Appearance
Driving assists
The assists sit on top of the same physics and run inside the core, so a replay reproduces them and a hash sees them (ADR-0013). They are all off in the core's default definition; a preset may switch some on (the RWD sports car and the open-wheeler ship with ABS, traction and stability control, the electric crossover with traction control). Each is a stateless stage between the input and the wheel solve: every substep it reads the current slips, speed and yaw rate and scales this substep's brake capacities, throttle and steer angle.
| Assist | Reads | Acts on | Telemetry |
|---|---|---|---|
abs | each wheel's braking slip ratio | that wheel's brake capacity (never to 0) | AbsActivity |
tractionControl | the largest driven drive slip | the throttle to the power unit | TcActivity, ThrottleEffective |
stabilityControl | yaw rate against neutral steer | one wheel's brake, the throttle | EscYawError, EscBrakeTorque |
steeringAssist | speed | the road-wheel angle | SteerAssistScale |
ABS scales a wheel's brake capacity from 1 at the slip target (the tire's peak, 0.12 by default) down to a floor at the release slip (0.3), and stands down below 2 m/s so the car can lock its wheels to a stop. It is an ideal, continuous ABS without the cycling of a production system; the validation page reports the stopping distance with and without it.
Traction control uses the same shape on the largest driven-wheel drive slip to scale the throttle. It governs the launch; the inertia a clutch dumps into the wheels on an upshift is the transmission's business, and the automatic lifts the throttle during the shift for that reason.
Stability control compares the yaw rate with the neutral-steer reference V · tan δ / L, capped at what the tires' friction allows, and past a dead band brakes the outer front wheel when the car yaws faster than the reference (oversteer) or the inner rear when slower (understeer), with a torque proportional to the error, and cuts the throttle. The brake goes through the ordinary bounded constraint, so the wheel can still lock exactly.
The steering assist caps the road-wheel angle at L · a_lim / V², the angle a steady turn at the chosen lateral acceleration needs, so a keyboard gets full lock at walking pace and a few degrees at speed. The sandbox turns it on for keyboard driving.