Embedded System in Automobile

By : Amit Kumar SahRoll No: 09/ECE/73NIT Durgapur

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 partof a larger device).”

• FPGA (Field-Programmable Gate Array) : A type of logic chip that can be programmed & supports thousands of gates•ASIC (Application-specific integrated circuit): An integrated circuit (IC) that has been customized for a specific use

Embedded system components

Characteristics of embedded systems

Sophisticated functionality. Often have to run sophisticated algorithms or multiple algorithms. Often provide sophisticated user interfaces.

Real-time operation . Must finish operations by deadlines Many systems are multi-rate must handle operations at widely

varying rates Low manufacturing cost. Low power. Designed to tight deadlines by small teams.

Automotive Systems: Technology in today's vehicle

Air Bags The Black Box Anti-lock Brake

System(ABS) Adaptive Cruise Control Drive by wire Satellite Radio Eg:XM Telematics Eg:OnStar Rain-sensing Wipers Emission Control

Traction Control Automatic Parking In-vehicle entertainment Heads-up display Night Vision Back-up collision sensor Navigation Systems Tire Pressure Monitor Climate Control

Air Bags : Principle of function

It 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-

Working

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:(1) It determines if a severe enough

impact has occurred to warrant deployment of the air bag;

(2) It monitors the air bags components;

(3) It permanently records information.

Black Box – Exterior View

Black Box – Interior View

Anti-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 road On preventing wheel lock-up:

Reduces the total braking distance as far as possible

Increase vehicle stability Maintains steer ability even in case of all-out

braking

Without ABS The vehicle in no longer steerable

when driver hits the brake

With ABS The vehicle remains steerable even during

panic

Principle of functioning

Wheel-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

Advantage 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

Dynamic Traction & Stability Control

The 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 conditions

The 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 methods In the wheel brakes In the drivetrain control

Dynamic Traction & Stability Control

Fig: The Principle of Functioning of TCS with brakes

Intelligent Cruise Control

Cooperative 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

How 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 wire

Drive-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 technology

Toyota’s Autonomous Vehicle Technology

Conclusion : It’s a connected drive

THANK YOU