Embedded System

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Embedded System in Automobile

Byk.Krishna praneeth(13761A1008)Embedded System- Definition?

An embedded system is acombination of hardware andsoftware which creates adedicated computer systemthat performs specific, pre-defined tasks and which isencapsulated within thedevice it controls (if it is part of a larger device).Beginning course details and/or books/materials needed for a class/project.2Characteristics of embedded systemsSophisticated functionality. Often have to run sophisticated algorithms or multiple algorithms. Often provide sophisticated user interfaces. Real-time operation .Must finish operations by deadlinesMany systems are multi-rate must handle operations at widely varying ratesLow manufacturing cost.Low power.Designed to tight deadlines by small teams.Beginning course details and/or books/materials needed for a class/project.3Automotive Systems: Technology in today's vehicleAir BagsThe Black BoxAnti-lock Brake System(ABS)Adaptive Cruise ControlDrive by wireSatellite Radio Eg:XMTelematics Eg:OnStarRain-sensing WipersEmission ControlTraction ControlAutomatic ParkingIn-vehicle entertainmentHeads-up displayNight VisionBack-up collision sensor Navigation SystemsTire Pressure MonitorClimate ControlBeginning course details and/or books/materials needed for a class/project.4Air Bags : Principle of functionIt is from the Newton's 2nd law of motion It basically restrains the continuous motion of the passenger, by giving a soft surface to land on.AIR BAGS are among the most important safety improvements added to cars and light trucks in recent years, providing extra protection for front-seat occupants in head-on crashes.And of late, every passengers protection

Fig : Air Bag- WorkingBeginning course details and/or books/materials needed for a class/project.5

Event Data Recorder-EDR or the The "Black Box"The Event Data Recorder (EDR) in an automobile is based upon the sensors and microprocessor computer system that are used to activate the airbag in the vehicle during a crash. The SDM, which is controlled by a microprocessor, has multiple functions:It determines if a severe enough impact has occurred to warrant deployment of the air bag;It monitors the air bags components;It permanently records information.

Black Box Exterior ViewBlack Box Interior ViewBeginning course details and/or books/materials needed for a class/project.7Anti-lock Braking System(ABS)Up until the seventies, hitting the brakes too hard could lead to an accident. The reason: When the coefficient of slip between tires and road surface is too low, hitting the brakes can cause wheel lock-up. The vehicle is no longer steerable and goes into a skid. In particular, this danger is present On wet or slippery road surfaces with different levels of grip between tires and roadOn preventing wheel lock-up:Reduces the total braking distance as far as possibleIncrease vehicle stabilityMaintains steer ability even in case of all-out brakingBeginning course details and/or books/materials needed for a class/project.8

Principle of functioningWheel-speed sensors detect whether a wheel is showing a tendency to lock-up In case of a lock-up tendency, the electronic control unit reduces the braking pressure individually at the wheel concerned High-speed correction of the braking pressure up to shortly before the lock-up threshold The brake-fluid return together with the closed-loop brake circuits makes this a safe, reliable, and cost-effective system

Beginning course details and/or books/materials needed for a class/project.12Advantage

A gain for driving safety The vehicle remains steerable, even in case of panic braking Shorter stopping distances on practically all road surfaces Many accidents are avoided

Embedded Navigation System

Another advancement of the embedded system in automobiles is thenavigational system using GPS system. This navigational system consists of an embedded circuitry built with a GPS receiver, a gyroscope, a DVD-ROM, main controller and a display system.

How it works :The GPS receiver receives the current longitude and latitude values that are compared with the stored map. The Gyroscope and other sensors provide the road direction and speed. From all the information gathered at the main controller, the display system displays a navigation or route map of the destination in the display screen

Dynamic Traction & Stability ControlThe traction control system is required to prevent driver error from overloading any of the four wheels and causing slip, through either throttle or brake application Drastically improve vehicle performance and safety by maintaining optimal wheel traction in all road conditionsThe basic principle is always the adaptation of the wheel torque to the coefficient of friction between the wheel and the road surface. To this end, the systems make use of different intervention methodsIn the wheel brakes In the drivetrain control

Beginning course details and/or books/materials needed for a class/project.16Dynamic Traction & Stability Control

Fig: The Principle of Functioning of TCS with brakesBeginning course details and/or books/materials needed for a class/project.17Embedded Rain-Sensing System

Embedded rain-sensing system in automobiles is another automation system implemented with use of electronic system. In this, an optical sensor is placed on small area of the front windshield glass (opposite to rear-view mirror). This optical sensor is placed at an angle to emit the infrared light which then reads amount of light by it when the light is reflected back. This light is reflected in cases where the windshield is wet or dirty. Thus the optical sensor determines necessary speed and frequency of windshield wiper depends on reflected light into the sensor.

Intelligent Cruise ControlCooperative Adaptive Cruise Control with Collision Warning (CACC + CW) CACC: Cruise at given speed when the road is clear (cruise control) otherwise follow the car in front, using radar (adaptive) and/or communications (cooperative). CW: Warn the driver when an object is being approached too fast, or is too close

Beginning course details and/or books/materials needed for a class/project.19How it works :

Uses forward-looking radar, installed behind the grill of a vehicle, to detect the speed and distance of the vehicle ahead of it. Can automatically adjust speed in order to maintain a proper distance between vehicles in the same lane

Drive by wireDrive-by-Wire replaces mechanical connections push rods,rack & pinion, steering columns, overhead cams, cables by mechatronic connections sensors, actuators, embedded microprocessors, control software

Fig: Drive-by-Wire Throttle Control

Fig: Future Car with drive by wire technologyBeginning course details and/or books/materials needed for a class/project.21Conclusion : Its a connected drive

Beginning course details and/or books/materials needed for a class/project.22Thank you QUERIES?