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SimUV4.1: Normalize tire slip and forces 

git-svn-id: https://svn.code.sf.net/p/speed-dreams/code/trunk@9347 30fe4595-0a0c-4342-8851-515496e4dcbd
This commit is contained in:
harunasan 2024-02-29 05:39:15 +00:00
parent a1da9aae3a
commit 2dc3ee6e4e
1 changed files with 41 additions and 6 deletions
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47
src/modules/simu/simuv4.1/wheel.cpp
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@ -305,6 +305,8 @@ void SimWheelConfig(tCar *car, int index)
carElt->_tyreT_out(index) = wheel->Ttire;
carElt->_tyreCondition(index) = 1.0;
carElt->_tyreTreadDepth(index) = wheel->treadDepth;
carElt->_tyreCurrentPressure(index) = wheel->pressure;
carElt->_tyreCompound(index) = wheel->tireSet;
wheel->mfC = (tdble)(2.0 - asin(RFactor) * 2.0 / PI);
wheel->mfB = Ca / wheel->mfC;
@ -660,7 +662,7 @@ void SimWheelUpdateForce(tCar *car, int index)
mu = wheel->mu * (wheel->lfMin + (wheel->lfMax - wheel->lfMin) * exp(wheel->lfK * wheel->forces.z / wheel->opLoad));
//temperature and degradation
if (car->features & FEAT_TIRETEMPDEG)
if (car->features & FEAT_TIRETEMPDEG)
{
tireCond = wheel->currentGripFactor;
mu *= tireCond;
@ -875,15 +877,16 @@ void SimUpdateFreeWheels(tCar *car, int axlenb)
void SimWheelUpdateTire(tCar *car, int index)
{
if (car->carElt->info.skillLevel <= 3)
{
return;
}
if (car->carElt->info.skillLevel <= 3)
{
return;
}
tWheel *wheel = &(car->wheel[index]);
tdble normalForce = wheel->forces.z;
tdble slip = wheel->tireSlip;
tdble skidSlip = wheel->tireSlip;
tdble lateralForce = fabs(wheel->forces.y);
tdble longForce = fabs(wheel->forces.x);
tdble absForce2 = fabs(normalForce * 0.5);
@ -895,6 +898,17 @@ void SimWheelUpdateTire(tCar *car, int index)
tdble wheelSpeed = fabs(wheel->spinVel * wheel->radius);
tdble deltaTemperature = wheel->Ttire - Tair;
// Normalize slip. Not realistic, but prevents extreme spiking when high wheelspin occurs
// when trying to recover from bumpy surfaces such as gravel traps.
if (slip >= 1)
{
slip = 1;
}
else
{
slip = slip;
}
// Calculate factor for energy which is turned into heat, according papers this seems to be pretty constant
// for a specific construction and constant slip (empiric value with model validation, called hysteresis).
// A value of 0.1 is available in papers, so for 10% slip I head for 0.1, where 0.05 come from rolling and
@ -905,6 +919,27 @@ void SimWheelUpdateTire(tCar *car, int index)
// Calculate energy input for the tire
tdble energyGain = normalForce * wheelSpeed * SimDeltaTime * hysteresis;
// Normalize lateral and longitudinal forces if they peak too far past the operating threshold.
// This is done to (slightly) even out tire heating so huge differences in tire pressure are not necessary
// for cars with a lot of weight on one axle or the other.
if (lateralForce >= wheel->opLoad * 2)
{
lateralForce = wheel->opLoad * 2;
}
else
{
lateralForce = lateralForce;
}
if (longForce >= wheel->opLoad * 2)
{
longForce = wheel->opLoad * 2;
}
else
{
longForce = lateralForce;
}
// Modifiers for energy input from lateral and longitudinal forces.
latMod = ((lateralForce * absForce2) * wheel->latHeatFactor) * SimDeltaTime * 0.0004;
longMod = ((longForce * absForce2) * wheel->latHeatFactor) * SimDeltaTime * 0.0004;
@ -964,7 +999,7 @@ void SimWheelUpdateTire(tCar *car, int index)
wheel->currentPressure = wheel->Ttire / Tair * wheel->pressure;
// Wear
double deltaWear = (wheel->currentPressure - SimAirPressure) * slip * wheelSpeed * SimDeltaTime * normalForce
double deltaWear = (wheel->currentPressure - SimAirPressure) * skidSlip * wheelSpeed * SimDeltaTime * normalForce
* wheel->wearFactor * 0.00000000000009;
wheel->currentWear += deltaWear;