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TTAutomotive joins FlexRay consortium
The standards battle to define the protocols used in
electronically-controlled vehicles has come to an amicable close with
the announcement Tuesday (March 15) that TTAutomotive has joined the
FlexRay consortium as a development member.
TTAutomotive is a subsidiary of TTTech Computertechnik AG (Vienna,
Austria) which developed the original Time-Triggered Architecture.
Developed during the 1990s at the Technical University of Vienna by
professor Hermann Kopetz, the deterministic time-triggered protocol was
used in early studies of the drive-by-wire systems now under
development. TTTech formed a consortium, and Motorola's semiconductor
products sector and others were early members.
Later, the major automotive companies formed the FlexRay consortium,
partly out of intellectual property concerns with TTTech. FlexRay has
become the dominant standard, with early silicon already on the market.
FlexRay Network
The amount of in-vehicle electronics has increased
significantly in recent years, and the trend is expected to continue as
automakers introduce further advances in safety, reliability and
comfort. Advanced automotive control systems that combine multiple
sensors, actuators and electronic control units (ECUs) are demanding
communications technology that traditional in-vehicle networks can't
adequately deliver. The FlexRay™ protocol answers that demand with a
high speed, deterministic and fault tolerant communications technology.
Designed specifically for in-vehicle networking, FlexRay won't replace
existing networks, but instead it will work in conjunction with already
well-established systems, such as the controller area network (CAN),
local interconnect network (LIN) and media oriented systems transport
(MOST). An in-vehicle network with
FlexRay serving as the backbone provides determinism for engine control
and fault tolerance for steer-by-wire, brake-by-wire and other advanced
safety applications.
FlexRay speeds automotive safety applications
FlexRay was born out of necessity. As automobile manufacturers began
investigating new power train, chassis, and by-wire control systems, two
companies in particular, BMW and DaimlerChrysler, realized that the
current in-vehicle networking solutions did not meet their needs. They
required a very fast, deterministic, and fault-tolerant protocol that
could satisfy the speed, reliability, and safety requirements of such
applications as brake-by-wire and steer-by-wire.
Other available protocols, such as controller area networks (CANs)
and media oriented systems transport (MOST) networks, either don't have
the data rate or the functionality suitable for advanced power train,
chassis, and by-wire applications. FlexRay has been under development
since 2000, when BMW, DaimlerChrysler, Philips, and Motorola (and later
its spinoff Freescale Semiconductor, in 2004) founded the FlexRay
Consortium with the expressed goal of developing "an advanced
communications technology for high-speed control applications in
vehicles to increase safety, reliability, and comfort." Since then, most
of the automotive industry's major players have joined the consortium.
FlexRay: The Next Generation In-Vehicle Network
You may have seen a recent commercial showing a car
automatically correcting itself to prevent a rollover accident or
perhaps a vehicle automatically braking to prevent a rear-end collision
with the car in front of it. In recent years, the amount of electronics
used in automobiles has increased significantly. This trend is expected
to continue as automobile manufacturers initiate further advances in
safety, reliability, and comfort. The introduction of advanced control
systems, which combine multiple sensors, actuators, and electronic
control units (ECU), has begun to place boundary demands on the existing
Controller Area Network (CAN) communications bus found in most of
today’s automobiles. As a result, initiatives by automobile
manufacturers and suppliers have led to the creation of FlexRay, an open
standard for a new deterministic, fault-tolerant, and high-speed bus
system. Today, CAN is used in the automotive industry as the primary
in-vehicle network for enabling any device to communicate and work with
any other device on the network without creating a great strain on the
bus. This communication is ideal for powertrain and body electronic
applications, such as acceleration skid control (ASC), which requires
communications between multiple devices including engine timing and
carburetor control units to reduce torque when drive- wheel slippage
occurs.
Five steps to FlexRay
FlexRay comes onto the road with single-channel high-speed power-train, driver-assistance, and comfort automotive electronics applications. On the new BMW X5, FlexRay is used in suspension control, allowing for a gentle learning phase with low risk for engineers and developers before applying the fault-tolerant, deterministic protocol to safety relevant driving functions using two communication channels and bus guardian supervision. In developing FlexRay applications, there are five basic steps that design engineers can apply leading to a robust network topology.
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