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Embedded Systems Seminar Fall 2005 Elliot Jaffe. Vehicular Technologies. Sensors, Networks and Processors. Applicable Vehicles Potential Uses Aside: Automotive equipment lifecycle Networking Processing Sensors Conclusions. Applicable Vehicles. Potential Uses. Lifecycle Management
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Embedded Systems Seminar Fall 2005 Elliot Jaffe Vehicular Technologies
Sensors, Networks and Processors • Applicable Vehicles • Potential Uses • Aside: Automotive equipment lifecycle • Networking • Processing • Sensors • Conclusions
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
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
Inertial Sensors active stabilization and navigation applications Wheel Speed Occupant Position Weight Driver Seat Position Tire Inflation Safety and Security Sensors
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
Range Finding • RADAR • Radio Detection and Ranging • LADAR • Laser Detection and Ranging • SONAR • Sound Navigation and Ranging
Conclusion • Applicable Vehicles • Potential Uses • Aside: Automotive equipment lifecycle • Networking • Processing • Sensors