Formula One Technology for Industry
In today's high-tech world of motor racing, winning depends
on the performance of components such as displacement
sensors. These sensors are widely used in Formula One racing
and other racing series to control and monitor a number of
critical control functions that will trim a few tenths of a second
off a car's lap time - this being the difference between success
and failure!
The use of displacement sensors and a computerised data
logging system allow the race engineer to perfect the performance
of a racecar for individual circuits during pre-race practice.
Data from the car is transmitted via the onboard telemetry system
after each lap of the circuit. This data is displayed graphically on
a computer screen so the engineer can advise the driver how the
car is performing at various parts around the circuit. After each
practice run the car returns to the pits so that the mechanics can
make immediate adjustments to the suspension, wing settings etc.
Before the introduction of these computerised data logging systems,
the race engineer had to rely on the ability of the driver to supply the
necessary information. This technology is also used to evaluate and
assist young drivers as they learn to compete at the highest levels
of their sport.
Ultra Slim Linear Potentiometer
Used in areas where compactness and
reliability are a design consideration.
Throttle pedal measurement is a
typical example.
Applications requiring displacement sensors on a racing car are
numerous and depend on the race series. These sensors have to
operate in a hostile environment and are subjected to extreme
vibration and high temperature. This requires racing teams to
demand a level of sensor reliability normally reserved only for
the aerospace industry.
The most successful displacement sensor manufacturer to
exploit the developments in motor sport electronics throughout
the last decade has been Active Sensors. Formed in 1992 in
Christchurch, Dorset the company developed motor sport sensors
using aerospace technology. Active works in partnership with the
engineers responsible for the control and data-logging systems
in the UK and overseas (50% of the sensors manufactured by
Active are exported).
Rotary Potentiometers
They convert rotary movement into a
proportional voltage output.
Throttle actuating, gearbox actuating
and chassis movement are typical
examples.
To keep on the pace of new developments all the teams design
a new car every year. Very few chassis and engine components
are carried over into the new season and the car has to get from
the CAD system to the test track in less than twelve weeks.
A build schedule this demanding requires a rapid response from
all their suppliers. Active Sensors achieves this by investing
strategically in engineering personnel, and in the latest CNC
technology that will carry out all the company's machining
requirements in-house. The creation of a composite materials
laboratory for sensor element production also allows faster
design and manufacture.
Communication between the race team and its component
suppliers is important to the success of the new cars development
and the right decisions at this stage will save many hours of
frustration at the test track.
Linear Potentiometers
Designed to convert a linear movement
into a proportional voltage output.
Suspension movement and motion
system feedback sensors are typical uses.
Control
Throttle control in Formula One is a closed loop electro-hydraulic
system (fly-by-wire) that requires a displacement sensor on the
driver's pedal and one on the actuating mechanism mounted
on the engine. This arrangement allows faster acceleration and
also preserves the engine life by restricting over revving during
a race. The pedal sensor is normally a special design, twin
output linear potentiometer with a measurement range of 50mm
(the pedal displacement). A twin output sensor is specified for
system integrity. If the signal from either sensor is lost then
the car stops! The on-board computer monitors both output
signals from the throttle pedal and engine mounted sensors.
If an error develops on either output signal, the computer
switches to the other (known as redundancy).
The engine-mounted sensor is either a high performance rotary
potentiometer or RVDT (rotary variable differential transformer).
Rotary sensors are specified for the throttle actuating mechanism
as carburettors are rotary in design and have relatively small
angles of movement (approximately 90 degree's rotation).
The clutch operation is also a closed loop electro-hydraulic system.
The driver operates the clutch by moving a finger paddle mounted
behind the steering wheel. This arrangement can improve the
handling of the car through corners as the drivers can then keep
their left foot on the brake pedal to control their speed (commonly
known as left foot braking).
Wire Operated Sensors
Designed to work where there are
installation difficulties.
The sensor body is located away
from the component that requires
measuring and is connected via the wire.
As space on the steering wheel is limited, one of the sensors that
can be used is a miniature rotary potentiometer. This would be fitted
directly to the driver's wheel with the connections to the system
loom being made through the steering column via a multi-pin
connector. This multi-pin connector also carries the signal
connections for the gear select switches, the radio and the
steering wheel dash LCD display.
The sensor mounted on the clutch actuating mechanism is a
special design short stroke LVDT (linear variable differential
transformer). The LVDT would have a measurement range of
approx 6mm and due to limits on installation space, have a
short body to stroke length ratio. The clutch control sensors
would also have twin outputs for total system integrity.
As most racing cars are designed with a sequential gearbox
(similar to a motorbike gearbox) the gear change is also operated
from the steering wheel by means of a simple push button switch.
This is known as a semi-automatic gearbox and allows for a
quicker gear change because the drivers can keep their hands
on the steering wheel at all times. A sequential gearbox also
allows more control of gear selection using clever control software.
A racecar can now go from sixth gear at top speed straight into
second gear at the push of a button. This is a very useful aid to
the racing driver as they can concentrate on cornering rather
than looking for the right gear. The car will accelerate through
the gears as normal until the next braking point and the process
is then repeated. The sensor used as the feedback device to
position the gearbox actuator is a high performance twin output
rotary potentiometer. The potentiometer is preferred to a RVDT
because of its angular range capability (typically 350 degrees).
Not all gearbox operation is semi-automatic and in other racing
series a manual gearbox is used. These gearboxes are also fitted
with a rotary sensor to give gear selection indication only
(no control capability). This sensor would be a single output
rotary potentiometer because redundancy is not necessary,
as sensor failure would not stop the car.
LVDT & RVDT Sensors
LVDT's are often used on clutch actuation
and for monitoring brake disc wear
RVDT's are ideal for throttle actuation
mechanisms.
Measurement
One of the area's in motor sport where the displacement sensor
is having a lot of success is in suspension movement measurement.
All race car's are effected by the slightest change in the suspension
set up, so the more information a racer has, the more chance they
have of winning. The signal from a linear or rotary potentiometer
is fed into a data logger mounted on the car. This data logger will
then transmit the signal to the pits via a radio, or it can be down
loaded when the car returns to the garage. A race engineer will
examine this information on their computer screen and calculate
any adjustments that may be needed to the suspension.
Another area of continuous development is the braking systems
used in motor racing. Brake disc wear is now monitored with the
mounting of a miniature linear sensor (LVDT) in the brake calliper.
As brake disc width and diameter is controlled by the rulebook
(28mm width in F1), hard braking circuits can wear a disc by as
much as 50%. This is probably the harshest environment for a
sensor on a racecar as brake disc temperatures can reach
800 degree's C under braking.
Hydraulic fluid level measurement is also achieved using
displacement sensors mounted in the fluid reservoirs. Due to
the corrosive nature of most system fluids, a sensor with a
sealed construction and high specification wiring would be
specified. This measurement is made using either a linear
potentiometer or LVDT depending on the signal conditioning
available in the electronics system.
Industry
Formula One racing is probably the most demanding automotive
application for control and measurement sensors. General vehicle
manufacturers also take advantage of the latest technology to
help develop modern cars and trucks.
These developments by Active have enabled the company to
increase the range of their industrial displacement sensors based
on fly-by-wire technology.
Industries to benefit are flight simulation, manufacturing, power
generation, hydraulic & pneumatic control and scientific research.
Typical applications include sensors for positioning systems in
machine building, speed control of rollers in the converting
industry and feedback sensors in robotics.
The company's developments have kept the likes of Schumacher,
Hakkinen and Coulthard on track using the latest technology.
Formula One technology is now available to industry and with it's
proven track record it is hard to beat!
_______________________________________________________
For further information about Active Sensors product range
call them on +44(0) 1202 480620
or visit their web site: www.activesensors.com
November 2000
