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resuming vehicles tuning (wip)
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@JulioJerez
JulioJerez committed Nov 2, 2022
1 parent 452d3d5 commit 9e2f73f
Showing 1 changed file with 15 additions and 87 deletions.
102 changes: 15 additions & 87 deletions newton-4.00/sdk/dNewton/dModels/dVehicle/ndMultiBodyVehicle.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -867,7 +867,6 @@ void ndMultiBodyVehicle::CoulombTireModel(ndMultiBodyVehicleTireJoint* const, nd

contactPoint.m_material.m_staticFriction0 = maxForceForce;
contactPoint.m_material.m_dynamicFriction0 = maxForceForce;

contactPoint.m_material.m_staticFriction1 = maxForceForce;
contactPoint.m_material.m_dynamicFriction1 = maxForceForce;
contactPoint.m_material.m_flags = contactPoint.m_material.m_flags | m_override0Friction | m_override1Friction;
Expand All @@ -881,90 +880,26 @@ void ndMultiBodyVehicle::BrushTireModel(ndMultiBodyVehicleTireJoint* const tire,
ndAssert(tireBody != otherBody);
ndAssert((tireBody == contactPoint.m_body0) || (tireBody == contactPoint.m_body1));

#if 0
const ndVector contactVeloc0(tireBody->GetVelocityAtPoint(contactPoint.m_point));
const ndVector contactVeloc1(otherBody->GetVelocityAtPoint(contactPoint.m_point));
const ndVector relVeloc(contactVeloc0 - contactVeloc1);

const ndFloat32 relSpeed = relVeloc.DotProduct(contactPoint.m_dir1).GetScalar();
if (ndAbs(relSpeed) > ndFloat32(1.0e-5f))
{
ndFloat32 longitudialSlip = ndFloat32(0.0f);
if (relSpeed < ndFloat32(-1.0e-5f))
{
// tire is in traction mode.
const ndVector rotationVeloc(tireBody->GetOmega().CrossProduct(contactPoint.m_point - tireBody->GetMatrix().m_posit));
ndFloat32 wr = ndAbs(rotationVeloc.DotProduct(contactPoint.m_dir1).GetScalar()) + ndFloat32(1.0e-4f);
longitudialSlip = -relSpeed / wr;
}
else
{
// tire is in breaking mode.
const ndVector tireVeloc(tireBody->GetVelocity());
const ndFloat32 vr = ndAbs(tireVeloc.DotProduct(contactPoint.m_dir1).GetScalar());
longitudialSlip = relSpeed / vr;
}

ndAssert(longitudialSlip >= 0.0f);
const ndVector tireVeloc(tireBody->GetVelocity());
const ndFloat32 sideSpeed = ndAbs(tireVeloc.DotProduct(contactPoint.m_dir0).GetScalar());
const ndFloat32 tireSpeed = ndAbs(tireVeloc.DotProduct(contactPoint.m_dir1).GetScalar());
const ndFloat32 lateralSlip = sideSpeed / tireSpeed;

const ndFloat32 den = ndFloat32(1.0f) / (longitudialSlip + ndFloat32(1.0f));
const ndFloat32 v = lateralSlip * den;
const ndFloat32 u = longitudialSlip * den;

const ndTireFrictionModel& info = tire->m_frictionModel;
const ndFloat32 cz = info.m_laterialStiffness * v;
const ndFloat32 cx = info.m_longitudinalStiffness * u;

const ndFloat32 gamma = ndMax(ndSqrt(cx * cx + cz * cz), ndFloat32(1.0e-8f));
const ndFloat32 frictionCoefficient = contactPoint.m_material.m_staticFriction0;
const ndFloat32 normalForce = contactPoint.m_normal_Force.GetInitialGuess() + ndFloat32(1.0f);

const ndFloat32 maxForceForce = frictionCoefficient * normalForce;
const ndFloat32 b = ndFloat32(1.0f) / (ndFloat32(3.0f) * maxForceForce);
const ndFloat32 c = ndFloat32(1.0f) / (ndFloat32(27.0f) * maxForceForce * maxForceForce);
const ndFloat32 f = (gamma < ndFloat32(3.0f) * maxForceForce) ? gamma * (ndFloat32(1.0f) - b * gamma + c * gamma * gamma) : maxForceForce;

const ndFloat32 lateralForce = f * cz / gamma;
const ndFloat32 longitudinalForce = f * cx / gamma;

contactPoint.m_material.m_staticFriction0 = lateralForce;
contactPoint.m_material.m_dynamicFriction0 = lateralForce;

contactPoint.m_material.m_staticFriction1 = longitudinalForce;
contactPoint.m_material.m_dynamicFriction1 = longitudinalForce;
contactPoint.m_material.m_flags = contactPoint.m_material.m_flags | m_override0Friction | m_override1Friction;

if (tireBody->GetId() == 3)
{
//ndTrace(("id: %d longitudinal:%f lateral::%f norm:%f\n", tireBody->GetId(), longitudinalForce, lateralForce, normalForce));
}
}

#else

//tire non linear brush model is only considered
//when is moving faster than 0.5 m/s (approximatly 1.0 miles / hours)
//this is just an arbitrary limit, based of the model
//not been defined for stationary tires.
const ndVector contactVeloc0(tireBody->GetVelocity());
const ndVector contactVeloc1(otherBody->GetVelocityAtPoint(contactPoint.m_point));
const ndVector relVeloc(contactVeloc0 - contactVeloc1);
const ndFloat32 relSpeed = ndAbs(relVeloc.DotProduct(contactPoint.m_dir1).GetScalar());
const ndVector lateralDir = contactPoint.m_dir1;
const ndVector longitudDir = contactPoint.m_dir0;
const ndFloat32 relSpeed = ndAbs(relVeloc.DotProduct(longitudDir).GetScalar());
if (relSpeed > ndFloat32(0.5f))
{
// tire is in breaking and traction mode.
const ndVector contactVeloc(tireBody->GetVelocityAtPoint(contactPoint.m_point) - contactVeloc1);

const ndVector tireVeloc(tireBody->GetVelocity());
const ndFloat32 vr = contactVeloc.DotProduct(contactPoint.m_dir1).GetScalar();
const ndFloat32 vr = contactVeloc.DotProduct(longitudDir).GetScalar();
const ndFloat32 longitudialSlip = ndAbs(vr) / relSpeed;

const ndFloat32 sideSpeed = ndAbs(relVeloc.DotProduct(contactPoint.m_dir0).GetScalar());
//const ndFloat32 lateralSlip = sideSpeed / relSpeed;
const ndFloat32 sideSpeed = ndAbs(relVeloc.DotProduct(lateralDir).GetScalar());
const ndFloat32 lateralSlip = ndMin(sideSpeed / relSpeed, ndFloat32(0.25f));

ndTrace(("(%d: %f %f) ", tireBody->GetId(), longitudialSlip, lateralSlip));
Expand All @@ -988,29 +923,22 @@ void ndMultiBodyVehicle::BrushTireModel(ndMultiBodyVehicleTireJoint* const tire,
const ndFloat32 normalForce = contactPoint.m_normal_Force.GetInitialGuess() + ndFloat32(1.0f);

const ndFloat32 maxForceForce = frictionCoefficient * normalForce;
//const ndFloat32 f = (gamma < ndFloat32(3.0f) * maxForceForce) ? gamma * (ndFloat32(1.0f) - b * gamma + c * gamma * gamma) : maxForceForce;
ndFloat32 f = maxForceForce;
if (gamma < (ndFloat32(3.0f) * maxForceForce))
{
const ndFloat32 b = ndFloat32(1.0f) / (ndFloat32(3.0f) * maxForceForce);
const ndFloat32 c = ndFloat32(1.0f) / (ndFloat32(27.0f) * maxForceForce * maxForceForce);
f = gamma * (ndFloat32(1.0f) - b * gamma + c * gamma * gamma);
}
//else
//{
// ndTrace(("saturated tire %d (%f %f)\n", tireBody->GetId(), f, gamma));
//}

const ndFloat32 lateralForce = f * cz / gamma;
const ndFloat32 longitudinalForce = f * cx / gamma;

contactPoint.OverrideFriction1Accel(-vr / timestep);

contactPoint.m_material.m_staticFriction0 = lateralForce;
contactPoint.m_material.m_dynamicFriction0 = lateralForce;

contactPoint.m_material.m_staticFriction1 = longitudinalForce;
contactPoint.m_material.m_dynamicFriction1 = longitudinalForce;
contactPoint.OverrideFriction0Accel(-vr / timestep);
contactPoint.m_material.m_staticFriction0 = longitudinalForce;
contactPoint.m_material.m_dynamicFriction0 = longitudinalForce;
contactPoint.m_material.m_staticFriction1 = lateralForce;
contactPoint.m_material.m_dynamicFriction1 = lateralForce;
contactPoint.m_material.m_flags = contactPoint.m_material.m_flags | m_override0Friction | m_override1Friction;

if (tireBody->GetId() == 3)
Expand All @@ -1022,8 +950,6 @@ void ndMultiBodyVehicle::BrushTireModel(ndMultiBodyVehicleTireJoint* const tire,
{
CoulombTireModel(tire, contactPoint, timestep);
}

#endif
}

void ndMultiBodyVehicle::PacejkaTireModel(ndMultiBodyVehicleTireJoint* const tire, ndContactMaterial& contactPoint, ndFloat32 timestep) const
Expand Down Expand Up @@ -1096,9 +1022,11 @@ xxxx++;
if (contactPathLocation < ndFloat32 (0.71f))
{
// align tire friction direction
const ndVector fronDir(contactPoint.m_normal.CrossProduct(tireBasisMatrix.m_front));
contactPoint.m_dir1 = fronDir.Normalize();
contactPoint.m_dir0 = contactPoint.m_dir1.CrossProduct(contactPoint.m_normal);
const ndVector longitudinalDir(contactPoint.m_normal.CrossProduct(tireBasisMatrix.m_front).Normalize());
const ndVector lateralDir(longitudinalDir.CrossProduct(contactPoint.m_normal));

contactPoint.m_dir1 = lateralDir;
contactPoint.m_dir0 = longitudinalDir;

// check if the contact is in the contact patch,
// the is the 45 degree point around the tire vehicle axis.
Expand Down

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