FlexRay References...
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FlexRay - The
Communication System for Advanced Automotive Control Applications
In recent years there has been a
significant increase in the amount of electronics that have been
introduced into the car, and this trend is expected to continue as car
manufacturers introduce further advances in safety, reliability and
comfort. The introduction of advanced control systems combining multiple
sensors, actuators and electronic control units are beginning to place
demands on the communication technology that were not previously
addressed by existing communication protocols. Additional requirements
for future in-car control applications include the combination of higher
data rates, deterministic behavior and the support of fault tolerance.
Flexibility in both bandwidth and system extension will also be key
attributes as the need for increased functionality and on-board
diagnostics also increase. Availability, reliability and data bandwidth
are the key for targeted applications in Powertrain, Chassis and Body
control, and these must also be supported within the automotive
environment which presents some unique challenges.
Introduction of FR goes together with the introduction of complex
control systems within a car
In September 2000, BMW and
DaimlerChrysler joined hands with Philips and Motorola to set up the
FlexRay Consortium which is an initiative to develop a protocol for
high-speed control applications in vehicles. The FlexRay protocol is
expected to be a comprehensive communication system, providing speed,
flexibility and scalability for complex networks. Currently, the FlexRay
Consortium is made up of a core team of seven partners which include
BMW, Bosch, DaimlerChrysler, Freescale, General Motors, Philips and
Volkswagen. Plus there are dozens of other automotive companies that are
members including Asian firms like Toyota, Nissan, Honda and Hyundai.
FlexRay’s aim is to provide a common standard for automotive by-wire
technology. Its members account for seven of every 10 new vehicles
manufactured annually. According to the consortium, FlexRay will become
the de facto standard for high-speed control applications within
vehicles.
FlexRay™ Communications System
The FlexRay Communications System is designed to
provide high-speed deterministic distributed control for advanced
automotive applications. Its dual-channel architecture offers
system-wide redundancy that meets the reliability requirements of
emerging safety systems, such as brake-by-wire. With 10 Mbps throughput
per channel, the FlexRay system can also be employed as a vehicle-wide
network backbone, working in conjunction with already well-established
systems, such as CAN and LIN. It can drive down costs by reducing the
number of parallel CAN networks used to solve bandwidth bottlenecks.
What is FlexRay?
FlexRay is a fast, deterministic and fault-tolerant
bus system for automotive use, based on the experience of
DaimlerChrysler with the development of prototype applications and the
byteflight communication system developed by BMW. Byteflight was
developed by BMW especially for use in passive safety systems (airbags).
In order to fulfill the requirements of active safety systems,
byteflight was further developed by the FlexRay consortium in particular
in relation to time-determinism and fault tolerance. Today, the
automotive manufacturers BMW, DaimlerChrysler, General Motors, Ford,
Volkswagen as well as the companies Bosch, Motorola and Philips
Semiconductors are represented in the FlexRay consortium as Core
partners. The data exchange between the numerous number of control
devices, sensors and actuators in automobiles is nowadays mainly carried
out via CAN networks. However, the introduction of the new x-by-wire
systems results in increased requirements especially with regard to
error tolerance and time-determinism of message transmission. FlexRay
fulfils these increased requirements by message transmission in fixed
time slots and by fault-tolerant and redundant message transmission on
two channels.
