Discover New Applications For Low-Cost Solutions Discover ... - Xilinx

y Liza Boland
System Architect, Consumer & Automotive Technologies
Xilinx, Inc.
liza.boland@xilinx.com
A modern Formula 1 (F1) car communicates
an enormous amount of data to the
engineering teams that support it. How the
teams collect, analyze, and react to that
data is vital to competitiveness. The collectanalyze-and-respond
process is also subject
to change, as the sport’s rule-makers aim to
reduce onboard electronics to control costs
and achieve closer racing competition.
Throughout the last decade, the electronics
department at BMW WilliamsF1, led by
Steve Wise along with engineers Dave
Walker and Ian Cartwright, can claim to
have been in the driver’s seat as onboard electronics
have spread to every extremity of a
Formula 1 chassis.
The team is now running its fifth-generation
VCM (vehicle control and monitoring)
unit; the current Stage 5 VCM uses a
Xilinx Virtex-E XCV600-E FPGA alongside
a Texas Instruments DSP. Shown in
Figure 1, the VCM controls all aspects of the
2003 FW25’s chassis (other than the
engine). And the team is continuing to
extend and refine the unit’s capabilities.
Adapting to Rule Changes
Rules change quickly in F1 racing. Teams
must be able to respond with a competitive
solution that meets every new detail. The
regulatory landscape has been especially
volatile over the last decade. Driver aids
such as active suspension, anti-lock braking,
traction control, and launch control
all have been banned at one time. Some
driver-assist features have been granted a
reprieve for this year – only to be completely
outlawed for the 2004 season.
The ability to quickly add and remove
functional blocks is therefore critical to
each team’s ability to compete and to
demonstrate compliance.
Successive generations of the BMW
WilliamsF1 VCM have made great use of
FPGAs to achieve rapid compliance. This
flexibility has allowed BMW WilliamsF1
to migrate more and more sophisticated
functions into hardware as new generations
Figure 1 – The VCM controls all of the race car’s chassis functions except the engine.
of FPGA silicon offer extra capacity and
complexity.
Controlling an F1 Car
The VCM is a data logger and processor on
a grand scale. Its vehicle control functions
include overseeing the hydraulically actuated
gear change, which calls for the VCM to
initiate a gear shift either in response to a
driver request or automatically.
Shifting Gears
The gear change sequence in a F1 gearbox
requires precise control over the positions
of the gearbox actuators, as well as controlling
the clutch and coordinating engine
revolutions per second with the BMW
engine controller. A typical gear change
takes less than 50 ms. The system also prevents
the driver from damaging or overrevving
the engine.
For the 2003 racing season, the VCM is
allowed to initiate all gear changes with no
input from the driver. But automatic gear
changes will be outlawed for 2004, requiring
the driver to initiate each gear change
manually. Once the driver has initiated the
change, the VCM will be allowed to handle
the rest of the gear change sequence.
Traction
The VCM also handles traction control by
performing calculations based on complex
tire models to predict the amount of wheel
slip required to achieve maximum traction
and minimum tire wear. The VCM calculates
control targets and sends this data to
the engine controller.
Generating control signals for the
hydraulically actuated differential also
comes under the VCM’s domain – with the
aim of providing maximum traction from
each of the rear wheels to optimize stability
of the car when cornering.
Launch Control
The use of “launch control” – which optimizes
the car’s standing start as it leaves the
grid – has received much press coverage in
recent seasons. Incoming rules will outlaw
this feature, but for the 2003 season, the
launch start controller is a functional block
within the VCM. Clutch and engine targets
communicated by the VCM help the
car to accelerate from the grid to 100 m/hr
in less than three seconds.
Real-Time Feedback
The VCM displays driver information signals
and warning indicators on the steering
wheel. Even though a modern F1 steering
wheel can cost upwards of $33,000, there is
relatively little intelligence onboard – that is,
until next year’s BMW WilliamsF1 team
adds a Xilinx FPGA to perform some of the
instrumentation processing functions locally.
Fall 2003 Xcell Journal 47