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+--- Thread: Code question for CARDYNAMICS::ApplyWheelForces (/showthread.php?tid=1540)
Code question for CARDYNAMICS::ApplyWheelForces - LBodnar - 07-31-2011
Code:
//calculate brake torque
btScalar wheel_brake_torque = (0 - wheel[i].GetAngularVelocity()) / dt * wheel[i].GetInertia() - wheel_drive_torque + tire_friction_torque;
if (wheel_brake_torque > 0 && wheel_brake_torque > brake[i].GetTorque())
{
wheel_brake_torque = brake[i].GetTorque();
}
...What does AngularVelocity / dt * Inertia term represent?
Consider half-braked wheel at constant high speed. In such condition brake force should equal friction force. But Velocity / dt * Inertia will be non-zero, increase with speed and depend on iteration time step. Why is it there?
- NaN - 07-31-2011
Not the most readable piece:
Code:
btScalar dw = 0 - wheel[i].GetAngularVelocity();
btScalar lockup_torque = wheel[i].GetInertia() * dw / dt; // torque to lock a free rotating wheel
btScalar wheel_brake_torque = lockup_torque - wheel_drive_torque + tire_friction_torque;- LBodnar - 07-31-2011
NaN Wrote:Code:btScalar dw = 0 - wheel[i].GetAngularVelocity();
btScalar lockup_torque = wheel[i].GetInertia() * dw / dt; // torque to lock a free rotating wheel
dw / dt should be angular accelaration, so how come dw = - Velocity?
- NaN - 07-31-2011
Lock up torque, as torque required to lock a free rotating wheel, reduce its angular velocity to zero.