and the

    1930s.The first fully practical system was developed in the 1950s by RCA Labs.

    Since the 1980s, when Mercedes-Benz and Bundeswehr University, Munich built a

    driverless car through the EUREKA Prometheus Project,) significant advances

    have been made in both technology and legislation relevant to autonomous cars.

    Numerous major companies and research organizations have developed working

    prototype autonomous vehicles, including Mercedes-Benz, General Motors,

    Continental Automotive Systems, Autoliv Inc., Bosch, Nissan, Toyota, Audi,

    Vislab from University of Parma, Oxford University and Google. In 2010, four

    electric autonomous vans succesfully drove 8000 miles from Italy to China. The

    vehicles were developed in a research project backed by European Union funding,

    by Vislab of the University of Parma, Italy. In july 2013 Vislab world premiered

    BRAIVE, a vehicle that moved autonomously on a mixed traffic route open to

    public traffic.As of 2013, three U.S. states have passed laws permitting

    autonomous cars: Nevada, Florida and California. In Europe, cities in Belgium,

    France and Italy are planning to operate transport systems for driverless cars.

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    HOW THE CAR WILL DETECT TRAFFIC LIGHTS

    A sensor ACTINOMETER is used to detect the intensity of radiation

    Light of different colors will radiate different -2-intensity of radiation

    Which will be detected by the sensor

    If the detected intensity is of red colour or yellow colour then controller

    will send a command to stop the vehicle .

    The command will be followed by robot (to convert the computer command

    into mechanical input)

    Fig 1.2--An Infrared image seen from a Driverless car

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    ACTINO METER:-

    Actinometers are instruments used to measure the heating power of radiation.

    They are used in meteorology to measure solar radiation as pyrheliometers. An

    actinometer is a chemical system or physical device which determines the

    number of photons in a beam integrally or per unit time. This name is commonly

    applied to devices used in the ultraviolet and visible wavelength ranges. For

    example, solutions of iron (III) oxalate can be used as a chemical actinometer,

    while bolometers, thermopiles, and photodiodes are physical devices giving a

    reading that can be correlated to the number of photons detected.

    Fig 1.3 - An Actinometer

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    TECHNOLOGIES MAKING SYSTEM FULLY AUTONOMOUS

    (2) ANTI-LOCK BREAKING SYSTEM :-

    Fig 2.1-Anti-lock Breaking System

    Anti-lock braking system (ABS) is an automobile safety system that allows the

    wheels on a motor vehicle to maintain tractive contact with the road surface

    according to driver inputs while braking, preventing the wheels from locking up

    (ceasing rotation) and avoiding uncontrolled skidding. It is an automated system

    that uses the principles of threshold braking and cadence braking which were

    practiced by skillful drivers with previous generation braking systems. It does this

    at a much faster rate and with better control than a driver could manage.

    ABS generally offers improved vehicle control and decreases stopping distances

    on dry and slippery surfaces for many drivers; however, on loose surfaces like

    gravel or snow-covered pavement, ABS can significantly increase braking distance,

    although still improving vehicle control. Since initial widespread use in production

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    cars, anti-lock braking systems have evolved considerably. Recent versions not

    only prevent wheel lock under braking, but also electronically control the front-

    to-rear brake bias. This function, depending on its specific capabilities and

    implementation, is known as electronic brake force distribution (EBD), traction

    control system, emergency brake assist, or electronic stability control (ESC).

    Fig 2.2-Diagram showing how ABS works

    The anti-lock brake controller is also known as the CAB (Controller Anti-lock

    Brake). Typically ABS includes a central electronic control unit (ECU), four wheel

    speed sensors, and at least two hydraulic valves within the brake hydraulics. The

    ECU constantly monitors the rotational speed of each wheel; if it detects a wheel

    rotating significantly slower than the others, a condition indicative of impending

    wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the

    affected wheel, thus reducing the braking force on that wheel; the wheel then

    turns faster. Conversely, if the ECU detects a wheel turning significantly faster

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    than the others, brake hydraulic pressure to the wheel is increased so the braking

    force is reapplied, slowing down the wheel. This process is repeated continuously

    and can be detected by the driver via brake pedal pulsation. Some anti-lock

    systems can apply or release braking pressure 15 times per second. Because of

    this, the wheels of cars equipped with ABS are practically impossible to lock even

    during panic braking in extreme conditions. The ECU is programmed to disregard

    differences in wheel rotative speed below a critical threshold, because when the

    car is turning, the two wheels towards the center of the curve turn slower than

    the outer two. For this same reason, a differential is used in virtually all road

    going vehicles. If a fault develops in any part of the ABS, a warning light will

    usually be illuminated on the vehicle instrument panel, and the ABS will be

    disabled until the fault is rectified.

    Modern ABS applies individual brake pressure to all four wheels through a control

    system of hub-mounted sensors and a dedicated micro-controller. ABS is offered

    or comes standard on most road vehicles produced today and is the foundation

    for electronic stability control systems, which are rapidly increasing in popularity

    due to the vast reduction in price of vehicle electronics over the years. Modern

    electronic stability control systems are an evolution of the ABS concept. Here, a

    minimum of two additional sensors are added to help the system work: these are

    a steering 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

    does not coincide with what the steering wheel sensor reports, the ESC software

    will brake the necessary individual wheel(s) (up to three with the most

    sophisticated systems), so that the vehicle goes the way the driver intends. The

    steering wheel sensor also helps in the operation of Cornering Brake Control

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    (CBC), since this will tell the ABS that wheels on the inside of the curve should

    brake more than wheels on the outside, and by how much.

    ABS equipment may also be used to implement a traction control system (TCS) on

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

    controller can detect the situation and take suitable action so that traction is

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

    brakes simultaneously. Upon the introduction of the Subaru Legacy in 1989,

    Subaru networked the four channel anti-lock brake function with the all wheel

    drive system so that if the car detected any wheel beginning to lock up, the

    variable assists the all wheel drive system installed on vehicles with the automatic

    transmission would engage to ensure all wheels were actively gripping while the

    anti-lock system was attempting to stop the car.

    COMPONENTS:-

    There are four main components of ABS: speed sensors, valves, a pump, and a

    controller. -

    Speed sensors

    A speed sensor is used to determine the acceleration or deceleration of the

    wheel.These sensors use a magnet and a coil of wire to generate a signal. The

    rotation of the wheel or differential induces a magnetic field around the sensor.

    The fluctuations of this magnetic field generate a voltage into the sensor.Since

    the voltage inducted on the sensor is a result o