In 2006, McLaren Electronics was chosen by the FIA to supply Standard ECUs (electronic control units) to all teams in Formula One. The system debuted on all cars at the start of the 2008 season, and has been reliably controlling the complete powertrain ever since.

Topology

The control system is based on the STAR topology, now in its second generation. This topology, which was pioneered by McLaren Electronics in 1998, is built around one central ECU which is responsible for the intelligence behind all the functions on the car. The ECU currently used as the central ECU in this system is the TAG-310B. This ECU hosts the majority of the I/O, with additional interface units being used to consolidate localised I/O.

HIU-3s (hub interface units) are used at each corner of the car to interface to sensors located at the wheels. These units send all signals back to the TAG-310B via a two-wire CAN network, thus vastly reducing the number of wires through the wishbones.

A PBOX2006 (power box) provides regulated power supplies around the car as well as providing the high power ignition and injection drive stages for eight cylinders.

Drive-by-Wire

A Formula One car is equipped with all of the familiar controls such as steering wheel, throttle pedal, brake pedal as well as paddles on the steering wheel to change gears. Of all the controls that the driver has at his disposal, only the steering wheel and brake controls are mechanically coupled to the car. All other controls feed into the ECU as signals, with the ECU being responsible for controlling actions according to driver inputs.

The Standard ECU is responsible for controlling many aspects of a Formula One car including:

• Engine
• Clutch
• Gearbox
• Differential
• Fuel system
• DRS (drag reduction system)

Taking the gearbox as an example, with the seamless shift gearbox fitted to most Formula One cars it is possible to perform an upshift at full throttle, with no loss of drive. Such a shift requires the control system to maintain full knowledge of the angle of every gear at all times. Gear engagement must be timed to 1/10,000sec accuracy. Due to the tremendous torque from the engine, if the timing is wrong, or the knowledge of the gear angles is incorrect, the gearbox will fail catastrophically during the shift.

Along with the gearbox, many other aspects of the car that the ECU is responsible for controlling require the control system to behave without fault to keep the car running. In the three full race seasons that McLaren Electronics has been supplying control systems into Formula One, not one failure of a car during a race can be attributed to the control system not behaving as it was designed.

Secure

One key motivation for the FIA choosing a Standard ECU for Formula One was to prevent driver aids. Until the system was introduced, it was very difficult to police aids such as traction control and launch control. In over 15 years of supplying electronics into Formula One, McLaren Electronics has pioneered innovative security mechanisms to ensure that only approved versions of software can be used in the ECU.

Versatility

The TAG-310B has been used in Formula One since the start of the 2005 race season. In that time, it has witnessed a number of changes in the regulations affecting the design of the cars. Such is the versatility of this ECU; the TAG-310B has been capable of supporting these changes without requiring any re-design.

Examples:

• V10, V8
• Movable front wing
• Movable rear wing
• Launch control
• Traction control
• Seamless shift

Such is the versatility of the TAG-310B, it can be used for a variety of control applications, including vehicle R&D and prototype activities. The unit features a comprehensive set of I/O, communications links and processing power to make it universally applicable.

Continued Innovation

McLaren Electronics’ existing contract to supply Standard ECUs into Formula One stretches until the end of 2012. Whilst the TAG-310B is a hugely capable ECU, McLaren Electronics has a commitment to continuously improve and develop its products in line with the latest technology. Since 2008, McLaren Electronics has been developing a successor to the TAG-310B. The new unit called the TAG-320 features the following improvements over the TAG-310B:

In addition to the well established security mechanisms of the TAG-310B, that prevent teams from running non-approved versions of software, the TAG-320 takes this protection even further with a new memory protection architecture. This allows it to accommodate multiple applications on a single processor, whilst guaranteeing that each application will be totally isolated and protected from the others. The only signals that can be communicated between applications are those for which the FIA has granted permission.