The document discusses embedded systems in automobiles, which combine hardware and software to control various functions, including airbags and traction control. It highlights the importance of real-time operation, low cost, and quick response in these systems, alongside the role of the Controller Area Network (CAN) for communication between microcontrollers. The text concludes by emphasizing the shift from mechanical to electronic systems in modern vehicles and the need for attention to safety and security in automotive embedded system design.

1. Embedded System in Automobiles
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2. EMBEDDED SYSTEM
• A combination of hardware and software which together form a
component of a larger machine.
• An example of an embedded system is a microprocessor that
controls an automobile engine.
• An embedded system is designed to run on its own without human
intervention, and may be required to respond to events in real
time.

3. Block Diagram of A Typical Embedded System

4. 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.
• Hard real time: missing deadline causes failure.
• Soft real time: missing deadline results in degraded performance.
Many systems are multi-rate: must handle operations at widely varying rates.
• Low manufacturing cost.
• Low power.
• Designed to tight deadlines by small teams.

5. APPLICATIONS IN AUTOMOTIVE SYSTEM
• Air Bags
• Traction Control
• The Black Box
• Automatic Parking
• Anti-lock Brake
• Adaptive Cruise
• Heads-up display Control
• Night Vision
• Drive by wire
• Satellite Radio E.g.: XM
• Back-up collision sensor
• Telematics E.g.: OnStar
• Rain-sensing Wipers
• Navigation Systems
• Emission Control
• Tire Pressure Monitor
• Climate Control

7. CAN (CONTROLLER AREA NETWORK)
• CAN is a hardware and software communication protocol for in-vehicle networks in cars.
• The applications of CAN in automobiles include engine control communications, body control, and
on-board diagnostics.
• A CAN bus enables microcontrollers in a car to talk to each other without the need for a network
host.
• A typical automobile today has dozens of microcontrollers that communicate with each other via
various CAN buses.
Key Features
Transmission Format: Asynchronous
Drive Voltage: High: 2.75v ~ 4.5v; Low: 0.5v ~ 2.25v;
Differential: 1.5v ~ 3.0v
Network Topology: Point to Point
Standards: ISO 11898/11519
Maximum Data Rates: 1Mbps at 40m, 125Kbps at
500m, 50kbps at 1000m
Circuit Type: Differential
Physical Layer: Twisted Wire Pair, 9 pin D-Sub

8. CAN BUS INTERFACE
Transmission
Control Node
Airbags
Control Nodes
ABS Node
Cruise Control
Node
Window
Mirror Control
Engine Control
Unit ECU CAN Buses

9. AIRBAG SYSTEM
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10. EDR-ELECTRONIC DATA RECORDERS
• Electronic data recorders- similar to the ‘Black Box’ flight recorders used on
airplanes
• It records a few seconds of a vehicle’s operation immediately before the crash.
• EDRs usually are connected to a vehicle’s air bag control system and
continuously record and rerecord data from connected sensors.
• In an accident in which air bags are deployed , EDR records are captured for
analysis.

12. EDR BLOCK DIAGRAM

13. ANTI-LOCK BRAKE SYSTEM (ABS)
The antilock braking system is designed to
prevent wheels locking or skidding, no
matter how hard brakes are applied, or
how slippery the road surface.
The primary components of the ABS
braking system are:
• Electronic control unit (ECU)
• Hydraulic control unit or modulator
• Power booster & master cylinder
assembly
• Wheel sensor unit

14. BASIC ANTI-LOCK BRAKE SYSTEM
sensor sensor
sensorsensor
Brake
BrakeBrake
Brake
ABS
control
module
Hydraulic
Pump

15. 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.

16. The vehicle is remains no longer steerable
when the driver hits the brake
The vehicle remains steerable
even during panic braking

17. TRACTION CONTROL
• Traction Control works by regulating the distribution of torque to
each wheel of the vehicle.
• This stops the tires from spinning, and ensures that the car moves
forward.
• It also ensures that brake pressure is electronically controlled at
each wheel to suppress wheel spin and maintain optimum traction,
so drive force is optimally distributed to all four wheels.

18. VEHICLE STABILITY CONTROL (VSC)
• System that ensures control in concerning situations the way ABS does under
braking and TRC does under acceleration .
• The VSC system utilizes electronics sensors in conjunction with the ABS and
TRC hardware to help control any potential understeer or oversteer situations.
• Understeer is when the vehicle loses front-wheel traction and wants to push
forward nose first
• OverSteer is when the rear wheels lose traction and tail begins to slide

20. CRUISE CONTROL SYSTEM
• The cruise control system controls the
speed of the car by adjusting the throttle
position, so it needs sensors to tell it the
speed and throttle position.
• It also needs to monitor the controls so it
can tell what the desired speed is and
when to disengage.

21. Adaptive Cruise Control

22. 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.
Principle of Operation of
Adaptive Cruise Control

24. • CACC system is effective when the
adaptive cruise control fails to perform
correctly due to the radar's line-of-
sight scanning.
• When the car approaches a sharp
curve, the DSRC system warns the
adaptive cruise control system of any
slow moving vehicles just around the
turn.
• Dedicated Short Range
Communications (DSRC) is a data-only
automotive communication protocol.

26. • Vehicle to vehicle DSRC would enable information about an approaching
emergency vehicle to be relayed from vehicle to vehicle forward through traffic.
• This would help to clear the way for the emergency vehicle and reduce the risk to
other vehicles.
APPROACHING EMERGENCY VEHICLE WARNING
Information about
approaching emergency
vehicle sent ahead through
vehicle using DSRC

27. DRIVE BY WIRE
• This technology replaces the traditional
mechanical control systems with electronic
control systems using electromechanical
actuators and human-machine interfaces.
• It means Drive by wire replaces mechanical
connections – push rods, rack & pinion,
steering columns, overhead cams, cables –
by mechatronic connections – sensors,
actuators, embedded microprocessors,
control software

28. Drive by wire involves 3 main
systems:
• Steer by Wire
• Throttle by Wire
• Brake by Wire

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32. CONCLUSION
• In the recent years, more and more equipment in automotive are changing
from mechanical systems to electronic systems.
• Embedded system is a core of vehicle electronic systems because of its
flexibility and versatility.
• The electronics revolution has influenced almost every aspect of automotive
design including the powertrain, fuel combustion, crash protection and the
creation of a comfortable cabin and nearly wireless environment.
• It is necessary to pay more attention to the fields of environments, safety and
security, which are the most significant and challenge field of automotive
embedded system design.

33. REFERENCES
• www.wikipedia.org
• http://www.cvel.clemson.edu/
• http://auto.howstuffworks.com/
• http://www.toyota.com.au/
• http://www.cdxetextbook.com/

34. Thank You
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