void
SimWheelUpdateRotation(tCar *car)
{
int i;
tWheel *wheel;
tdble deltan;
tdble cosaz, sinaz;
for (i = 0; i < 4; i++) {
wheel = &(car->wheel[i]);
/*calculate gyroscopic forces*/
cosaz = cos(wheel->relPos.az);
sinaz = sin(wheel->relPos.az);
if( (i == 0) || (i == 1) ){
wheel->torques.y = wheel->torques.x * sinaz;
wheel->torques.x = wheel->torques.x * cosaz;
} else {
wheel->torques.x = wheel->torques.y =0.0;
}
deltan = -(wheel->in.spinVel - wheel->prespinVel) * wheel->I / SimDeltaTime;
wheel->torques.x -= deltan * wheel->cosax *sinaz;
wheel->torques.y += deltan * wheel->cosax *cosaz;
wheel->torques.z = deltan * wheel->sinax;
/*update rotation*/
wheel->spinVel = wheel->in.spinVel;
FLOAT_RELAXATION2(wheel->spinVel, wheel->prespinVel, 50.0f);
wheel->relPos.ay += wheel->spinVel * SimDeltaTime;
FLOAT_NORM_PI_PI(wheel->relPos.ay);
car->carElt->_wheelSpinVel(i) = wheel->spinVel;
}
}
void
SimWheelUpdateRotation(tCar *car)
{
int i;
tWheel *wheel;
for (i = 0; i < 4; i++) {
wheel = &(car->wheel[i]);
wheel->spinVel = wheel->in.spinVel;
FLOAT_RELAXATION2(wheel->spinVel, wheel->prespinVel, 50.0f);
wheel->relPos.ay += wheel->spinVel * SimDeltaTime;
FLOAT_NORM_PI_PI(wheel->relPos.ay);
car->carElt->_wheelSpinVel(i) = wheel->spinVel;
}
}
void SimWheelUpdateForce(tCar *car, int index)
{
tWheel *wheel = &(car->wheel[index]);
tdble axleFz = wheel->axleFz;
tdble vt, v, v2, wrl; // wheel related velocity
tdble Fn, Ft;
tdble waz;
tdble CosA, SinA;
tdble s, sa, sx, sy; // slip vector
tdble stmp, F, Bx;
tdble mu;
tdble reaction_force = 0.0f;
wheel->state = 0;
// VERTICAL STUFF CONSIDERING SMALL PITCH AND ROLL ANGLES
// update suspension force
SimSuspUpdate(&(wheel->susp));
// check suspension state
wheel->state |= wheel->susp.state;
if ((wheel->state & SIM_SUSP_EXT) == 0) {
wheel->forces.z = axleFz + wheel->susp.force;
reaction_force = wheel->forces.z;
wheel->rel_vel -= SimDeltaTime * wheel->susp.force / wheel->mass;
if (wheel->forces.z < 0.0f) {
wheel->forces.z = 0.0f;
}
} else {
if (wheel->rel_vel < 0.0) {
wheel->rel_vel = 0.0;
}
wheel->rel_vel -= SimDeltaTime * wheel->susp.force / wheel->mass;
wheel->forces.z = 0.0f;
}
// update wheel coord, center relative to GC
wheel->relPos.z = - wheel->susp.x / wheel->susp.spring.bellcrank + wheel->radius;
// HORIZONTAL FORCES
waz = wheel->steer + wheel->staticPos.az;
CosA = cos(waz);
SinA = sin(waz);
// tangent velocity.
vt = wheel->bodyVel.x * CosA + wheel->bodyVel.y * SinA;
v2 = wheel->bodyVel.x * wheel->bodyVel.x + wheel->bodyVel.y * wheel->bodyVel.y;
v = sqrt(v2);
// slip angle
if (v < 0.000001f) {
sa = 0.0f;
} else {
sa = atan2(wheel->bodyVel.y, wheel->bodyVel.x) - waz;
}
FLOAT_NORM_PI_PI(sa);
wrl = wheel->spinVel * wheel->radius;
if ((wheel->state & SIM_SUSP_EXT) != 0) {
sx = sy = 0.0f;
} else if (v < 0.000001f) {
sx = wrl;
sy = 0.0f;
} else {
sx = (vt - wrl) / fabs(vt);
sy = sin(sa);
}
Ft = 0.0f;
Fn = 0.0f;
s = sqrt(sx*sx+sy*sy);
{
// calculate _skid and _reaction for sound.
if (v < 2.0f) {
car->carElt->_skid[index] = 0.0f;
} else {
car->carElt->_skid[index] = MIN(1.0f, (s*reaction_force*0.0002f));
}
car->carElt->_reaction[index] = reaction_force;
}
stmp = MIN(s, 1.5f);
// MAGIC FORMULA
Bx = wheel->mfB * stmp;
F = sin(wheel->mfC * atan(Bx * (1.0f - wheel->mfE) + wheel->mfE * atan(Bx))) * (1.0f + stmp * simSkidFactor[car->carElt->_skillLevel]);
// load sensitivity
mu = wheel->mu * (wheel->lfMin + (wheel->lfMax - wheel->lfMin) * exp(wheel->lfK * wheel->forces.z / wheel->opLoad));
F *= wheel->forces.z * mu * wheel->trkPos.seg->surface->kFriction * (1.0f + 0.05f * sin(-wheel->staticPos.ax * 18.0f)); /* coeff */
//For debug weather with some tracks
#ifdef SD_DEBUG
GfLogDebug("Simu v2 kFriction : %f ", wheel->trkPos.seg->surface->kFriction);
#endif
wheel->rollRes = wheel->forces.z * wheel->trkPos.seg->surface->kRollRes;
car->carElt->priv.wheel[index].rollRes = wheel->rollRes;
if (s > 0.000001f) {
// wheel axis based
Ft -= F * sx / s;
Fn -= F * sy / s;
}
FLOAT_RELAXATION2(Fn, wheel->preFn, 50.0f);
FLOAT_RELAXATION2(Ft, wheel->preFt, 50.0f);
wheel->relPos.az = waz;
wheel->forces.x = Ft * CosA - Fn * SinA;
wheel->forces.y = Ft * SinA + Fn * CosA;
wheel->spinTq = Ft * wheel->radius;
wheel->sa = sa;
wheel->sx = sx;
wheel->feedBack.spinVel = wheel->spinVel;
wheel->feedBack.Tq = wheel->spinTq;
wheel->feedBack.brkTq = wheel->brake.Tq;
car->carElt->_wheelSlipSide(index) = sy*v;
car->carElt->_wheelSlipAccel(index) = sx*v;
car->carElt->_reaction[index] = reaction_force;
}
