Drive-by-wire technology replaces traditional mechanical systems with electronic systems controlled by electronic control units (ECUs). ECUs consist of microcontrollers, sensors, power switches, drivers, and voltage regulators. They connect sensors and actuators to a central ECU. Modern cars contain up to 100 ECUs communicating over automotive bus protocols like CAN, LIN, and FlexRay. This allows for advanced driver assistance systems like anti-lock braking systems and electronic stability control.

2. o Recently Drive-by-wire
(DBW)technology appear on
Automotive industry.
o Replaces the traditional
mechanical systems with
electronic systems.
o ECU is used in the automotive
domain.

3. o Electronic Control Unit(ECU)consists of:
• Microcontroller(s).
• Sensors.
• Power switches.
• Drivers.
• Voltage regulator(s).

4. o Connect the sensors and actuators
directly to central ECU.
o Its disadvantage:
1-Very high number of connectors.
2-High length network cable.
Point to Point Network

5. Single Bus Network
o Automotive applications ECUs
communicate through automotive bus
protocols:
• CAN.
• LIN.
• Felx Rays.

6. “It would be easy to say the modern car is a
computer on wheels, but it’s more like 30 or
more computers on wheels. “
Bruce Emaus,
The chairman of SAE International embedded
software standards committee.
SAE: Society of Automotive Engineers

7. CAN
CAN
Power Train
Light
Sub-Bus
ITS
Window Lift
Interior
Light
Lock
Mirror
Lock
Mirror
Lock
Lock
Seat
Htng
Seat
Htng
Instruments
Central
Body Ctrl
Climate
Universal Motor
Universal Panel
Light
Roof
1 backbone, 13 nodes
8 subnets, 1-8 local nodes
52 nodes total
St-Wheel Panel
x6
Htng
Htng
Seat
Wiper
Trunk
WHtg
Universal Light

8. LEXUS LS-460
o Released in Sep., 2006.
o More than 100 ECUs when all
optional equipment are installed.
o About 7,000,000 lines of code.
o One modern car is packed with up to 100 million lines of
computer code, more than the F-22 Raptor Jet fighter.
o More luxurious cars can contain up to 100 Electronic Control
Unit (ECU).

9. •Door/window/seat:
Mirror,Central ECU,
Mirror, Switch, Window
Lift,
Seat Control Switch,
Door Lock, etc.
Roof:
(high amount of wiring)
Rain Sensor, Light Sensor,
Light Control, Sun Roof
…
(Rain Sensor needs to be
interrogated every 10-20ms)
Seat:
many Seat Position Motors,
Occupancy Sensor,
Control Panel
Steering Wheel:
(very many controls are going to be
positioned on the steering wheel)
Cruise Control, Wiper,
Turning Light, …
Optional: Climate Control,
Radio, Telephone, etc.
Climate:
many Small Motors
Control Panel

10. Features of Automotive Embedded Systems
o ECUs are used for :
• energy saving & low emission
• safety (active & passive)
• comfortableness, convenience, entertainment
• cost & weight reduction
o ECUs are connected with several in-vehicle networks.
o High reliability and safety requirements
o Strict real-time property required
o Severe environmental conditions (temperature, EMC)
o Severe production cost restriction

11. o The speed of the car and the
rotational speed of the wheel are
monitored, and a skid is detected.
o When a skid is detected, hydraulic
pressure to the brake is reduced to
stop the skid.
Applications of Automotive Embedded Systems
Anti-lock Breaking System(ABS)

12. o Safety Requirement Design:
• Continuous reduction of hydraulic
pressure causes non-braking.
• If some fault is detected, ABS stops
functioning.
• Then ,the brake works though a
skid cannot be avoided.
Applications of Automotive Embedded Systems
Anti-lock Breaking System(ABS)

13. Traction Control System(TCS)
o Prevent loss of traction of driven
road wheels.
o Enhances driver control as throttle
input applied is mismatched to road
surface conditions (due to varying
factors) being unable to manage
applied torque.
Applications of Automotive Embedded Systems

14. o Consider the secondary function of
APS.
o Helps limit tire slip in acceleration
on slippery surfaces.
Applications of Automotive Embedded Systems
Traction Control System(TCS)

15. o Improves the safety of a vehicle's
stability by detecting and reducing
loss of traction (skidding).
o When ESC detects loss of steering
control, it automatically applies the
brakes to help "steer" the vehicle
where the driver intends to go.
o
Applications of Automotive Embedded Systems
Electronic Stability Control(ESP)

16. Applications of Automotive Embedded Systems
Electronic Stability Control(ESP)
o Braking is automatically applied to
wheels individually.
o Some ESC systems also reduce engine
power until control is regained.
o ESC does not improve a vehicle's
cornering performance; instead, it
helps to minimize the loss of control.

17. Airbag
o Airbag control system:
• Monitors various sensors including
accelerometers and detects a collision.
• If a collision is detected, the ignition
of a gas generator propellant is
triggered to inflate a bag.
o Real-Time Constraint:
• The trigger must be within 10-20msec.
after the collision.
Applications of Automotive Embedded Systems

18. Pre-crash Safety System (PCS)
o When an obstacle is detected with stereo camera and wave radar
• the system retracts the seatbelts, warns the driver, and applies the brake.
o Driver's condition (eg. face direction) is monitored.
Applications of Automotive Embedded Systems

19. Car Navigation System
o The current position of the car obtained from GPS,
gyroscope, and others is displayed with the map.
Applications of Automotive Embedded Systems

20. Classification of Automotive Embedded Systems
o Powertrain and Control
▶ Engine, automatic transmission, hybrid control, ...
▶ Steering, brake, suspension, ...
o Body Electronics
▶ Instrument panel, key, door, window, lighting, …
▶ Air bag, seat belt, ...
o Multimedia Applications
▶ Car audio, car navigation, traffic information, ...
▶ Electronic toll collection (ETC), backguide monitor, ...
o Integrated Systems/Services
▶ Electronic stability control, pre-crash safety, …
▶ Parking assistance, lane keeping assistance, ...

21. o Stage 1:
ECU is applied to various component independently network is not used.
o Stage 2:
ECU exchanges data for improving the quality
o Stage 3:
• Each system still operates autonomously.
• some services are provided with multiple ECUs connected via
networks.
• Mechanical backup system still exists even if an electronic system fails.
Evolution Steps of Automotive Control Systems
Evolution of automotive control systems and networks
is well understood with the following 4 stages.
(Current) integrated systems/services

22. o Stage 4:
• Networks with outside of the car (communication with another car and
the road) are intensively used.
• Mechanical systems (incl. backups) are replaced with ECUs and
networks.
• A failure of electronic systems is life-critical.
Evolution Steps of Automotive Control Systems
(Future) (true) by-wire systems

23. Problems of Automotive Embedded Systems
o Complicated system design
• Increasing development cost and time
• How to achieve high reliability and safety?
o Large-scale and complicated software
• How to effectively reuse existing software?
o Too large number of ECUs
• Increasing cost
• Insufficient space (in a car) for ECUs
o Complicated network architecture
• Increasing design complexity

24. Platform-base Development
Conventional Component-base Development
o Each ECU (component) is developed independently.
o Automotive component supplier develops both of the hardware and
software of ECU.
o Car (system) is designed by integrating the ECUs developed by different
suppliers.
Platform-base Development
o Platform should be developed at first.
o Platform = Hardware + Software + Network
o Application software should be developed on the Platform .

25. Automotive Architecture
AUTOSAR (Automotive Open System Architecture)
o global partnership of carmakers, car component ,electronics,
semiconductor, software industries
o founded in 2003.
o defines a methodology that supports a distributed, function-
driven development process.
o standardizes the software-architecture for ECU.
o Core partners:
▶ BMW ▶ Daimler ▶ PSA Peugeot Citroen
▶ Bosch ▶ Ford ▶ Toyota Motor
▶ Continental ▶ GM ▶ Volkswagen

26. Automotive Architecture
JASPAR (Japan Automotive Software Platform Architecture)
o Car makers and other companies develop network technology,
middleware, software platform for automotive control systems.
o founded in 2004.
o Board Members
▶ Toyota Motor ▶ Honda ▶ DENSO
▶ Nissan ▶ Toyota Tsusho Electronics
o Members
about 100 carmakers, car component suppliers, semiconductor companies,
and software companies
o Major Activities and Results
▶ Standardization related to FlexRay (wiring rule, ...)
▶ Development of software platform based on AUTOSAR Standard.
▶ Development of design guidelines for ISO 26262.

27. Automotive Network protocol
Speed[bit/s]
Byteflight
optical bus
LIN
master-slave
single wire bus
no quartz
CAN-B
event triggered
fault tolerant
dual wire
CAN-C
event triggered
dual wire
Flex Ray
25.6M
20K
10M
1M
125K
incremental cost per node [$]
D2B, MOST
token ring
optical bus
1 2 4.5 10

28. Automotive Network dominos
o Class A:
• low cost and data rate lower than 10 kbps
• Example: LIN
• used for body domain light functions.
o Class B:
• data rate (10‐125 kbps)
• Example : low‐rate CAN
• used for data exchange between ECUs to reduce the number of sensors
by sharing information.

29. Automotive Network dominos
o Class C:
• data rate (125kbps‐1Mbps)
• Example : high‐speed CAN
• used for power train and chassis domain functions (ABS & EPS)
o Class D:
• data rate (over 1Mbps)
• Example : MOST (media‐oriented system transport)
• multimedia data and safety critical applications .

30. Automotive Network Triggered
Event Triggered:
o Messages are transmitted due to occurrence of significant events
o Example :a door has been closed.
o No detection of node failure, no grantee for certain constrains.
Time Triggered:
o Frames are transmitted at predetermined points in time .
o Example: TDMA.
o Behavior is fully predictable, detection of failure. but, inefficient
utilization, not extendable.