Vehicular Technologies

Embedded Systems SeminarFall 2005

Elliot Jaffe

Sensors, Networks and Processors

● Applicable Vehicles● Potential Uses● Aside: Automotive equipment lifecycle● Networking● Processing● Sensors● Conclusions

Applicable Vehicles

Potential Uses

● Lifecycle Management– Equipment Monitoring, Maintenance, Performance

● Awareness of the Environment– Weather Conditions, Air Pressure, Road Surface

● Awareness of the Operators– Physical State, Mental State, Comfort

● Global vs. Local Interactions– Convoys, Traffic Planning, Collision Detection

Automotive Component Lifecycle

● Long lead times between conception and wide spread deployment

● Case in point: Anti-Lock Brakes (ABS)– Bosch 1930’s– First Electronic system in production: 1978

● Trucks and Mercedes-Benz

– Standard Equipment – 1985 (Ford Grenada Mk3)– GM stops offering ABS as Standard Equipment on

most of its 58 vehicles in 2003

Automotive Component Requirements

● Low Cost● Mass Production (availability, liability)● Dependability (reliability, safety)● System Modularity● Easy Field Maintenance● Simple MMI (drivers are not experts)● Security (against prohibited actions)

Automotive Component Lifecycle

Source: Integrated Vehicle Control System Technology — Steering, Braking, Suspension, and Powertrain Systems, Aloysius J. (Alois) Seewald, TRW Automotive Chassis

Networking

● Many bus definitions– http://www.interfacebus.com/Design_Connector_Automotive.

html

– Class A: UART < 10kbps

– Class B: non-critical 10kbps to 125kbps

– Class C: real-time high-data: 125kbps – 1Mbps

– Emissions/Diagnostics

– Mobile Media

– X-By-Wire: replace mechanical systems ● -40 +125C

Examples

● LIN- local interconnect network– http://lin-subbus.org– 20Kbps– Master/slave architecture

● CAN – controller area network (ISO 11898)– http://www.ni.com/automotive/can.htm– High speed: 1Mbps

● Engine and powertrain– Low speed: 128kbps

● Body and comfort devices

Networking

● X-By-Wire Architecture– Proposed by Consortium in 1996-1998– Time Triggered Protocol (1993)– Considered failure modes and requirements– Composability– Timeliness– Fault Tolerance– http://www.vmars.tuwien.ac.at/projects/xbywire/projects/new-home.html

X-By-Wire

Processing

● First Microprocessor, 1978 Cadillac Seville– Trip Computer, 6802

● Freescale (Motorola) MPC563 32bit microprocessor– 63-105 MIPS– -40C – 125C– 2.6V Core Operating Voltage– 5V I/O Operating Voltage– 0.8, 1.12W Power dissipation (typical, max)– 512K Flash RAM, 32K RAM– 32 Channel A/D (10 bits)

Source: www.freescale.com

Sensors

● Engine and Drivetrain Sensors● Emissions Control System Sensors● Safety and Security Sensors● Other Internal Sensors

Engine and Drivetrain Sensors

• Throttle Position– Monitors the position of the accelerator pedal and the throttle

linkage, so the ECM can make accurate air/fuel mixture adjustments

• Barometric Air Pressure (BAP– Reads changes in barometric (air) pressure. The ECM uses this

information to adjust timing advance and air/fuel ratio• Mass Air flow/ MAF

– Measures the amount of air drawn through the engine's air intake, so the computer can compensate for altitude and temperature

Engine and Drivetrain Sensors

• Permanent magnet vehicle speed sensor– A permanent magnet generator– Produces a pulsing (ac) voltage when it spins – Voltage level and number of pulses increase with

vehicle speed

• Knock / Detonation– Listens for engine "ping" so the ECM can retard the

spark timing, and thereby reduce emissions and overheating, if the engine is knocking

Engine and Drivetrain Sensors

• Magnetic Fluid Level– Used for brake fluid, coolant, washer fluid and oil

level sensing

• Temperature– Air Temperature– Coolant Temperature– HVAC Temperature– Transmission Temperature

                       

       

Emission Control Sensors

● Required due to emission control legislation● EGR Valve

– Recalculates a measured amount of exhaust gas into the engine's air intake, to lower combustion temperatures and reduce emissions, especially NOx

● Ported Vacuum Switch– Senses engine temperature, and opens or closes

vacuum lines to various emissions-related components

Safety and Security Sensors

• Inertial Sensors– active stabilization and

navigation applications

• Wheel Speed

• Occupant Position– Weight– Driver Seat Position

• Tire Inflation

Other Interior Sensors

● Climate Control Systems● Ambient Air Temperature● Seat Temperature● Air Flow● Audio Volume (for Active Feedback)● Ambient Light (for auto-tint)

External Sensors

● DARPA Grand Challenge● http://www.darpa.mil/grandchallenge/TechPapers/AutonomousVehicleSystems.pdf

● Range Finding● Obstacle Detection● Terrain Detection

Team CIMAR

U. Indiana: Rubicon

Stanford

Range Finding

• RADAR– Radio Detection and

Ranging

• LADAR– Laser Detection and

Ranging

• SONAR– Sound Navigation and

Ranging

Detection in Operation

Conclusion

● Applicable Vehicles● Potential Uses● Aside: Automotive equipment lifecycle● Networking● Processing● Sensors