vehicular technologies embedded systems seminar fall 2005 elliot jaffe
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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
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