Parameters

The following parameters are required to use the FIALA tire model:
Parameter Details Unit
unloaded_radius Distance between the WC and the contact point of tire in unloaded conditions.

Used in computation of tire effective penetration.

Length
width Section width of the tire.

Used in the calculation of aligning torque Tz for pure elastic deformation conditions.

Length
aspect_ratio Tire Sidewall profile aspect ratio. Describes the sidewall height as a percentage of the tire section width.

Not used in force calculation.

-
vertical_stiffness Vertical tire stiffness.

Used in normal load calculation.

Force/Length
vertical_damping Vertical tire damping coefficient.

Used in normal load calculation.

Force*Time/Length
rolling_resistance Used in rolling resistance moment calculation. This represents the shift in the longitudinal direction of the center of vertical load. Length
cslip Derivative of the longitudinal force with respect to the longitudinal slip in pure rolling conditions. Force
calpha Tire cornering stiffness. Derivative of the tire lateral force with respect to the slip angle (alpha) at zero lateral slip. Force/Angle
cgamma Derivative of the lateral force with respect to camber at zero camber angle. Force/Angle
mgamma Camber angle after which the camber thrust starts to decrease. -
cspin Coefficient for twisting torque. -
umin Minimum friction coefficient. -
umax Maximum friction coefficient. -
rlenx Relaxation length in x direction, used in case of transient fiala. Length
rleny Relaxation length in y direction, used in case of transient fiala. Length
rolling_radius_factor

For better estimation of force values.

Rolling radius = loaded radius + ROLLING_RADIUS_FACTOR *(unloaded radius - loaded radius)
-
Low_speed_threshold The speed at which artificial damping starts to act. Length/Time
damp_x Numerical damping in x when the tire deformation in x goes out of bounds. -
damp_y Numerical damping in y when the tire deformation in y goes out of bounds. -