This information is part of the Modelica Standard Library maintained by the Modelica Association.

Simplified model of the resistance of a rolling wheel, dependent on vertical wheel load (due to gravity, i.e. static only), inclination and rolling resistance coefficient:

flange.f = Cr * fWeight * cos(alpha)

The rolling resistance coefficient C_r is either constant (given by the parameter CrConstant) or prescribed by the input cr.

The inclination is either constant (parameter inclinationConstant) or prescribed by the input inclination. This corresponds to the road rise over running distance of 100 m which, in general, is written as a percentage and is equal to tan(α). For example for a road rising by 10 m over 100 m the grade = 10 % and, thus, the inclination is 0.1. Positive inclination means driving uphill, negative inclination means driving downhill, in case of positive vehicle velocity.

Note

The rolling resistance is independent of velocity here, but changes its direction with the direction of velocity. To avoid numerical problems around zero velocity, the rolling resistance is regularized accordingly within [-v0, v0]. Therefore static friction at vehicle's standstill is not taken into account.

useSupport	Value: false Type: Boolean Description: = true, if support flange enabled, otherwise implicitly grounded
fWeight	Value: Type: Force (N) Description: Wheel load due to gravity
useCrInput	Value: false Type: Boolean Description: Enable signal input for Cr
CrConstant	Value: 0.01 Type: Real Description: Constant rolling resistance coefficient
useInclinationInput	Value: false Type: Boolean Description: Enable signal input for inclination
inclinationConstant	Value: 0 Type: Real Description: Constant inclination = tan(angle)
reg	Value: Modelica.Blocks.Types.Regularization.Exp Type: Regularization Description: Type of regularization
v0	Value: 0.1 Type: Velocity (m/s) Description: Regularization below v0